Can an adult without genetic lactase persistence still develop a tolerance for dairy foods?

Question

While investigating the rise of adult lactose tolerance, I came across the news that China has been encouraging its citizens to drink more milk, even though most of the Asian population lacks the SNP (single-nucleotide polymorphism) which conveys lactase persistence.Is it still possible for an adult without lactase persistence to build-up a tolerance for lactose over time? If so, what's the mechanism?

Answer 1

Recent studies have shown that the symptoms of lactose intolerance can be relieved in some people by changing the population of their intestinal microbes, called the microbiome, to encourage lactose-digesting bacteria. Specifically, bacteria, called "lactic acid bacteria," eat the lactose but produce the byproduct lactic acid instead of gas. While lactic acid has no nutritional value, it does not produce the unpleasant symptoms of lactose intolerance. This adaptation of the intestinal microbiome may be how some ancient pastoral populations with no genetic evidence of lactase persistence tolerated a dairy-rich diet.

Ingesting lactic acid bacteria as a probiotic can alleviate the symptoms of lactose intolerance, but these bacteria may not persist in the colon. A promising new strategy is to "feed" the lactic acid bacteria a complex sugar that they can digest but humans cannot. In initial clinical trials, subjects using this "prebiotic" reported improved lactose tolerance and had a corresponding shift in their intestinal microbiome. Larger clinical trials are in progress.

If you want to read more about the topic you can go to https://medicalxpress.com/news/2019-04-microbiome-reverse-lactose-intolerance.html