CHICAGO -- Eating lots of nuts or peanut butter may help ward off diabetes, a study of more than 83,000 nurses suggests.
Women who reported eating the equivalent of a handful of nuts or one tablespoon of peanut butter at least five times a week were more than 20 percent less likely to develop adult-onset, or type 2, diabetes than those who rarely or never ate those products.
Researchers from Harvard University's School of Public Health analyzed data on 83,818 women ages 34 to 59 who were followed for up to 16 years. The researchers said the findings would probably apply to men as well.
The findings appear in Wednesday's Journal of the American Medical Association.
"Nuts in the past have been considered as an unhealthy food because of the high-fat content," said Harvard researcher Dr. Frank Hu. "Conventional wisdom says that high-fat foods will increase obesity and type 2 diabetes."
But research in the past decade has shown that nuts generally contain good kinds of fat as well as other nutrients that can help keep cholesterol at healthy levels.
They also contain fiber and magnesium, which help maintain balanced insulin and glucose levels. Insulin helps the body convert sugar into energy. Diabetes happens when the body cannot produce or properly use insulin.
During the government-funded study, 3,206 women developed diabetes.
Women who ate lots of nuts led slightly healthier lifestyles than other women, which could have reduced their risk of developing diabetes. But Hu said the results held up even when the researchers compared nut consumption in subgroups of women, such as among smokers or those who were active.
The researchers did not determine what kinds of nuts women were eating. Most nuts contain unsaturated fats, which can help lower cholesterol levels, and relatively small amounts of saturated fats, which can raise levels of the bad kind of cholesterol.
Nuts and peanut butter - peanuts are actually classified as legumes but have many of the same qualities as nuts - are among foods sometimes recommended for diabetics, who are prone to cardiovascular disease.
Some brands of peanut butter, however, may contain high amounts of sugar or fatty preservatives, so people are advised to check the label, said Martha Funnell, head of health care and education for the American Diabetes Association and a University of Michigan diabetes educator.
Funnell said the study's message should be that nuts and peanut butter can be beneficial if they are eaten instead of - rather than in addition to - lots of refined grains and foods high in saturated fats.
"That doesn't mean that you need to go out and start eating a jar of peanut butter on top of everything else that you're eating," said Funnell, who also happened to be one of the nurses studied.
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