The study published on Tuesday in Circulation Research, an American Heart Association journal, showed that eating five servings (28-gram per serving) of nuts per week among people with type 2 diabetes had a 17 percent lower risk of total cardiovascular disease incidence compared with those who ate less than a single serving per month.
The participants also reported a 20 percent lower risk of coronary heart disease and a 34 percent lower risk of heart disease death, according to the study.
Harvard University researchers used self-reported diet questionnaires from 16,217 participants before and after they were diagnosed with type 2 diabetes and asked them about their consumption of both peanuts and tree nuts over a period of several years.
They found that eating all kinds of nuts offered some heart benefits, but tree nuts such as walnuts, almonds, cashews, pistachios, pecans and hazelnuts were strongly associated with reduced heart risk compared with peanuts that grow underground.
Also, after being diagnosed with diabetes, those who increased their nuts intake had an 11 percent lower risk of cardiovascular disease and a 25 percent lower risk of heart disease death, according to the study.
"It seems never too late to improve diet and lifestyle after diagnosis among individuals with type 2 diabetes," said the paper's lead author Liu Gang with the Harvard T.H. Chan School of Public Health.