Silvia Berciano knew that the brain plays a role in obesity.
And a number of other eating disorders or compulsions in which studies have shown people’s brains can predispose them.
But Berciano, a nutrition and genomics researcher at Tufts University, wanted to know what role the brains of people without any of those disorders played in their eating.
So she and her colleagues set up a study to look at how variations in genes might influence people’s eating preferences.
“These had only been studied in the context of pathology, never in a healthy population,” Berciano told Healthline. “So we thought if we could find an association among healthy people, then it must be important.”
What researchers learned
Their study was presented last month at the Experimental Biology 2017 meeting in Chicago.
What the researchers concluded was that gene variants — small differences in people’s genetic makeup — predispose even healthy people to eat lots of certain foods, even if they know these foods are not good for them.
Berciano said the research could help people with certain gene variants find other ways to satisfy their cravings, potentially leading to better strategies to help them stick with the diets they want.
The 818 subjects of the study had already had their genomes mapped in a previous study. Berciano and her colleagues excluded from the study anyone with any kind of health problem — including kidney disease, heart disease, and eating disorders.
They homed in on 38 specific genes that have been tied to psychological traits and that they thought might influence food preferences.
Then the subjects each filled out a questionnaire about what they typically ate and how much.
The researchers analyzed the answers for statistically significant associations with the participants’ individual genetic variations.
They found a number of them.
Chocolate, salad dressings, and other cravings
For example, people with a variation in the gene that is tied to the ability to process the hormone oxytocin, which promotes feelings of calmness, bonding, and affection, ate more chocolate.
If this oxytocin receptor gene had an A allele, they ate about 13 more grams of chocolate per day than others.
Those that inherited the genetic variation from both parents had a higher body mass index (BMI) than other subjects, putting them in the obese category.
This suggests that with less ability to get the stress-reducing benefits of oxytocin, subjects with the A allele relied on chocolate to keep them calm.
This knowledge could help them redirect their cravings.
“Finding other ways to promote oxytocin could help them avoid boosting it through something like chocolate,” Berciano suggested.
Variations in other genes were tied to how much salt or added fats, like salad dressings, people consumed.
Environment, culture, taste, and availability also drive food preferences as well, but the study concludes that genes that drive psychological traits also have a role to play in shaping food preferences.
Berciano said researchers now need to look into whether the associations between gene variants and food preferences also affect a broader swath of the population. The study only included Caucasian subjects in Minneapolis and Salt Lake City.
Her next step is looking through information collected from the Boston Puerto Rican Health Study longitudinal project to search for associations.