MALNUTRITION

Good nutritional status is essential to the maintenance of health and quality of life among older people. Normal changes associated with aging, along with physical illness and cognitive or emotional problems, can lead to dietary changes and contribute to undernutrition. Consequently, any deterioration in nutritional status can be considered a major determinant of morbidity and mortality in persons, especially those living in institutions or nursing homes.

Numerous changes in body composition occur after the age of seventy. Decreased bone mass, changes in the size of body organs, decreases in skeletal muscle and body water, and changes in body fat content contribute to losses in lean and fat body mass. Age-related decline in height is common, but its physiological or clinical importance to health is unknown. However, weight losses after age fifty are generally associated with deterioration in nutritional and overall health and mobility (Losonczy et al.)

Food and nutrient needs

Although food intake tends to decrease with age as a function of social, psychological, and physiological changes, distinct requirements exist for a range of nutrients to compensate for age-related changes in absorption, utilization, and excretion (ADA). For example, even though energy needs decline with age because of decreased basal metabolism, reduction in lean body mass, and a more sedentary lifestyle (Ausman and Russell), it becomes difficult to ensure adequate diet quality (Blumberg) when daily energy intake is too low (less than 1,500 calories or 6.3 megajoules). Furthermore, protein requirements exceed those of younger adults (1.0 to 1.25 gram/kilogram versus 0.8 gram/kilogram body weight, respectively) (Garry and Vellas), which argues for continued consumption of sufficient intakes of high-quality protein food. Finally, even though vitamin A requirements lessen with age, other nutrient needs may increase.

In addition to appropriate intakes of energy and high-quality protein, and sufficient complex carbohydrates and fats (especially the mono- and polyunsaturated fats), older people require specific levels of micronutrients (vitamins and minerals) to ensure metabolic function and overall health. Also, since degenerative changes of aging are believed to result, in part, from the oxidative destruction of cells and tissues, much recent study has centered on the risk-lowering properties of antioxidant nutrients that may protect against such damage at the cellular level (Masaki et al.). Emerging research thus is now targeting nutrients found in a group of common foods, many of which have antioxidant properties. These so-called functional foods are ordinary foods eaten in usual quantities.

Micronutrient requirements, published as the dietary reference intakes, or DRIs (NAS), were revised in 2001 for all age groups (see Table 1), and new evidence is emerging on the potential protective nature of adequate intake levels of specific vitamins and minerals in aging individuals. Nutrients such as folic acid, riboflavin, and vitamins B₆, B₁₂, and C may prevent some age-related decline in memory loss (Rosenberg and Miller), and reduce risk for vascular disease. Adequate calcium is needed to prevent osteoporosis, and vitamin D can have favorable effects on muscle strength, bone mineral, and fracture risk (Heaney). Vitamins A and C and zinc are essential for competent immune system response and wound healing (Chandra). The antioxidants alpha-tocopherol (vitamin E), beta-carotene, and vitamin C may have consequences for aging and longevity (Hallfrisch et al.). These nutrients may also protect against cataract formation and age-related macular degeneration (Jacques), and the carotenoids lutein and zeaxanthin may protect the retina (Blumberg). Vitamin E in foods or supplements helps lessen risk of developing disorders such as Alzheimer's dementia and Parkinson's disease (Perkins et al.) as well as atherosclerosis (Kromhout). Vitamin K helps maintain bone density and lowers risk of reduced bone mass (Ferland). Sufficient dietary fiber is essential for prevention and/or treatment of constipation, hemorrhoids, diverticulosis, hiatal hernia, varicose veins, diabetes, elevated blood lipids, and obesity, and adequate fiber intake has also been related to decreased rates of heart disease and cancer (Ausman and Russell). Finally, adequate fluid intake is essential to prevent dehydration, which results in constipation, fecal impaction, cognitive impairment, functional decline, and, in extreme cases, death.

A varied diet can provide nutrient balance and adequate quantities of healthful foods. Physical activity, wise food selection, and greater intakes of enriched foods help increase total intake, nutrient density, and micronutrient levels. The modified Food Guide Pyramid was developed in the United States for people over the age of seventy to help them select appropriate foods (Russell et al.). This guide emphasizes nutrient-dense foods, dietary fiber, sufficient fluid intake, and the role of dietary supplements in maintaining adequate nutrient intakes. Recommendations include eating whole-grain cereals and breads; dark green, orange, and yellow fruits and vegetables to favor those with high levels of antioxidants; and using low-fat dairy products. The narrower base of the modified pyramid reflects the decreased needs for energy (calories) among older people.

Causes of malnutrition

In community-dwelling older people, dietary and nutritional adequacy depend on the ability to purchase and prepare food, and to eat independently. Among those living in institutions, the availability of dietary assistance when needed and appropriate meal presentation are additional nutrition considerations. The presence of disease or chronic conditions such as mobility problems, depression, or dementia, or medications with an effect on appetite can lead to a worsening nutritional situation. Aging adults, particularly those dependent on others, have been recognized as a group at nutritional risk (Sullivan and Walls). In sum, inadequate food intake and/or increased nutritional requirements can lead to malnutrition, and poor nutritional status is considered a key determinant of morbidity and mortality in elderly individuals (Sullivan and Walls).

In older people, most malnutrition is the consequence of decreased or inappropriate food intake. Common causes are loss of appetite, dysphagia, oral health problems such as poor dentition or dryness of the mouth, depression, polymedication, inappropriate use of restricted or modified diets, physical and cognitive impairments, dementia, slowness in eating, inability to feed oneself, inadequate assistance in eating, sub-optimal dining environment, and limited menu choices (Keller; Sullivan et al.). In addition, sensory problems, such as olfactory or taste dysfunction, may affect desire for and appreciation of food, thereby diminishing intake and increasing risk of chronic diseases. Finally, it has been shown that people with adequate dental status (especially those with natural teeth) have better dietary patterns than those with ill-fitting dentures or who are toothless, and this contributes to higher protein, vitamin, and mineral levels, and lower fat and cholesterol intakes. On the other hand, obesity in elderly people may be related to dietary imbalances, such as insufficient fruit and vegetable intakes and excessive meat intakes, or consumption of easily prepared, easy-to-chew, empty-calorie foods, which may contribute to or exacerbate health problems.

Weight loss, which signals an imbalance between energy intake and expenditure, is a well-known marker of nutritional status in older people. It leads to decline in functional abilities, increased risk of hip fracture, and early institutionalization and mortality, independent of coexisting disease states. Furthermore, this phenomenon has been observed in studies of widely different groups of elderly persons, ranging from those in good health (Harris et al.) to hospital patients (Franzoni et al.) and to individuals who require home care in order to continue living in the community (Payette et al.).

Loss of skeletal muscle mass, or sarcopenia (Rosenberg) is observed with aging even in well elderly people at a stable, healthy weight and the obese (Melton et al.). Sarcopenia is associated with decreased functional abilities and increased risk of falls among very old people (Rosenberg). This lowers energy needs (Poehlman et al.) and increases the likelihood of mobility problems and fractures resulting from osteoporosis (Melton et al.). In addition, it appears that older people with both sarcopenia and obesity are more likely than their nonobese sarcopenic or nonsarcopenic counterparts to suffer from physical disabilities and problems with balance and gait, and to experience falls (Baumgartner).

It now appears that many diseases associated with aging, including heart disease, diabetes, and infectious diseases, are associated with weight loss and wasting, or cachexia (Roubenoff and Harris). Intensive nutritional intervention has the potential to halt and reverse weight loss, and may even contribute to weight gain (Franzoni et al.), which could delay mortality in elderly chronic care patients (Keller). Indeed, it has been shown that women who maintain a consistent body weight after menopause are less likely to suffer fractures than those who systematically lose weight (Cummings et al.).

Prevalence of malnutrition

Estimates of nutrition risk in older persons vary by setting. For example, while it has been reported that some 15 percent of community-dwelling elders are undernourished, the prevalence of protein-energy malnutrition (PEM) among those living in nursing homes or institutions may range from 30 to 60 percent (Omran and Morely), depending on the component measured.

Risk of PEM increases with loss of appetite, decrease in usual weight, increased percentage of weight change in the previous year, and low body mass index (BMI) (White et al.). It has been suggested that loss of more than 4 percent of body weight in a one-year period predicts an increased risk of mortality. Indeed, weight loss alone usually heralds increased morbidity and mortality in elderly people (Losonczy et al.). Furthermore, unintentional weight loss is generally associated with advanced age, lower educational level, and poor health status. In the long-term care setting, malnourished residents are older and more dependent on others, and require more eating assistance than those with adequate nutrition status. Among participants in the Canadian Study of Health and Aging, low BMI, poor appetite, weight loss, and low levels of albumin (a protein that reflects nutrition status in older people) were highly intercorrelated and characterized nutritional risk, which was a significant independent predictor of mortality (Keller and Ostbye).

