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Nuts get a bad rap. A lot of people still see them as salty, fatty, and high calorie -- a junk food deserving exile to the carts of vendors or the snack bowls of dingy, smoky bars.
But nutritionists say that certain nuts deserve an honored spot in the kitchen of every healthy eater (as long as you're not allergic, of course.) Nuts have lots of protein, fiber, healthy monounsaturated fats, vitamins, nutrients, and antioxidants. And many studies have shown that nuts have powerful cholesterol-lowering effects.
The benefits were clear enough for the FDA in 2003 to issue a "qualified health claim" for peanuts and certain tree nuts -- almonds, hazelnuts, pecans, some pine nuts, pistachios, and walnuts. The claim states that while research is not conclusive, there is good evidence that nuts can lower the risk of heart disease.
So it's time to dust off your nutcrackers or pull the lid off a can of nuts. Taken in moderation, these nuts are good for you.
Walnuts
"Walnuts are great because they have high levels of omega-3 fatty acids," says American Dietetic Association spokeswoman Suzanne Farrell, MS, RD. "Other nuts don't."
Omega-3 fatty acids are also found in fatty fish like tuna and salmon. We know that omega-3 fatty acids lower levels of triglycerides, a type of fat in the bloodstream. Experts are not exactly sure how. Omega-3 fatty acids may also slow down the growth of plaques in the arteries and reduce swelling throughout the body.
There are a number of small studies that show that walnuts help lower cholesterol.
One 2004 study of 58 adults with diabetes looked at the effects of eating a handful of walnuts each day in addition to a healthy diet. The researchers found that on average, people who ate the walnuts had an increase in their good HDL cholesterol and a drop of 10% in their bad LDL cholesterol levels. The results were published in the journal Diabetes Care.
Walnuts received their own, separate qualified health claim from the FDA in 2004, stating that they may reduce the risk of heart disease.
Almonds
Many studies show that almonds have real health benefits too. Like other nuts, they are high in protein, fiber, healthy monounsaturated fats, minerals, and other nutrients. They are also high in vitamin E, an antioxidant.
One researcher, David Jenkins MD, has done many studies of the effects of almonds. In a 2002 study, he tested 27 men and women with high cholesterol over three months. People who ate about a handful of almonds a day lowered their bad LDL cholesterol by 4.4%. Those who ate two handfuls lowered it by 9.4%. The results were published in the journal Circulation.
Jenkins also studies the effects of almonds along with other cholesterol-lowering foods. In a study published in the American Journal of Clinical Nutrition in 2005, he and other researchers tested cholesterol-lowering drugs against cholesterol-lowering foods in a group of 34 adults with high cholesterol. Almonds, soy protein, legumes, oats, and fruits and vegetables were among the chosen foods. The results were striking. The diet lowered cholesterol levels about as well as cholesterol drugs.
Other Nuts
"Basically, nuts are good," Farrell tells WebMD. "They're high in vitamins, minerals, and good monounsaturated fat, which can lower cholesterol."
Along with almonds and walnuts, the FDA gave its qualified health claim to peanuts, hazelnuts, pecans, some pine nuts, and pistachios.
Many studies back up their benefits. For example, one small 2001 study compared a standard cholesterol-lowering diet with a diet that replaced one-fifth of the calories with pecans. When compared to the standard diet, the pecan diet lowered bad LDL cholesterol by 10.4% and decreased triglycerides by 11.1%. It also raised the levels of good HDL cholesterol by 5.6%. The results were published in The Journal of Nutrition.
Not all nuts offer equal benefits. The FDA cut Brazil nuts, macadamia nuts, cashew nuts, and some varieties of pine nuts from the qualified health claim. This is because of their high fat content. But in moderation, even these nuts may have some of the same benefits.
For instance in one small study, 17 men with high cholesterol ate about 1.5 to 3.5 ounces of macadamia nuts each day. After four weeks, their total cholesterol dropped an average of 3% and their bad LDL cholesterol dropped 7%. The results were published in The Journal of Nutrition in 2003.
Getting Nuts Into Your Diet
Nuts are easy to work into your meal plan. Some nuts traditionally come still in the shell. But you can buy most of them pre-shelled at a grocery store. They don't need any preparation. Just eat a handful as a snack or add them to a trail mix. You don't need very many anyway.
You can also use nuts as a condiment. Sprinkle them on your salad, cereal, yogurt, fruit, vegetables, or entrees, suggest Keecha Harris, DrPh, RD and Ruth Frechman, RD, both spokeswomen for the ADA. Use nuts in pasta salads or in hot soups.
However, don't get seduced by anything less than a pure nut. "When you're choosing nuts, make sure to get them raw and unsalted," Farrell tells WebMD. Honey-roasted, chocolate covered, and other candied nuts give you extra calories that you don't need.
How Much Do You Need?
You can get the health benefits of nuts from just a handful a day. About 1 to 1.5 ounces is plenty, experts say. The high protein and fiber in nuts make them very filling. Make sure you don't overdo it.
"Although nuts have a lot of benefits, they're also high in calories that can add up fast," says Farrell. Gaining weight is likely to undo any of the heart-healthy effects of these foods.
The best way to add nuts to your diet is to use them to replace less healthy fats -- like saturated fats in meats. That way you're gaining the benefits of nuts without adding more calories.
Published November 2005.
SOURCES: Suzanne Farrell, MS, RD, spokeswoman, American Dietetic Association. Ruth Frechman, RD, spokeswoman, American Dietetic Association. Keecha Harris, DrPH, RD, spokeswoman, American Dietetic Association. FDA web site. American Dietetic Association web site. National Heart, Lung, and Blood Institute web site. American Heart Association web site. Kris-Etherton, P. Circulation, Nov. 19, 2002; vol 106: pp 2747-2757. Jenkins, D. American Journal of Clinical Nutrition, February 2005; vol 81:pp 380-87. Jenkins, D. Journal of the American Medical Association, July 23-30, 2003; vol 290: pp 502-510. Jenkins, D. et al. Circulation, Sept. 10, 2002; vol 106: pp 1327-1332. Manohar, L. The Journal of Nutrition, April 2003; vol 133: pp 1060-1063. Sujatha, R et al. The Journal of Nutrition, 2001; vol 131: pp 2275-2279. Tapsell, L. Diabetes Care, December 2004; vol 27: pp 2777-2783. Zambon, D. Annals of Internal Medicine, April 4, 2000; vol 132: pp 538-546.