Indeed, people who are lactose intolerant will almost always have the above situation after drinking milk. However, drinking milk can actually cause stomach pain and diarrhea for other reasons. It's not just lactose intolerance that will appear. Gao specially sorted out three common reasons to share with you!
Causing 1 lactose intolerance
Gao said that lactose is digested by lactase in the intestine and hydrolyzed into glucose and galactose. "Lactose intolerance" means that the body can't digest lactose, has poor tolerance to foods containing lactose, and has diarrhea, abdominal pain, flatulence, farting and burping. Also known as lactose malabsorption.
The common cause of lactose intolerance is the weakening of lactase gene in the body, which leads to the lack of lactase that can help lactose digestion. In addition, it may be that there is not enough lactase in the villi of small intestine, or a small part of it is caused by the damage of intestinal mucosa.
Many people are curious, why it is good to drink milk when I was a child, but this symptom appears when I grow up? Gao explained that lactase activity in the body is the highest in the newborn period, and then decreases with age.
The change of lactase activity in human body is actually related to eating habits. In the neonatal period, the baby takes breast milk as the staple food, and the main component of carbohydrates in breast milk is lactose, so there is a highly active lactase in the baby's intestine to decompose lactose.
With the growth, the diet tends to be diversified, and the source of carbohydrates is no longer only lactose, but also various polysaccharides, so the activity of lactase in the body naturally begins to decrease. The results showed that the activity of lactase began to decline after about 2 years old, and by the age of 8, the activity of lactase in the body was similar to that of adults.
Gao pointed out that about 80 ~ 90% adults in Taiwan Province Province have lactose intolerance to varying degrees; Only about 50% people in the west have lactose intolerance, which is related to the evolution of human race.
Reason 2 Casein sensitivity
Besides lactose, protein in milk is also one of the culprits that affect stomach discomfort. Milk consists of water, lactose, fat, protein, minerals and vitamins. In protein, casein is the main protein, accounting for 80% of the total protein, and the other 2 become whey protein.
Casein is divided into many different forms, such as a 1-β, A2-β and so on. A 1-beta and A2-beta are very similar in structure. However, it was found that protein in the form of a 1-β in casein enters the gastrointestinal tract, which will increase inflammatory factors and immune response, and make the gastrointestinal tract appear similar to lactose intolerance.
Gao mentioned that other studies have found that casein in the form of a 1-β may also cause lactose malabsorption and aggravate the symptoms of lactose intolerance.
Reason 3 Whey protein is sensitive.
Besides milk, people with fitness habits will also choose whey protein (also called high protein) as a supplementary source of protein. However, some people will feel uncomfortable or have diarrhea after drinking whey protein supplements, which may be because the stomach and intestines are sensitive to whey protein.
Gao said that studies have found that whey proteins in milk, such as α or β-lactoglobulin, may also cause gastrointestinal discomfort, leading to abdominal pain, vomiting, diarrhea and other symptoms. This is also one of the reasons for stomach discomfort after drinking milk.
And how to drink milk without worrying about diarrhea, abdominal pain, flatulence and farting? It is suggested that it may take 1~2 minutes to heat milk, because high temperature can denature whey protein, and when the structure changes, it will not cause gastrointestinal discomfort.
In addition, you can also drink yogurt directly, because when milk is fermented, lactase secreted by lactic acid bacteria has decomposed some lactose, which makes the lactose content of yogurt much lower than that of fresh milk, which can reduce lactose intake and avoid uncomfortable symptoms.
Gao reminded that calcium in milk is a very important nutrient for human body. It is suggested that adults try to drink a glass of milk in the morning and evening to achieve a balanced nutrition. Therefore, if drinking milk will cause stomach discomfort, try the above method.