Fighting diabetes through research on local whole-grain foods

GNET Members gather in front of the Harvard T.H. Chan School of Public Health during the last GNET Symposium in the fall of 2011.

gnetType 2 diabetes has reached epidemic proportions in many countries around the world, including many low and middle-income countries, as global free trade continues to fuel rapid economic and nutrition transitions. Traditional staple foods, once rich in whole grains and dietary fiber, have been replaced by highly refined carbohydrates such as polished white rice. This nutrition “transition” has resulted in a major reduction in the overall quality of carbohydrates in the diet. Research has shown that consumption of high-quality carbohydrates, such as whole grains, can reduce the risk of developing diabetes by improving blood glucose and insulin levels. Adopting a diet that is rich in whole grains could be a cost-effective, feasible, and sustainable approach to diabetes prevention, particularly in low- and middle-income countries which must simultaneously manage infectious disease and malnutrition.

This is the philosophy behind the Global Nutrition & Epidemiologic Transition Initiative: a collaborative initiative launched by researchers from the Departments of Epidemiology and Nutrition at the Harvard T.H. Chan School of Public Health, with the ultimate goal of helping to prevent the global diabetes epidemic by improving the carbohydrate quality of staple foods. Pilot projects are ongoing in a number of countries to not only assess the effect of substituting whole grain alternatives for refined carbohydrate staples on intermediate markers of diabetes risk but to also assess the cultural acceptability and feasibility of these interventions in local communities. The team plans to use results from the pilot studies to design larger studies that can test whether whole grain dietary modifications can have a long-lasting, measurable impact.

Locations of Current Projects

2015 age-adjusted comparative prevalence of diabetes in the fourteen GNET countries/territories (data obtained from International Diabetes Federation: Diabetes Atlas, 2015)

Studies are currently taking place in 14 countries throughout the world. The collaboration is managed by a team of Nutritionists, Epidemiologists, and Biostatisticians at the Harvard T.H. Chan School of Public Health in Boston.

The first studies were conducted in China and India, which are estimated to have the highest number of individuals living with diabetes in the world.  White rice, a refined carbohydrate, is a staple food in both countries. We began pilot studies in Shanghai, China and Chennai, India to determine whether substituting brown rice, a whole grain, for white rice is culturally acceptable in these populations, which have had little or no previous exposure to brown rice. In taste tests and focus group discussions, participants indicated a willingness to consume brown rice after learning about its nutritional value and health benefits.  This suggested that large-scale promotion of the benefits of brown rice is needed to improve societal perceptions, and the majority expressed willingness to participate in a long-term brown rice intervention study.

In China, participants recruited from the Shanghai Institute of Biological Sciences were randomized to consume either brown rice or white rice twice a day (lunch and dinner) for 4 months, during which time biological markers of diabetes risk were evaluated. Participants collected their rice containers each day at one of two cafeterias on campus during lunch hour, and returned empty containers to weigh leftovers. Participants were also given scales so that quantities of rice consumed at home could be recorded.  This study was made possible by funding from the Chinese Academy of Sciences as well as from an anonymous foundation.  More information on the Shanghai study can be found in this 2009 article from the Harvard Public Health Review.

In India, we received a Fogarty International Research Collaboration Award (FIRCA) to conduct a similar “next phase” intervention study. We have also submitted an application for D-START (Diabetes, Supporting TrAnslational Research and Twinning), an initiative launched by the International Diabetes Federation, which aims to support the development of innovative projects in low and middle-income countries.

Diabetes, once considered rare in sub-Saharan Africa, is also increasing at alarming rates, as many countries experience rapid economic development. Tanzania and Nigeria are both undergoing such epidemiological transitions. Because (white) rice is not the only staple food in these countries, we have begun studies in Dar es Salaam, Tanzania and Abuja, Nigeria to identify whole grain alternatives for other refined carbohydrate staples such as ugali in Tanzania and fufu in Nigeria.

Latin America is also experiencing a diabetes epidemic. We have begun similar pilot studies in San Juan, Puerto Rico, Mexico City, Mexico and San Jose, Costa Rica.

We look forward to establishing additional collaborations in other countries around the world that are experiencing the nutrition transition, to make our initiative a truly global one.


*Slide courtesy of Dr. Mohan, MDRF, Chennai, India

GNET Phases