For millennia, the population in Greenland enjoyed a relatively sugar-free diet. Without the need to rapidly process certain carbohydrates, many lost the function of a key sucrose-processing enzyme.
To find out what this loss means for the health of today’s population, a team of researchers led by scientists at the University of Copenhagen analyzed the health of thousands of Greenlandic people.
The gene at the center of the study produces the enzyme sucrase-isomaltase. At some point in Greenland’s history it mutated until it no longer functioned. More than a third of its descendants now carry at least one of these broken forms.
For the rest of us, working versions of the enzyme sit in the wall of our intestines, where they digest dietary carbohydrates like sucrose (the kind of sugar you can sprinkle in your coffee) and isomaltose (a component of caramelized glucose). .
Based on the results of previous studies on children, this sugar-absorbing enzyme is essential for good health. Without it, consuming any significant amount of sugary food causes diarrhea, intestinal irritation, and vomiting. Whether this applies to adults, however, remains an open question.
More than 6,000 Greenlandic volunteers were assessed for blood chemistry, diet and diabetes history along with studies of their genes. All were over 18 years of age.
Surprisingly, while children suffered severe backlash from sugar consumption to the extent that it could affect their development, adults more or less flourished.
The results associated the possession of two copies of the inactive gene with a lower body mass index and a lower percentage of fat, as well as a healthier lipid profile.
One group within the study population also showed interesting levels of a chemical called acetate. The circulation of this short-chain fatty acid has been linked with decreased appetite, indicating that loss of this key enzyme may have some benefits in a world where it is difficult to avoid high-energy foods.
Researchers suspect that a surplus of simple carbohydrates in the gut may favor the microflora that converts it to acetate, turning it from a potential irritant into a tool for a healthy diet.
Experimental results based on mice engineered to resist the absorption of sucrose also showed that they stored less fat when fed a diet rich in energy.
Whether this knowledge can inform future generations of fat-fighting treatments is hard to say. Further studies are needed to fully explore the consequences of inhibiting otherwise functional forms of sucrase-isomaltase in the guts of individuals who may need help managing their sugar digestion.
This research was published in gastroenterology,