If you have type 2 diabetes and you want to do your heart a favour, a new study suggests you should let your diet get a little nutty.
Folks with type 2 diabetes who ate five or more servings of certain kinds of nuts weekly dropped their odds of heart disease by about 20%, compared to people who ate less than a serving a month. A serving in the study was defined as one ounce.
Not all nuts are created equal
Noshing five or more weekly servings of nuts also appears to lower the risk of premature death from heart disease or any other cause by about one-third for people with type 2 diabetes.
Not all nuts are created equal, however. Nuts grown on trees seemed to provide more heart-health benefits than peanuts, which grow underground.
Tree nuts include walnuts, almonds, cashews, Brazil nuts, pistachios, pecans, macadamias, hazelnuts and pine nuts.
"Our findings suggest that nut consumption, especially tree nuts, is beneficial for the prevention of cardiovascular disease [heart disease and stroke] and premature deaths among individuals with diabetes," said study author Gang Liu. He's a research associate in the department of nutrition at the Harvard T.H. Chan School of Public Health, in Boston.
The study was funded by the US National Institutes of Health.
More research needed
What is it about nuts that makes them so heart-healthy for people with diabetes?
Liu said that nuts seem to help control blood sugar, blood pressure and cholesterol. Eating nuts also appears to help dampen inflammation and improve blood vessel health.
The current study focused on people with type 2 diabetes, and Liu said there isn't yet enough research to know if nuts would provide the same benefit to people with type 1 diabetes.
However, when asked if people without diabetes might see heart benefits from nuts, he said, "Based on our findings and existing evidence, I would say that nuts are beneficial for people with and without diabetes."
Heart specialist Dr Terrence Sacchi agreed that nuts can be beneficial. "This observational study provides more evidence that certain types of nuts perhaps have some effect on diabetes and heart disease," Sacchi said. He's the chief of cardiology at NewYork-Presbyterian Brooklyn Methodist Hospital in New York City.
But Sacchi added a few caveats. "Nuts are good in moderation, but you can't be eating 18 handfuls of nuts. A serving is a handful. Nuts contain a lot of fat; it's good fat, but gaining weight would counteract any benefit," he explained.
No proven cause and effect
Sacchi also pointed out that it's important to limit the salt in nuts, because excess salt can increase your heart disease and stroke risk. He said the best type of nuts are raw, unsalted nuts.
The study included diet and health information from more than 16 000 people before and after they were diagnosed with type 2 diabetes. The study covered about two decades. Because it was an observational study, it cannot prove cause and effect.
During the study period, more than 3 000 people developed heart disease or stroke. More than 5 600 of the study volunteers died. Of those, nearly 1 700 died from heart disease or stroke.
The researchers found that when people ate more nuts after a diabetes diagnosis, they lowered their risk of heart disease or stroke more than 10%. Eating more nuts was also tied to about a 25% reduction in premature death from heart disease or another cause.
Each additional serving of nuts was linked to a 3% decreased risk of heart disease and stroke, as well as a 6% drop in the risk of dying of cardiovascular disease.
The study findings were published online in the journal Circulation Research.
Image credit: iStock