Your Genes May Have a Sweet Tooth

Dec. 7, 2007 -- Got a sweet tooth? It may be carved into your DNA, a new study shows.

People have a natural affinity for sugar, but some people like sugar more than others, note the sweet tooth researchers.

They studied 324 pairs of British female twins. The group included 149 pairs of adult identical twins, who have identical genes, and 175 sets of adult fraternal twins, who share half of their genes.

After an overnight fast, the twins drank sugary water. It wasn't a fancy drink with lots of flavors -- just sucrose (sugar) dissolved in water.

Each twin rated the drink on a scale ranging from "the greatest imaginable dislike" to "the greatest imaginable like."

Identical twins were more likely than fraternal twins to give the drink the same rating.

Genes explain about half of the variation in how much people enjoyed the drink, according to the researchers, who included Kaisu Keskitalo, a graduate student at Finland's University of Helsinki.

Individual differences explained the rest of the variation. In other words, genes didn't totally explain why some people are especially fond of sugar's taste.

The twins also completed questions about how much they like, crave, and eat six sweet foods: sweet desserts, sweets, sweet pastry, ice cream, hard candy, and chocolate.

Genes appear to affect those traits, too. But it's not yet clear which genes are involved, or if the findings also apply to men.

The study appears in The American Journal of Clinical Nutrition.