The report, published by a team of researchers from the Madras Diabetes Research Foundation and published in The International Journal of Food Science and Nutrition, has been compiled over 20 years and took into account interviews with 1,875 men and women.
It found that modern varieties of oils used in Indian cooking, such as palm and sunflower oils, were found to increase the risk for patients to develop insulin resistance and elevated glucose levels than traditional sesame and groundnut oils.
First of its kind
Diabetologist Dr V Mohan, the corresponding author of the study, told FoodNavigator-Asia that the results to his knowledge provide the first epidemiological evidence from India when looking at the effects on cooking oils on adults in relation to diabetes. "This finding is the first of its kind among Asian Indians, whose diets are very low in n3 fatty acid, and hence have a higher n6:n3 ratio compared to recommended levels.
"[The research] relates the main plant-based vegetable cooking oils among urban adults in Chennai and their association to metabolic syndrome." These oils vary in PUFA [n6 and n3], MUFA and SFA fatty acid composition.
However, Mohan stressed that the research was a cross-sectional study of data, and more studies and clinical trials are needed among the same population group to further confirm the results.
While sesame, groundnut and sunflower oil each contain the same quantity of fat, the traditional oils have better omega-3 fatty acid profiles, which keeps cholesterol, triglyceride and glucose under manageable levels.
The study revealed that those who eat food prepared with groundnut or sesame oil have a relatively lower risk of high blood pressure, diabetes and central obesity than the other research groups.
It also found that sunflower oil was more likely to be used by wealthier populations. Its use has grown threefold in developing countries like India over the last two decades.
Diabetes on the rise
An estimated 62.4mn people have diabetes in India, and a further 77.2mn have been diagnosed with pre-diabetes. More than 17% of the population of Chennai, where the research took place, are diabetic. Other studies have found that Indians are genetically more susceptible to the disease.
"The diet as a whole, both in terms of quality and quantity, need to be considered, and not just cooking practices alone," continued Mohan.
"We have several other findings from the same Chennai Urban study to show the association of refined cereals with metabolic syndrome, dietary glycemic load and their association with low HDL cholesterol levels and the risk of Type 2 diabetes, as well as low fruit and vegetable intake and cardio vascular risk factors."
Nutritionists say studies have shown that a high intake of carbohydrates from refined grains will increase the risk of diabetes. This will be exacerbated by a low consumption of vegetables and fruits and lack of physical activity.
Vegetable oil is the major source of visible fats contributing to more than half of Indians’ daily fat calories. The study showed that visible fats and oils are the second highest contributors of energy intake at 12.4% energy/day, next only to refined cereals at 45.8%.
"Asian indian diets are high in carbohydrates, at 60-65% energy/day, and low in n3, so the use of PUFA-rich oil could further increase the dietary n6:n3 ratio and subsequent metabolic ill health," added Mohan.