Poor diet amplifies genetic risk of high cholesterol among Indians: Study

CHENNAI: Poor dietary quality may magnify the genetic predisposition to high cholesterol among Asian Indians, a study involving researchers from Chennai and the United Kingdom has found, highlighting the potential importance of healthier eating habits in addressing inherited cardio metabolic risks.

The study, published in the peer-reviewed journal PLOS ONE on October 14, found that individuals with a higher genetic risk had significantly higher total cholesterol and low-density lipoprotein (LDL) cholesterol levels when they consumed a poor-quality diet.

The differences were not statistically significant among those whose diets were classified as medium or high quality. The research was conducted by scientists from the Madras Diabetes Research Foundation (MDRF) and Dr Mohan’s Diabetes Specialities Centre in Chennai, in collaboration with the University of Reading, United Kingdom. It examined the interaction between genetic susceptibility and overall dietary quality in influencing cholesterol levels, a key risk factor for cardiovascular disease.

Titled ‘Low diet quality increases the genetic risk of high blood cholesterol levels in Asian Indian adults [CURES–165]’, the study analysed data from 1,020 adults aged 25-80 years who participated in the Chennai Urban Rural Epidemiology Study (CURES). The participants included 452 men and 568 women.

Researchers examined three genetic variants in the TCF7L2 and FTO genes, which have previously been associated with metabolic disorders, and calculated a genetic risk score based on the number of risk alleles carried by each participant. Dietary habits were assessed using the Indian Diet Quality Score (IDQS), which evaluates eight food groups relevant to Indian eating patterns.

The analysis identified statistically significant interactions between genetic risk and diet quality for total cholesterol and LDL cholesterol, with p-values of 0.003 and 0.005, respectively. The associations remained significant after correction for multiple statistical comparisons.

Among participants with poor-quality diets, those in the higher genetic-risk group had significantly higher total and LDL cholesterol levels than those in the lower-risk group. However, no statistically significant differences between the genetic-risk groups were observed among participants with medium- or high-quality diets.

The findings suggest that the relationship between genetic susceptibility and cholesterol levels may vary according to dietary quality. However, researchers cautioned that the observational study establishes an association rather than proving that improving diet can reverse genetic risk.

The study also found that participants with a higher genetic risk score had significantly higher fasting plasma glucose and glycated haemoglobin (HbA1c) levels, indicators of blood glucose regulation. The associations had p-values of 0.005 and 0.006, respectively.

Dr V Mohan, chairman of MDRF and Dr Mohan’s Diabetes Specialities Centre, and a co-author of the study, said that the findings indicated that genetic predisposition did not necessarily determine metabolic outcomes.

“An important message from this study is that our genes need not determine our metabolic destiny. We found that individuals with a higher genetic predisposition had significantly higher cholesterol levels when their diet quality was poor. However, these differences were not observed among those consuming healthier diets,” he added.

Prof K S Vimaleswaran, senior scientist at the University of Reading, said that people could improve their dietary habits even though they could not change the genes they inherited. “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,” he added. “Research provided a foundation for further studies into personalised nutrition for the Indian population.”

Dr Manahil M Bineid, University of Reading, the first author of the paper, said that the findings reinforced the importance of healthy eating habits, particularly among Indians already at increased risk of diabetes and cardiovascular disease.

The IDQS assessed the consumption of pulses and legumes, milk and milk products, fruits and vegetables, white rice, edible fats and oils, added sugar, added salt, and poultry and eggs. By considering overall dietary patterns, the researchers sought to capture the combined influence of different food groups on metabolic health.

The findings come against the backdrop of India’s growing burden of diabetes, abnormal blood lipid levels and cardiovascular disease. They also contribute to the emerging field of nutrigenetics, which examines how genetic variations interact with dietary factors, and could inform future research into personalised approaches to disease prevention.

Researchers acknowledged limitations, including the study’s cross-sectional design, which prevents the establishment of cause and effect. Dietary intake was assessed using self-reported information, which may be affected by recall errors. Further prospective studies and dietary intervention trials are therefore needed to determine whether improving diet quality can reduce cholesterol-related risks among genetically susceptible individuals.

The findings point to the potential of combining genetic risk assessments with dietary evaluations to identify people who may benefit from targeted nutritional interventions. While further evidence is needed before such an approach can be translated into clinical practice, the study highlights overall diet quality as an important factor in understanding cholesterol risk among Asian Indians.

IN A NUTSHELL

• Higher genetic-risk group had higher total and LDL cholesterol levels than those in the lower-risk group

• No significant differences among participants with medium- or high-quality diets

• Higher genetic risk score had significantly higher fasting plasma glucose and HbA1c levels

• Relationship between genetic susceptibility and cholesterol levels may vary as per dietary quality

• Findings contribute to the understanding of nutrigenetics, which examines how genetic variations interact with dietary factors

• Study examined 3 genetic variants and 8 food groups