Nuts & Heart Health

There's good news if you're nuts about nuts. Over the past decade, a substantial amount of research has suggested that eating nuts in moderation—including peanuts and most tree nuts—can help keep your heart healthy.

Many studies suggest that including nuts in the diet may reduce the risk of heart disease. Although more research is needed, both large-scale population studies, as well as clinical studies, have concluded that eating nuts is associated with a lower risk of heart disease.

In 2003, the U.S. Food & Drug Administration announced that it would allow certain types of nuts to make a qualified heart health claim. Specifically, the FDA allows the following statement to appear on the packages of whole or chopped peanuts, almonds, hazelnuts, pistachios, walnuts and pecans:

"Scientific evidence suggests, but does not prove, that eating 1.5 ounces per day of most nuts, as part of a diet low in saturated fat and cholesterol and not resulting in increased caloric intake, may reduce the risk of coronary heart disease. See nutrition information for fat content."

The FDA indicated that this claim does not apply to cashews, macadamia nuts, Brazil nuts and pine nuts.

Additionally, major dietary recommendations such as the Dietary Guidelines for Americans (2005) and the American Heart Association Dietary Guidelines (2000), among others, all included eating nuts as a part of a balanced diet in their guidelines. But because nuts contain approximately 160 to 200 calories and 13 to 20 grams of fat per one-ounce serving, it's important to enjoy nuts in moderation and without increasing the overall calories consumed as part of any diet plan.

How do nuts help?

Most tree nuts and peanuts contain significant amounts of monounsaturated and polyunsaturated fats. They are naturally cholesterol free, contain 0 g trans fat and contain substantially less saturated fat than monounsaturated and polyunsaturated fat. Replacing foods in the diet that are high in saturated fats with plant foods that are high in unsaturated fats—like peanuts, almonds, hazelnuts, pistachios, walnuts, and pecans—can lower LDL ("bad") cholesterol while leaving HDL ("good") cholesterol levels unchanged. Doing so helps reduce the risk of heart disease.

But the exact way in which nuts help reduce heart disease risk may not be due solely to the "good" fats found in nuts. Nuts are good sources of many other nutrients, such as dietary fiber, several B vitamins, antioxidant vitamin E, magnesium and copper. In a recent article, researchers from the Pennsylvania State University suggest that the cholesterol lowering effect of nuts is about 25% higher than would be expected based solely on the "good" fat content of nuts. It appears that besides the "good" fats in nuts, one or more of these other nutrients may help provide the additional cholesterol lowering benefit, hence heart protective effects. More study is needed in this area, but the preliminary results are interesting.

While the research on nuts' beneficial effects on heart health is positive, nuts are still a calorically dense food. For that reason, it's important not only to substitute them in place of foods that contain higher amounts of saturated fat, but to do so without increasing the total number of calories in your diet that you need to maintain a healthy body weight.

Nuts Are Recommended in Heart Healthy Eating Plans

Two diets in particular—DASH (Dietary Approaches to Stop Hypertension), developed by scientists supported by the National Institute of Health (NIH) and The Portfolio Diet, designed by scientists at the University of Toronto—include nuts in their plans for healthy eating. These diets were designed based on optimal dietary patterns to reduce the risk of heart disease by lowering high blood pressure or blood cholesterol levels.

The DASH eating plan, rich in magnesium, potassium, calcium, protein and fiber, includes whole grain products, fish and poultry, and also recommends eating four to five servings of nuts, seeds and legumes a week. In the DASH eating plan, a serving of nuts is equal to one ounce. Nuts, seeds and legumes provide magnesium, potassium and fiber. The DASH study found that elevated blood pressure can be reduced by eating a diet low in saturated fat, total fat and cholesterol, and rich in fruits, vegetables and low-fat dairy foods.

The Portfolio Diet is a plant-based diet, low in saturated fat and dietary cholesterol, and includes foods that contain cholesterol-lowering components (viscous fiber, soy and other vegetable proteins, plant sterols and certain nuts). Specific foods used in the diet that are sources of cholesterol-lowering components included almonds, soy milk and soy burgers, oat bran cereal and oat bran bread, barley, lentils, beans and plant sterol-enriched margarine. In this study, people on a 2,000-calorie diet ate one ounce of almonds each day as well as other foods believed to have cholesterol-lowering properties, substituting them for other foods with less favorable profiles with respect to cholesterol. Results showed that LDL ("bad") cholesterol levels were reduced by about 30%. This reduction was similar to what was seen with prescription cholesterol-lowering drugs, suggesting that heart disease risk reductions may be the same as well. This study suggests that combining multiple cholesterol-lowering food components or foods, such as nuts, in the same dietary portfolio may increase the effectiveness of diet on reducing the risk of heart disease.

References:

  1. http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf
  2. Svetkey LP, et al. The DASH diet, sodium intake and blood pressure trial (DASH-Sodium): rationale and design. DASH-Sodium Collaborative Research Group. J am Diet Assoc. 1999; 8(suppl): S96-104.
  3. Jenkins D, et al. Effects of dietary portfolio of cholesterol-lowering foods vs. lovastatin on serum lipids and c-reactive protein. JAMA. 2003; 290: 502-510.

* Scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts, such as almonds, peanuts, hazelnuts, pecans, pistachios, and walnuts, as part of a diet low in saturated fat & cholesterol and not resulting in increased caloric intake may reduce the risk of coronary heart disease.