Amino Acids

Amino acids

Description

Amino acids are known as the building blocks of protein, and are defined as the group of nitrogen-containing organic compounds composing the structure of proteins. They are essential to human metabolism, and to making the human body function properly for good health. Of the 28 amino acids known to exist, eight of them are considered "essential," defined as those that can be obtained only through food. These essential amino acids are tryptophan, lysine, methionine , phenylalaine, threonine, valine, leucine, and isoleucine. The "non–essential" amino acids include arginine , tyrosine, glycine, serine, glutmamic acid, aspartic acid, taurine, cycstine, histidine, proline, alanine, and creatine , which is a combination of arginine, glycine, and methionine.

The human body, minus water, is 75% amino acids. All of the neurotransmitters (proteins) but one are composed of amino acids; and 95% of hormones are amino acids. Amino acids are key to every human bodily function with every chemical reaction that occurs.

Amino acids occur naturally in certain foods, such as dairy products, meats, fish, poultry, nuts, legumes, and eggs. Those sources are considered more complete than vegetable protein, such as beans, peas, and grains, also considered a good—even if not complete—source of amino acids.

Amino acids became popular as dietary supplements by the end of the twentieth century for various uses, including fitness training, weight loss, and certain chronic diseases. Claims exist in holistic medicine that indicate amino acid supplements taken in the proper dosage can aid also in fighting depression, allergies, heart disease , gastrointestinal problems, high cholesterol , muscle weakness, blood sugar problems, arthritis, insomnia , bipolar illness, epilepsy, chronic fatigue syndrome, autism, attention-deficit hyperactivity disorder (ADHD), and mental exhaustion.

Description

Amino acid therapy as a supplemental aid to a healthy diet joined the fitness craze in the United States by the end of the 1990s. According to author Brenda Adderly in Better Nutrition, in September of 1999, "The creation of new protein from amino acids and the breaking down of existing protein into amino acids are ongoing processes in our bodies. If, for example, you are working out and developing certain muscles, amino acids come to the rescue with new protein to build muscle cells," Adderly noted. "Similarly, when you eat a complete protein, such as meat or beans and rice, the body breaks down the amino acids in that food for later use." Understanding the balance of amino acids in the body can be often the first clue to understanding why a person suffers many ailments, ranging from depression to upset stomach to obesity . Deficiencies in the proper balance of amino acids is likely to occur in those with poor diets . Because stress , age, infection, and various other factors including the amount of exercise a person does, can also affect the levels of amino acids, people with healthy, nutritious diets could also find that they also suffer deficiencies. Adderly adds that, "Not only are the symptoms of amino acid deficiencies wide ranging, but there are no RDAs (recommended daily allowances) or other guidelines, to help us tell if we are least covering all the bases. Add to that the complicated matter of keeping track of all 28 some with names most of us have never even heard and the situation begins to seem overwhelming."

Essential amino acids

The amino acids, which are derived only from food and that the body cannot manufacture, perform various functions.

• Tryptophan. This is considered a natural relaxant, helps alleviate insomnia; helps in the treatment of migraine headaches; helps reduce the risk of artery and heart spasms; and works with lysine to reduce cholesterol levels.
• Lysine. Aids in proper absorption of calcium ; helps form collagen for bone cartilage and connective tissues; aids in production of antibodies, hormones, and enzymes. Research has indicated it also might be effective against herpes by creating the balance of nutrients that slows the growth of the virus causing it. A deficiency could result in fatigue , lack of concentration, irritability, bloodshot eyes, retarded growth, hair loss, anemia , and reproductive problems.
• Methionine. Properties include providing the primary source of sulfur that can prevent disorders of the hair, skin, and nails; lowers cholesterol by increasing the liver's production of lecithin ; reduces liver fat; protects kidneys; and promotes hair growth.
• Phenylalaine. This serves the brain by producing norepinephrine, the chemical that is responsible for transmitting the signals between the nerve cells and the brain; can maintain alertness; reduces hunger pains; acts as an antidepressant; and improves memory.
• Threonine. Makes up a substantial portion of the collagen, elastin, and enamel protein; serves the liver by preventing buildup; aids the digestive and intestinal tracts to function better; and acts as a trigger for metabolism.
• Valine. Promotes mental energy; helps with muscle coordination; and serves as a natural tranquilizer.
• Leucine. Works with isoleucine to provide for the manufacture of essential biochemical processes in the body that are used for energy, increasing the stimulants to the upper brain for greater mental alertness.