Weight loss and undernutrition in dementia

"Dementia" is a generic term covering degenerative diseases of the brain leading to problems with memory and other cognitive functions. Decreased food intake, eating behavior disturbances, and loss of body weight are significant problems among patients with Alzheimer's dementia (AD) (White et al.). Indeed, it is typically observed that AD patients are at greater risk of weight loss and a worsening in their nutritional status than individuals without cognitive problems. Data collected over time suggest that weight loss precedes the onset or diagnosis of dementia (Barrett-Connor et al.) or occurs in the early stages of the disease (White et al.). While weight loss and undernutrition in this group are believed to have multiple origins, it also appears that resting metabolic rate is no higher in those with AD than in older persons with no cognitive problems (Donaldson et al.). Finally, although a poor dietary environment can have a negative effect on food intake, adequate nutritional status can be maintained even among institutionalized older people as long as patients have a favorable eating environment and appropriate dietary assistance (Shatenstein and Ferland).

Consequences of undernutrition

In elderly people, weight loss and undernutrition affect functional and cognitive abilities, and the immune response (Chandra). This may result in serious complications including difficulty in swallowing, dehydration, and pressure ulcers. Poor nutritional status also leads to decreased lean body mass, and lessened muscular strength and aerobic capacity. These changes contribute to a state of chronic fatigue, as well as alterations in gait and balance, which increase the probability of falls and fractures. For many older people, this sequence of events leads to a deterioration in their overall quality of life, causing the affected individual to become increasingly dependent on others. The ultimate cost to the individual and society is great.

Bryna Shatenstein

See also Congregate and Home Delivered Meals; Dementia; Dental Care; Nutrition; Sarcopenia; Taste and Smell; Vitamins.

BIBLIOGRAPHY

American Dietetic Association. "Position of the American Dietetic Association: Nutrition, Aging, and the Continuum of Care." Journal of the American Dietetic Association. 100 (2000): 580–595.

Ausman, L. M., and Russell, R. M. "Nutrition in the Elderly." In Modern Nutrition in Health and Disease, 9th ed. Edited by M. E. Shils, J. A. Olson, M. Shike, and A. C. Ross. Baltimore: Williams & Wilkins, 1999. Pages 869–881.

Barrett-Connor, E.; Edelstein, S.; Corey-Bloom, J.; and Wiederholt, W. "Weight Loss Precedes Dementia in Community-Dwelling Older Adults." Journal of American Geriatrics Society 44 (1996): 1147–1152.

Blumberg, J. "Nutritional Needs of Seniors." Journal of the American College of Nutrition 16 (1997): 517–523.

Chandra, R. K. "Effect of Vitamin and Trace Element Supplementation on Immune Response and Infection in Elderly Subjects." Lancet 340 (1992): 1124–1127.

Cummings, S. R.; Nevitt, M. C.; Browner, W. S.; Stone, K.; Fox, K. M.; Ensrud, K. E.; Cauley, J.; Black, D.; and Vogt, T. M. "Risk Factors for Hip Fracture in White Women. Study of Osteoporotic Fractures Research Group." New England Journal of Medicine 332, no. 12 (1995): 767–773.

Donaldson, K. E.; Carpenter, W. H.; Toth, M. J.; Goran, M. I.; Newhouse, P.; and Poehlman, E. T. "No Evidence for a Higher Resting Metabolic Rate in Noninstitutionalized Alzheimer's Disease Patients." Journal of American Geriatrics Society 44, no. 10 (1996): 1232–1234.

Ferland, G. "The Vitamin K-Dependent Proteins: An Update." Nutrition Reviews 56, no. 8 (1998): 223–230.

Franzoni, S.; Frisoni, G. B.; Boffelli, S.; Rozzini, R.; and Trabucchi, M. "Good Nutritional Oral Intake is Associated with Equal Survival in Demented and Nondemented Very Old Patients." Journal of the American Geriatrics Society 44 (1996): 1366–1370.

Garry, P. J., and Vellas, B. J. "Aging and Nutrition." In Present Knowledge in Nutrition, 7th ed. Edited by E. E. Ziegler and L. J. Filer, Jr. Washington, D.C.: ILSI Press, 1996. Pages 414–419.

Hallfrisch, J.; Muller, D. C.; and Singh, V. N. "Vitamin A and E Intakes and Plasma Concentrations of Retinol, Beta-Carotene, and Alpha-Tocopherol in Men and Women of the Baltimore Longitudinal Study of Aging." American Journal of Clinical Nutrition 60 (1994): 176–182.

Harris, T. B.; Looker, A. C.; Madans, J.; and Bacon, E. C. "Weight Loss and Risk of Hip Fracture in Postmenopausal White Women Aged 60–74. The NHANES-1 Epidemiologic Follow Up Study." Journal of American Geriatrics Society 40 (1992): SA5.

Heaney, R. P. "Age Considerations in Nutrient Needs for Bone Health: Older Adults." Journal of the American College of Nutrition 15 (1996): 575–578.

Jacques, P. F. "The Potential Preventive Effects of Vitamins for Cataract and Age-Related Macular Degeneration." International Journal of Vitamin and Nutrition Research 69 (1999): 198–205.

Keller, H. H. "Weight Gain Impacts Morbidity and Mortality in Institutionalized Older Persons." Journal of American Geriatrics Society 43, no. 2 (1995): 165–169.

Keller, H. H., and Ostbye, T. "Do Nutrition Indicators Predict Death in Elderly Canadians with Cognitive Impairment?" Canadian Journal of Public Health 91, no. 3 (2000): 220–224.

Kromhout, D. "Fatty Acids, Antioxidants, and Coronary Heart Disease from an Epidemiological Perspective." Lipids 34, supp. (1999): S27–S31.

Losonczy, K. G.; Harris, T. B.; Cornoni-Huntley, J.; Simonsick, E. M.; Wallace, R. B.; Cook, N. R.; Ostfeld, A. M.; and Blazer, D. G. "Does Weight Loss from Middle Age to Old Age Explain the Inverse Weight Mortality Relation in Old Age?" American Journal of Epidemiology 141, no. 4 (1995): 312–321.

Masaki, K. H.; Losonczy, K. G.; Izmirlian, G.; Foley, D. J.; Ross, G. W.; Petrovitch, H.; Havlik, R.; and White, L. R. "Association of Vitamin E and C Supplement Use with Cognitive Function and Dementia in Elderly Men." Neurology 54 (2000): 1265–1272.

Melton, L. J.; Khosla, S.; Crowson, C. S.; O'Connor, M. K.; O'Fallon, W. M.; and Riggs, B. L. "Epidemiology of Sarcopenia." Journal of the American Geriatrics Society 48 (2000): 625–630.

National Academy of Sciences (NAS). "Dietary Reference Intakes: Applications in Dietary Assessment," 2000. www.nap.edu

Omran, M. L., and Morely, J. E. "Assessment of Protein Energy Malnutrition in Older Persons, Part 1: History, Examination, Body Composition, and Screening Tools." Nutrition 16 (2000): 50–63.

Payette, H.; Coulombe, C.; Boutier, V.; and Gray-Donald, K. "Weight Loss and Mortality Among the Free-Living Frail Elderly: A Prospective Study." Journal of Gerontology: Medical Sciences 54A (1999): M440–M445.

Perkins, A. J.; Hendrie, H. C.; Callahan, C. M.; Gao, S.; Unverzagt, F. W.; Xu, Y.; Hall, K. S.; and Hui, S. L. "Association of Antioxidants with Memory in the Multiethnic Elderly Sample Using the Third National Health and Nutrition Examination Survey." American Journal of Epidemiology 150 (1999): 37–44.

Poehlman, E. T. "Energy Expenditure and Requirements in Aging Humans." Journal of Nutrition 122 (1992): 2057–2065.

Rosenberg, I. H. "Sarcopenia: Origins and Clinical Relevance." Journal of Nutrition 127 (1997): 990S–991S.

Rosenberg, I. H., and Miller, J. W. "Nutritional Factors in Physical and Cognitive Functions of Elderly People." American Journal of Clinical Nutrition 55 supp. (1992): 1237S–1243S.

Roubenoff, R., and Harris, T. B. "Failure to Thrive, Sarcopenia, and Functional Decline in the Elderly." Clinical Geriatric Medicine 13 (1997): 613–621.

