Along with a well-documented obesity epidemic in the US, there is a twin epidemic of type 2 diabetes that now afflicts approximately 16 million Americans, and counting.

Frank Hu, assistant professor of nutrition and cardiovascular disease in the Department of Nutrition, has been tracking the diabetes trend. His ongoing research has revealed the power of prevention in stemming the epidemic. Last year, the American Heart Association named Hu’s work on women’s risk factors for diabetes as a Top Ten Research Advance for 2001 (Diabetes, in turn, is a major risk factor for developing cardiovascular disease). The paper appeared in the September 13, 2001 issue of the New England Journal of Medicine and was based on the Nurses’ Health Study. It was the second time the Heart Association recognized Hu and colleagues. In 1997, he was honored for his study on the relationship between types of dietary fats and coronary heart disease in women.

In their latest paper published in the February 5 issue of the Annals of Internal Medicine, Hu and colleagues firmly implicate a "western" diet, one familiar to many Americans, in the diabetes epidemic.

Diabetes is a disease centered on the hormone insulin, which is produced by the pancreas and helps the body use sugar for energy. There are two types of diabetes: type 1 and type 2. People with type 1 diabetes, formerly known as juvenile-onset diabetes, are generally diagnosed as children or young adults, and they cannot produce insulin. People with type 2 diabetes do not produce enough insulin and/or they cannot use the hormone effectively. However, type 2 diabetes is largely preventable. In fact, Hu says that approximately 90 percent of all cases of type 2 diabetes could be prevented if people changed their eating, drinking, exercise and smoking habits.

Diabetes is an insidious disease. The illness can rob people of their sight (diabetes is the leading cause of new blindness cases in the US), create serious foot ailments that lead to amputations, increase the risk of heart attack or stroke by four to six times, and cause kidney failure that, in turn, forces people to use dialysis machines to survive.

There was a time when type 2 diabetes was called "adult-onset" diabetes to differentiate the disease from juvenile-onset diabetes (type 1 diabetes). In recent years, however, an increasing numbers of children and young people are affected by type 2 diabetes.

Now, the disease is popping up with more frequency not only in Western countries but also in developing countries. Urban areas of China, for example, have seen dramatic increases in type 2 diabetes rates, said Hu.

So where did the type 2 diabetes epidemic come from? Hu said that many of the risk factors have been identified. Obesity is the single most important risk factor, explaining about 60 percent of US cases. Related to obesity is diet. In their Annals of Internal Medicine paper this week, Hu and colleagues described two types of diet: "prudent" and "western." A prudent diet consists mainly of fruits, vegetables, whole grains, fish and poultry. A western diet embraces red meat, desserts, high-fat dairy products and processed foods.

Using data from the Health Professionals Follow-Up Study, Hu analyzed the eating patterns of more than 42,000 men between the ages of 40 and 75 tracked for 12 years. He found that men who followed the western diet were 60 percent more likely to develop type 2 diabetes than those who ate a prudent diet. The men at higher risk also tended to be overweight and younger, less physically active, and more likely to smoke cigarettes than those who followed the prudent diet.

Hu suggested that the key to reduce diabetes risk is to follow a healthy eating pattern. He does not advocate a low-fat diet for diabetes prevention. Instead, eating the right types of fat (unsaturated fat from liquid vegetable oils instead of trans fat from partially hydrogenated oils) and the right types of carbohydrates (fiber-rich, whole-grain products instead of highly-processed refined grains) is the foundation of healthy eating.

There are other risk factors for type 2 diabetes, many of which Hu has explored in previous papers. Exercise, even moderate exercise, seems to help prevent diabetes in both men and women. Over the past two years, Hu has published papers indicating that an hour of moderate exercise every day, such as brisk walking, may cut a woman’s risk of becoming diabetic nearly in half and decrease a man’s chance of becoming diabetic by nearly 30 percent.

Prolonged television watching has also been implicated because "couch potatoes" not only are more sedentary but also tend to eat unhealthier foods. Hu has found that men who spend three to five hours watching TV every day were nearly twice as likely to develop diabetes than those who watch one hour or less per week.

Smoking also increases the risk of becoming diabetic, while drinking alcohol in moderation decreases the risk ("moderation" means one to two drinks for women each day and two to three drinks for men).

"These messages of eating right, not smoking and exercising are not new," said Hu, "but with recent studies, we have better pinpointed risk factors for diabetes in a more rigorous and scientific way. Now, we must work to communicate our findings to the public. Nearly all of type 2 diabetes cases are preventable. That’s a powerful public health message."