Three studies presented by Italian researchers at a conference of the European Society of Human Genetics this weekend point toward a new approach to diet and weight loss. When it comes to food and taste preferences, it may all depend on the genetics of “food liking.”
Researchers found that gene variants, or small differences in each person’s genetic makeup, may strongly affect how people perceive food tastes. Those specific gene variants could be used to personalize a diet, incorporating 19 genes already linked to a person's metabolism.
In one study, researchers found that people on this sort of gene-based diet lost 33 percent more weight than people on a standard diet. In the race for lost pounds, a 33 percent advantage can make all the difference.
The Genetics of 'Food-Liking'
How many times have you tried to share something when eating out, only to discover that your dining companion has vastly different tastes? What new genetic research suggests is that your preference for different tastes may be determined in part by differences in your genes.
Using two separate approaches, researchers looked at the association between bitter taste receptors in the mouth and coffee liking, and then used a two-step genome-wide association study to look for genes related to 42 other taste preferences.
Coffee liking was significantly linked to a specific gene variant, and the genome-wide association study revealed a further 17 independent genes that influence whether or not a person likes artichokes, bacon, broccoli, chicory, dark chocolate, blue cheese, ice cream, liver, and other foods.
“For food preferences we have just scratched the surface, we are at the moment contacting other scientists around the world in order to expand the number of subjects to help understand the genes behind food liking and their impact on health status,” said Nicola Pirastu, a researcher at the University of Trieste and the Burlo Garofolo Pediatric Institute in Trieste, Italy.
Salty or Sweet?
How much salt you eat can greatly affect your blood pressure and overall heart health, and it turns out that your genes may either be helping or hindering you when it comes to curbing your salt intake.
The researchers recorded taste responses from around 900 healthy adults in north eastern Italy. Using a genome-wide association study, researchers found that there was a significant link between a variation on the KCNA5 gene and a preference for salt.
“We have found a relation between differences in salty taste perception and a region close to a very good candidate gene… [The] genetics of food preferences can tell us additional information about peoples’ metabolism which would be very difficult to obtain otherwise,” said Antonietta Robino, also of the University of Trieste and the Burlo Garofolo Pediatric Institute.
The Power of Gene-Based Diets
To test the power of tailored diets for weight loss, 191 obese study participants were randomly divided into two groups: 87 were put on a diet catering to genetic variants for metabolism and taste, while 104 were put on a control diet. People in both groups each eliminated 600 calories from their daily diets.
DNA from the test group was analyzed for 19 genes known to impact metabolism and for genes that affect taste, and their diets were adjusted to accommodate for things such as liking the taste of fats.
“Regarding the gene-based diet, when I got to analyze the data, I was actually a bit skeptical that we would be able to find any differences,” Pirastu said. “It’s like having two cars which start at the same point and they move in directions which differ for only a degree. At first they will look as though they are parallel, but after 10 km they will actually be far apart.”
After two years, those on the gene-based diet had lost 33 percent more weight. “One of the main contributions will be in making the diets more pleasurable and thus more acceptable. Genetics in this sense will help understanding what people do not like in specific foods,” Pirastu said. In the future, that could mean diet foods and health foods tailored specifically to your metabolism and taste preferences.
In the future, the researchers hope to conduct a double-blind study in which knowledge of a person's genetic profile won’t affect the outcome, Pirastu said.