Russell, R. M.; Rasmussen, H.; and Lichtenstein, A. H. "Modified Food Guide Pyramid for People Over Seventy Years of Age." Journal of Nutrition 129, no. 3 (1999): 751–753.

Shatenstein, B., and Ferland, G. "Absence of Nutritional or Clinical Consequences of Decentralized Bulk Food Portioning in Elderly Nursing Home Residents with Dementia in Montreal." Journal of the American Diet Association 100, no. 11 (2000): 1354–1360.

Sullivan, D. H., and Walls, R. C. "Impact of Nutritional Status on Morbidity in a Population of Geriatric Rehabilitation Patients." Journal of the American Geriatrics Society 42 (1994): 471–477.

White, H.; Pieper, C.; Schmader, K.; and Fillenbaum, G. "Weight Change in Alzheimer's Disease." Journal of the American Geriatrics Society 44, no. 3 (1996): 265–272.

MANAGED CARE

See Medicare

Malnutrition

Definition

Malnutrition is a condition that develops when the body does not get the proper amount of protein, energy (calories), vitamins , and other nutrients it needs to maintain healthy tissues and organ function.

Description

Poor eating habits or lack of available food may lead to malnutrition. Malnutrition occurs in children who are either undernourished or overnourished. Children who are overnourished may become overweight or obese, which may lead to long-term health problems and social stress.

Undernutrition

Undernutrition is a consequence of consuming little energy and other essential nutrients, or using or excreting them more rapidly than they can be replaced. This state of malnutrition is often characterized by infections and disease. Malnutrition intensifies the effect of every disease. Severe malnutrition is most often found in developing countries. Rarely in the United States do children suffer from severe malnutrition that is not related to severe chronic illness. Deficiency in one nutrient occurs less often than deficiency in several nutrients. A child suffering from malnutrition is usually deficient in a variety of nutrients.

The leading cause of death in children in developing countries is protein-energy malnutrition . This type of malnutrition is the result of inadequate intake of protein and energy. Children who are already undernourished can suffer from protein-energy malnutrition when rapid growth, infection, or disease increases the need for protein and essential nutrients.

Overnutrition

In the United States, nutritional deficiencies have generally been replaced by dietary imbalances or excesses associated with many of the leading causes of death and disability. Overnutrition results from eating too much, eating too many of the wrong foods, not exercising enough, or taking too many vitamins or other dietary replacements.

Risk of overnutrition is also increased by being more than 20 percent overweight, consuming a diet high in fat and salt, and taking high doses of:

• nicotinic acid (niacin) to lower elevated cholesterol levels
• vitamin B₆ to relieve premenstrual syndrome
• vitamin A to clear up skin problems
• iron or other trace minerals not prescribed by a doctor

Nutritional disorders can affect any system in the body and the senses of sight, taste, and smell. Malnutrition begins with changes in nutrient levels in blood and tissues. Alterations in enzyme levels, tissue abnormalities, and organ malfunction may be followed by illness and death.

Complications

Poorly nourished children often have weakened immune systems, thus increasing their chances of illness. Underweight, malnourished teenagers (such as those with an eating disorder) have an increased risk of osteoporosis and may not have menstrual periods. They may have heart and other organ problems with severe malnutrition. Malnutrition, if left untreated, can lead to physical or mental disability, or even death.

Children who are overweight have an increased risk for long-term conditions and diseases, including cardiovascular disease, high cholesterol , high blood pressure, type 2 diabetes, asthma , sleep apnea, and certain cancers. Health consequences range from a higher risk of premature death to chronic conditions that reduce a person's quality of life.

Demographics

Malnutrition is a major cause of illness and death throughout the world. Throughout the developing world, malnutrition affects almost 800 million people, or 20 percent of the population. Approximately half of the 10.4 million children who die each year are malnourished. It often causes disease and disability in the children who survive. Diarrheal diseases are also a major world health problem, and may be a cause of malnutrition. Nearly all of these deaths occur in impoverished parts of Africa and Asia, where they often result from contamination of the water supply by animal and human feces.

Worldwide, the most common form of malnutrition is iron deficiency, affecting up to 80 percent of the population, as many as four or five billion people.

In contrast, children in many parts of the world are becoming increasingly overweight. What was thought of as a problem for industrialized nations only until recently, is now affecting children in developing countries. Approximately 25–30 percent of school-age children in the United States are overweight.

Causes and symptoms

Worldwide, poverty and lack of food are the primary reasons why malnutrition occurs. Families of low-income households do not always have enough healthy food to eat. When there is a household food shortage, children are the most vulnerable to malnutrition because of their high energy needs.

There is an increased risk of malnutrition associated with chronic diseases, especially disease of the intestinal tract, kidneys, and liver. Children with chronic diseases like cancer , cystic fibrosis , AIDS , celiac disease , and intestinal disorders may lose weight rapidly and become susceptible to malnutrition because they cannot absorb valuable vitamins, iron, and other necessary nutrients. Children who are lactose intolerant have difficulty digesting milk and milk products, and may be at risk for malnutrition, particularly a calcium deficiency.

Symptoms of malnutrition vary, depending on what nutrients are deficient in the body. Unintentionally losing weight may be a sign of malnutrition. Children who are malnourished may be skinny or bloated and may be short for their age (stunted). Their skin is pale, thick, dry, and easily bruised. Rashes and changes in pigmentation are common.

Hair is thin, tightly curled, and easily pulled out. Joints ache and bones are soft and tender. The gums bleed. The tongue may be swollen, or shriveled and cracked. Visual disturbances include night blindness and increased sensitivity to light and glare.

Other symptoms of malnutrition include:

• fatigue
• dizziness
• anemia
• diarrhea
• disorientation
• goiter (enlarged thyroid gland)
• loss of reflexes and lack of coordination
• muscle twitches
• decreased immune response
• scaling and cracking of the lips and mouth

Children who are overnourished are visibly overweight or obese, and consume more food than their bodies need (or expend too little energy through physical activity).

When to call the doctor

Parents who worry about malnutrition can discuss their concerns with a doctor, registered dietitian, or other health care provider. Though not an exhaustive list, treatment should be sought for a child if:

• there is a change in bodily functions (impairment)
• the child is not growing
• the child faints
• the child rapidly loses hair
• a girl at puberty stops menstruating or is underweight and fails to start menstruating

Diagnosis

Overall appearance, behavior, body-fat distribution, and organ function can alert a family physician, internist, or nutrition specialist to the presence of malnutrition. Parents may be asked to record what a child eats during a specific period. X rays or a CT scan can determine bone density and reveal gastrointestinal disturbances, as well as heart and lung damage.

Blood and urine tests are used to measure levels of vitamins, minerals, and waste products. Nutritional status can also be determined by:

• comparing a child's weight to standardized charts
• calculating body mass index (BMI) according to a formula that divides height into weight
• measuring skin-fold thickness or the circumference of the upper arm

Treatment

Normalizing nutritional status starts with a nutritional assessment . This process enables a registered dietitian or nutritionist to confirm the presence of malnutrition, assess the effects of the disorder, and formulate a diet that will restore adequate nutrition. For children suffering malnutrition due to an illness or underlying disorder, the condition should be treated concurrently.

Nutritional concerns

Children who cannot or will not eat, or who are unable to absorb nutrients taken by mouth, may be fed intravenously (parenteral nutrition) or through a tube inserted into the gastrointestinal tract (enteral nutrition).

Tube feeding is often used to provide nutrients to children who have burns , inflammatory bowel disease, or other long-term conditions that cause chronic malnutrition or malabsorption (e.g. cystic fibrosis or AIDS), and interfere with the ability to take in enough calories. This procedure involves inserting a thin tube through the nose and carefully guiding it along the throat until it reaches the stomach or small intestine. If long-term tube feeding is necessary, the tube may be placed directly into the stomach or small intestine through an incision in the abdomen.

Tube feeding cannot always deliver adequate nutrients to children who:

• are severely malnourished
• require surgery
• are undergoing chemotherapy or radiation treatments
• have been seriously burned
• have persistent diarrhea or vomiting
• have a gastrointestinal tract that is not functional

Intravenous feeding can also supply some or all of the nutrients these children need.

Doctors or registered dietitians can help parents can monitor overweight or obese children. These professionals may suggest a weight loss program if the child is more than 40 percent overweight. Keeping weight gain under control can be accomplished by changing eating habits, lowering fat intake, and increasing physical activity.

