What About Food?
What About Food?
By Ellen Coleman
Whatever Happened to FOOD?
Nutrition research generally focuses on the effect of individual nutrients or food components on health and disease. To understand mechanisms, it?s necessary to use single nutrients or dietary constituents so that complex interactions don?t make the interpretation of experimental results impossible. However, foods contain a large number of biologically active ingredients and athletes eat foods, not nutrients or dietary components. Trying to understand the full impact of diet on health when considering only isolated food components is comparable to missing the forest for the trees.
The influence of diet on health occurs not only from the subtle effects of numerous individual food components, but from whole foods and the associated interactions that occur among these components. Mark Messina PhD and colleagues refer to this concept as ?food synergy? and recommend emphasizing dietary patterns, rather than individual foods or nutrients (see Messina and colleagues, 2001).
There are three basic principles athletes can follow to obtain a healthy diet (see ADA, 2002). Moderation refers to eating a wide selection of foods within and among the five major food groups daily. No one major food group is more or less important than any other food group. Moderation should also include appropriate portion size. Balance refers to eating relatively more servings from the larger food groups at the bottom of the Food Guide Pyramid and fewer servings from the smaller food groups at the top of the pyramid. Dietary adequacy can be obtained by including a variety of nutrient-dense foods such as grains, fruits, and vegetables.
Athletes should try to obtain their nutrients from foods rather than relying on supplements. Although supplements are suggested when food intake is not adequate to meet specific needs, a balanced diet remains the ideal source of nutrients. In addition to having a variety of nutrients, foods contain bioactive compounds such as phytochemicals and dietary fiber that have health benefits (see ADA, 2002). Supplements don?t contain these compounds in the same chemical form or proportion as found in food. By taking a vitamin C pill, athletes miss out on the dietary fiber, limonene (an anticancer phytochemical), potassium, and energy they would obtain from eating an orange.
Nutrients in food are also often ?packaged? more effectively than they are in supplements. Milk contains both calcium and lactose and lactose increases the absorption of calcium. Most calcium supplements do not contain lactose.
Protein-rich foods serve as ?timed release? sources of amino acids and other nutrients necessary for muscle protein synthesis. Compare a tasteless 500 milligram arginine supplement to one cup of a low-fat fruited yogurt that contains 10 grams of high quality protein, 18 different amino acids (including 300 milligrams of arginine), carbohydrate, calcium, magnesium, and potassium.
Nutrition is a relatively young science. Foods may contain other nutritional substances that have not yet been identified. Diet, not supplements, is the preferred vehicle to achieve nutritional adequacy (see ADA, 2002). Taking supplements as an alternative to appropriate food choices may have a negative effect on performance because the athlete does not address dietary composition (carbohydrate, protein, fat, and calories). Athletes also get more nutritional bang for their buck with foods than supplements.
The Dietary Approaches to Stop Hypertension (DASH) trial illustrated the importance of food synergy and the complex relationship between diet and disease. The DASH trial established that: 1) a dietary pattern rich in fruits and vegetables reduced blood pressure; 2) a dietary pattern also rich in low-fat dairy products and reduced in fat further lowered blood pressure; and 3) a reduced sodium intake produced even greater reductions in blood pressure (see Appel et al, 1997; Sacks et al, 2001).
In addition to promoting food synergy, an emphasis on dietary patterns rather than on individual foods or nutrients is easier for athletes to translate into dietary behavior.
Appel LJ, Moore TJ, Obarzenek E, et al. A clinical trial of the effects of dietary patterns on blood pressure. New England Journal of Medicine. 1997;336:1117-1124.
Messina M, Lampe JW, Birt DF, et al. Reductionism and the narrowing nutrition perspective: time for reevaluation and emphasis on food synergy. Journal of the American Dietetic Association. 2001;101:1416-1419.
Position of the American Dietetic Association: total diet approach to communicating food and nutrition information. Journal of the American Dietetic Association. 2002;102:100-108.
Sacks FM, Svetkey LP, Vollmer WM et al. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. New England Journal of Medicine. 2001; 344:3-10.
Miles of smiles,
Ellen Coleman, RD, MA, MPH