Eggs include eggs, duck eggs, goose eggs, quail eggs, etc. and their processed salted eggs, tea eggs, pine eggs (preserved eggs), etc. As the eggs that birds breed for the next generation, eggs are extremely rich in nutrients and have very high nutritional value.

　　The protein content of eggs is about 12%, and its amino acid composition is closest to what the human body needs. It is the highest nutritive value and highest quality protein in natural food, surpassing other animal foods such as meat.

　　 Eggs contain 10% to 15% of fat. Most of the fat is found in egg yolks, and egg white contains very little fat. The fat of egg yolk is easy to digest and absorb, because its rich lecithin plays an emulsifying role. Egg yolk is the best source of phospholipids. The lecithin it contains has the effect of lowering blood cholesterol and can promote the absorption and utilization of fat-soluble vitamins such as vitamin A, vitamin D, and vitamin E.

　　Eggs (mainly egg yolks) are rich in vitamins, and the variety is complete, including all B vitamins, vitamin A, vitamin D, vitamin E, vitamin K and a small amount of vitamin C.

　　Eggs are also a good source of minerals. The mineral content of egg yolk is ~, and trace elements such as iron, zinc and selenium are particularly abundant.

　　 Of course, egg nutrition is not perfect. Egg yolk contains more saturated fatty acids and more cholesterol, and the harm of both is well-known to the cardiovascular system. Cholesterol is a lipid compound widely present in animal foods. Its physiological functions in the body are: ① participating in the formation of cell membranes; ② participating in the formation of nerve tissues; ③ is the raw material for the synthesis of certain hormones (such as sex hormones); ④ formation The bile salts in bile emulsify fat in the intestine and promote fat digestion; ⑤ is the raw material for synthesis of vitamin D. These effects are beneficial to the human body, but excessive intake of cholesterol is harmful and can cause dyslipidemia, especially when cholesterol and saturated fatty acids are taken together, its effect of raising serum cholesterol (blood lipids) is very obvious. However, some studies have shown that the effect of self-lipid metabolism on blood cholesterol is much greater than the effect of dietary cholesterol intake. That is to say, the intake of cholesterol in the diet (such as egg yolk) does not play the most critical role in the concentration of cholesterol (blood lipid) in the blood. Based on the above knowledge, in order to prevent adverse reactions caused by excessive cholesterol in the diet, the "Dietary Guidelines for Chinese Residents 2007" recommends that the daily dietary cholesterol intake should not exceed 300 mg. This number is exactly the same as the recommendations of the American Heart Association (AHA) and the World Health Organization (WHO).

　　Cholesterol in eggs is mainly concentrated in egg yolk. Goose* yellow content is the highest, cholesterol contains 1 ??696 mg per 100 g of goose egg yolk; egg yolk also contains 1 510 mg of cholesterol per 100 g; duck egg yolk has more cholesterol than egg yolk; quail egg yolk is less than egg yolk . A medium-sized egg weighs about 60 grams, an egg yolk weighs about 20 grams, and has a cholesterol content of about 300 mg. Therefore, "Dietary Guidelines for Chinese Residents 2007" recommends daily intake of 25 to 50 grams of eggs. Roughly equivalent to ~ 1 egg. It is unscientific to eat 2 or more eggs every day.

　　The above dietary cholesterol intake limit recommendations are for healthy adults. If they are hyperlipidemia, the cholesterol limit should be stricter. The daily intake should not exceed 200 mg. In this case, even if you only eat 1 egg (yolk) per day, cholesterol is obviously excessive, so it is recommended that patients with hyperlipidemia eat 2 to 3 eggs per week.