Chennai: People with higher genetic risk had higher cholesterol than those with lower risk only when their diets were poor, a city-based study has shown. Among those with better-quality diets, the gap was not statistically significant.The findings, based on a study of 1,020 adults published in the peer-reviewed journal PLOS ONE, suggest that what people eat may influence how inherited susceptibility is reflected in their cholesterol levels. “It shows our genes need not determine our metabolic destiny,” said Madras Diabetes Research Foundation chairperson Dr V Mohan. “By changing what is on the plate, people can keep cholesterol levels under control despite high genetic predisposition,” he said.Researchers from Madras Diabetes Research Foundation and University of Reading in the UK analysed data from 452 men and 568 women, aged 25 to 80, as a part of the Chennai Urban Rural Epidemiology Study (CURES). They examined three genetic variants in two genes — TCF7L2 and FTO — previously associated with diabetes and other metabolic traits.Participants were grouped by the number of risk-associated copies of the variants they carried. To assess eating patterns, researchers used a questionnaire covering the previous year and an Indian Diet Quality Score based on eight food groups — pulses and legumes, milk products, fruits and vegetables, white rice, edible fats and oils, added sugar, added salt, and poultry and eggs. Participants were divided into three equally sized groups with low, medium or high diet-quality scores.Within the lowest diet-quality group, participants with higher genetic risk had significantly higher total cholesterol and LDL, often called “bad” cholesterol, than those with lower genetic risk. That difference was not statistically significant in either the medium- or high-quality diet group, said the study’s first author Manahil M Bineid from the University of Reading.Higher genetic risk was also associated with higher fasting blood glucose and HbA1c, a measure of longer-term blood sugar levels. “This reinforces the importance of healthy eating habits, particularly in Indians who are already at increased risk of diabetes and cardiovascular disease,” Bineid said.The findings point to a factor people could change, said Professor K S Vimaleswaran from the University of Reading. “While we cannot change the genes we inherit, we can certainly improve our dietary habits,” he said. “A balanced diet with adequate fruits, vegetables, pulses and other nutritious foods, along with moderation in refined carbohydrates, added sugars, salt and unhealthy fats, remains an important strategy for improving metabolic health.”The researchers said the study has its limitations as it is cross-sectional and has no long-term follow-up. The study also relied on participants recalling what they ate, which can introduce errors, and its genetic score covered only three variants. “Nevertheless, what is clear is that a better diet may help change bad genetics,” Dr Mohan said.Researchers also see potential for personalised nutrition — dietary advice informed by a person’s genetic and metabolic characteristics. The researchers suggest that combining information on genetic susceptibility with dietary assessment could eventually help identify individuals who may benefit from more targeted nutritional interventions. “This may still be far away, but we know the path,” he added.
