Phytochemicals are an important aspect of human diet and consequent athletic performance. "Phyto" is a Greek work for plant life, and the phytochemicals are a very broad range of substances that are ingested through food, but that do not themselves possess any nutritional value, in terms of energy, vitamin, or mineral contribution. Most foods, except those that are heavily refined such as sugar, contain one form of phytochemical or another. The primary sources of these substances are fruits, vegetables, whole grains, and most beans.
The phytochemicals are substances that influence the function and the outcome of various bodily systems, as opposed to directing or dictating that function. The phytochemicals that are of most interest to humans are those that act to protect the body from illness or disease.
Phytochemicals have long been recognized by various cultures throughout the world as possessing special qualities in relation to human health. The ancient system of traditional Chinese medicine (TCM), and its reliance upon herbs such as ginseng, is an example of the extent to which various phytochemicals have been used. A more recent phytochemical medicinal application was the synthesis of salicylic acid, first extracted from the bark of a willow tree, in the manufacture of the most commonly used of aspirin, the nonsteroidal anti-drugs (NSAIDs), created in 1899.
As phytochemicals enter the body as the components of a broad range of plant products consumed as food, each with its own chemical complexity, the action of the various phytochemicals on the human systems is equally diverse. No phytochemical is believed to be essential to optimal body function as, in many cases, the action of the phytochemical is a counteraction of an unrelated environmental impact on the body. The following are the more common types of desirable actions and related food sources for each phytochemical:
- Antibacterial agents: Allicin, the active ingredient of garlic and other plants that provides this vegetable with its characteristic strong odor, is well known as a substance that acts as an effective agent against harmful bacteria entering the body.
- Antioxidants: This term is broadly and often incorrectly applied to a variety of plant sources. An antioxidant is a substance that tends to act against molecules in the body that have an unpaired electron, known as free radicals, which themselves tend to form cells that often contribute to the formation of cancer-causing cells. The phytochemicals present in items such as fruits, carrots, onions, and other vegetables are well-regarded antioxidants. Lycopene is the phytochemical compound found in the skin of tomatoes, and it is a powerful antioxidant, particularly with respect to preserving the health of the cells in the cardiovascular system.
- Alkaloids: The most important alkaloid is caffeine. Caffeine is the world's most consumed stimulant, possessing a powerful effect on the central nervous system. In excess amounts, caffeine is counterproductive to the health of the body.
- Digoxin: This is found naturally in the foxglove plant, which grows in various parts of North America and Europe. It is a well regarded as a medication in the treatment of heart failure, as it acts to regulate and to strengthen a failing heart rate.
- Flavanoids: The flavanoid group, which are present in a number of fruits, such as cranberries, raspberries, grapes, and blueberries, often act as antioxidants. Flavanoids also work to inhibit the progress of low-density lipoproteins in the cardiovascular system, the form of cholesterol that causes plaque and contributes to the narrowing of arteries and the development of arteriosclerosis. Red wine has been long regarded as possessing this antioxidant quality.
- Beta-sitosterol; This substance is found in peanuts, wheat germ, and various rice products; these agents tend to reduce cholesterol levels, especially in men with prostate problems.
While phytochemicals can be added to an existing diet by way of supplements, the best and most absorptive fashion that such chemicals can be introduced into the body is through a balanced diet that has significant fresh fruits and vegetables. As a general rule, the closer to the natural or whole food state, the more likely the food is to possess phytochemicals. An example is whole grain products; much of the phytochemical presence is contained in the grain or kernel shell. When the grain is removed during processing, a large measure of the phytochemicals in the grain are removed.
Two food types that are sometimes overlooked by those seeking the advantages of phytochemicals are dried fruits, which lose little of their natural phytochemical effect in this state, and various herbs and spices commonly employed in food preparation. Most dried herbs such as basil, thyme, and oregano are rich in various phytochemicals. The active ingredient in many types of red pepper, capsicum, is an effective antioxidant agent.