Preventing diabetes - Good Medicine

Natural Health, April, 2004 by Kathy Doheny

The Cookie Monster's got some stiff competition: America is smack (snack?) in the midst of an obesity epidemic. Nearly two-thirds of the adult population is overweight or obese, according to a report in the Journal of the American Medical Association, and we're growing bigger every year.

What effect does this have? Start with the incidence of diabetes, which is skyrocketing and getting worse by the day. "It's paralleling the rise we see in obesity," says Michael T. Murray, N.D., co-author of How to Prevent and Treat Diabetes With Natural Medicine.

More than 18 million Americans already have diabetes, while another 20 million are in an early stage called "impaired glucose tolerance" or "pre-diabetes." Now, consider the prediction, issued by the federal Centers for Disease Control and Prevention, that one in three babies born in 2000 will eventually develop diabetes. It's not just your chubby Aunt Grace who's at risk, it's you, your spouse, your friends and your children.

Type 2 diabetes is a condition in which the body no longer uses the hormone insulin properly to convert food to energy. (Less than 10 percent of diabetes cases are type 1, formerly called juvenile-onset, in which the body fails to produce any insulin.) Getting diagnosed with diabetes doesn't just mean a lifetime of oral medication or insulin injections; it indicates a substantial chance of developing heart disease, kidney failure, poor circulation, and vision problems that can lead to blindness.

But with careful attention to diet and exercise, says Eugene J. Barrett, M.D., president of the American Diabetes Association, type z diabetes can be prevented or delayed in at least 70 percent of those at risk--and Murray says that number could be as high as 90 percent.

change your risk factor

Lifestyle changes can actually reverse the body's declining ability to use insulin. Losing excess weight and exercising regularly is what makes the difference, according to the Diabetes Prevention Program, a major clinical trial that was halted when the positive results became overwhelmingly apparent. The study involved 3,234 people with impaired glucose tolerance, which is where blood-sugar levels fall between normal range (139 mg/dl or less) and the range that warrants a diagnosis of diabetes (200 mg/dl or above).

In the study, reported in the New England Journal of Medicine, one group of subjects followed a healthy diet and got moderate exercise, such as brisk walking for 30 minutes five days a week; they were told to reduce their weight by at least 7 percent. After a three-year follow-up, the incidence of full-blown diabetes was reduced by 58 percent in this group and by 31 percent in a group taking the prescription drug metformin as compared with subjects taking a placebo.

the role of fat cells

How do extra pounds drive up your risk of becoming diabetic? "We used to think of fat cells as storage sites for excess calories," says Murray. "But they are metabollically and hormonally active."

Compounds secreted from fat cells, such as a newly discovered protein called adip0itectin, can help control blood sugar and block hardening of the arteries, says Murray. Conversely, as the number and size of fat cells increase, the level of adiponectin can decline.

"The increase in diabetic risk really takes off at about a body mass index of 27," says Christopher Saudek, M.D., director of the Johns Hopkins Diabetes Center in Baltimore and co-author of The Complete Diabetes Prevention Plan. Body mass index is a measure of height to weight, with z5 or more considered overweight. If you are 5 feet 5 inches tall and weigh 162, or 6 feet and 199, your BMI is 27. (For a BMI calculator, see nhlbisupport.com/bmi/bmicalc.btm.)

For Asian Americans, studies have suggested that the risk begins at a body mass index of z4. Most people can aim for a BMI of 25 to minimize their risk, Saudek says, while 23 is a better target for Asian Americans.

the diet debate

All the experts agree that gradually reducing portion sizes and total calories and increasing whole grains and total fiber intake is a good start for weight loss. But defining the ideal diet sparks controversy.

The American Diabetes Association suggests reducing total fat, especially saturated fat, but doesn't specify a percentage of total calories for fat intake. And while some studies have found that moderate alcohol intake reduces the risk of type 2 diabetes, the ADA stops short of recommending it.

The ADA also views total carbohydrates eaten as more important than the glycemic index of foods. This is a ranking of how quickly your blood-sugar level will increase after you eat specific foods; the higher the index ranking, the faster your blood sugar will rise. Yet Murray, among others, advises paying strict attention to the glycemic index and a related measure called the giycemic load. (See "The Glycemic Solution" at left.)

Other promising dietary responses include:

* Maintaining complex carbohydrates while lowering fat may facilitate weight loss in those with impaired glucose tolerance, according to a study published this year in the Archives of Internal Medicine. During a 12-week program, subjects getting 63 percent of their calories from carbohydrates, 18 percent from fat and 19 percent from protein lost more weight than a control group whose intake ratio was 45/41/14. (The participants on the higher-carb, lower-fat diet who also exercised boosted their weight loss by 50 percent.)