Prognosis

Some children with protein-energy malnutrition recover completely. Others have many health problems throughout life, including mental disabilities and the inability to absorb nutrients through the intestinal tract. Prognosis is dependent on age and the length and severity of the malnutrition, with young children having the highest rate of long-term complications and death. Death usually results from heart failure, electrolyte imbalance, or low body temperature. Children with semiconsciousness, persistent diarrhea, jaundice , or low blood sodium levels have a poorer prognosis.

A good prognosis exists for overweight children who make lifestyle changes and adhere to a diet and exercise program.

Prevention

Every child admitted to the hospital for poor weight gain or malnutrition should be screened for the presence of illnesses and conditions that could lead to protein-energy malnutrition. Children with higher-than-average risk for malnutrition should be more closely assessed, and evaluated often.

Nutritional concerns

Proper nutrition is required to ensure optimal health. Consumption of a wide variety of foods, with adequate vitamin and mineral intake, is the basis of a healthy diet. Researchers state that no single nutrient is the key to good health, but that optimum nutrition is derived from eating a diverse diet, including a variety of fruits and vegetables. Because foods such as fruits and vegetables provide many more nutrients than vitamin supplements, food is the best source for acquiring needed vitamins and minerals.

Breastfeeding a baby for at least six months is considered the best way to prevent early-childhood malnutrition. The United States Department of Agriculture and Health and Human Services recommends that all Americans over the age of two:

• consume plenty of fruits, grains, and vegetables
• eat a variety of foods that are low in fats and cholesterol, and contain only moderate amounts of salt, sugars, and sodium
• engage in moderate physical activity for at least 30 minutes, at least several times a week
• achieve or maintain their ideal weight
• use alcohol sparingly or avoid it altogether

Iron deficiency can be prevented by consuming red meat, egg yolks, and fortified breads, flour, and cereals.

KEY TERMS

Anemia —A condition in which there is an abnormally low number of red blood cells in the bloodstream. It may be due to loss of blood, an increase in red blood cell destruction, or a decrease in red blood cell production. Major symptoms are paleness, shortness of breath, unusually fast or strong heart beats, and tiredness.

Electrolytes —Salts and minerals that produce electrically charged particles (ions) in body fluids. Common human electrolytes are sodium chloride, potassium, calcium, and sodium bicarbonate. Electrolytes control the fluid balance of the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body.

Minerals —Inorganic chemical elements that are found in plants and animals and are essential for life. There are two types of minerals: major minerals, which the body requires in large amounts, and trace elements, which the body needs only in minute amounts.

Nutrient —Substances in food that supply the body with the elements needed for metabolism. Examples of nutrients are vitamins, minerals, carbohydrates, fats, and proteins.

Vitamins —Small compounds required for metabolism that must be supplied by diet, microorganisms in the gut (vitamin K) or sunlight (UV light converts pre-vitamin D to vitamin D).

Parental concerns

Infants, young children, and teenagers need additional nutrients to provide for growth requirements. This is also true for women who are pregnant or breastfeeding; a mother's nutritional status affects her baby. Nutrient loss can be accelerated by diarrhea, excessive sweating, heavy bleeding (hemorrhage), or kidney failure. Nutrient intake can be restricted by age-related illnesses and conditions, excessive dieting, severe injury, serious illness, a lengthy hospitalization , or substance abuse.

Children usually eat as much or as little as they need in order to feel satisfied. Children should be allowed to select what they want to eat among healthy food choices; they should be allowed to stop eating when they feel full. An underweight, overweight, or normal weight child should be allowed to decide how much to eat or whether to eat at all, within reason.

Parents must proactively prevent childhood obesity by recognizing weight imbalances when they begin. They can help an overweight child to lose weight (if medically necessary) by being supportive, rather than scolding. Parents should offer their children nutritious food choices and encourage physical activity. With proper intervention, an overweight child is not destined to become an overweight adult, but weight loss goals should be realistic.

Resources

BOOKS

Kleinman, Ronald E., and the American Academy of Pediatrics Committee on Nutrition. Pediatric Nutrition Handbook, 5th ed. Elk Grove Village, IL: American Academy of Pediatrics, 2003.

Physicians Committee for Responsible Medicine. Healthy Eating for Life for Children. Hoboken, NJ: Wiley, 2002.

Willett, Walter C., and P.J. Skerrett. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. New York: Simon & Schuster Source, 2002.

ORGANIZATIONS

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 60007-1098. (847) 434-4000.

American College of Emergency Physicians. 1125 Executive Circle, Irving, TX 75038-2522. (800) 798-1822.

American College of Nutrition. 300 S. Duncan Ave. Ste. 225, Clearwater, FL 33755. (727) 446-6086.

American Dietetic Association. 120 South Riverside Plaza, Suite 2000, Chicago, IL 60606-6995. (800) 877-1600.

Food and Nutrition Information Center. Agricultural Research Service, USDA, National Agricultural Library, Room 105, 10301 Baltimore Boulevard, Beltsville, MD 20705-2351. Web site: <www.nal.usda.gov/fnic/fniccomments.html>.

Mary K. Fyke Crystal Heather Kaczkowski, MSc.

Malnutrition

Malnutrition is a condition in which a person's diet is inadequate to meet minimum daily requirements for nutrients such as proteins, fats, vitamins, and minerals. It is caused by one of two factors. First, a person simply may not get enough food to eat and, thus, fails to take in the nutrients needed to remain healthy. Someone who is hungry all the time obviously is not eating enough food to remain healthy. Second, a person may eat a limited diet that fails to deliver vital nutrients to the body. Anyone who tries to survive on a diet consisting of potato chips, candy bars, and sodas will not be getting the complete range of nutrients his or her body needs.

Individuals at risk for malnutrition

The single most important factor that leads to malnourishment is poverty. Vast numbers of people who live in less-developed countries of the world either do not get enough to eat or do not eat the correct foods. Those who are most at risk of malnutrition where conditions of poverty exist are infants, children, pregnant women, and the elderly.

Malnutrition is not restricted to less-developed nations, however. Even countries with high standards of living, such as the United States, have their share of poor people who are underfed or poorly fed and may develop malnutrition. According to some estimates, at least 20 million Americans go hungry periodically within any given month.

Throughout the world, the death toll from malnutrition caused by hunger is estimated to range from 40,000 to 50,000 people a day. An additional 450 million to 1.3 billion people face the prospect of starvation from their limited food supplies.

Elderly people in nursing homes or hospitals suffering from long-term illnesses or chronic metabolic disorders (which affect the way one's body processes food for energy) are also at risk for malnutrition. Health professionals have procedures to monitor the nutritional condition of these individuals. Malnutrition is also experienced by those suffering from a condition called anorexia nervosa, a disorder marked by a person's intentional refusal to eat properly that can lead to starvation.

Nutritional deficiency diseases

The human body requires a wide range of nutrients in order to remain healthy, grow normally, and develop properly. These nutrients include carbohydrates, fats, proteins, vitamins, and minerals. Other substances, such as water and fiber, have no nutritional value but are needed to maintain normal body functions.

Words to Know

Bone marrow: The spongy center of many bones in which blood cells are manufactured.

Dermatitis: An inflammation of the skin that is often a symptom of a vitamin deficiency disorder.

Edema: An abnormal collection of fluids in the body tissues.

Hemolytic anemia: A type of anemia caused by destruction of red blood cells at a rate faster than which they can be produced.

Hemorrhage: Bleeding.

Kwashiorkor: A protein-deficiency disorder found among children characterized by wasting, loss of hair and skin pigmentation, anemia, blindness, and other symptoms.

Marasmus: A protein- and calorie-deficiency disorder characterized by the wasting away of muscle and skin in children.

Night blindness: Inability to see at night often caused by a vitamin A deficiency.

Protein: Large molecules that are essential to the structure and functioning of all living cells.

Nutrients serve a number of functions in the human body. Carbohydrates and fats, for example, are used by the body to produce the energy humans require to stay alive and healthy and to grow and develop normally. Proteins are used in the production of new body parts, to protect the body against disease and infection, in the regulation of bodily functions, and in a variety of other ways. Vitamins and minerals are used in the body for a number of different purposes, such as controlling the rate at which many chemical changes take place in the body. Overall, more than 50 different nutrients are needed to keep the human body healthy. The absence of any one of these nutrients can result in the development of a nutritional deficiency disease. Some common nutritional deficiency diseases are discussed below.

Kwashiorkor and marasmus. Kwashiorkor (from the West African word for "displaced child") is a nutritional deficiency disease caused when infants and very young children are weaned from their mother's milk and placed on a diet consisting of maize flour, cassava, or low-protein cereals. That diet is generally high in calories and carbohydrates, but low in protein. The most striking symptom of kwashiorkor is edema, a bloating caused by the accumulation of liquids under the skin. Other symptoms may include loss of hair and skin pigmentation, scaliness of the skin, and diarrhea. As the disease progresses, a person may develop anemia (a disorder in which a person's red blood cell count is low and they lack energy), digestive disorders, brain damage, a loss of appetite, irritability, and apathy (lack of interest in things).

