We can easily see various claims about the acidity and alkalinity of food and the acidity and alkalinity of the human body, one of which is widely circulated and cited by many people (or products) but cannot be verified is: Nobel Prize Professor Lei Weng believes that acidic constitution is the source of all diseases. It is also said that the famous Japanese doctor of medicine Yanagizawa also did an experiment: looking for blood samples from 100 cancer patients. As a result, the blood of 100 cancer patients was acidic, that is, acidic constitution. This is a sounding but persuasive statement. It is often used to educate everyone to eat more alkaline foods and less acidic foods.

　　 As we all know, everyday foods are acidic and alkaline. Acidity and alkalinity do not refer to the acid-base feel of the taste of the mouth, but to the physiological distinction. Vinegar is sour, but it is a typical alkaline food. After digestion and absorption of food, the final product of metabolism in the body, in addition to our well-known water and carbon dioxide, there are residues of other elements. These elements are divided into two types. One type is acid-forming elements including sulfur, phosphorus, nitrogen, chlorine, etc. Acidic; the other is alkali-forming elements including potassium, sodium, calcium, magnesium, etc., which are alkaline. If an acid-forming element prevails after a certain food is metabolized, it is acidic food. On the contrary, if there are more alkali-forming elements, it is alkaline food. Determining whether a food is acidic or alkaline cannot be determined by taste, but by testing, that is, burning the food to ashes, testing its pH value with test paper, or more accurately, determining the amount of acid and alkali elements.

　　 Generally speaking, vegetables, fruits, seaweeds, milk, etc. are alkaline foods; acidic foods include food, fish, meat, eggs, etc. This is only a general rule. To determine whether a food is acidic or alkaline, it must be tested. Unfortunately, there are not many foods that have been tested so far. Many popular science authors are based on their own experience. (It can also be imagined) To judge the acidity and alkalinity of food, this leads to different opinions. For example, peanuts are said to be alkaline or acidic. What is the nature? No one has tested it. .

　　According to the information currently available, there are not many studies on the detection of food acidity and alkalinity, especially the domestic detection in this respect is simply blank. Search for "alkaline foods" or "acidic foods" by subject words in the CHKD journal database, you will find that in this database containing nearly 3.87 million medical (and related disciplines) literature, about "alkaline foods" or "acidic foods" The study of "food" turned out to be "0" (as of January 9, 2007)! As a control, the search for the subject word "food" resulted in 24,208 reports. The database contains academic journals of almost all medical (and related disciplines) from 1994 to 2006. This shows that there is very little detection or research on acidic foods and alkaline foods in academia, the reason is very simple, because the significance of studying food acidity or alkalinity is not great.

　　 Contrary to academic research, there are many folk sayings about alkaline foods and acidic foods. Search Baidu for "acidic foods" online. "Alkaline foods", you will get 141,000 web pages (as of 22:00 on January 8, 2007). Various claims about alkaline foods are good for health and acidic foods are not good for health. Food (alkaline food is the opposite) can acidify the body, accelerate aging, promote tumors, generate high blood pressure, blood lipids and blood sugar, cause sub-health, affect memory, reduce immunity, affect organ functions, affect cell functions... and even Decide to have a girl! In short, all unhealthy are related to acidic foods, and alkaline foods are related to health. This typical dualistic thinking, exaggerated expressions, and lack of necessary academic support are all in line with the characteristics of folk medicine.

　　 Acidic foods and alkaline foods are just borrowed from the simple terminology of Western medicine (also can be said to be chemistry), and then copied and developed themselves in the style of folk medicine: food is divided into acidic and alkaline , Acidic food makes the human body acidic, alkaline food makes the human body alkaline, acidic human body (acidic constitution) is unhealthy, alkaline human body is healthy. Acidic and alkaline can achieve "acid-base balance" by "acid-base neutralization" . A complete and almost impeccable "theory" was produced in this way.

