Can you overeat sugar without harming your health? — Yes, if you are a Greenlander.

Sugar deservedly has a bad reputation among nutritionists and doctors. Its most common form, sucrose, is fatal to human health. Of course if we consume large doses of it. Some specialists believe that such sugar should be completely eliminated from the diet.

However, there are some people who are almost completely unaffected by sucrose. These are some of the indigenous people of Greenland. This was discovered by Danish scientists, whose work was published in the journal Gastroenterology.

A unique mutation in DNA gives “immunity” to sugar

Researchers from the University of Copenhagen have discovered that in part of the Greenlandic population there is a specific genetic mutation. It is detected in 2–3 percent of the population of this island, which is formally part of Denmark.

The mutation involves an enzyme called saccharase-isomaltase. It is responsible for digesting sugars in the small intestine. Saccharase, in turn, is responsible for decomposing sucrose, a common food sugar.

People with the mutation have a congenital deficiency of sucrase-isomaltase. As a result, the sugar is not absorbed from the intestines into the blood.

"Instead, it is fed by intestinal bacteria that produce acetate. This is a short-chain fatty acid with interesting properties. Previous studies have shown that acetate reduces appetite, increases metabolic rate and improves immune function", explains Mette K. Andersen, lead author of the study.

Deficiency of sugar-digesting enzymes may give disease symptoms

The effects of saccharase-isomaltase deficiency in Greenlanders are impressive.

“People with this mutation have a lower BMI and body weight, less body fat (especially in the abdominal region), lower cholesterol levels and are generally healthier than the rest of the population”, calculates Professor Anders Albrechtsen of the University of Copenhagen.

Scientists suspect that this mutation appeared in Greenland because the people there had very little sugar in their diet for many centuries.

“The diet was based on the meat of fish, seals, cetaceans and reindeer, with a small addition of plant products. In such a situation, the enzyme used to digest sugars was not very useful”, says Prof. Albrechtsen.

As a result, some of the population developed mutations and became deficient.

However, it is worth remembering that saccharase-isomaltase deficiency is also considered a disease. It is sometimes referred to as the “Eskimo effect”. After eating sugar, symptoms appear such as:

• abdominal pain,
• bloating,
• diarrhea.

“However, in Greenlanders with the mutation, such complaints occur only during childhood. Then, we think, the intestinal bacteria adapt to the presence of sugar in food and are able to process it into other chemical compounds”, explains Professor Torben Hansen of the University of Copenhagen.

Sugar — how does it harm health?

Large amounts of sugar in the diet have a very bad effect on human metabolism. They promote overweight and obesity, type 2 diabetes and cardiovascular diseases such as atherosclerosis and hypertension. Unfortunately, for most of us, the taste of sugar is very pleasant. For our ancestors, it was associated with ripe fruit, rich in valuable nutrients.

Sugar is also bad for your oral health. The bacteria living in it feed on sugar and produce acidic substances that damage tooth enamel. This is how caries occurs. It is worth remembering that the deficiency of saccharase-isomaltase, which occurs in Greenlanders, does not protect against this disease.

Fructose — why is it so dangerous?

Sucrose, which is our “home” sugar, consists in equal proportions of glucose and fructose. The latter occurs naturally in fruit in small amounts and is what gives sugar its appetizing sweetness. Corn glucose-fructose syrup (HFCS) is also a mixture of fructose and glucose in proportions of 55 to 45 percent, and the health effects of sucrose and HFCS appear similar.

Glucose is the primary “fuel” for our cells. However, fructose in large doses is very harmful. The body quickly converts it into fat tissue. Its excess, especially in the abdominal area — the so-called visceral fat — promotes many dangerous diseases.