According to new research published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association, Asian men and women living in Japan who ate peanuts (on average 4-5 peanuts/day) had a lower risk of having an ischemic stroke or a cardiovascular disease event compared to those who did not eat peanuts.
While previous research has linked peanut consumption to improved cardiovascular health in Americans, the researchers in this study looked specifically at the relationship between peanut consumption and the incidence of different types of stroke (ischemic and hemorrhagic) and cardiovascular disease events (such as stroke and ischemic heart disease) in Japanese men and women.
“We showed for the first time a reduced risk for ischemic stroke incidence associated with higher peanut consumption in an Asian population,” said lead study author Satoyo Ikehara.
“Our results suggest that adding peanuts to your diet has a beneficial effect on the prevention of ischemic stroke.”
Peanuts are rich in heart-healthy nutrients, such as “monounsaturated fatty acids, polyunsaturated fatty acids, minerals, vitamins and dietary fiber that help lower risk of cardiovascular disease by reducing risk factors, including high blood pressure, high blood levels of ’bad’ cholesterol and chronic inflammation,” Ikehara said.
The researchers looked at how frequently participants reported eating peanuts in relation to the prevalence of strokes and cardiovascular disease.
The analysis included individuals from the Japan Public Health Center-based Prospective Study who were recruited in two phases, in 1995 and 1998-1999, for a total of more than 74,000 Asian men and women aged 45 to 74.
Participants completed a detailed lifestyle survey, which included questions about their peanut eating frequency. They were monitored for about 15 years — until 2009 or 2012, depending on when they were first enrolled.
The incidence of stroke and ischemic heart disease was established by connecting with 78 participating hospitals in the research locations.
Other health conditions, such as smoking, nutrition, alcohol intake, and physical activity, as reported by participants in questionnaires, were taken into account by the researchers. During the follow-up period, researchers discovered 3,599 strokes (2,223 ischemic and 1,376 hemorrhagic) and 849 cases of ischemic heart disease.
Peanut consumption was divided into four quartiles, with 0 peanuts per day being the lowest intake and 4.3 unshelled peanuts per day (median) being the highest. In comparison to a peanut-free diet, researchers discovered that eating 4-5 unshelled peanuts per day was connected with:
- 20% lower risk of ischemic stroke;
- 16% lower risk of total stroke; and
- 13% lower risk of having cardiovascular disease (this included both stroke and ischemic heart disease).
- A significant association was not found between peanut consumption and a lower risk of hemorrhagic stroke or ischemic heart disease.
The link between peanut consumption and lowered risk of stroke and cardiovascular disease was consistent in both men and women.
“The beneficial effect of peanut consumption on risk of stroke, especially ischemic stroke was found, despite the small quantity of peanuts eaten by study participants,” Ikehara said.
“The habit of eating peanuts and tree nuts is still not common in Asian countries. However, adding even a small amount to one’s diet could be a simple yet effective approach to help reduce the risk of cardiovascular disease.”
The American Heart Association recommends eating about five servings of unsalted nuts per week; one serving is ½ ounce (2 tablespoons) of nuts. Besides peanuts, the Association also says other healthy nut options include unsalted cashews, walnuts, pecans, macadamia nuts and hazelnuts.
Several limitations were noted in the study, including the validity and reliability of peanut consumption measurements in the data collection and analysis.
Bias caused by these measurements may lead to errors in the association. However, a measurement error correction analysis was performed, and the associations proved to be accurate.
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