Why Asian immigrants to US are at increased type 2 diabetes risk

A new study has revealed why Asian Americans at higher risk of developing type 2 diabetes than Caucasian Americans, and prone to develop the disease at lower body weights.

According to researchers, the transition from traditional high-fiber, low-fat Asian diets to current westernized diets, and this may pose extra risks to those of Asian heritage.

George King, M.D., Chief Scientific Officer at Joslin Diabetes Center and Professor of Medicine at Harvard Medical School said that both Asian Americans and Caucasian Americans at risk of type 2 diabetes who adopted a rigorously controlled traditional Asian diet lowered their insulin resistance, which is a leading risk factor for developing the disease, insulin resistance is a condition in which the body struggles to use the hormone insulin, which helps to metabolize sugar.

King said that when both groups of participants then switched to consuming typical western fare, the Asian Americans experienced greater increases in insulin resistance than did the Caucasian Americans.

For the first eight weeks, all the participants ate a traditional high-fiber East Asian diet with 70 percent of calories from carbohydrates, 15 percent from protein and 15 percent from fat, and providing 15 g fiber/1,000 kcal. The food was prepared fresh by local chefs and delivered every two days.

For the second eight weeks, 33 of the volunteers (20 Asian Americans and 13 Caucasian Americans) transitioned to a typical low-fiber western diet with 50 percent of calories from carbohydrates, 16 percent from protein and 34 percent from fat, and providing 6 g fiber/1,000 kcal. Seven volunteers (4 Asian Americans and 3 Caucasian Americans) stayed on the traditional Asian diet to act as controls for the study.

Meeting with the trial participants every two weeks, the Joslin team adjusted individual diets as needed to keep their weights relatively steady, so that changes in their metabolism were not driven primarily by changes in weight.

Maintaining those steady body weights for trial participants was a challenge, King remarks. "It was almost impossible to prevent people from losing weight on the Asian diet, and that was not because the food wasn't good!" he says. "And almost everybody gained weight on the western diet, and we had to work very hard so they didn't gain too much."

The researchers suggested that the combination of high fiber and low fat in the traditional diet may help to explain the decrease in insulin resistance, especially for the Asian American participants and those on the traditional Asian diet lowered their LDL cholesterol, a potential benefit for cardiovascular health.

The study was published in the journal PLOS One.