　　But what is the actual situation? Eating acidic (alkaline) foods can really make the body’s internal environment acidic ( Alkaline)? According to common physiological knowledge, this is very difficult to happen. Because there are three buffer systems in human blood, such as carbonate, phosphate and protein, which keeps the acidity and alkalinity of the blood relatively constant and the pH value ( A measure of acidity and alkalinity, 7 is neutral, less than 7 is acidic, and more than 7 is alkaline) to maintain between 7.35 and 7.45. Clinically, only severe vomiting occurs, a large amount of stomach acid is lost, and a large amount of alkaline drugs are ingested. Or when the respiratory system is abnormal, acidosis or alkalosis will occur. The effect of food''s acidity or alkalinity on blood acidity and alkalinity, if any, is very small. The kind that wants to be changed by acidic or alkaline foods (even if it is (Chronic changes) The blood acidity and alkalinity efforts have no basis. Similarly, the claim that the acidic constitution is regarded as the "source of all diseases" is also unfounded. At present, the only support for alkaline foods is more beneficial to health than acidic foods. The evidence is just that "human blood is alkaline". Besides that, we have not seen more in-depth academic research. Whether it is epidemiological investigation or laboratory research, there are very few, let alone intervention trials.

　　Under the influence of traditional culture, folk medicine usually has a very strong vitality in China. The biggest feature of folk medicine is that it emphasizes theory and practice, and the same is true of acidic foods and alkaline foods. In the case of testing the acidity and alkalinity of food (testing the acidity and alkalinity of food is not an easy task), we see a lot of knowledge about "inference": acidic (alkaline) food is divided into strong acids (alkali) ) Sexual, neutral acid (alkaline) and weak acid (alkaline) foods; even more outrageous is a food acid-base neutralization table marked from the "Jinzhou Memory Research Society", which quantifies the acidity and alkalinity of food , Such as eating 100 grams of rice (acid) requires 100 grams of potatoes (alkaline) to neutralize, or 10 grams of sea to bring neutralization, and 200 grams of cucumber can be used to neutralize. I really don’t know how they “calculated” them. Besides, there is no acid-base neutralization reaction in the blood at all! What makes people cry is that this bad data is actually cited by the official "Nutrition Catering Training Materials"!

　　 is not necessary The actual measurement research not only caused inconsistencies in the classification of acidic foods and alkaline foods, but also led to divergent opinions on the recommended ratio. Some people suggested that the ratio of acidic and alkaline foods should be 1:3; others also suggested 1:4; There are suggestions 3:7. These ratios, especially the first two, are obviously inconsistent with the ratio of various types of foods recommended in the Dietary Guidelines (Pagoda) of the Chinese Nutrition Society, so it is unreliable to use the acidity and alkalinity of food to guide people''s diet. Therefore, the Chinese Dietetic Association’s “Dietary Guidelines for Chinese Residents (2007)” (edited by the Chinese Nutrition Society and published by the Tibet People’s Publishing House on page 10) in January this year clearly states: “From a nutritional perspective, these statements (acid food (Alkaline food and acidic constitution, etc.) lack scientific basis, so it is not worth advocating."

　　 Summary:

　　 Food is acidic and alkaline. Because the human body is neutral and alkaline, alkaline food may be more beneficial to health than acidic food. However, neither the benefits of alkaline foods nor the disadvantages of acidic foods can be exaggerated. To the extent that "food must be called acid-base", it goes too far. Therefore, Ge Keyou, chairman of the China Nutrition Society, deputy director of the National Food and Nutrition Advisory Committee, and vice chairman of the Chinese Student Nutrition and Health Promotion Association, said: "In fact, it is wrong to say that food will destroy the body''s acid-base balance. Because the body''s self-regulation mechanism Very strong, not a simple chemical reactor. A person can only cause acid-base imbalance when metabolism is impaired. A normal person cannot possibly cause acid-base imbalance due to food problems."