Milk and its products are one of the essential components of many healthy dietary patterns around the world. However, many people have misconceptions about the "lactose" contained in milk. Does lactose in milk and its products cause diabetes? Can diabetics drink milk? If they are lactose intolerant, do they need to avoid milk altogether?
Lactose: "This sugar" is not "other sugar"
The lactose contained in milk makes many diabetics smell "sugar" and change color. As everyone knows, unlike other simple sugars (such as sucrose, glucose, etc.), lactose has unique features in its structure and metabolic processes.
Slow digestion, slow glycemic rise: Under the same conditions, lactose is absorbed more slowly than other sugars. Correspondingly, it raises blood sugar much more slowly. The GI values of sucrose and white sugar were 65 and 83.8, respectively, while lactose was only 46.
Other components in milk can delay the digestion and absorption of lactose: the rate at which sugar in food is digested and absorbed can be affected by many factors. The abundance of protein, fat and other components in milk will delay the emptying of the stomach and reduce the rate of digestion and absorption of sugar. Lactose has a GI of 46, while milk has a GI of only 27.6, making it a proper hypoglycemic index food.
The average milk consumption in Europe and the United States is more than 300 kg per person per year, while that of mainland residents is only 21.7 kg, a difference of 15 times. In the recent "grading" of beverages piloted in Shanghai, the content of "non-dairy sugar" is used as the standard for grading nutritious beverages, rather than "sugar" in general, so as to avoid people reducing their intake of sufficient dairy products due to misconceptions about lactose.
Milk has many benefits for diabetes prevention and control
Milk is rich in nutrients, suitable in proportion, easy to digest and absorb, can provide a good source of high-quality protein, especially calcium, and is a natural food with high nutritional value.
The whey protein in cow's milk has the ability to enhance the postprandial glycemic response, stimulate incretin secretion, increase insulin sensitivity, and reduce postprandial blood sugar levels. In addition, the maintenance of intracellular and extracellular calcium balance is important for the normal release of insulin. Calcium deficiency can lead to parathyroid hormone secretion, which promotes the flow of calcium from the outside of the cell into the cell, resulting in cellular calcium overload and impaired insulin sensitivity.
Therefore, the five editions of the dietary guidelines issued by the Chinese Nutrition Society to meet the health and nutritional needs of Chinese residents are encouraged to consume sufficient milk and dairy products in mainland China. In 2023, the National Health Commission issued the "Dietary Guidelines for Adults with Diabetes", which also recommends that diabetic patients should consume dairy products every day.
For diabetic patients, please refer to:
1. Choose milk and its products without additional sugar, the sugar content of natural milk is about 4.5-5%, and you can pay attention to the food label when purchasing;
2. Calculate the energy of dairy products in the whole day's energy;
3. Choose the right time to drink, for diabetic patients with large blood sugar fluctuations, you can choose between meals.
Drinking milk may reduce the risk of type 2 diabetes in lactose intolerant people
Lactose intolerance, as the name suggests, is the body's intolerance to "lactose". Lactose cannot be directly absorbed by the body and needs to be broken down into glucose and galactose under the action of lactase before it can be absorbed by the body. When the human body lacks or produces insufficient lactase, the lactose in milk cannot be fully decomposed, and part of the lactose is fermented directly from the small intestine into the large intestine, which stimulates the intestinal mucosa and produces symptoms such as bowel sound, abdominal distension and diarrhea.
Is it true that lactose intolerant people should avoid drinking milk altogether? The latest scientific research has given an unexpected answer. On January 22, 2024, a research team from the Albert Einstein College of Medicine in the United States published a research paper entitled "Variant of the lactase LCT gene explains association between milk intake and incident type 2 diabetes" in the world-renowned academic journal Nature Metabolism. The study showed that in lactose intolerant people, milk intake altered levels of specific bacteria and circulating metabolites in the gut microbiome, which was associated with a reduced risk of developing type 2 diabetes, and that each glass of milk intake was associated with a 30% reduction in the risk of developing type 2 diabetes.
The study found that in lactose intolerant subjects, each additional serving of milk intake (i.e., one glass of liquid milk) was associated with a reduced risk of developing type 2 diabetes by about 30%, while no such association was found in lactose tolerant people. To validate this, they also replicated 167172 subjects at the UK Biobank to get similar results.
So, even for lactose intolerant people, it's a shame to completely abandon milk, so how do you "shake hands" with milk?
You can drink a small amount of milk and gradually increase the amount of drinking: the amount of a single drink can be increased gradually from one-third cup (about 50ml), which can stimulate and induce the expression of lactase genes; it can also be eaten with other foods: do not drink milk on an empty stomach, you can eat it with cereals to delay the speed of lactose entering the intestine and control the intolerance reaction within an acceptable range for the human body; or choose yogurt (sugar-free) or low-lactose milk products: you can check the food label of the product to know the level of lactose (carbohydrate) content. It is important to note that milk should be avoided for people who have identified a cow's milk protein allergy.
Editor: Wu Baixin
Source: Department of Clinical Nutrition, Shanghai Sixth People's Hospital