Lactose intolerance:

Cause
In mammals (especially infants), lactase mainly exists in the brush border of the small intestine mucosa, and is distributed in the form of foci. The activity is highest in the jejunum. After most mammals are weaned, lactose is no longer the main source of food. Enzyme activity gradually decreases, but there are still some people whose lactase activity lasts until adulthood. This part of people whose lactase activity continues is generally the herders of Northern Europe, the Middle East and Africa, and this part of the population generally has a long-term drinking habit.
A large number of studies have shown that the lactase activity of mammals has a typical physiological decrease with age, and the irreversible decline of adult lactase is controlled by genes. If a person with lactase deficiency consumes a lot of lactose at one time, the lactose cannot be digested and absorbed in time. After entering the colon, it is decomposed by intestinal bacteria, producing a large amount of short-chain fatty acids such as lactic acid and formic acid and hydrogen, which will increase the osmotic pressure and cause the intestinal cavity The increase in water content in the body causes symptoms such as abdominal distension, bowel irritation, intestinal colic and watery diarrhea.
harm
For humans, lactose intolerance limits people's consumption of milk and dairy products to a large extent, resulting in huge health care expenditures. Lactose intolerance causes children to suffer from calcium deficiency, chondrosis, weight loss, physical and mental retardation, and adults, especially menopausal middle-aged and elderly women, are prone to symptoms such as osteoporosis. For the breeding industry, the huge economic loss caused by the death of piglets due to the piglet's diarrhea caused by lactose intolerance cannot be ignored.
The research team directed by the academician, using modern molecular biology and genetic engineering technology, has developed a new type of high-efficiency lactase production technology. Its effectiveness, thermal stability, stress resistance and broad-spectrum are superior to those of foreign commercial production of lactase. The unit expression of lactase is nearly 6 grams per liter, which is 6 times that of foreign commercial production of genetically engineered Aspergillus. At the same time, the expressed lactase can also be secreted out of the cell by itself, which solves the problems of low unit yield and difficulty in post-enzyme processing during the production of lactase in one fell swoop.
diagnosis
For the diagnosis of lactose intolerance, the currently established methods are mainly clinical diagnosis of human lactose intolerance. The main effective diagnostic methods are as follows: ①jejunal mucosal biopsy and determination of lactase content. This method is the most direct way to diagnose lactase deficiency and is known as the "gold standard". However, because this method is difficult to operate and is an invasive operation, it is rarely used in clinical practice. ②Stool acidity detection. This method is mainly applied to some special patients, such as infants and young children. Under normal circumstances, the stool is neutral, weakly acidic or weakly alkaline. In the case of lactase deficiency in the body, the acidity of the stool will increase after eating food containing lactose, which can be used to screen the subject for lactase deficiency. ③ Determination of blood glucose. After the subject takes a certain dose of lactose, the blood glucose concentration is measured every 15 minutes. If the blood glucose rise is less than 1.1mmol/L from the basic value, it indicates that the lactase is lacking, because this method is affected by gastric emptying, intestinal peristalsis, etc. The influence of many factors, so individual differences are large. In addition, hydrogen breath test (HBT), symptom score blood and urine galactose measurement are also commonly used clinically to diagnose human lactose intolerance, but there are few studies on the diagnosis of lactose intolerance in other animals. .
Prevention and treatment
The treatment of lactose intolerance is closely related to its clinical type. Infants and young children with congenital lactase deficiency should be supplemented with an appropriate amount of lactose when eating foods containing lactose. For secondary lactose intolerance, the primary disease must be treated and done well. Nutritional management. For refractory diarrhea or malnutrition caused by congenital and secondary lactose intolerance, water and electrolyte disorders should be corrected in time to avoid the abuse of antibiotics, while maintaining the original diet to ensure that the body receives sufficient energy.
Prevention method
Ingest small amounts of dairy products multiple times. Even individuals with lactase deficiency can tolerate a small amount of milk without symptoms of intolerance. Limit the total amount of lactose intake in a day, the general limit of lactose is 12 grams. A small amount of multiple consumption can also alleviate the lactose intolerance reaction, and it is advisable to consume no more than 250ml at a time. As long as you can grasp the reasonable interval and total daily milk intake each time you drink milk, you can avoid the symptoms of lactose intolerance. Please note that those who are allergic to infant milk should choose goat milk or other dairy products.
By supplementing lactase with foreign aid, lactose intolerance can be effectively resolved.