Most children do not die of kwashiorkor directly. Instead, they develop infections that, if left untreated, can be fatal. They die from measles, the flu, diarrhea, or other conditions that could be treated relatively easily in a healthy child.

Marasmus (from the Greek word for "to waste away") is a more severe condition than kwashiorkor. It results when a person's diet is low in both calories and protein. The disease is characterized by low body weight, wasting of muscle tissue, shriveled skin, and diarrhea. The most prominent feature of marasmus is a severely bloated belly. A child with marasmus has the appearance of an old person trapped in a young person's body.

Scurvy. Scurvy is one of the oldest deficiency diseases recorded and the first one to be cured by adding a vitamin to the diet. It was a common disease among sailors during the age of exploration of the New World. Portuguese explorer Vasco da Gama (c. 1460–1524) is said to have lost half his crew to scurvy in his journey around the Cape of Good Hope at the end of the fifteenth century.

The main symptom of scurvy is hemorrhaging, the heavy discharge of blood that results when a blood vessel is broken. The gums swell and usually become infected. Wounds heal slowly and the bleeding that occurs in or around vital organs can be fatal. The disease is slow to develop and its early stages are characterized by fatigue (tiredness), irritability, and depression. In the advanced stages of the disease, laboratory tests will show an absence of the vitamin needed to protect against the disease.

In 1747, a British naval physician, James Lind (1716–1794), discovered the cause of scurvy. He found that sailors who were given oranges, lemons, and limes to eat along with their regular food did not develop scurvy. In spite of this finding, it was not until the end of the eighteenth century that the British navy finally had its sailors drink a daily portion of lime or lemon juice to prevent scurvy. The American slang term for English sailors, "limeys," originated from that practice.

The active ingredient in citrus fruits that prevents scurvy was not discovered until the 1930s. Then, two research teams, one headed by Hungarian-American biochemist Albert Szent-Györgyi (1893–1986) and the other by American biochemist Charles G. King, found that the antiscurvy agent in citrus fruits is a compound now known as vitamin C.

Beriberi. Beriberi is a disease that occurs widely in China, Indonesia, Malaysia, Burma, India, the Philippines, and other parts of Asia and the South Pacific Ocean. It is characterized by edema (accumulation of water in body tissues), fatigue, loss of appetite, numbness or tingling in the legs, and general weakness of the body. In fact, the name beriberi comes from the Singhalese word for "weakness."

Beriberi is caused by an absence of vitamin B₁ (thiamine) in the diet. The disease can be prevented by eating foods that are rich in this vitamin, foods such as meats, wheat germ, whole grain and enriched bread, legumes (beans), peanuts, peanut butter, and nuts.

Pellagra. The symptoms of pellagra are sometimes referred to as the "three Ds": diarrhea, dermatitis, and dementia. Dermatitis refers to skin infections while dementia means deterioration of the mind. If the disease is not treated, it may lead to death. The cause for pellagra was discovered in the early twentieth century by Joseph Goldberger (1881–1929), a member of the United States Public Health Service. Goldberger established that pellagra is caused by an insufficient amount of niacin (vitamin B₃).

Niacin occurs naturally in foods such as liver, meat, fish, legumes, and dried yeast. Today it is added to many processed foods such as bread, flour, cornmeal, macaroni, and white rice. This practice has essentially eliminated pellagra as a medical problem in developed countries, although it remains a serious health problem in some less-developed countries of the world.

Rickets. Rickets is a bone disorder caused by a lack of vitamin D. Vitamin D is often called the "sunshine" vitamin because it can be produced in the human body by the effects of sunlight on the skin. Rickets was once a common disease of infants and children. However, all milk and infant formulas now have vitamin D added to them. Thus, the disorder is rarely seen today in countries where "fortified" milk is available. Symptoms of rickets include legs that have become bowed by the weight of the body and wrists and ankles that are thickened. Teeth may be badly affected and take a longer time to mature.

Other vitamin deficiency diseases. The most common problem associated with a deficiency of vitamin A is night blindness. Night blindness is the inability to see well in the dark. Vitamin A is needed for the formation of a pigment needed by the eyes for night vision. Another eye disease caused by vitamin A deficiency is xerophthalmia, which can lead to blindness. This condition affects the cells of the cornea, other eye tissues, and the tear ducts, which stop secreting tears. Vitamin A deficiency is also responsible for a number of skin conditions, problems with tasting and smelling, and difficulties with the reproductive system.

Important sources of vitamin A that can protect against such problems include fish-liver oils, butter, egg yolks, green and yellow vegetables, and milk.

Vitamin E and K deficiencies are rare. A deficiency of vitamin E may be related to sterility (inability to have children) and to more rapid aging. Vitamin K promotes normal blood clotting.

Vitamin B₁₂ (cobalamin) provides protection against pernicious anemia and mental disorders. Vitamin B₆ also protects against anemia as well as dermatitis, irritability, and convulsions.

Mineral deficiency diseases. About 25 mineral elements are required in the human body for the maintenance of good health. Calcium and phosphorus, for example, are needed to produce teeth and bones. Diseases resulting from the lack of a mineral are relatively rare among humans. One of the exceptions is the disorder known as goiter. Goiter is a condition caused by an insufficient amount of iodine in the diet. Iodine is used by the thyroid to produce hormones that control the body's normal functioning as well as its normal growth. If sufficient iodine is not available in a person's diet, the thyroid gland begins to enlarge its cells in an effort to produce the needed hormones. This enlargement produces the characteristic swelling in the neck characteristic of goiter. Today, goiter has virtually disappeared from most developed nations because of the practice of adding small amounts of iodine (in the form of sodium iodide) to ordinary table salt.

Perhaps the most common of all mineral deficiency disorders is anemia. The term anemia literally means "a lack of blood." The condition is caused when the number of red blood cells is reduced to a level lower than that necessary for normal body functioning.

The human body gets the energy it needs to stay alive and function normally by oxidizing nutrients in cells. The oxygen needed for this process is carried from the lungs to cells on red blood cells. The "working part" of a red blood cell is a complex molecule called hemoglobin. Each hemoglobin molecule contains a single atom of iron at its center. The iron atom combines with oxygen from the lungs to form a compound known as oxyhemoglobin. It is in this form that oxygen is transferred from the lungs to cells.

If the body fails to receive sufficient amounts of iron, an adequate number of hemoglobin molecules will not be formed. In that case, there are not enough functioning red blood cells to carry all the oxygen that cells need to produce energy. A person becomes weak and listless and may suffer headaches, soreness of the mouth, drowsiness, slight fever, gastrointestinal disturbances, and other discomforts.

More than 30 different forms of anemia have been recognized. These forms may result from a wide range of causes. For example, a person who has surgery may lose enough blood to develop anemia. A form of anemia known as aplastic anemia develops when bone marrow is destroyed by radiation, toxic chemicals, or certain types of medication. Loss of bone marrow inhibits the production of red blood cells. Hemolytic anemia is caused by the rupture of red blood cells, a problem that can be caused by hereditary factors or by toxic agents.

Treatment

The treatment for malnutrition and for nutrient deficiency diseases is obvious: a person who lacks adequate amounts of food or fails to eat the right kinds of food must change his or her diet. That instruction is easy to give but in many parts of the world it is impossible to follow. Marasmus, kwashiorkor, beriberi, scurvy, rickets, and other deficiency disorders are common in less-developed countries of the world because sufficient food is either not available or, if it is, it is not sufficiently nutritious.

In more-developed countries of the world, people often have ready access to nutritious foods in sufficient quantities so that malnutrition is less of a problem than it is in less-developed countries. In addition, a very large variety of supplements are available, such as vitamin and mineral pills. Anyone who fears that he or she may not be receiving enough of any given vitamin or mineral can easily supplement his or her diet with products available at the corner grocery store.

[See also Blood; Nutrient deficiency diseases; Nutrition; Sicklecell anemia ]

Malnutrition

Definition

Malnutrition is the condition that develops when the body does not get the right amount of the vitamins, minerals, and other nutrients it needs to maintain healthy tissues and organ function.

Description

Undernutrition

Malnutrition occurs in people who are either undernourished or overnourished. Undernutrition is a consequence of consuming too few essential nutrients or using or excreting them more rapidly than they can be replaced.

