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Some people prefer pickles, while others have a sweet tooth. A new study sheds light on why people differ in how they experience sweet foods. It turns out that people who aren’t fond of sweets may carry a genetic defect that makes it harder for them to digest sucrose.
Genetic defects in sucrose absorption are often linked to irritable bowel syndrome. But the authors of this new study suggested that a defect affecting the sucrase-isomaltase (SI) gene might also influence how much we enjoy sweet foods.
What Did the Scientists Discover?
To investigate this, scientists from the University of Nottingham (UK) and the University of Copenhagen (Denmark) first used laboratory mice. These rodents lacked the SI gene, and the researchers observed that the animals had a significantly lower preference for sucrose.
Next, the team analyzed data from about 6,000 people in Greenland and 135,000 people in the UK — the latter from the UK Biobank. The scientists found that the Greenlandic participants carried a completely dysfunctional SI gene, meaning they couldn’t digest sucrose. They consumed significantly less sugar than people with a functional SI gene.
Meanwhile, British participants with a partially functional SI gene — almost 10 percent of the cohort — showed a much lower preference for sweet foods compared with those who had a fully functional SI gene.
“If you don’t like sweet foods, you might have reduced SI function, but it’s likely that other, more powerful factors contribute to a decreased craving for sweets,” said Dr. Mette Andersen, a co-author of the study and an associate professor at the University of Copenhagen, in an interview with BBC Science Focus.
The study also links excessive sugar consumption to obesity and diabetes. The authors say the findings could prompt pharmaceutical companies to develop drugs that help people cut back on sugar.
The results of the study were published in the journal Gastroenterology.
