Diabetes & Nutrition Part I: New Dietary Findings

Weight is Key to Fending off Type 2 Diabetes

A trio of studies published late last year in the journal Archives of Internal Medicine shed new light on the importance of diet in risk of developing type 2 diabetes - especially the role of calories. The bottom line from all three studies is that calories trump all else, and that our main goal in preventing type 2 should be to eat less high-calorie, low-benefit foods.

Fruit Drinks are Culprits; Fruits & Veggies Help

In the first study (1), which followed nearly 44,000 Afro-American women for 10 years, the risk of developing type 2 was 24% higher for those who consumed two or more soft drinks daily compared with women who drank them rarely. Sipping fruit drinks was even riskier, with a 31% increased risk for those drinking them twice daily.

Diet soft drinks as well as grapefruit and orange juice did not up the risk for diabetes. Unlike other fruit drinks, these juices contain mostly naturally occurring sugars which may have different metabolic effects than the high-fructose corn syrup used to sweeten other juice drinks.

In the second study(2), blood levels of vitamin C (an indicator of fruit and vegetable intake) and fruit and veggie consumption were measured in about 22,000 people without diabetes. After a dozen years, those with the highest vitamin C levels were 62% less likely to develop the disease. A similar but smaller risk reduction of 22% was observed for those eating even modest amounts of fruits and veggies.

In the last study(3), 60% of the nearly 49,000 women participants continued with their regular diet while 40% were assigned to a low fat diet with added fruits, veggies and grains. Although the diet was not designed for weight loss, those in the low-fat diet group lost about 5 pounds more over an 8 year period compared to the "usual diet" group. The researchers concluded that losing weight - rather than eating less fat - was more important in preventing type 2.

For Diabetics, Recommended Diet May Need Changing

...or so suggests a new study(4) that is one of the longest and largest to assess the impact of foods with a low glycemic index (GI). Low GI foods don't raise blood sugar as much as foods with a higher GI.

People with type 2 were assigned to one of two diets. The first emphasized "brown foods" such as whole grain bread and breakfast cereal, brown rice and potatoes with the skin on. This high fiber, high cereal diet is what is usually recommended for those with diabetes.

The other diet focused on low GI foods which included beans, peas, lentils, pasta, quickly boiled rice and certain breads like pumpernickel and rye, as well as oatmeal and oat bran cereals.

Both diets were low in saturated and trans fats. Both groups were told to limit their consumption of white flour and to eat five servings of vegetables and three servings of fruit daily.

At the end of six months, people on the low GI diet kept their blood sugar under better control and had slight reductions in HA1C levels - a measure of blood sugar levels over time. They also experienced significant increases in "good" HDL cholesterol, which is good for heart health. That's important because diabetic men have twice the risk for heart disease and women four times the risk. Also, drugs used to control type 2 have not shown the expected benefits in terms of reducing heart disease.

The bottom line is that high fiber foods are fine, but include beans and nuts and try to eat more low GI foods

References

1. Palmer JR, et al. Sugar-Sweetened Beverages and Incidence of Type 2 Diabetes Mellitus in African American Women. Arch Int Med 168:1487-92, 2008.
   
2. Harding A-H, et al. Plasma Vitamin C Level, Fruit and Vegetable Consumption, and the Risk of New-Onset Type 2 Diabetes Mellitus: The European Prospective Investigation of Cancer-Norfolk Prospective Study. Arch Int Med 168:1493-99, 2008.
   
3. Tinker LF, et al. Low-Fat Dietary Pattern and Risk of Treated Diabetes Mellitus in Postmenopausal Women: The Women's Health Initiative Randomized Controlled Dietary Modification Trial. Arch Int Med 168:1500-11, 2008.
   
4. Jenkins DJ, et al. Effect of a low-glycemic index or a high-cereal fiber diet on type 2 diabetes: a randomized trial. JAMA 300:2742-53, 2008.