Genetics may be behind a sweet tooth

TORONTO (CP) — Whether a pre-schooler has a sweet tooth, is partial to snacks rich in fat, or has an aversion to bitter vegetables like broccoli could be linked to genetics, researchers suggest.

A study by University of Guelph researchers found almost 80 per cent of a group of 47 children aged 18 months to five years old carried at least one of three genetic variants related to taste receptor cells in taste buds, which could predispose them to poor snacking habits.

“Kids are eating a lot more snacks now than they used to, and we think looking at how genetics can be related to snacking behaviour is important to understanding increased obesity among kids,” said Elie Chamoun, a PhD candidate in the department of Human Health and Nutritional Sciences, who led the research as part of the ongoing Guelph Family Health Study.

“This new research could help parents understand how their kids taste, and tailor their diet for better nutritional choices.”

The research, published in the journal Nutrients, involved tracking the children’s diets over a three-day period as well as testing their saliva to determine their genetic taste profile. Snacks made up about one-third of the kids’ diets.

Almost half of the youngsters were found to carry the genetic variant associated with a sweet tooth, and it turned out those kids consumed more calories from sugar in their snacks, said Chamoun.

“That tended to happen more in the evening,” he said. “It’s likely these kids snacked more in the evening because that’s when they are at home and have more access to foods with high sugar.

“So perhaps parents may want to limit the access to sweet food to children in the evening, especially if they have this trait.”

Children in the study with the genetic variant related to fat-taste sensitivity were found to consume snacks with what’s called “higherenergy density,” such as cookies and chips.

People with this genetic variant may have low oral sensitivity to fat and therefore consume more fatty foods as a result, said Chamoun.

“Higher-energy density snacks... have a higher number of calories for their weight. Those are snacks you want to avoid.”

When it came to kids with the genetic variant related to an avoidance of bitter vegetables, “we predicted that they would have generally more unhealthy snacks as a result of this trait,” he said.

“So these children also had a high-energy density of snacks, just like (children with) the fat trait.”

Statistics show that almost a third of Canadian children aged five to 17 – an estimated 1.6 million young people – are either overweight or obese, putting them at risk for such chronic conditions as Type 2 diabetes and cardiovascular disease.

Chamoun said the reason the researchers are studying snacking behaviours and their possible genetic underpinnings is because children tend to form their eating habits by the age of five.

“If these genetic variants... are actually (leading) these children to consume more sugary snacks or more energy-dense snacks, then this is an unhealthy pattern that can lead to overweight and obesity in the long term,” he said.

While acknowledging there is a complex constellation of genetic factors that can predispose a person to obesity, Chamoun said “taste is what we believe to be one piece in that puzzle.”