Roles of certain non–essential amino acids

• Glycine. Facilitates the release of oxygen for the cell–making process; key role in manufacturing of hormones and health of immune system.
• Serine. Source of glucose storage by the liver and muscles; provides antibodies for immune system; synthesizes fatty acid sheath around nerve fibers.
• Glutamic acid. Nature's "brain food" that increases mental prowess; helps speed the healing of ulcers; aids in combatting fatigue.

Creatine in the spotlight

One of the most discussed amino acid supplements available on the market is creatine monohydrate. The body produces small amounts of creatine in the kidneys, liver, and pancreas, making it a non-essential acid. With most diets that include red meat or fish, also come a few grams of creatine. It is stored in muscle cells and is used in activities, such as weight lifting and sprinting, providing the necessary thrust of energy for such activities. But the natural supply of creatine produced by the body is quickly depleted. After approximately 10 seconds, when muscle fatigue becomes apparent, the daily production is used.

According to Timothy Gower, writing for Esquire in February of 1998, "Scientists identified creatine 160– odd years ago, but only in the 1980s did they figure out that muscle cells can be 'loaded' with up to 30% more of the compound than they normally carry. Since then, several studies have shown that weight lifters primed on the supplement tire less easily, allowing them to work out longer." Gower also noted that creatine users find that the weight they add on is fat-free, whether that is lean tissue or some is water weight, no one has yet determined, since muscle cells do fill with water during creatine loading. Additionally, while it can add to the burst of the energy a sprinter needs to perform well, creatine does not do anything for the marathon runner going for several hours.

Commercially available since 1993, the long-term effects still remain unknown. One 2002 study did show that creatine use improved rehabilitation for injured athletes and another has shown that using the supplement does not increase risk of injury. It should be noted that some 20–30% of people researched showed no improvement using creatine. One early report indicated that creatine could be beneficial for some people in spurring metabolism, burning calories and helping in weight loss. Those reports were as yet inconclusive.

General use

Amino acid supplements to a healthy diet are used for various purposes. The most common uses include: sustaining strength in weight training to build muscles; improving heart and circulatory problems or diseases, particularly in the aging ; the treatment of chronic fatigue syndrome; treating depression and anxiety ; treating eating disorders, such as bulimia and/or anorexia, along with overeating; increasing memory; building up and sustaining the body's immune system in fighting bacteria and viruses. It is important to note that, while the necessity and role of all amino acids has been verified in the maintenance of optimum health, research is not extensive enough to provide indisputable verification of the touted benefits of such supplements over the long term.

Nonetheless, some members of the scientific medical community would seem to confirm what amino acid proponents have long believed to be true. One such study from the Journal of the American College of Cardiology brought good news for the millions suffering from chronic heart failure. Dr. Rainer Hambrecht and colleagues from the University of Leipzig, (Germany) tested the amino acid L-arginine on 38 heart-failure patients. Knowing that the human body converted it into nitric oxide, a chemical that relaxes blood vessels, the researchers gave one group 8 g of it daily for four weeks; another group simply did forearm exercises; and a third group combined the supplement with the exercise. The people who took the supplement alone increased their blood-vessel dilation by a factor of four, as did the exercise group. Those who took both the supplement and performed the exercise increased it by six. More recent studies on arginine in 2002 found that the supplement may help reduce risk of postoperative infections . Further, arginine may enhance women's sexual function.

Supplements are recommended by alternative medical practitioners particularly for those who are not getting a proper diet, especially vegetarians who might not be getting a balance of complete protein, as well as athletes, anyone under severe stress, and anyone whose alcohol intake level is moderate to high.

