Sucrase-Isomaltase Deficiency as a Health-Inducing Mutation
Researchers here note that the uncommon sucrase-isomaltase deficiency found in some Greenland populations may be generally beneficial to long-term health in adults, removing many of the downsides to ingesting sucrose. Humans did not evolve in a sugar-rich environment, and we are poorly adapted to the consequences of the high sugar intake that characterizes wealthier populations. An identified and useful mutation in a human population can be the first step on the road to a therapy that can improve health, and perhaps that will happen here.
Researchers analysed data from 6,551 adult Greenlanders and conducted experiments on mice. The results demonstrate that carriers of the genetic variation have what is known as sucrase-isomaltase deficiency, meaning that they have a peculiar way of metabolizing sugar in the intestine. Simply put, they do not absorb ordinary sugar in the bloodstream the way people without the genetic variation do. Instead, sugar heads directly into their intestine.
"Gut bacteria convert the sugar into a short-chain fatty acid called acetate, which in previous studies has been shown to reduce appetite, increase metabolism, and boost the immune system. That is most likely the mechanism happening here. Adult Greenlanders with the genetic variation have lower BMI, weight, fat percentage, and cholesterol levels, and are generally significantly healthier. They have less belly fat and might find it easier to get a six pack. It is amazing and surprising that a genetic variation has such a profoundly beneficial effect."
While the variation has clear health benefits for adult Greenlanders, it is problematic for their children. "Younger carriers of the variation experience negative consequences due to their different type of sugar absorption. For them, consuming sugar causes diarrhea, abdominal pain and bloating. Our guess is that as they age, their gut bacteria gradually get used to sugar and learn how to convert it into energy." The research team hope that they can use the results of their new study to lay the groundwork for developing new drugs that might one day be used to treat cardiovascular disease and obesity.
Link: https://science.ku.dk/english/press/news/2021/for-some-greenlanders-eating-sugar-is-healthy/