Harvard School of Public Health researchers reviewed the findings of four previous studies conducted in the United States, Australia, China and Japan. None of the participants had diabetes at the start of the studies. Overall, the trials included more than 350,000 participants tracked anywhere from four to 22 years.
Researchers led by Qi Sun found a strong association between eating white rice and type 2 diabetes, and the link was stronger in women than in men, according to the study published online March 15 in the British Medical Journal.
The more white rice a person ate, the greater his or her risk for diabetes. For example, for each serving of white rice (assuming 158 grams/6 ounces per serving) there was a 10 percent increased risk of diabetes, the Harvard team estimated.
Compared to brown rice, the white variety has lower levels of nutrients such as fiber, magnesium and vitamins, the team noted. Intake of some of these nutrients are also associated with lowering a person’s risk of diabetes, the researchers said.
White rice — the main type of rice eaten worldwide — also scores high on the glycemic index (GI), a measure of how foods affect blood sugar levels. High GI diets are associated with an increased risk of type 2 diabetes, the research team said.
“These findings are very significant,” says registered dietitian Karen Congro, director of The Wellness for Life Program at The Brooklyn Hospital Center, in New York City. She agreed with the researchers that, “because it is a simple carbohydrate, white rice is also a high glycemic food and can be responsible for high spikes in blood sugar, even for people without diabetes.”
Another expert said lifestyle changes, including food choices, are key to warding off diabetes.
“In our developed societies, we are exercising less and eating more, causing the profound increases in obesity and diabetes that are associated with increased morbidity and mortality,” said Dr. Spyros Mezitis, an endocrinologist at Lenox Hill Hospital in New York City. “Our research should focus on how to eat less, consume foods of lower glycemic index and exercise more to prevent diabetes and obesity,” he said.
According to Congro, there are healthier alternatives to white rice.
“When you eat white rice often, you are missing an opportunity to have fiber in your diet,” she said. “You are also missing a variety of vitamins that are stripped away in the process of making white rice.”
Whole grains, including barley or quinoa, may be healthier options. “Buckwheat is [also] delicious and high in antioxidants, including Rutin, which is linked to improved circulation and prevention of blood vessel blockage due to LDL cholesterol,” Congro said. “There is a whole world of whole grains that people should consider exploring.”
The study found a link between white rice consumption and diabetes, but it did not prove that the food causes the blood-sugar disease.