Infants, young children, and teenagers need additional nutrients. So do women who are pregnant or breastfeeding. Nutrient loss can be accelerated by diarrhea, excessive sweating, heavy bleeding (hemorrhage), or kidney failure. Nutrient intake can be restricted by age-related illnesses and conditions, excessive dieting, food allergies, severe injury, serious illness, a lengthy hospitalization, or substance abuse.

The leading cause of death in children in developing countries is protein-energy malnutrition. This type of malnutrition is the result of inadequate intake of calories from proteins, vitamins, and minerals. Children who are already undernourished can suffer from protein-energy malnutrition (PEM) when rapid growth, infection, or disease increases the need for protein and essential minerals. These essential minerals are known as micronutrients or trace elements.

Two types of protein-energy malnutrition have been described—kwashiorkor and marasmus. Kwashiorkor occurs with fair or adequate calorie intake but inadequate protein intake, while marasmus occurs when the diet is inadequate in both calories and protein.

About 1% of children in the United States suffer from chronic malnutrition, in comparison to 50% of children in southeast Asia. About two-thirds of all the malnourished children in the world are in Asia, with another one-fourth in Africa.

Overnutrition

In the United States, nutritional deficiencies have generally been replaced by dietary imbalances or excesses associated with many of the leading causes of death and disability. Overnutrition results from eating too much, eating too many of the wrong things, not exercising enough, or taking too many vitamins or other dietary replacements.

Risk of overnutrition is also increased by being more than 20% overweight, consuming a diet high in fat and salt, and taking high doses of:

• Nicotinic acid (niacin) to lower elevated cholesterol levels
• Vitamin B₆ to relieve premenstrual syndrome
• Vitamin A to clear up skin problems
• Iron or other trace minerals not prescribed by a doctor.

Nutritional disorders can affect any system in the body and the senses of sight, taste, and smell. They may also produce anxiety, changes in mood, and other psychiatric symptoms. Malnutrition begins with changes in nutrient levels in blood and tissues. Alterations in enzyme levels, tissue abnormalities, and organ malfunction may be followed by illness and death.

Causes and symptoms

Causes

Poverty and lack of food are the primary reasons why malnutrition occurs in the United States. Ten percent of all members of low income households do not always have enough healthful food to eat. Protein-energy malnutrition occurs in 50% of surgical patients and in 48% of all other hospital patients.

Loss of appetite associated with the aging process. Malnutrition affects one in four elderly Americans, in part because they may lose interest in eating. In addition, such dementing illnesses as Alzheimer's disease may cause elderly persons to forget to eat.

There is an increased risk of malnutrition associated with chronic diseases, especially disease of the intestinal tract, kidneys, and liver. Patients with chronic diseases like cancer, AIDS, intestinal parasites, and other gastric disorders may lose weight rapidly and become susceptible to undernourishment because they cannot absorb valuable vitamins, calories, and iron.

People with drug or alcohol dependencies are also at increased risk of malnutrition. These people tend to maintain inadequate diets for long periods of time and their ability to absorb nutrients is impaired by the alcohol or drug's affect on body tissues, particularly the liver, pancreas, and brain.

Eating disorders. People with anorexia or bulimia may restrict their food intake to such extremes that they become malnourished.

Food allergies. Some people with food allergies may find it difficult to obtain food that they can digest. In addition, people with food allergies often need additional calorie intake to maintain their weight.

Failure to absorb nutrients in food following bariatric (weight loss) surgery. Bariatric surgery includes such techniques as stomach stapling (gastroplasty) and various intestinal bypass procedures to help people eat less and lose weight. Malnutrition is, however, a possible side effect of bariatric surgery.

Symptoms

Unintentionally losing 10 pounds or more may be a sign of malnutrition. People who are malnourished may be skinny or bloated. Their skin is pale, thick, dry, and bruises easily. Rashes and changes in pigmentation are common.

Hair is thin, tightly curled, and pulls out easily. Joints ache and bones are soft and tender. The gums bleed easily. The tongue may be swollen or shriveled and cracked. Visual disturbances include night blindness and increased sensitivity to light and glare.

Other symptoms of malnutrition include:

• anemia
• diarrhea
• disorientation
• night blindness
• irritability, anxiety, and attention deficits
• goiter (enlarged thyroid gland)
• loss of reflexes and lack of muscular coordination
• muscle twitches
• amenorrhea (cessation of menstrual periods)
• scaling and cracking of the lips and mouth.

Malnourished children may be short for their age, thin, listless, and have weakened immune systems.

Diagnosis

Overall appearance, behavior, body-fat distribution, and organ function can alert a family physician, internist, or nutrition specialist to the presence of malnutrition. Patients may be asked to record what they eat during a specific period. X rays can determine bone density and reveal gastrointestinal disturbances, and heart and lung damage.

Blood and urine tests are used to measure the patient's levels of vitamins, minerals, and waste products. Nutritional status can also be determined by:

• Comparing a patient's weight to standardized charts
• Calculating body mass index (BMI) according to a formula that divides height into weight
• Measuring skinfold thickness or the circumference of the upper arm.

Treatment

Normalizing nutritional status starts with a nutritional assessment. This process enables a clinical nutritionist or registered dietician to confirm the presence of malnutrition, assess the effects of the disorder, and formulate diets that will restore adequate nutrition.

Patients who cannot or will not eat, or who are unable to absorb nutrients taken by mouth, may be fed intravenously (parenteral nutrition) or through a tube inserted into the gastrointestinal (GI) tract (enteral nutrition).

Tube feeding is often used to provide nutrients to patients who have suffered burns or who have inflammatory bowel disease. This procedure involves inserting a thin tube through the nose and carefully guiding it along the throat until it reaches the stomach or small intestine. If long-term tube feeding is necessary, the tube may be placed directly into the stomach or small intestine through an incision in the abdomen.

Tube feeding cannot always deliver adequate nutrients to patients who:

• Are severely malnourished
• Require surgery
• Are undergoing chemotherapy or radiation treatments
• Have been seriously burned
• Have persistent diarrhea or vomiting
• Whose gastrointestinal tract is paralyzed.

Intravenous feeding can supply some or all of the nutrients these patients need.

Prognosis

Up to 10% of a person's body weight can be lost without side effects, but if more than 40% is lost, the situation is almost always fatal. Death usually results from heart failure, electrolyte imbalance, or low body temperature. Patients with semiconsciousness, persistent diarrhea, jaundice, or low blood sodium levels have a poorer prognosis.

Some children with protein-energy malnutrition recover completely. Others have many health problems throughout life, including mental retardation and the inability to absorb nutrients through the intestinal tract. Prognosis for all patients with malnutrition seems to be dependent on the age of the patient, and the length and severity of the malnutrition, with young children and the elderly having the highest rate of long-term complications and death.

Prevention

Breastfeeding a baby for at least six months is considered the best way to prevent early-childhood malnutrition. The United States Department of Agriculture and Health and Human Service recommend that all Americans over the age of two:

• Consume plenty of fruits, grains, and vegetables
• Eat a variety of foods that are low in fats and cholesterols and contain only moderate amounts of salt, sugars, and sodium
• Engage in moderate physical activity for at least 30 minutes, at least several times a week

• Achieve or maintain their ideal weight
• Use alcohol sparingly or avoid it altogether.

Every patient admitted to a hospital should be screened for the presence of illnesses and conditions that could lead to protein-energy malnutrition. Patients with higher-than-average risk for malnutrition should be more closely assessed and reevaluated often during long-term hospitalization or nursing-home care.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD, editors. "Malnutrition." Section 1, Chapter 2. In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Flancbaum, Louis, MD, with Erica Manfred and Deborah Biskin. The Doctor's Guide to Weight Loss Surgery. West Hurley, NY: Fredonia Communications, 2001.

PERIODICALS

Alvarez-Leite, J. I. "Nutrient Deficiencies Secondary to Bariatric Surgery." Current Opinion in Clinical Nutrition and Metabolic Care 7 (September 2004): 569-575.

Amella, E. J. "Feeding and Hydration Issues for Older Adults with Dementia." Nursing Clinics of North America 39 (September 2004): 607-623.

Bryan, J., S. Osendorp, D. Hughes, et al. "Nutrients for Cognitive Development in School-Aged Children." Nutrition Reviews 62 (August 2004): 295-306.

Grigsby, Donna G., MD. "Malnutrition." eMedicine December 18, 2003. 〈http://www.emedicine.com/ped/topic1360.htm〉.

Gums, J. G. "Magnesium in Cardiovascular and Other Disorders." American Journal of Health-System Pharmacy 61 (August 1, 2004): 1569-1576.

Halsted, G. H. "Nutrition and Alcoholic Liver Disease." Seminars in Liver Disease 24 (August 2004): 289-304.

