By Merritt McKinney
NEW YORK, May 10 (Reuters Health) - Eating a diet rich in high-fiber fruits,
vegetables and grains may help people with diabetes keep their blood sugar under
control, according to a report.
In people with type 2 diabetes, or non-insulin dependent diabetes, blood
sugar levels rise as the body becomes resistant to insulin, the hormone that
processes sugar in the body. Medication can help keep the condition in check, as
can weight control, exercise and a healthy diet.
A diet rich in fiber has been shown to lower cholesterol in diabetics, but
the effect of fiber on blood sugar has been controversial, one of the study's
authors, Dr. Abhimanyu Garg, of the University of Texas Southwestern Medical
Center in Dallas, told Reuters Health in an interview.
Current guidelines of the American Diabetic Association (ADA) recommend
consuming 20 to 35 grams of fiber each day, but Garg and his colleagues set out
to see whether a diet containing even more fiber would help diabetics keep blood
sugar under control. In the study, 12 men and 1 woman with diabetes consumed two
diets for 6 weeks each. One diet contained 24 grams of fiber each day, while the
other contained 50 grams of fiber. Both diets contained the same amount of
calories and neither included foods that had been fortified with fiber.
The weight of the participants and their daily calories did not vary between
the diets, but the high-fiber diet led to a significant reduction in blood sugar
levels, the researchers report in the May 11th issue of The New England Journal
of Medicine. On average, blood sugar levels were 8.9% lower on the high-fiber
diet. And as expected, the high-fiber diet reduced concentrations of cholesterol
and triglycerides, which have been linked to heart disease.
The researchers conclude that "dietary guidelines for patients with diabetes
should emphasize an overall increase in dietary fiber through the consumption of
unfortified foods, rather than the use of fiber supplements."
Garg and his colleagues conclude that diabetics should be encouraged to eat
more fiber-rich foods, especially those that include high levels of so-called
soluble fiber. Foods rich in soluble fiber include cantaloupe, grapefruit,
orange, papaya, raisins, lima beans, okra, sweet potato, zucchini, granola and
oat bran.
"We should not be forgetting about diet," Garg said in the interview.
Unfortunately, most diabetics do not consume enough fiber to meet even the
current ADA guidelines, which recommend 20 to 35 grams of fiber each day. On
average, Americans consume just 17 grams of dietary fiber each day.
The researcher said that part of the problem may be that many physicians and
other health professionals have not been convinced about the benefits of a
high-fiber diet for diabetics. "If our study convinces them, people would be
more willing to recommend dietary fiber," Garg said.
He also noted that much attention has been paid to the benefits of a
Mediterranean diet, which contains olive oil and other healthier fats. But it is
important to remember that the Mediterranean diet also contains lots of
fiber-rich foods like fruits, vegetables and grains, according to Garg.
In an editorial that accompanies the study, Dr. Marc Rendell from Creighton
Diabetes Center in Omaha, Nebraska, points out that the decrease in high blood
sugar is comparable to that achieved with an oral diabetes drug.
Despite the improvements achieved with foods that naturally contain fiber,
however, Rendell writes that foods that are fortified with fiber should not be
ignored. People are more likely to stick to a healthy diet if they like the
foods, so there is a need for functional foods that would lower blood sugar
levels, just as specially designed margarine can help reduce cholesterol,
according to Rendell.
