If high cholesterol runs in your family, you might wonder how much your eating habits can really make a difference. A new study suggests the relationship between diet and genetics may be more complicated than previously understood.
Researchers studying 1,020 adults in southern India found that people with certain genetic variations were more likely to have higher cholesterol if they also ate lower-quality diets. Among those with healthier eating patterns, however, the researchers didn't find the same significant difference in cholesterol levels. The findings, published in PLOS One, suggest that diet quality may influence how inherited genetic differences relate to cholesterol.
The research, conducted by scientists at the University of Reading in the United Kingdom and the Madras Diabetes Research Foundation in India, examined adults ages 25 to 80 living in Chennai. Researchers collected information about their eating habits, analyzed their genetic profiles and measured cholesterol and other markers of metabolic health.
Rather than looking at individual foods, the team evaluated participants' overall diets. Higher-quality diets generally included more fruits, vegetables, beans, lentils and dairy products, while lower-quality diets tended to contain more refined grains, added sugar, salt and certain other foods.
The researchers also examined three genetic variations previously linked to metabolic conditions, including type 2 diabetes and obesity. They divided participants into groups based on how many of these variations they carried, then compared their cholesterol levels across different diet-quality groups.
Among participants with lower-quality diets, those carrying more of the genetic variations had higher total cholesterol and LDL cholesterol, often called "bad" cholesterol, than those carrying fewer. But among participants whose diets received medium or high scores, cholesterol levels did not differ significantly between the genetic groups.
That doesn't mean eating well cancels out genetic risk. The study identified an association, not a cause-and-effect relationship, and the interaction between diet quality and genetics accounted for only a small portion of the differences in cholesterol levels.
Still, the findings offer another perspective on the role of food in long-term health. While genetics can influence cholesterol, researchers are increasingly interested in whether everyday eating patterns may affect how those inherited tendencies are expressed.
"Our genes do not have to decide our health," said Vimal Karani, a professor at the University of Reading who led the study.
There are important limitations. Researchers assessed participants' diets and cholesterol at a single point in time, so they couldn't determine whether changing eating habits would improve cholesterol levels. Dietary information was also self-reported, and more than half of the participants had type 2 diabetes. Because the study focused on adults in one region of India, the findings may not apply to other populations.
The researchers say additional studies are needed to determine whether improving diet quality can reduce cholesterol levels among people with different genetic backgrounds. For now, the findings raise an intriguing possibility: The relationship between the genes we inherit and our cholesterol levels may depend, at least partly, on what we eat.
The research received support from the British Nutrition Foundation and a scholarship from Saudi Arabia's Ministry of Higher Education.