Reid, C. L. "Nutritional Requirements of Surgical and Critically-Ill Patients: Do We Really Know What They Need?" Proceedings of the Nutrition Society 63 (August 2004): 467-472.

ORGANIZATIONS

American College of Nutrition. 722 Robert E. Lee Drive, Wilmington, NC 20412-0927. (919) 452-1222.

American Institute of Nutrition. 9650 Rockville Pike, Bethesda, MD 20814-3990. (301) 530-7050.

Food and Nutrition Information Center. 10301 Baltimore Boulevard, Room 304, Beltsville, MD 20705-2351. 〈http://www.nalusda.gov/fnic〉.

OTHER

World Health Organization (WHO) Nutrition web site. 〈http://www.who.int/nut/index.htm〉.

KEY TERMS

Anemia— Not enough red blood cells in the blood.

Anorexia nervosa— Eating disorder marked by malnutrition and weight loss commonly occurring in young women.

Bariatric— Pertaining to the study, prevention, or treatment of overweight.

Calorie— A unit of heat measurement used in nutrition to measure the energy value of foods. A calorie is the amount of heat energy needed to raise the temperature of 1 kilogram of water 1°C.

Kwashiorkor— Severe malnutritution in children primarily caused by a protein-poor diet, characterized by growth retardation.

Marasmus— Severe malnutritution in children caused by a diet lacking in calories as well as protein. Marasmus may also be caused by disease and parasitic infection.

Micronutrients— Essential dietary elements that are needed only in very small quantities. Micronutrients are also known as trace elements. They include copper, zinc, selenium, iodine, magnesium, iron, cobalt, and chromium.

Malnutrition

BIBLIOGRAPHY

Malnutrition describes the measurable impairment to individual health and well-being resulting from insufficient or unbalanced food intake relative to physiological needs. The term is often compared and contrasted with hunger, which refers to the subjective feeling of discomfort caused by lack of food, and food insecurity, which describes lack of access to nutritionally adequate food in a socially acceptable manner. Malnutrition usually arises in situations of national or regional food shortage (its acute form is famine ), where geographic regions or nations lack adequate food supply, and food poverty, where households lack resources (entitlements ) to produce or acquire adequate nourishment. But individual food deprivation also occurs when national and household availabilities are adequate but distribution is inequitable; in famine situations, some always eat well. World hunger is a composite term covering insufficient availability, access, and utilization of food at global, national, household, and individual levels.

The United Nations Food and Agricultural Organization (FAO) and the World Bank, working from national food production and trade statistics along with household income figures relative to the price of a minimum food basket, estimate that some 800 million people in developing countries are food insecure. This is despite aggregate increases in agricultural production and improvements in market infrastructure that, since the 1970s, have made it technically possible to feed everyone a nutritionally adequate basic diet. The largest proportions of food-insecure households and undernourished children exist in South Asia, where endemic poverty is high; numbers are growing also in sub-Saharan Africa, where political instability and HIV-AIDS interfere with food production, marketing, income generation, and intergenerational care.

Within households, pregnant and lactating women, adolescent girls, infants and young (especially weaning-aged) children, and elders are particularly vulnerable to malnutrition where they suffer intrahousehold discrimination in access to food and care relative to their nutritional needs. This vulnerability is further elevated by excessive workloads, infections, malabsorption syndromes, environmental contamination, and insufficient health services. Public health nutritionists study nutrition over the life cycle, beginning with gestational nutrition and breast-feeding, to identify these culturally specific ageand gender-related patterns of malnourishment and to institute more effective food and nutrition policies and practices.

Undernutrition includes both protein-energy (protein-calorie) malnutrition and specific micronutrient deficiencies. Manifestations include growth failure in children, underweight and weight loss in adults, extra burdens of disease, and functional impairments to physical activity, work performance, cognitive abilities, reproductive outcomes, and social life. From the 1930s through the late 1960s, nutritionists working with the FAO, the World Health Organization (WHO), and the United Nations University (UNU) made prevention of protein deficiency (the “protein gap”) the priority for interventions. In the 1970s emphasis shifted to energy (calories) on the reasoning that if nutritionally deprived children (or adults) could get sufficient quantities of their traditional balanced diet, protein would take care of itself. Increasing food energy also fit the agricultural-intensification agenda of the green revolution that was producing piles of rice, wheat, and to a lesser extent maize in Asia and Latin America but reducing protein-balanced cereal-legume crop mixes. Malnutrition, conceptualized as a factor in longer-term national economic growth and development, also became part of integrated national nutrition and rural development strategies. These strategies were promoted by the World Bank and other foreign-assistance agencies, which launched national maternal-child health and school feeding programs, targeted food subsidies, agricultural diversification and marketing programs as well as income generation and nutrition and health education efforts. Basic needs investments in education, health, clean water, and sanitation tried to address poverty alleviation and malnutrition together while contributing to longer-term economic growth.

In the late 1980s and early 1990s priorities and framing shifted yet again, this time to ending “hidden hunger.” With UNICEF taking the lead, the World Summit for Children (WSC) in 1990 set goals to reduce—by half—mild to moderate energy-protein malnutrition, which had been implicated in more than half of child deaths in the developing world, and virtual elimination of vitamin A, iodine, and iron deficiencies as public health problems. By this time dietary diversification had practically eliminated beriberi (thiamin deficiency, associated with polished rice diets), pellagra (niacin deficiency, associated with maize), kwashiorkor (protein deficiency, associated with dependence on a starchy tuber or sap), rickets (associated with too little vitamin D and exposure to sunlight), and scurvy (vitamin C deficiency). The WSC initiatives combined nutrient supplementation, food fortification, and food-based strategies as strategies to end vitamin A deficiency blindness and impaired immune response, cretinism and goiter (associated with severe gestational and later deficiencies of iodine), and severe iron deficiency anemias. At the same time the WSC’s goal was to correct more moderate deficiencies, which researchers showed could depress physical and intellectual development, work performance, and child survival.

Subsequently the World Food Summit (1996) and the Millennium Development Goals set additional targets and action plans for reducing world hunger numbers and proportions by half, along with their causes, by 2015. In follow-up, nongovernmental organizations (NGOs) and community-based organizations, collaborating with governments and international agencies, increasingly frame approaches in terms of livelihood security (income generation, microcredit, female education) and rights-based development or the right to adequate food (emphasizing government accountability and public-private-community partnerships and participation). NGOs also play a growing role in humanitarian assistance, including the SPHERE project, which disseminates principles, minimum technical standards, and best practices for responding to disasters. Although international famine early warning systems— and attendant obligations for food aid response—have eliminated most severe malnutrition apart from areas of political instability, active conflict, or oppression, seasonal and chronic malnutrition persist where people lack access to markets and government or international assistance and among those experiencing the immediate economic displacements of globalization. Local and global studies analyzing these contexts of malnutrition suggest that to reduce malnutrition and poverty everywhere, it is necessary to overcome the economic, political, and social exclusion of women by improving women’s education, entitlements, livelihoods, and empowerment, especially across South Asia, and providing fairer access to land, water, infrastructure, and terms of trade.

Although conventionally through the 1980s malnutrition usually referred to undernutrition, caused primarily by poverty and improper diet, there has since been increased attention to overweight, obesity, and nutritional “diseases of civilization,” including diabetes, coronary heart disease, and certain cancers associated with unhealthy diets and behaviors. These syndromes are on the rise also in developing countries, which are experiencing dietary transitions away from traditional, balanced local diets based on grains, legumes, oilseeds, and small amounts of animal protein plus fruits and vegetables toward modern, unbalanced, global diets characterized by more processed and “fast” foods that are higher in fats and simple sugars. Nutritionists studying the etiology of malnutrition now find overweight and underweight individuals residing in the same households, as both low-and higher-income people fill up on cheaper, calorie-dense snacks and sugary beverages. Genetically modified foods and corporate control over the global food system are additional contentious issues for the present and future.

SEE ALSO Disease; Famine; Food; Green Revolution; Needs, Basic; Nutrition; Poverty; Public Health; Undereating; World Bank, The

BIBLIOGRAPHY

DeRose, Laurie, Ellen Messer, and Sara Millman, eds. 1998. Who’s Hungry? And How Do We Know? Food Shortage, Poverty, and Deprivation. Tokyo: United Nations University Press.

Food and Agricultural Organization. 2006. State of Food Insecurity in the World. http://www.fao.org/SOF/sofi/.

Runge, C. Ford, Benjamin Senauer, Philip G. Pardey, and Mark W. Rosegrant. 2003. Ending Hunger in Our Lifetime: Food Security and Globalization. Baltimore, MD: Johns Hopkins University Press.

