ACSM'S Health & Fitness Journal:
DEPARTMENTS: You Asked For It: Question Authority
Nieman, David C. Dr.P.H., FACSM
David C. Nieman, Dr.P.H., FACSM, is professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, North Carolina, an active researcher; and author of several textbooks on health and fitness. Send your questions firstname.lastname@example.org.
Q:ARE EGGS GOOD FOR MY HEALTH AND FITNESS OR NOT? I AM VERY CONFUSED BECAUSE SOME REPORTS EMPHASIZE THAT EGGS PROVIDE MANY GOOD NUTRIENTS, WHEREAS OTHERS CLAIM THAT PEOPLE EATING ONE OR MORE EGGS A DAY DIE AT AN EARLIER AGE.
A:There is probably more misinformation on eggs than any other food in our diets. The bottom line is that a moderate intake of eggs is compatible with good health and provides sound nutrition support for physically active individuals.
A study by Harvard Medical School researchers has caused much confusion, especially because of widespread review by the popular media (1). This study showed that middle-aged men who ate seven or more eggs a week had a higher risk of earlier death. Men with diabetes doubled their risk of early death by eating seven or more eggs a week. A subsequent report from the same research team showed that daily consumption of eggs was linked to an increased risk of type 2 diabetes in men and women (2). These studies have caused much concern regarding whether eggs should be included in a healthy diet.
The media headlines on the first Harvard study of 21,327 male physicians were misleading, and the details are revealing (1). For a 20-year period, 1,550 of the men had heart attacks, 1,342 had strokes, and more than 5,000 died. "Egg consumption was not associated with (heart attack) or stroke," the researchers wrote. Risk of early death was not elevated until men ate seven or more eggs a week, and the risk went up only 23%. Adding to the confusion is that men who ate the most eggs also were older, fatter, less likely to exercise, and more likely to drink alcohol and smoke cigarettes - all factors that can affect the risk of heart attack and death. These factors were adjusted for in the analysis, but this process is not perfect.
Most other major studies have failed to demonstrate that eating up to an egg a day increases death rates from any cause, including heart disease (3-7). Three of the highest egg-consuming countries in the world are Japan, Spain, and France, which also happen to have some of the lowest rates of heart disease among industrialized countries. Most of the early concern about eggs was due to the high cholesterol content of eggs, approximately 212 mg per average egg yolk (5). The American Heart Association and other health organizations recommend that people aim for less than 300 mg dietary cholesterol a day from all sources. Eggs typically supply one third of the cholesterol people ingest from the diet, with meats and dairy products supplying the rest.
Despite the concern over the cholesterol found in the egg yolk, nearly all studies have shown that eggs do not cause large increases in blood cholesterol levels (8). In fact, if an individual with a 190 mg/dl blood cholesterol adds one egg to the diet each and every day, the blood cholesterol will go up within 2 to 3 weeks to 194 mg/dl, hardly a meaningful difference. A recent study showed that consuming a large quantity of eggs (12 per week) during a 6-week endurance exercise training program did not negate improvements in plasma lipid profiles when compared with those using no eggs at all (9).
Healthy adults can continue to enjoy eggs as part of a balanced diet, and there is little reason to suggest that "no eggs at all" is a preferable approach. The American Heart Association agrees that eggs can fit within heart-healthy guidelines when cholesterol from other sources, especially red meats, is limited. Eggs have nutritional benefits, containing 13 essential vitamins and minerals, high-quality protein, healthy unsaturated fats, and antioxidants, for only 74 calories (Table).
TABLE Nutritional Co...Image Tools
Eggs are an excellent source of choline, an essential nutrient for humans. Other significant choline sources are beef and chicken liver, foods few Americans enjoy. A significant gap exists between current and recommended intake levels of choline. Choline is necessary for the synthesis of acetylcholine, an important neurotransmitter involved in memory storage and muscle control. Choline also is a precursor of betaine, an osmolyte used by the kidney to control water balance.
One large egg provides 6.3 g of protein, with 3.6 g in the egg white and 2.7 g in the egg yolk. Eggs have the highest quality protein in the entire food supply with the amino acid pattern almost matching the human requirement for essential amino acids. Cooked egg protein is more digestible than raw egg protein. A recent study showed that ingesting 20 g of whole egg protein immediately after intensive resistance exercise stimulated muscle protein synthesis above levels achieved when no egg protein was consumed (9).
Eggs often are blamed for the company they keep because people typically consume eggs with foods high in disease-causing saturated fats including bacon, red meat, butter, and whole milk. This menu can be easily substituted with a vegetable omelet, whole wheat toast, soft margarine without trans fat, and fruit juice. The average American eats approximately four eggs a week, and there is no health or fitness rationale to crusade for a lower intake. Eggs are found in more than 900 American foods, according to the U.S. Department of Agriculture, add to the enjoyment of cooking and eating, and support a physically active lifestyle.
1. Barraj L, Tran N, Mink P. A comparison of egg consumption with other modifiable coronary heart disease lifestyle risk factors: a relative risk apportionment study. Risk Anal
2. Dawber TR, Nickerson RJ, Brand FN, Pool J. Eggs, serum cholesterol, and coronary heart disease. Am J Clin Nutr
3. Djoussé L, Gaziano JM. Egg consumption in relation to cardiovascular disease and mortality: the Physicians' Health Study. Am J Clin Nutr
4. Djoussé L, Gaziano JM, Buring JE, Lee IM. Egg consumption and risk of type 2 diabetes in men and women. Diabetes Care
5. Hu FB, Stampfer MJ, Rimm EB, et al
. A prospective study of egg consumption and risk of cardiovascular disease in men and women. JAMA
6. Kritchevsky SB. A review of scientific research and recommendations regarding eggs. J Am Coll Nutr
. 2004;23(6 Suppl):596S-600S.
7. Moore DR, Robinson MJ, Fry JL, et al
. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr
8. Nakamura Y, Iso H, Kita Y, et al. Egg consumption, serum total cholesterol concentrations and coronary heart disease incidence: Japan Public Health Center-based prospective study. Br J Nutr. 2006;96(5):921-8.
9. Qureshi AI, Suri FK, Ahmed S, Nasar A, Divani AA, Kirmani JF. Regular egg consumption does not increase the risk of stroke and cardiovascular diseases. Med Sci Monit
10. Vislocky LM, Pikosky MA, Rubin KH, et al. Habitual consumption of eggs does not alter the beneficial effects of endurance training on plasma lipids and lipoprotein metabolism in untrained men and women. J Nutr Biochem. 2009;20(1):26-34.