White rice polished to a shine, a maida parotta slick with oil, vegetables cooked in coconut oil and an extra spoonful of ghee: familiar staples on many Indian plates could add up to a diet that works against healthy cholesterol levels, particularly when fruits, vegetables and fibre take a back seat.Now, a study of 1,020 adults in Chennai suggests that for Indians genetically predisposed to high levels of bad cholesterol or LDL, the quality of their everyday diet could make a crucial difference in their blood markers. Those who ate a medium-or high-quality diet could completely offset the genetic risk of high LDL and total cholesterol. Those who ate poorly ended up being susceptible to higher levels of both.The findings offer an important message for people who believe that high cholesterol is an inevitable consequence of their genes: inherited susceptibility need not be the whole story. “While genes can influence a person’s risk of metabolic disorders, dietary habits may modify how that risk manifests. Even if you are born with the tendency to high cholesterol and high diabetes, you can still keep your cholesterol levels down by following a healthy diet,” says Dr V Mohan, chairman of Dr Mohan’s Diabetes Specialities Centre and the Madras Diabetes Research Foundation (MDRF), and one of the authors of the paper.The study, titled “Low diet quality increases the genetic risk of high blood cholesterol levels in Asian Indian adults [CURES–165]”, was published in PLOS ONE. It draws on data from the Chennai Urban Rural Epidemiology Study (CURES), a long-running research programme.What did the study find?The researchers studied 1,020 adults aged between 25 and 80, including 452 men and 568 women. They examined three genetic variants — TCF7L2 rs7903146, FTO rs8050136 and rs1588413 — and combined them into a genetic risk score. Diet quality was assessed using an Indian Diet Quality Score covering eight food groups: pulses and legumes, fruits and vegetables, milk products, white rice, edible fats and oils, added sugar, added salt, and poultry and eggs.The researchers found that a higher genetic risk score was associated with a significantly higher total cholesterol and LDL cholesterol among participants in the low diet-quality group. The differences were not statistically significant among those in the medium- and high-quality diet groups. The interaction between genetic risk and diet quality was statistically significant for total cholesterol and LDL cholesterol.The study also found associations between the genetic risk score and higher fasting blood glucose as well as glycated haemoglobin (HbA1c), a measure of average blood sugar over the preceding two to three months. “What we showed in this study is that those who have a certain genetic variant are more likely to get high cholesterol. But this was influenced very much by the diet they took,” he says. Asked how soon the findings could translate into practical screening, he suggests that people did not need to wait for genetic testing; they can make changes in their plate right away.Story continues below this adWhy a study in Chennai matters to other IndiansAlthough the participants were in Chennai, Dr Mohan clarifies that they were not limited to people of Tamil origin or to one dietary community. CURES, he explains, draws on a representative sample of the city, which has residents from different linguistic and regional backgrounds. “Chennai, being a cosmopolitan city like Mumbai or Delhi, has people from several communities, including Telugu-speaking residents, Marwaris, Jains, Bengalis, people from Uttar Pradesh, Bihar and the Northeast,” Dr Mohan says.He also refers to the nationwide ICMR-INDIAB study, which examined diet and health indicators across states and Union Territories. That study, too, found similar patterns in the relationship between carbohydrate consumption and diabetes across different parts of India, despite regional differences in staple foods.“Just because you eat pav or chapatis in Mumbai and we eat white rice here doesn’t mean the readings will be different. It’s the overall carbohydrate overload that’s the deciding factor,” he says, referring to the broader dietary findings from the INDIAB study. “When we eat more carbohydrates than what the body needs for energy, the excess is converted into fat in the liver. This fat is released into the bloodstream as triglycerides. When triglyceride levels rise, the liver releases more triglyceride-rich particles into the bloodstream.As these particles are broken down, they exchange fats with LDL and HDL (good) cholesterol, changing their composition. This can lead to the formation of smaller, denser LDL particles, which are more likely to contribute to plaque build-up in artery walls. However, high triglycerides do not always mean that total LDL cholesterol will rise; they can also make LDL particles more harmful even when LDL levels appear normal. They simultaneously reduce the protective HDL.”Story continues below this adExcess carbohydrate intake can also contribute to weight gain and insulin resistance, further affecting how the body processes fats. However, carbohydrates do not uniformly raise LDL cholesterol; the effect depends on the type and quantity consumed, the overall dietary pattern and individual metabolic factors. Replacing some refined grains with whole grains, pulses, vegetables and other fibre-rich foods can help improve overall lipid health.What should people watch out for?Dr Mohan identifies refined carbohydrates as a key dietary concern. For example, he suggests unpolished brown rice as a healthier choice than polished white rice, while whole-grain wheat is preferable to refined wheat flour such as maida. “Saturated fats, including those found in coconut oil, palm oil, ghee and butter, can increase cholesterol. Go for unsaturated ones. Groundnut, mustard and sesame (gingelly) oils are sources of monounsaturated fat while sunflower oil contains polyunsaturated fat,” he says.It is the overall diet, not one foodThe researchers assessed overall diet quality and did not establish that any one oil, grain or individual food caused the cholesterol differences. Dr R M Anjana, managing director of Dr Mohan’s Diabetes Specialities Centre and a co-author of the paper, says, “People don’t eat one specific food. Everything contributes to how your body behaves.” However, she singles out highly refined carbohydrates, sweets and sugary drinks as the fastest triggers of an unhealthy dietary pattern. “Excess refined carbohydrates can be metabolised into sugar, while excess energy intake can contribute to fat accumulation. Foods high in saturated and trans fats can also adversely affect lipid levels. But if you have a bit of carbohydrate and add protein to it, the risk comes down. If you have something that’s a little high in fat, just increase the fibre content with it to negate the effect. Your plate should be about balancing the equation, not eliminating food groups,” she says.What should a healthy Indian plate look like?Dr Anjana recommends a simple plate-based approach: half the plate should comprise fruits and vegetables, including green leafy vegetables. The remaining half should be divided into two quarters: one for protein and the other for non-starchy carbohydrates. Water and dairy foods such as milk and curd can be included alongside the meal. The proportions may need to be adapted to a person’s body mass index (BMI), diabetes status, and other nutritional needs.Story continues below this adShe also advises choosing less-processed foods wherever possible. Whole fruit is preferable to fruit juice or packaged fruit drinks. Vegetables that can be eaten raw, such as carrots, cucumbers and tomatoes, should be washed thoroughly; other vegetables can be cooked minimally. “Try to avoid anything that comes out of a packet,” she says, acknowledging that this can be difficult in busy modern lives.How diet lowers LDL cholesterolWhile dietary changes can improve cholesterol levels, the extent of improvement varies between individuals, says Dr Anjana. “Dietary changes may have a particularly significant effect on triglycerides, while LDL cholesterol can also have a familial tendency. What we do know is that a healthy food choice will improve all of the cholesterol parameters.”Cholesterol-lowering medication may be necessary when lifestyle changes do not produce a significant improvement. “Someone with only mildly elevated LDL may see an improvement with diet and exercise but people with substantially elevated levels may need medication. Do not delay treatment if cholesterol remains well above the required target,” she advises.