Nov. 26, 2002 -- You stick it in the kids' lunchbox and it sticks to the roof of their mouths. And now, researchers say that peanut butter may help stick it to the nation's diabetes epidemic.
In a new study, Harvard researchers found that women who regularly consume peanut butter and nuts have a reduced risk of type 2 diabetes compared to those who don't -- and the more they eat, the lower the risk. Their findings are published in the Nov. 27 edition of the Journal of the American Medical Association.
"While peanut butter and nuts do contain lots of fats, most are unsaturated fats -- the healthy monounsaturated and polyunsaturated fats that previous research shows can improve glucose and insulin stability," says researcher Rui Jiang, MD, of Harvard School of Public Health.
Women who reported eating a tablespoon of peanut butter at least five times a week had a 21% reduced risk of type 2 diabetes compared to those who rarely or never ate it, according to the study. A 27% decrease was noted in women who consumed five ounces of nuts each week compared to women who never or almost never consumed nuts.
The findings are based on questionnaires sent every four years to 83,000 women participating in Harvard's ongoing Nurses' Health Study, which has tracked their dietary and health habits over 16 years. During that time, the researchers documented 3,200 new cases of type 2 diabetes in these women.
"We didn't distinguish what types of nuts were consumed -- we just asked if they ate nuts or peanut butter and did the calculations," Jiang tells WebMD. "But we do not expect the association to differ by the type of nuts, because they have a similar nutrient profile. Most nuts, as well as peanut butter, are rich in the healthy types of fats and a good source of antioxidant vitamins, plant protein, and dietary fiber."
Type 2 diabetes is among the fastest-growing epidemics in the U.S. During the 1990s, the number of new diagnoses jumped 50%, reports the CDC. About 200,000 Americans die from its complications each year, which include heart disease and stroke.
In the December 1999 issue of the American Journal of Clinical Nutrition, Penn State researchers found that a diet rich in nuts and other foods high in monounsaturated fats reduced risk of heart disease by 21%, compared to a 12% drop noted in a more traditional low-fat diet.
A one-ounce serving of peanuts supplies about 14% of the daily recommendation for protein, 8% of fiber. It also contains 25% of vitamin E, 20% of niacin, 12% of magnesium, and 10% of copper, folate, and potassium. That handful of nuts also contains about 170 calories.
That's why the Harvard researchers and others urge that regular peanut butter and nut consumption be used as its original intention -- as a replacement for meat and other foods, not in addition to them. Peanut butter was originally used as a nutrient-rich meat alternative for patients of health guru (and later cereal baron) John Harvey Kellogg, who patented the creamy spread and introduced it as such at the St. Louis World's Fair in 1904.
"There is quite a body of literature showing that regular nut consumption can have all these benefits, but if it promotes increased body weight, we may be buying one advantage and losing on another," says Rick Mattes, PhD, RD, of Purdue University. "And that's where our research comes in."
He is currently investigating the best way to eat nut products in order to reap the maximum benefit of his previous research -- that peanuts and peanut butter satisfy hunger longer than other snacks. "We have already found that people who regularly consume nuts spontaneously eat less at other times of the day," he tells WebMD. "Our newest study, which we're doing right now, is to test when and how it is best to eat nut products so you don't gain weight, such as with a meal, before a meal, after a meal -- and in what form."