By Kathy McManus, M.S., R.D., L.D.N.
You may often hear disparaging comments about nuts, because they contain fat, but this idea stems from the misleading concept that all fats are bad. Despite what you’ve heard, not all fats are created equal. Researchers and clinicians now know certain fats (trans fat and saturated fat) contribute to heart disease, while others (polyunsaturated and monounsaturated) actually reduce the risk of a heart attack.
A variety of population studies have reported that increased nut consumption is associated with a reduction in heart-disease risk. In one study, by substituting one ounce of nuts for an equivalent amount of calories from carbohydrate, the risk of developing heart disease was reduced by 35%. If the nuts replaced saturated fat, the risk was reduced by 45%.
A study done at Harvard showed that peanuts and peanut butter may help to prevent type 2 diabetes. Researchers found that consuming a half serving (one tablespoon) of peanut butter or a full serving of peanuts or other nuts (1 ounce), five or more times a week is associated with a 21% and 27% reduced risk of developing type 2 diabetes. The researchers said their findings may stem from the fact that higher intakes of fiber and magnesium and foods with a low glycemic index (healthy carbohydrate) have been associated with reduced risk of type 2 diabetes in several studies
The basis for growing interest in the role of monounsaturated fat is from research in regions around the Mediterranean Sea. A landmark study showed that people in Crete who eat about 43% of calories from fat (mostly monounsaturated) had a low incidence of heart disease. Although the fat in nuts have different proportions of monounsaturated and polyunsaturated fats, most nuts are predominantly monounsaturated fat.
Walnuts are a little different. Walnuts contain more polyunsaturated fat. Walnuts also have the omega-3 fatty acid that is also found in fish oil. These omega-3 fats have been shown to reduce the incidence of dying suddenly from a life-threatening arrythmia
Although relatively high in calories for their size, the advantage of eating nuts involves how packed they are with nutrients. Dietary fiber, magnesium, copper, folic acid, potassium and protective phyto-chemicals are found in nuts, all contributing to cardiovascular health. Because they come from plants, nuts are naturally cholesterol-free and provide one of the best plant sources of protein. This protein is high in arginine, which may help to keep blood vessels open and prevent clotting.
With the growing popularity of nuts, we must also realize that although a healthy option, they must be eaten in moderation. Should we all sit in front of our TVs, eat the entire can of nuts in an hour, and complain when we gain weight? Of course not. Healthy eaters avoid excessive calories.
A reasonable goal is to eat one ounce of nuts per day. Some studies suggest the fat in nuts allows for a feeling of satiety or satisfaction even with a smaller serving.
Source: USDA Nutrient Database for Standard Reference, Release 13
Almonds, pecans, pistachios, peanuts, walnuts, filberts, cashews, hazelnuts … your choices abound! Sprinkle nuts on top of your favorite salad, casserole or dessert. Add them to your oatmeal, breads, pastas or stir-fry. Get creative! Make trail mix with dried fruits and mixed nuts; divide into small bags for a satisfying snack. Try nut butters for a healthy alternative to regular butter or margarine.
It doesn't matter how you get in your ounce of nuts — just enjoy!
Kathy McManus, M.S., R.D., L.D.N. is the director of the department of nutrition at Brigham and Women's Hospital and director of nutrition and behavioral modification program for the Program for Weight Management at Brigham and Women's Hospital. Emily Werner is a dietetic intern at Brigham and Women's Hospital.