Let’s face it: We were brainwashed. For years, nutritional gurus strummed a one-note samba: All fats are bad. And many of us played along, giving up some of our favorite foods. Like nuts.
“Eighty to 90 percent of calories [in nuts] are from fat. So they were labeled as a high-fat food,” said Frank Hu, an assistant professor of nutrition at the Harvard School of Public Health. And, for the last two or three decades, he said, “health-conscious people tended to avoid them to lose weight and avoid heart disease.”
“We’ve been so biased about fat,” said Jeffrey Blumberg, a nutrition professor at Tufts University. “The thinking was that any high-fat food is bad.”
At long last, nutritionists are changing their tune. Now, they concede, there are both good fats and bad fats, and nuts are good again because they contain “the good kind of fat,” said Dr. George Blackburn, director of the center for nutrition and medicine at Beth Israel Deaconess Medical Center. They’re also good, he said, because “they satisfy in small portions.”
The emerging consensus is that saturated fats (the kind found in meat and dairy products) are the bad ones because they raise LDL or bad cholesterol in the blood. Monounsaturated and polyunsaturated fats (the kind found in nuts and olive, canola, corn, safflower and sunflower oils) are good because, though high in fat and calories, they do not raise LDL. In fact, polyunsaturated fats can actually lower LDL.
The same principle holds for peanuts and peanut butter, too, even though peanuts, despite their name, are technically classified as legumes, not nuts. Peanuts are good for you because they’re high in monounsaturated fats.
For the record, It’s only fair to note that this good-fat, bad-fat message is heavily promoted by some food industry groups, including the International Tree Nut Council, which sponsored a conference on the health benefits of nuts this fall at Georgetown University. The nut folks are also sponsoring a number of ongoing studies of the nutritional pros and cons of nuts.
But, with that caveat in mind, consider the growing evidence that nuts are good for you:.
The Iowa Women’s Health Study of 34,000 women, conducted between 1986 and 1992, found that women who ate nuts had a 35 percent reduction in heart attacks, compared to those who didn’t.
In 1992, a California study of 34,000 Seventh Day Adventists (who don’t drink or smoke) found that those who ate a small handful of nuts five days a week had 50 percent fewer heart attacks than those who didn’t. And no matter how the researchers sliced up the data looking at men alone, women alone, young people, old people, vegetarians or meat-eaters, the protective effect of nuts on the heart held up, said Dr. Gary Fraser, leader of the study and a cardiologist at Loma Linda University. The gist of 20 other studies, he said, is that regular consumption of nuts lowers blood cholesterol 8 to 10 percent.
In 1998, the Nurses Health Study of 86,000 female nurses confirmed the heart benefits of nuts, showing that women who ate at least 5 ounces of nuts a week had 40 percent fewer heart attacks than those who didnt. Many of the women who ate nuts substituted nuts for greasy steaks and fries, but the protective effect of nuts held true even for those who made less-drastic diet changes, said Hu, of Harvard, the lead author.
Preliminary results from a similar study, the Physicians Health Study, suggest that there are fewer sudden deaths among men who eat nuts, suggesting a similar heart-protecting effect in men, although, so far, the research has not been published.
It’s much less clear whether eating nuts helps prevent cancer. So far, limited data in human studies suggests no dramatic benefit. In rats, a study paid for by the Almond Board of California and conducted by Paul Davis, a research nutritionist at the University of California at Davis, found that rats that were fed almonds were less likely to develop precancerous changes in the colon after being injected with a cancer-causing chemical, compared to rats that didn’t get almonds.
Naturally, there’s a downside to this good PR for nuts: Because of their high-fat content, nuts are loaded with calories. But that doesn’t automatically mean they’re diet-busters. In fact, a nibble or two of nuts a day may actually help with weight loss, provided you don’t go overboard on overall calories.
In research presented last year at a scientific meeting, Kathy McManus, a registered dietitian at Brigham and Women’s Hospital in Boston, studied 101 overweight people who were put on either low- or moderate-fat diets that didn’t exceed 1,200 calories a day for women or 1,500 for men.
At the end of the 18-month study, the people on the low-fat diet had typically dropped out and regained some of their lost weight, while the moderate fat group was maintaining weight loss. Those on the moderate fat diet ate an ounce of nuts a day (170 calories worth), plus a tablespoon of oil and a teaspoon or two of peanut butter.
“The point is that, with a moderate-fat diet, people seem to be able to stay with a diet longer,” said McManus, whose research was paid for by three industry groups – the Institute and the International Tree Nut Council.
International Olive Oil Council, the Peanut
Among other things, she said, having an ounce or so of nuts in late afternoon can ward off the hungry horrors. You’re not so ravenous when you walk in the door, which means you’re less likely to eat a lot while you’re cooking dinner.
And there’s yet another reason to eat nuts: They are full of arginine, an amino acid that helps the body make nitric oxide, which helps blood vessels dilate, thus lowering blood pressure. They’re also loaded with vitamin E and other antioxidants, which prevent damage to DNA and cells from chemicals called free radicals.
The bottom line is that nuts are no longer taboo. If you want to add them to your diet, you probably should try eating them instead of something like cream or red meat. And keep portions modest, like the small packets of nuts that airlines hand out. In other words, don’t go totally nuts.
SIDEBAR: Going Nuts Over Nuts
For years, nuts were regarded as unhealthy because they are high in fat. But researchers believe nuts got a bad rap: they contain no cholesterol and are high in both polyunsaturated and monounsaturated fats, which are considered good because they promote a healthy heart. And nutrients in nuts compare favorably to common foods such as chicken and hamburger.
Calories (kcals)
Protein (grams)
Cholesterol (mg)
Saturated fat (grams)
Mono- un saturated fat (grams)
Poly unsaturated fat (grams)
Total fat (grams)
Almonds
578
21
0
4
32
12
51
Cashews
574
15
0
9
27
8
46
Hazelnuts
628
15
0
4
46
8
61
Macadamian
716
8
0
12
59
1
76
Pecans
691
9
0
6
41
22
72
Pistachios
567
21
0
4
25
14
46
Walnuts
654
15
0
6
9
47
65
Lean hamburger
268
24
78
7.2
8
1
18.3
Chicken
173
31
85
1.3
1.5
1
4.5
Butter
108
0.1
33
7.6
3.5
0.5
12.2
Note: Nutrient information is based on 3.5-ounce servings, except butter, which is based on one tablespoon. SOURCES: USDA Nutrient Database for Standard Reference, Bowe and Church’s Food Values of Portions Commonly Used