MELBOURNE, Australia — Eating brown rice instead of white rice may help prevent and control diabetes in rice-eating populations, new research suggests. In the first randomized controlled trial to compare the 2 in India, substituting brown rice for white rice in a population of overweight/obese individuals helped significantly reduce glucose levels and lower serum insulin.
The findings were reported by V. Mohan, MD, FRCP PhD, DSc, FNASc, from the Madras Diabetes Research Foundation, World Health Organization Collaborative Centre for Non-Communicable Disorders, Chennai, India, at the International Diabetes Federation World Diabetes Conference 2013 last month.
"This 1 single shift of changing the major staple in the diet from the highly polished white rice to brown rice helps reduce blood glucose levels at every point of the curve, with every meal — breakfast, lunch, and dinner," Dr. Mohan told attendees.
"It also helps to reduce the serum insulin levels, and therefore we hypothesize that, in populations where polished white rice is a staple food and constitutes more than 50% of the total calories consumed, just this 1 substitution itself may help in preventing and controlling diabetes."
Dr. Mohan said his team is now conducting a study in adults with prediabetes to see whether substituting brown rice for white will help prevent the development of type 2 diabetes.
Glucose Cut by 20%, Insulin by 60%, With Brown Rice
Dr. Mohan explained that consumption of rice varies across India, with South India and some parts of East India being places where rice is the staple of the diet, whereas in North India, it tends to be wheat in the form of bread. But even here, the wheat consumed is not whole wheat, and therefore it has a high glycemic index (GI), he observed.
Among Chennai adults, white rice, a refined grain with a high GI, provides about half of the daily calories and has been associated with risk for metabolic syndrome, he said.
In their study, he and his colleagues randomized 150 adults with a body mass index (BMI) of 23 or greater and no known chronic diseases to a diet based on either white rice or brown rice for 3 months; the rice in question was consumed as the major constituent of typical Indian meals for at least 6 days/week during the period in question. At the end of each 3-month period, there was a washout of 2 weeks, and the participants swapped to the alternative rice.
Habitual dietary intake was assessed with food frequency questionnaires at baseline and 24-hour recalls on a monthly basis. Height, weight, and waist circumference were measured at baseline and at the end of each month during the study period for each diet. Blood glucose and fasting insulin were also measured.
Five-day mean glucose concentrations were approximately 20% lower among those consuming a brown-rice–based diet, based on continuous glucose monitoring (-19.8%; P = .004), Dr. Mohan reported. And fasting insulin concentrations were 57% lower among those eating the brown-rice–based diet (P = .0001).
Although further confirmatory trials are needed, Dr. Mohan said that substituting brown rice for white rice is a promising strategy that his team is now exploring in their larger trial in adults with prediabetes.
"The results of this study, if found effective, could help alleviate the burden of diabetes and related chronic diseases in India," he observed.
Political Will Required to Change Mindset in India
Unfortunately, some politicians in India are currently providing cheap white rice, with a very high glycemic load, free or extremely cheaply, as an incentive to get people to vote for them, Dr. Mohan explained. And in some places, free televisions are being given out too, in exchange for votes.
"These poor people are used to physical activity; now they are all sitting watching TV," he observed. "The second thing they are doing is giving the worst kind of rice free or almost free. What they should be giving them is fruit or vegetables or subsidizing the cost of these. Instead, they are doling out one of the very factors that promote diabetes and obesity."
He noted that the reversal in fortunes of brown rice happened only in the past few decades, around 30 years ago. "One of the reasons brown rice went out of favor is because it doesn't look so good, it doesn't taste so good, and it doesn't look so sexy. But the biggest problem is the shelf life. With white rice, once you mill it, you can keep it for a couple of years, but the brown rice gets rancid quickly."
His institution is trying to tackle this problem by working to try to increase the shelf-life of brown rice.
"Our results could be translated to national-level policies, including provision of brown rice as a healthier alternative for white rice in government institutions and food programs," he noted.
They have also developed a white-rice variety with a more highly resistant starch and therefore a higher fiber content and a lower GI, for which they have applied for a patent. "Instead of doling out cheap white rice to people, why don't we invest in technology that makes it better and healthier?" he said.
Asked to comment, Anil Kapur, MD, from the World Diabetes Foundation, Gentofte, Denmark, told Medscape Medical News that doctors in India do know about the link with white rice and obesity/diabetes, "but they don't know what to do about it. You go to rural areas today in India, and you find diabetes prevalences almost touching those of urban areas, and 80% of the calories are from rice."
Addition of Plant Material Beneficial, but Expensive
Also reported at the Melbourne meeting was a small study by nutritionist Amy Liu from the Auckland Diabetes Center, New Zealand, and colleagues, who developed a white-rice alternative by replacing part of the rice with whole grains, pulses, nuts, and seeds. This was compared with white rice alone in 12 Chinese patients with non–insulin-dependent type 2 diabetes, in a repeated randomized crossover study.
Postprandial glycemia was 27% less than white rice after consumption of the rice mix (P < .001). And the mean length of time that postprandial glycaemia exceeded 10 mmol/L was 125 minutes for white rice compared with 95 min for the rice mix (P = .001).
Results of an exit questionnaire indicated that participants would consume the rice-mix meal on a frequent basis, with 2 people answering that they would be willing to completely replace white rice with the rice mix.
Using rice mix as an alternative to white rice is a feasible dietary approach to improve postprandial glycemia in patients with type 2 diabetes, particularly for people experiencing difficulties in reducing the amount of rice intake, said Ms. Liu.
Dr. Mohan said that while the addition of legumes, whole grains, pulses, nuts, and seeds is a good goal, in practice this would be too expensive for whole swaths of the population in India. But adding some plant material is a laudable goal, he said, noting that in India they are trying to encourage people to consume more legumes and leafy vegetables, where possible.
He said there are 2 main messages from his work. "If you can't get any other variety of rice [than high-GI white], cut it down and add more vegetables and legumes and you get more balance." Or for people who are not able to cut down the rice, "change the rice to brown rice or lower-GI rice."
"We have a plate concept: Half the plate should be green leafy vegetables, a quarter of the plate legumes, and only the last quarter rice. It's a very simple message," he told Medscape Medical News.
Dr. Mohan and Ms. Liu have reported no relevant financial relationships.
Medscape Medical News © 2014 WebMD, LLC
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Cite this: Replace White Rice With Brown to Cut Obesity and Diabetes - Medscape - Jan 16, 2014.