Genetic advantage
According to a new study by the University of Copenhagen, intestinal bacteria and the unique diet of the indigenous inhabitants of the island of Greenland provided them with a genetic variation, which gives an interesting advantage: adult homozygous carriers of the variation of the saccharase-isomaltase gene digest sugars differently than Europeans, in whom such a mutation occurs hundreds of times less often.
This genetic variant is common in Arctic populations and causes congenital deficiency of the enzyme sucrose-isomaltase, inability to break down and assimilate sucrose and isomaltose. Children with this genotype suffer from gastrointestinal disorders when consuming sucrose with food. The researchers undertook to describe the state of health of adults with a deficiency of sucrose-isomaltase.
Carbohydrates enter our body mainly in the form of polysaccharides (starch) and disaccharides (sucrose, lactose, etc.). But they are eventually absorbed only in the form of simple sugars (monosaccharides): glucose, fructose, galactose. When sucrose is hydrolyzed, glucose and fructose are formed, two glucose molecules are formed from isomaltose and maltose.
Together with colleagues from the University of Southern Denmark and a number of research institutes and government agencies in Greenland, the group analyzed data from 6,551 adult Greenlanders and conducted experiments on mice with a knockout sucrase-isomaltase gene.
Greenlanders with congenital sucrose-isomaltase deficiency on average have:
- lower BMI, approximately 2 kg/m2;
- smaller weight, about 4.8 kg;
- a lower proportion of body fat by about 3.3%;
- lower level of triglycerides (a marker of the risk of cardiovascular diseases and cholesterol) in the blood by 0.3 mmol/l.
The deficiency of sucrose-isomaltase leads to a change in the metabolism of sugars. They are not absorbed by cells from the bloodstream, but enter the intestine. In the intestine, bacteria convert sugars into acetates – salts and esters of acetic acid, which, as previous studies have shown, reduce appetite, accelerate metabolism and strengthen the immune system.
The reason for this widespread genetic variation among Greenlanders is due to a diet that has been different from the rest of the world for thousands of years. Their diet was low in sugar, for the most part they ate the meat and fat of fish, whales and seals.
The results were confirmed in mice with a knockout sucrose-isomaltase gene, which, compared with wild-type mice, had significantly higher levels of acetates in plasma in response to sucrose intake and had lower plasma glucose levels in the sucrose tolerance test.
Thus, sucrose-isomaltase is a promising drug target for the treatment of metabolic diseases.
Article by M.K.Andersen et al. Loss of sucrase-isomaltase function increases acetate levels and improves metabolic health in Greenlandic cohorts published in the journal Gastroenterology.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to the materials of the University of Copenhagen: For some Greenlanders, eating sugar is healthy.