An interesting clinical study by researchers at the A*STAR Singapore Institute for Clinical Sciences (SICS) could help health-conscious people make better informed decisions about their diet. Their study showed that when a carbohydrate rich meal was fed to people from three different ethnicities- Singaporean Indians, Chinese and Malay, the Indians had more insulin released into their bloodstreams compared to their Chinese and Malay compatriots in order to maintain the same blood sugar levels.
This is a very relevant study, since the results suggest that consuming fewer carbohydrates and choosing those with a lower impact on blood glucose levels could benefit population including Singaporean-Indians, that have a high prevalence of type 2 diabetes.
Most of the literature available today about blood glucose levels are largely based on Caucasian subjects consuming Western foods. However Dr. Christiani Jeyakumar Henry who led the study along with Verena Tan, suggests that Asians have a unique phenotype and different metabolic response to food. The institute he heads, SICS Clinical Nutrition Research Centre is focused on studying the metabolic response of the Asian phenotype in particular.
For the study, they chose 75 healthy Singaporean males — 25 from each ethnic group — and gave them a serving of either Jasmine rice, Basmati rice or a control course of glucose. The subjects’ blood glucose and insulin levels were measured before each meal, and then at fifteen- and thirty-minute intervals after eating. Overall, the Indians were found to have significantly higher blood insulin levels than the Chinese and Malay participants for up to two hours after every meal.
The researchers hypothesize that Indians, who are more resistant to the effects of insulin, secrete excess amounts of the hormone to maintain normal glucose levels. This insulin surge in turn makes them more resistant, “like a boxer receiving one-too-many punches,” says Henry. “It’s a vicious cycle.”
Read more about this in, Know your food- In conversation with Dr. Christiani Jeyakumar Henry
Another factor which influenced the blood glucose and insulin levels was the glycaemic index of the food consumed. So, glucose response or glycemic index (GI) measures the extent to which a carbohydrate-containing food raises blood glucose. It is compared to a reference food which is either pure glucose or white bread. So, foods in which carbohydrates could be easily digested and absorbed generally have a high GI and the sharpest increase in blood sugar after they are eaten. While, slowly or incompletely digested carbohydrates have a low GI, with a lower increase in blood sugar after eating.
Since Jasmine rice has a higher glycaemic and insulinaemic index than Basmati rice, it resulted in higher levels of glucose and insulin, regardless of ethnicity.
Since carbohydrates or rice in particular, forms a staple part of the Asian diet, the researchers suggest that choosing the rice variety and foods with lower glycemic index could help prevent the onset of type 2 diabetes.
The need of the hour is to have a ready reckoner which shows the glycaemic index of popularly consumed foods, which can aid people in making informed dietary decisions. Henry and his team at CNRC have managed to do that too, by publishing the glycaemic index values of 15 popular foods consumed in South-east Asia, including the fried Chinese breadstick, youtiao, the coconut-infused rice dish, nasi lemak, and iced green tea.
The original paper can be accessed here.