People who regularly eat a variety of nuts including walnuts, peanuts and tree nuts may be less likely to develop heart disease than individuals who rarely or never eat nuts, a new U.S. study from Harvard T.H. Chan School of Public Health in Boston suggests.
The researchers examined information on medical history, lifestyle and eating habits for more than 210,000 healthcare workers. During a follow-up period of more than 20 years, 14,136 people developed cardiovascular disease, including 8,390 coronary heart disease cases and 5,910 strokes.
Compared to people who rarely, if ever, ate nuts, people who had one 28-gram serving of nuts at least five times a week were 14% less likely to develop cardiovascular disease and 20% less likely to develop coronary heart disease, the study found.
Even so, people shouldn’t overdo it, and they should avoid salted nuts.
Nuts are high in calories and should be eaten in small portions and used to replace other protein foods rather than being added to the diet.
Eating nuts has long been linked to a lower risk of heart disease, diabetes, and high blood pressure, but much of this research has focused on overall intake rather than identifying specific types of nuts that may have the biggest benefit.
Walnuts, peanuts found to be especially protective
The current study looked at different types of nuts separately and found that people who ate walnuts at least once a week had a 19% lower risk of cardiovascular disease and a 21% lower risk of coronary heart disease than people who never at nuts.
At least two weekly servings of peanuts were linked with a 13% lower risk of cardiovascular disease and a 15% lower risk of coronary heart disease.
Two servings or more of tree nuts such as almonds, cashews and pistachios were linked to a 15% lower risk of cardiovascular disease and a 23% lower risk of coronary heart disease.
Researchers found no evidence of an association between total nut consumption and risk of stroke, but the risk of stroke was lower in people who consumed larger amounts of peanuts and walnuts. Peanut butter and tree nuts were not associated with stroke risk.
The study, however, wasn’t a controlled experiment designed to prove whether or how eating nuts might lower the risk of heart disease.
And it focused mainly on whites, which may mean the results don’t apply to people of other racial or ethnic groups.
What’s new is the pinpointing of the risk associated with eating particular nuts, such as walnuts and peanuts.
Notable nutrients in nuts
All nuts deliver plenty of heart-healthy unsaturated fats, calcium, magnesium, potassium, B vitamins, vitamin E and phytosterols, compounds that can help lower LDL cholesterol. Some types, though, deserve a shout-out for their exceptional nutrient contributions.
Almonds. Per 28 g (22 nuts): 170 calories, 6 g protein, 15 g fat, 3 g fibre | Notable: 7 mg vitamin E, nearly half a day’s worth for adults
Brazil nuts. Per 28 g (6 nuts): 187 calories, 4 g protein, 19 g fat, 2 g fibre | Notable: 107 mg magnesium (25 per cent of a day’s worth) and nearly 10 times the daily requirement for selenium, needed for antioxidant protection and thyroid function
Cashews. Per 28 g (18 nuts): 163 calories, 4 g protein, 13 g fat, 1 g fibre | Notable: 74 mg magnesium (adults need 400 mg per day)
Hazelnuts: Per 28 g (18 nuts): 183 calories, 4 g protein, 18 g fat, 3 g fibre | Notable: 4.3 mg vitamin E (adults need 15 mg per day)
Peanuts. Per 28 g (28 nuts): 166 calories, 7 g protein, 14 g fat, 2.4 g fibre | Notable: 4 mg niacin (one-quarter of a day’s worth); resveratrol, a phytochemical thought to contribute to longevity
Pecans: Per 28 g (20 halves): 201 calories, 2.7 g protein, 21 g fat, 4 g fibre | Notable: 6.7 mg gamma tocopherol, an anti-inflammatory form of vitamin E thought to protect against heart disease and prostate cancer
Pistachios. Per 28 g (49 nuts): 162 calories, 6 g protein, 13 g fat, 2 g fibre | Notable: 6.6 mg gamma tocopherol
Walnuts: Per 28 g (14 halves): 185 calories, 4.3 g protein, 18. 5 g fat, 2 g fibre | Notable: 2.6 g alpha linolenic acid (ALA), a plant omega-3 fat; women need 1.1 g per day and men require 1.6 g. (Walnuts are the only nut that contains ALA.)
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.