Excessive consumption of lean meat can also be detrimental to human health. If lean pork becomes the primary food source in one's daily diet, it increases the risk of cardiovascular diseases such as hyperlipidemia and atherosclerosis.
The Chinese Center for Disease Control and Prevention's Institute of Nutrition and Food Safety has measured the fat content in various types of animal meat. According to the "China Food Composition Table 2002," for a 100-gram serving, the fat content of various meats is as follows: rabbit meat at 2.2 grams, horse meat at 4.6 grams, beef at 4.2 grams, and lean pork at 7.9 grams. If lean pork is consumed in excess as a primary food source in the daily diet, it also increases the risk of cardiovascular diseases such as hyperlipidemia and atherosclerosis.
Recently, Dr. Bobis of the British Royal Institution, after analysis and research, has shown that the health risks of eating lean meat are even greater than those of fatty meat. This is because during the cooking process, lean meat automatically produces a carcinogenic substance—heterocyclic amines. Animal experiments have shown that heterocyclic amines are substances that damage genes and cause mutations in deoxyribonucleic acid (DNA). The heterocyclic amines in lean meat can be directly absorbed by the large intestine into the bloodstream. The higher incidence of colon cancer in Western countries compared to other nations is related to their frequent consumption of lean meat, especially a large amount of red steak.
In addition, lean meat is high in methionine. Methionine is an amino acid that the body needs to synthesize certain hormones and maintain skin health. However, under the catalytic activation of certain enzymes, methionine undergoes thermal and chemical processing to produce an organic substance called homocysteine. Modern medicine believes that homocysteine directly damages the endothelial cells of the arterial wall, promoting the deposition and infiltration of lipids such as cholesterol and triglycerides from the blood into the arterial wall, forming atherosclerotic plaques, which in turn leads to atherosclerosis. Eating too much lean meat increases methionine, which in turn increases homocysteine levels, accelerating the onset of atherosclerosis.
Therefore, one should not limit the consumption of lean meat simply because it contains less saturated fat. Generally, adults should consume 1 to 2 liang (50-100 grams) of meat per day, which can be adjusted up or down according to individual body weight and degree of obesity. If a protein supplement is needed, the intake of milk and soy products can be appropriately increased.
Western nutritionists believe that the lower incidence of breast and rectal cancer in Asian countries like China and Japan, compared to Western countries, is related to their regular consumption of soybeans and soy products. Soybeans contain an anti-cancer active substance—isoflavones, two-thirds of which are trihydroxyisoflavones. These have a significant anti-mutagenic effect on strong carcinogens such as benzo(a)pyrene and methylcholanthrene, and have a strong inhibitory effect on breast and colon cancer. Therefore, it is recommended that people eat less lean meat and more soybeans and their products to maintain good health.