1. Where does the saying “acidity is the source of all diseases” come from? This theory, which originated from a classic study of chronic kidney disease in the 1960s, suggested the nutritional acid load hypothesis of osteoporosis, which states that foods that are acidic after metabolism can cause damage to the bones, leading to osteoporosis and increasing the risk of fracture. This theory was soon extrapolated to healthy individuals, suggesting that chronic consumption of foods rich in animal protein could cause acidification and even osteoporosis. This theory has influenced nutritional research as well as dietary recommendations. In this way, a controversial information derived in a study of kidney disease patients was artificially amplified and extended to nutritional recommendations for healthy people, and finally to the claim that alkaline foods and alkaline drugs help prevent cancer, fight infections, fight allergies, and prevent obesity. Thus, the claim that acidification of the human body is the source of all diseases is deduced. In fact, this is not scientific. In addition, it is not very scientific to say that “acidic body” is the root cause of tumor, and it is suspected of reversing the cause-effect correlation. 2. Does the body have acidity or alkalinity? It is not scientific to say that “acidic body is the source of all diseases”, but does the human body have acidity and alkalinity? The answer is: yes, and different parts of the body have different pH values. So which indicator is used to determine the so-called “acidic body”? Stomach juice? Urine? Skin? The correct answer is – blood! The blood of a healthy person is usually weakly alkaline, with a pH value of 7.35-7.45. This is good for the absorption and utilization of protein and other nutrients, and keeps the body’s circulation and immune system in good condition, ensuring that people have plenty of energy. However, in the case of diseases, the acidity and alkalinity of blood may change, which is medically known as “acidosis” and “alkalosis”, for example, if a woman vomits frequently during pregnancy due to pregnancy reaction and loses a lot of stomach acid, it will cause metabolic alkalosis. If people do not eat staple foods or diabetics cannot make full use of carbohydrates, it can lead to ketoacidosis; respiratory obstruction and lung diseases can cause the respiratory center to be inhibited and the lung carbon dioxide cannot be discharged normally, which can lead to respiratory acidosis; hyperventilation caused by various reasons can lead to excessive CO2 (carbon dioxide) discharge, which can lead to respiratory alkalosis; skeletal muscle of athletes can produce a large amount of lactic acid into the blood after intense exercise. A large amount of lactic acid can enter the blood, at this time immediately draw blood to measure the PH value of the athlete’s blood, because the production rate of lactic acid is greater than the removal rate, the PH value may be slightly reduced at this time, but the blood PH value will return to normal after a few moments of rest. 3.Is there a difference between acidity and alkalinity in food? In nutrition, what determines the acidity and alkalinity of food is not the taste of food, nor the PH of food, but the ash of food, that is to say, whether a food is acidic or alkaline, we have to look at the substance left after it is burned into ash. (1) acidic food: refers to the chemical composition of the ash obtained after burning food mainly contains phosphorus, sulfur, chlorine and other elements, these elements dissolved in water to produce an acidic solution, this type of food mainly includes livestock, poultry, fish and shrimp, eggs, cereals and hard fruits such as peanuts, walnuts, hazelnuts. (2) alkaline food: refers to the chemical composition of the ash obtained by burning food mainly contains potassium, sodium, calcium, magnesium and other elements, these elements dissolved in water to generate alkaline solution, such foods include vegetables, fruits, beans, milk and hard fruits in almonds, chestnuts, etc.. And neutral food, including cooking oil, butter, starch and table sugar, etc. 4.Does the acidity and alkalinity of food affect the acidity and alkalinity of the body? In fact, our body has an elaborate and complex design, from the digestive system to the excretory system to the respiratory system all precisely control the acid-alkaline balance. Our lungs reduce the production of volatile acids in our body through the excretion of carbon dioxide; our kidneys regulate the acid-base balance as a process of acid excretion and alkaline preservation; and there are buffer pairs in our blood. They all play a very important role in maintaining the acid-base balance in the body. 5.Balanced diet is most important! We should not be too concerned about whether we eat acidic or alkaline food, we should pay more attention to the nutrients contained in the food itself. Nutritionists recommend that we eat more fresh vegetables and fruits, not because they are so-called “alkaline food”, but because they are rich in a variety of vitamins, minerals, dietary fiber and phytochemicals that are indispensable for maintaining human health. In fact, the important principle of a balanced diet is to diversify food and to ensure a reasonable mix of meat and vegetables. All kinds of food contain different nutrients, play different health roles, and are irreplaceable from each other. Pursuing the so-called “alkaline” foods and discarding “acidic” foods can only lead from one extreme to another, creating a new imbalance. We must remember that there is no such thing as bad food, only bad meals, and that a varied diet is the key to good health.