Tree nuts appear to be good for your heart, according to a quite good for reducing your risk of cardiovascular disease, according to a review of several medical studies. Researchers evaluated the results of 61 controlled trials of eating tree nuts and found that eating them can help reduce levels of total cholesterol, triglycerides, low-density lipoproteins (LDL cholesterol), blood pressure, and other risk factors for heart disease and stroke.
This type of review is called a meta-analysis, because it combines and analyzes data from several studies to improve the statistical importance of the findings.
Tree nuts include walnuts, almonds, pecans, pistachios, hazelnuts, cashews, and Brazil nuts. Peanuts are not a tree nut, but are a legume instead. Most of the studies involved walnuts, but the meta-analysis found that the amount of nuts consumed were more relevant to the benefit than the type of nut consumed.
The controlled trials included studies that compared adults on a diet with tree nuts compared to a diet without them. The trials lasted from 3 to 26 weeks long and involved 2,582 participants. The amount of nuts they ate ranged from 5 grams a day to 100 grams a day, or about 3.5 ounces. The researchers found that people who ate at least 2 ounces of nuts-about two servings-had stronger reductions of total cholesterol and LDL cholesterol.
"Our study results further support the growing body of research that tree nuts, such as walnuts, can reduce the risk of cardiovascular diseases," said one of the authors, Michael Falk, PhD, Life Sciences Research Organization. "Tree nuts contain important nutrients such as unsaturated fats, protein, vitamins and minerals. Walnuts are the only nut that provide a significant amount (2.5 grams per one ounce serving) of alpha-linolenic acid (ALA), the plant-based form of omega-3s."
The meta-analysis was funded by the International Tree Nut Council Nutrition Research and Education Foundation. It was published in the American Journal of Clinical Nutrition.