Preventing Diabetes: The Wellness Plan

from the Berkeley Wellness Letter, November 1996

Diabetes - which physicians noted hundreds of years ago was often a disease of the well-fed - is a breakdown in the body's ability to utilize glucose (blood sugar) efficiently. Glucose, the main sugar into which foods are digested, can be used by our cells only in the presence of the hormone insulin. In insulin-dependent diabetes mellitus, or Type I, which is usually diagnosed in young people, the body virtually stops producing insulin. In addition to modifying their diet, these diabetics (or almost all of them) must inject insulin for the rest of their lives. Type I accounts for only 5 to 15% of diabetes cases-and it is not on the rise. But the rate at which Americans develop non-insulin dependent diabetes mellitus, or Type II, is on the rise, and one reason is that the population is aging. Minorities (blacks, Latinos, American Indians) are at greater risk than others, but anybody can get the disease. It typically affects older people, and thus used to be called "adult-onset diabetes." In this kind of diabetes, the body produces insulin, often in increased amounts, but the cells become insulin-resistant. That is, glucose use declines as cells become resistant to the effects of insulin and thus blood levels of glucose rise. (This article is only about Type II, which we will call simply "diabetes.")

Diabetes greatly increases the risk for hypertension, stroke, and diseases of the heart, eyes, nerves, and kidneys. If diabetes is not diagnosed and treated, virtually all organs of the body can be damaged, leading eventually to death.

There is as yet no foolproof way to prevent diabetes, but there are steps you can take to improve your chances of avoiding it:

According to Dr. F. Xavier Pi-Sunyer, a well-known obesity researcher at St. Luke's-Roosevelt Hospital Center in New York, not all obese people become diabetic-but 90% of diabetics are overweight. In addition, where your body fat is distributed is important-those who gain weight around the middle ("apple-shaped&quot) are more susceptible than those who store fat around the buttocks and thighs ("pear-shaped"). There's evidence that both men and women who gain weight in adulthood increase their risk of diabetes. A recent study conducted at Harvard showed that adult women who gained 11 to 17 pounds since age 18 doubled their risk of diabetes; those who gained between 18 and 24 pounds almost tripled their risk.

If diabetes runs in your family and you're overweight, you're four times as likely to become diabetic as a person with neither risk factor, and twice as likely as a person with only one of these risk factors.

Whatever your family history, staying within a healthy weight range and losing weight if you are overweight will lower your risk of diabetes. Unfortunately, this is easy to say but hard for many people to do. Still, it is by no means impossible to lose weight and keep it off. If you tend to weight-cycle (that is, repeatedly lose pounds and gain them back), we urge you to keep trying. It's not true, as was once believed, that weight-cycling in itself is harmful to health. See the Wellness Letter, March 1996, for the latest healthy weight charts.

Some progress has been made in identifying the genes that predispose a person to diabetes and/or obesity, but it will undoubtedly take many more years of research before such knowledge will be of practical use. A family history of diabetes puts you at increased risk. This does not mean that people with a family history are certain to develop diabetes. But if the disease runs in your family, you should try to reduce other risk factors for diabetes.

While there's no guarantee that eating right will prevent diabetes, it is surely a worthwhile step to take. We recommend the same semi-vegetarian diet that is known to lower the risk of heart disease and cancer. It's low in fat, particularly animal fat, and is rich in fruits, grains, and vegetables, plus low-fat or nonfat dairy products. Such a diet is unlikely to promote weight gain and often promotes weight loss. It also provides the vitamins, minerals, and other nutrients you need to help prevent chronic diseases, including perhaps diabetes.

As we've previously reported, there is direct evidence that regular physical activity helps prevent diabetes. In one study, researchers from the University of California at Berkeley and Stanford University found that men who were very active-burning 3,500 calories in exercise weekly-were half as likely to develop diabetes as the most sedentary, who expended less than 500 calories weekly in leisure-time activity. Those who benefited most from exercise turned out to be those at highest risk for diabetes.

In 1993, a well-designed study of almost 7,000 Swedish men who were already diabetic or "borderline" found that more than half of those who lost weight and improved their physical fitness over a six-year period were able to reverse insulin resistance. Other good studies of both women and men have shown that vigorous exercise, even if done only once a week, has a protective effect against diabetes. This is not just because exercise can promote weight loss-physical activity lowers blood sugar whether you lose weight or not.

There's no evidence that any supplement can prevent diabetes, despite manufacturers' claims for chromium and other supplements. Diabetics often prove to be deficient in some vitamins and minerals, such as vitamin E, zinc, magnesium, and occasionally chromium. But these deficiencies may reflect, in part, a reduced ability to absorb and utilize nutrients, and may thus be a result of the disease, not the cause.

There's never good news about smoking. It boosts your risk of diabetes, and exacerbates the disease if you have it.