Good Nut-rition
For: Wellness Facts,
November 2002
The health reputation of nuts has been on a roller coaster. A few decades ago nuts were valued for their protein, vitamins, and minerals. Then in the 1980s nutritionists saw them primarily as compact sources of fat and calories (there is one low-fat nut—see quiz below). But since the early 90s, nuts have been on the rise, thanks to research pointing to their potential heart benefits.
Perhaps the most famous study to give nuts a boost was one of Seventh-Day Adventists from 1997: it found that those who ate nuts at least five times a week cut their risk of a heart attack in half, compared to those who ate nuts less than once a week. This was followed by other studies, such as two large ones involving only women, which also found that nut eaters had a lower risk of heart disease, even when researchers controlled for other variables that affect the risk. Other studies, most recently one using almonds, have suggested that nuts may help lower blood cholesterol levels.
There are plenty of substances in nuts that may explain these heart-healthy results: Nuts are rich in:
• monounsaturated fats (as are olive and canola oils) and polyunsaturated fats: these can lower blood cholesterol, especially when substituted for foods high in saturated fat, such as meat or cheese.• vitamin E, known to be cardio-protective.
• folic acid and other B vitamins: these may reduce the risk of heart disease by lowering blood levels of homocysteine (WELLNESS LETTER, November 1997).
• copper, potassium, and magnesium, all three linked to heart health.
• fiber and certain phytochemicals (notably saponins and sterols) that may act as antioxidants or lower cholesterol.
Why go nuts?
It's too early to say for sure that nuts can substantially lower the risk of heart disease. And nuts do have drawbacks. A hand-ful can pack as many calories as a piece of cake, and more fat ("dry-roasted" nuts are just as high in fat). If nuts lead to weight gain, that's bad for the heart. And they are often high in salt, though unsalted ones are widely available. A cup of salted peanuts has 1,000 milligrams of sodium, more than one-third the suggested daily intake.
So don't go overboard with nuts. Instead of using nuts as a snack, when you might eat large amounts, use them as part of a meal. Chopped nuts are tasty in fruit or vegetable salads, yogurt, oatmeal, home-baked breads and muffins, pancakes, casseroles, and pilafs. When possible, substitute nuts for foods rich in saturated fat. Peanut butter, for instance, is definitely a healthier choice for a sandwich than cheese or salami.
And by the way: Nut butters have many of the same nutritional advantages and disadvantages as nuts, except that most commercial peanut butter contains small amounts of hydrogenated vegetable oil, which can boost blood cholesterol levels. "Natural" varieties are usually just ground peanuts.
A nutty quiz
All nuts have a lot in common. With one exception, they have 160 to 190 calories and 14 to 19 grams of fat per ounce; at least three-quarters of the calories come from fat. But there are some nutritional differences among nuts, as this quiz reveals. Match the nut to its special trait.
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1. highest in fat 2. only low-fat nut; rich in fiber 3. rich in vitamin B-6 and heart-healthy oil 4. rich in vitamin E and folic acid 5. rich in selenium 6. not true nuts, but legumes 7. rich in copper, iron, and folic acid 8. rich in calcium, vitamin E, and fiber |
(a) almonds (b) brazil nuts (c) cashews (d) chestnuts (e) hazelnuts (f) macadamia (g) peanuts (h) walnuts |
Answers: 1 (f), 2 (d), 3 (h), 4 (e), 5 (b), 6 (g), 7 (c), 8 (a).
UC Berkeley Wellness Letter, April 1999