Preparations

Supplements of various amino acids are available primarily in capsule, tablet, or powder form. A common way of taking amino acids is in a "multiple" amino acid gel cap. These contain sources of protein from gelatin, soy, and whey. The market for supplements in wholesale, retail, and internet sales was estimated to reach into the millions of dollars, with literally hundreds available. Internet sales were a fast-growing area particularly with the use of such supplements as creatine powder publicized by well-known Olympic stars and professional athletes. Daily usage of creatine as evident from research indicated that usage should be leveled at 5 g of powder in a glass of orange juice, and could be taken up to four times a day during peak athletic training. Maintenance dosages were recommended at 5 g once a day.

Side effects

Because amino acids are naturally produced substances both in the human body and in the protein derived from animal and dairy products, as well as being present in food combinations such as beans and rice, such supplements are not regulated by the United States Food and Drug Administration (FDA), nor are there any specified daily requirements, and they also do not show up in either drug or urine tests. Amino acid supplements might be classified as having no affect at all. Long-term effects were not yet evident, however, due to the relatively recent phenomenon of use.

Interactions

Interactions of amino acids with drugs has not been sufficiently studied to determine yet if any adverse effects result from using amino acids with medications.

Resources

PERIODICALS

Adderly, Brenda. "Amino Acids." Better Nutrition (September 1999). Available from http://web2.infotrac.galegroup.com.

"Amino acid screening." Everything You Need to Know about Medical Tests, Annual. Springhouse Corporation: 1996. Available from http://web2.infotrac.com.

Antinoro, Linda. "Food and Herbs That Keep Blood Moving, Prevent Circulatory Problems." Environmental Nutrition (February 2000).

"Arginine Seems to Benefit Both Immune and Sexual Response." RN (February 2002): 22.

Austin Nutritional Research. "Amino acids." Reference Guide for Amino Acids. 2000. Available from http://www.realtime.net/anr/aminoacid.html.

Body Trends Fitness Products. "Amino acids." bodytrends.com commercial website. (2000). Available from http://wwwbodytrends.com.

"Creatine Supplementation Speeds Rehabilitation." Health and Medicine Week (January 21, 2002): 6.

Davidson, Tish. "Amino acid disorders screening." Gale Encyclopedia of Medicine. Edition 1. Detroit: 1999. Available from http://web2.infotrac.galegroup.com.

Dolby, Victoria. "Anxiety? Send herbs, 5–HTP, and amino acids to the rescue!" Better Nutrition (June 1998). Available from http://web2.infotrac.galegroup.com.

Gersten, Dennis J., M.D. "Amino Acids: Building Blocks of Life, Building Blocks of Healing." The Gersten Institute for Integrative Medicine. (2000). Available from http://www.imagery.com.

Gower, Timothy. "Eat Powder! Build Muscle! Burn Calories!" Esquire (February 1998). Available from http://www.brittannica.com.

Moyano, D.; Vilaseca, M.AA.; Artuch, R.; and, Lambruschini, N. "Plasma Amino Acids in Anorexia Nervosa." Nutrition Research Newsletter (November 1998). Available from http://web2.infotrac.com.

"Studies Say Creatine is OK." Obesity, Fitness & Wellness Week (January 12, 2002): 12.

Toews, Victoria Dolby. "6 Amino Acids Unleash the Energy." Better Nutrition (June 1999). Available from http://web2.infotrac.com.

Totheroh, Gailon. "Amino Acid Therapy Pays Off." Christian Broadcasting Network (10 May 1999). Available from http://www.cbn.com.

Tuttle, Dave. "Muscle's little helper." Men's Fitness (December 1998). Available from http://web2.infotrac.com.

Wernerman, Jan. "Documentation of clinical benefit of specific amino acid nutrients." The Lancet (5 September 1998). Available from http://web2.infotrac.galegroup.com/itw.

Williams, Stephen. "Passing the Acid Test." Newsweek (27 March 2000).

Jane Spehar

Teresa G. Odle