Australasian Science: Australia's authority on science since 1938

Sweetness Is in the Genes

Having a “sweet tooth” might be a matter of genetics, with a report published in Twin Research and Human Genetics finding that a single set of genes affects our perception of sweetness, regardless of whether we are tasting a natural sugar or a substitute.

Mr Daniel Hwang from the QIMR Berghofer Medical Research Institute said that the study of twins found “the first solid evidence that approximately 30% of variation in the perception of sweet taste can be attributed to genetic factors. It may be that people who need that extra teaspoon of sugar in their tea or coffee may have been born with a weaker perception of sweet taste.”

The research involved 243 pairs of identical twins, 452 pairs of fraternal twins and 511 individuals who tasted and then rated the intensity of four sweet solutions containing either fructose, glucose or two artificial sweeteners. Participants were asked to mark a line on a scale ranging from no sweet sensation to the strongest imaginable sweetness.

Hwang said the research could provide a clue to solving taste disorders, which can have a significant impact on peoples’ eating patterns and can be a risk factor for heart disease, diabetes and stroke. “Some people lose their sense of taste or can be affected by unpleasant taste sensations due to illness or injury, and people who are undergoing radiation for cancer are particularly susceptible,” he said.

Co-author Dr Danielle Reed from the Monell Chemical Senses Center in Philadelphia said that the next big question is if and how genes and early experiences interact to affect food choice. “Even though almost everyone – consumers, physicians and public health officials – wants to decrease the amount of sugar in our diets, right now we have no tool that has the sensory equivalence of sugar,” she said.

“However, if we can understand why some people have weaker sweetness perception, we might be able to adjust this attribute so we could reduce the amount of sugar in foods.”

Hwang pointed out that since 70% of sweet taste perception could be related to environmental factors, it is still possible for people to change their dietary habits. “Our next steps are to identify key genomic regions shared by people who are weak sweet tasters, in the hopes of understanding their weaker perception.”