World Health Organization. 2007. Global Database on Child Growth and Malnutrition. http://www.who.int/nutgrowthdb/.

Ellen Messer

Malnutrition

The nutritional requirements of the human body reflect the nutritional intake necessary to maintain optimal body function and to meet the body's daily energy needs. Malnutrition (literally, "bad nutrition ") is defined as "inadequate nutrition," and while most people interpret this as undernutrition , falling short of daily nutritional requirements, it can also mean overnutrition, meaning intake in excess of what the body uses. However, undernutrition affects more than one-third of the world's children, and nearly 30 percent of people of all ages in the developing world, making this the most damaging form of malnutrition worldwide.

The etiology of malnutrition includes factors such as poor food availability and preparation, recurrent infections, and lack of nutritional education. Each of these factors is also impacted by political instability and war, lack of sanitation, poor food distribution, economic downturns, erratic health care provision, and by factors at the community/regional level.

People at Risk

Certain people are more susceptible to malnutrition than others. For example, individuals in rapid periods of growth, such as infants, adolescents, and pregnant women, have higher nutritional needs than others, and are therefore more susceptible to the effects of poor nutrition. Those living in deprived socioeconomic circumstances or that lack adequate sanitation, education, or the means to procure food are also at risk. Most importantly, individuals at risk for systemic infections (particularly gastrointestinal ) and those who suffer with a chronic disease are at greatly increased risk because they require additional energy to support their immune system and often have decreased absorption of nutrients .

In fact, the relationship between malnutrition and infection is cyclical—infection predisposes one to malnutrition, and malnutrition, which impairs all immune defenses, predisposes one to infection. The World Health Organization (WHO) identifies malnutrition as "the single most important risk factor for disease" (WHO). Some research has identified malnourished children as being more likely to suffer episodes of infectious disease, as well as episodes of longer duration and greater severity, than other children. In particular, hookworm , malaria , and chronic diarrhea have been linked with malnutrition. These conditions are more prevalent in the developing world than in the industrialized world, though malnutrition exists worldwide, particularly in areas of poverty and among patients with chronic disease or who are hospitalized and on enteric feeding.

Necessary Nutrients

The WHO's Department of Nutrition for Health and Development is responsible for formulating dietary and nutritional guidelines for international use. Adequate total nutrition includes the following nutrients: protein , energy (calories ), vitamin A and carotene, vitamin D , vitamin E, vitamin K, thiamine, riboflavin, niacin , vitamin B6, pantothenic acid, biotin , folate , vitamin C, antioxidants , calcium , iron , zinc , selenium, magnesium, and iodine. Most important are protein and the caloric/energy requirement needed to utilize protein. If these elements are inadequate, the result is a protein-energy malnutrition (PEM), or protein-calorie malnutrition (PCM), which affects one in every four children worldwide, with the highest concentration in Asia. Chronic deficiencies of protein and calories result in a condition called marasmus , while a diet high in carbohydrates but low in protein causes a condition called kwashiorkor .

Malnutrition and Growth

Malnutrition from any cause retards normal growth. Growth assessments are therefore the best way to monitor a person's nutritional status. While there are a variety of methods used to measure growth, the most common are known as anthropometric indices, which compare an individual's age, height, and weight, each of which is measured against the others. The values are expressed as percentages, or percentiles, of the normal distribution of these measurements. So, for example, a child with a given height and age might rank in the 90th percentile for height based on all children of that particular age, meaning that 90 percent of children that age are shorter than this particular child. Through anthropometric studies, researchers have found that particular measurements correlate with specific growth trends, based on how the body normally changes over time. Abnormal height-forage (stunting) usually measures long-term growth faltering. Low weight-for-height (wasting ) correlates with an acute growth disturbance.

Malnutrition can have severe long-term consequences. Children who suffer from malnutrition are more likely to have slowed growth, delayed development, difficulty in school, and high rates of illness, and they may remain malnourished into adulthood.

Limited growth patterns are distributed unevenly across the globe. Eighty percent of children affected by stunting or wasting live in Asia, with 15 percent in Africa and 5 percent in Latin America. Low weight-for-age (underweight) is usually used as an overall measurement of growth status. More than 35 percent of all preschool-age children in developing countries are underweight. There are differences, however, across regions. "The risk of being underweight is 1.5 times higher in Asia than in Africa, and 2.3 times higher in Africa than Latin America" (Onis, p. 10). In some ways, these indices also enable an indirect understanding of the societal factors in these regions that contribute to malnutrition as mentioned above.

The Universal Declaration of Human Rights, established by the United Nations (UN) in 1948, identifies nutrition as a fundamental human right. Malnutrition remains one of the world's highest priority health issues, not only because its effects are so widespread and long lasting, but also because it can be eradicated. Given the multifactorial causes of malnutrition, interventions must be focused on both acute and broad goals. Current efforts are targeted at high-risk groups, particularly infants and pregnant women, for it is "in these populations and during these ages that nutritional interventions have the greatest potential for benefit" (Schroeder, p. 46). Even the simple supplementation of vitamin A or beta-carotene supplements during pregnancy can decrease maternal mortality by 40 percent. Interventions include direct food supplementation, food access, agricultural enrichment , nutritional education, and improved infrastructure related to hygiene , sanitation, and health care delivery. Each of these programs "must be tailored to the particular problems, cultural conditions, and resource constraints of the local context" (Schroeder, p. 417). Strategies for reducing the prevalence of malnutrition must effectively address its many causes.

see also Kwashiorkor; Marasmus; Nutrients; Nutrition.

Seema P. Kumar

Bibliography

Gillespie, Stuart, and Lawrence Haddad (2001). Attacking the Double Burden of Malnutrition in Asia and the Pacific. Washington, DC: International Food Policy Research Institute.

Onis, M.; Monteiro, C.; Akre, J.; and Clugston, G. (1993). "The Worldwide Magnitude of Protein-Energy Malnutrition." In Bulletin of the World Health Organization 71(6).

Schroeder, Dirk G. (2001). "Malnutrition." In Nutrition and Health in Developing Countries, ed. Richard Semba and Martin Bloem. Totowa, NJ: Humana Press.

Shannon, Joyce Brennflck (2001). Worldwide Health Sourcebook. Detroit, MI: Omnigraphics.

malnutrition The condition arising due to the lack of one or more of the nutrients that are required in the diet to maintain health. Malnutrition can result from a reduced intake of nutrients (undernourishment), an inability to use absorbed nutrients, failure to meet a required increase in nutrient intake, or nutrient losses. There are three stages in the process of malnutrition: first, the carbohydrate stores in the body are depleted; secondly, the fat reserves are metabolized (see fatty-acid oxidation); and finally, proteins are broken down to provide energy. Death may result after protein levels have been reduced to half their normal value. Kwashiorkor is a type of malnutrition that develops when the diet lacks proteins and hence essential amino acids. Malnutrition due to reduced absorption of nutrients in the intestine can develop with a cereal-based diet, due to sensitivity of the intestinal lining to gluten, a protein found in cereals. See also mineral deficiency.

malnutrition insufficiency of one or more nutritional elements necessary for health and well-being. Primary malnutrition is caused by the lack of essential foodstuffs—usually vitamins, minerals, or proteins—in the diet. In some areas of the world a poor economy or such regional conditions as drought or overpopulation cause a scarcity of certain foodstuffs, and a certain portion of the population is malnourished because essential nutrients are not available. However, even when food is plentiful, malnutrition can result from poor eating habits. Secondary malnutrition is caused by failure of absorption or utilization of nutrients (as in disease of the gastrointestinal tract, thyroid, kidney, liver, or pancreas), by increased nutritional requirements (growth, injuries, burns, surgical procedures, pregnancy, lactation, fever), or by excessive excretion (diarrhea).

malnutrition (mal-new-trish-ŏn) n. the condition caused by an improper balance between what an individual eats and what is required to maintain health. This can result from eating too little (subnutrition or starvation) but may also imply dietary excess or an incorrect balance of basic foodstuffs.

mal·nu·tri·tion / ˌmalnoōˈtrishən/ • n. lack of proper nutrition, caused by not having enough to eat, not eating enough of the right things, or being unable to use the food that one does eat.

malnutrition Condition resulting from a diet that is deficient in necessary components such as proteins, fats or carbohydrates. It can lead to deficiency diseases, increased vulnerability to infection and death.

malnutrition Disturbance of form or function arising from deficiency or excess of one or more nutrients. See also cachexia; obesity; protein‐energy malnutrition; vitamin toxicity.