Eating one egg a day can replenish the organism with the nutrients it needs without any particular harm, but it may have an effect on blood lipids in people with certain metabolic disorders. Eggs are rich in protein and have a very complete range of vitamins, including B vitamins, vitamin A, vitamin D, vitamin E and vitamin K, as well as trace amounts of vitamin C. Eggs are also rich in minerals such as calcium, phosphorus, iron, zinc and selenium. The fat content of the yolk is 10 to 15 percent, and the cholesterol in an egg is around 200 milligrams. Research has proved that for healthy people, eating one egg a day can replenish the body with proteins, vitamins, mineral elements, etc., with little or no effect on serum cholesterol levels. However, for some people with metabolic diseases, the extra extra cholesterol intake may affect the metabolism of blood lipids. Therefore, in healthy people, eating one whole egg (both egg white and egg yolk) per day will do more good than harm. People with metabolic diseases should follow their doctor’s advice.