Avoid type 2 diabetes with vegetables and low glycemic load

Veggie Nation

What should you eat to avoid type 2 diabetes?

Sixty-four thousand Chinese women have the answer.

Fresh from the earth

Researchers from the Institute for Medicine and Public Health at Vanderbilt University teamed up with scientists at the Shanghai Cancer Institute in China to examine the effect of fruit and vegetable intake on the risk of developing type 2 diabetes.

STUDY PROFILE:

• Researchers interviewed more than 64,000 healthy, diabetes-free women between the ages of 40 and 70 to assess dietary intake for each subject
• Following up more than four and a half years later, about 1,600 subjects had developed type 2 diabetes
• Overall, subjects with the highest intake of vegetables reduced their risk of type 2 diabetes by nearly 30 percent
• When intakes of specific types of vegetables were examined, each was “inversely and significantly associated with the risk of T2D.”
• The highest vegetable intake was more than 425 grams per day (one cup of cooked cauliflower weighs about 50 grams)
• Fruit intake was not linked to either a smaller or greater risk of type 2 diabetes

Writing in the March 2008 issue of The Journal of Nutrition, the Vanderbilt team cautions that their study does not prove that type 2 diabetes can be avoided by eating vegetables. But they also note that components of vegetables – such as fiber, antioxidants, magnesium, phytates, isoflavones, and lignans – “might have an additive or synergistic effect on lowering the risk of type 2 diabetes.”

Two to avoid

The Vanderbilt researchers mentioned one other quality that makes vegetables a good choice for those who want to avoid type 2 diabetes: Most vegetables score very low in the glycemic index (GI).

In previous e-Alerts I’ve told you about the importance of the glycemic index, which is a measurement system developed to help diabetic patients manage their blood glucose levels. This handy reference source indicates which foods have a high GI, and therefore will be the most likely to contribute to type 2 diabetes, obesity, and other chronic diseases including heart disease.

Which brings us to a couple of vegetables you might want to avoid if you’re pre-diabetic, or if you have type 2 diabetes: potatoes and corn.

A web site that reveals GI values for carbohydrates (carbs-information.com) provides a listing of foods and their GI ratings. A low GI is 55 and below, medium is 56 to 69, and anything above 69 is high and should be avoided.

For instance, the GI for broccoli is zero, but the GI for a comparable serving of sweetcorn is 54. Spinach and cauliflower both rate a zero, but a baked potato is 85.

Potatoes are starch, of course, and HSI Panelist Allan Spreen, M.D., explains that as soon as a starch hits enzymes in your mouth, they begin to break down into sugar.

Dr. Spreen: “The baked potato is as close to a pure, refined starch as you can get without actually refining it. I’d tell patients, if they felt obliged to eat a baked potato, to shell out most of it, add some butter, and eat the remainder, including the skin. That’s not only where the fiber is, but also where much of the nutrition is too.”

Because high GI food intake tends to make you hungry soon after eating (and hungrier for high GI foods), the glycemic index is an excellent resource for planning menus in diets designed to reduce weight.

Sources:
“Vegetable but Not Fruit Consumption Reduces the Risk of Type 2 Diabetes in Chinese Women” The Journal of Nutrition, Vol. 138, No. 3, March 2008, jn.nutrition.org
“Penalty Cuts Insurer Profit” Lisa Girion, The Los Angeles Times, 2/28/08, latimes.com