Who is lactose really harmful to? MD, PhD Hanna Stolińska

Lactose intolerance is a much more common problem than gluten intolerance. It most often affects adolescents and adults. Primary lactose intolerance occurs in up to 37% of adults. In Europe, its prevalence ranges from 2% in Scandinavia to 70% in the south of the continent. In Poland, this disorder is diagnosed in 17–37% of people. However, I have the impression that nowadays lactose intolerance has become a kind of fad. And there is certainly a fad for lactose-free dairy products. Why? Because such dairy products are mushrooming on the market, and more and more people are experiencing intestinal problems and cutting out lactose first. Lactose-free products taste sweeter than their standard counterparts because lactose is broken down into simple sugars. Many people turn to them for this very reason.

Lactose performs important functions in the body, influencing, among other things:

• the sense of taste,
• appetite,
• hormones,
• intestinal regeneration and function.

Lactose is broken down into a form that the body can absorb by an intestinal enzyme - lactase. 

Lactase activity is highest in newborns and infants, for whom milk is the main source of nutrition. After infancy, the activity of this enzyme drops by up to 90%. Reduced or absent lactase activity is the cause of lactose intolerance due to the inability to digest it. Lactose intolerance can be diagnosed when consuming products containing this sugar causes unwanted gastrointestinal symptoms, such as diarrhea and bloating, whereas a healthy person does not experience a range of problematic consequences.

It should be remembered that if lactose is cut out without a reason when we do not have lactose intolerance, the lactase enzyme disappears. When we return to traditional dairy after some time, we may experience intestinal problems that were not there before. The body needs time again to produce this enzyme.

In cases of severe intolerance, it is recommended to avoid products that contain even small amounts of milk or milk products. This includes certain types of bread, powdered drinks, powdered soups, canned meats, confectionery products, and many medications, in which lactose is often used as a carrier.

Products rich in dairy

For a food to be called low-lactose, the amount of this disaccharide in its composition must not exceed 2 g per serving.

The highest amounts of lactose per 100 grams of product are found in skimmed milk powder, whole milk powder, and sweetened and unsweetened condensed milk, with 51 g, 31 g, 10.3 g, and 9.4 g of lactose, respectively. Cow's, goat's, and sheep's milk contain 4.4 g to 5.1 g of lactose per 100 g of product. A similar amount of lactose is found in plain and fruit yogurts, kefir, and buttermilk. Yellow cheeses (0.1 g per 100 g of product) and processed cheese (1 g per 100 g of product) contain the lowest amount of milk sugar, but frequent consumption is not recommended due to their high energy value and high content of saturated fatty acids and cholesterol.

In a lactose-free diet, you can consume dairy without added lactose or use a lactase enzyme supplement that breaks down lactose. However, to be safe, it is better to completely cut out milk and its products.

A well-balanced lactose-free diet is suitable for people who struggle with lactose intolerance. Due to the significant reduction in dairy, there is an increased risk of deficiencies in fat-soluble vitamins, i.e., A, D, E and K, as well as calcium.

Plant-based products containing calcium include: sesame, poppy, sunflower, and chia seeds, broccoli, fortified plant-based drinks, tahini, almonds, hazelnuts, white beans, soy, green leafy vegetables (especially kale, spinach, cabbage, and Brussels sprouts), dried apricots and figs, oranges, seaweed, amaranth, quinoa, and also superfoods such as camu camu and baobab.

The most popular milk substitutes, used not only by people with lactose intolerance, are plant-based drinks. Fortified drinks, i.e., those enriched with vitamins and calcium, should be chosen, as they are thus a good source of these nutrients.

Vitamins in a lactose-free diet

When giving up dairy, special attention should be paid to vitamin D supplementation, which everyone should take, but when milk and its products are cut out, dietary intake is particularly limited. Vitamin A can be supplemented with eggs and fish, but above all with beta-carotene found in vegetables and fruits. Vitamin E is supplied mainly from oils and fatty products such as nuts, seeds, olives, and avocados. Vitamin K is found mainly in green leafy vegetables.

Intestinal microbiome — the hidden link

Scientists have discovered that people with lactose intolerance who carry the "GG" genotype have more Bifidobacterium probiotics in their intestines. According to one interesting explanation, undigested lactose can act as a prebiotic in the small intestine and feed beneficial bacteria. Therefore, people with lactose intolerance who still consume small amounts of dairy may have a more diverse microbiome. There is also evidence that Bifidobacterium helps maintain a healthy body weight, but a lactose-free diet should absolutely not be considered a method for weight loss. Improperly balancing it may affect the risk of nutrient deficiencies.