OH, NUTS!

Once a no-no because of fat content, some nuts are seen as good for the heart.
By SHARI ROAN
LOS ANGELES TIMES
Just a few years ago, nuts were dietary pariahs.
The perception was that they were fattening. And in the early '90s, fat was bad. Even the American Dietetic Association was recommending nuts only for weight gain.
By 1996, U.S. nut sales had dropped almost 40 percent from the lofty figures of the late 1980s. Then came the science. One after another, researchers have now shown that people who regularly eat nuts appear to have lower cholesterol levels and may have a decreased risk of heart disease. They've also found that nuts can satisfy appetites without causing weight gain.
Today, not only have nuts reappeared in kitchens nationwide, but in July the Food and Drug Administration granted manufacturers of certain types of nuts the right to place a "qualified" health claim on their products. Such permission means there is moderate evidence of a health benefit -- but too few studies to say with scientific certainty that nuts can, for example, reduce the risk of heart disease.
"In the food industry, it's one of the fastest turnarounds I've ever seen," says Pat Kearney, a consultant to the nut industry and a former U.S. Department of Agriculture official.
Type of fat matters
The story of nuts' transformation from an almost forbidden food to a healthful one is part of the dramatic reappraisal of the role of fat in the diet, experts say.
Throughout the 1990s, most nutrition experts preached that low-fat diets were the most healthful. More recent studies have indicated that the type of fat matters most and that some fat is good.
Fats are mixtures of fatty acids that fall into the categories of saturated, polyunsaturated and monounsaturated depending on their chemical composition. Saturation refers to whether all of the carbon atoms in the fatty acid chains are bonded to hydrogen atoms. In saturated fat -- found in high-fat cuts of meat, whole or 2 percent dairy products, palm oil and other foods -- all of the carbon atoms are saturated with hydrogen. This chemical composition tends to raise "bad" cholesterol in the body.
Unsaturated fat -- found in olive and canola oils in addition to most nuts -- has a space where a hydrogen atom would be and contains a double bond between carbon atoms. This chemical composition does not cause cholesterol to rise.
"People now recognize the dangers of saturated fat and that nuts have the right sort of fat," says Dr. David Jenkins, a nutrition researcher at the University of Toronto.
Lowering cholesterol
In a study published in the July 23 issue of the Journal of the American Medical Association, Jenkins showed that including almonds in the diet along with other cholesterol-lowering foods such as tofu, oat bran and olive oil was as effective as cholesterol-lowering statin drugs.
That study was only the latest in a line of positive research demonstrating that the fat in nuts isn't "bad" fat. A 1999 study from Pennsylvania State University, for example, found that people who adhered to a weight-loss diet high in unsaturated fats (provided by peanuts, which is technically a legume, and peanut butter) lowered their total cholesterol by 11 percent and their low-density lipoprotein, or bad, cholesterol by 14 percent. The diet contained 35 percent of calories from fat, but because the fat was mostly unsaturated, the subjects lost weight and lowered their cholesterol in levels similar to a group on a diet containing less than 20 percent of calories from fat.
A June 2002 study from Harvard University showed that people who ate nuts regularly had a lower risk of sudden cardiac death. And in November 2002, a study of more than 83,000 nurses found that eating nuts may help lower the risk of Type 2 diabetes.
Medicinal effect
Scientists now suggest that the complete chemical structure of many nuts -- unsaturated fat, protein, fiber and such antioxidant vitamins and minerals as vitamin E and magnesium -- has a medicinal effect. Nuts also contain a substance called resveratrol, which is increasingly thought to have antioxidant and anti-cancer properties.
Nuts have been part of the human diet since the dawn of civilization in Mesopotamia. "They have been preserved in the diet as valued foods. They've really been a part of so many cardiovascular disease-free cultures," such as those in the Mediterranean, Jenkins says.
But in contemporary culture, nuts are often roasted in hydrogenated oils and smothered in salt. "That has been a disaster because it raises cholesterol and blood pressure," he adds.
Changing image
Today, the nut industry is trying to portray its product in a new light. Although consumers can still find plenty of roasted, salted nuts in 32-ounce cans and nuts folded into sugary confections, their nutritionally higher-brow cousins can be found in produce sections of grocery stores and in healthful, whole-grain cereals and breads.
Besides lobbying long and hard for the FDA health claim, the nut industry has invested about $1 million per year for the last eight years in research, says Craig Duerr of the Almond Board of California in Modesto.
Various manufacturers also have altered their ads to tout nuts as a health food. In particular, the industry is trying to address one of the remaining concerns some health experts have about recommending nuts: calories. An ounce of nuts contains about 160 to 200 calories.
"I think some people worry about portion control," says Lola O'Rourke, a spokeswoman for the American Dietetic Association in Seattle. "Don't open a large bag of nuts and sit in front of it. Portion out an ounce or so."
Weight-gain study
Evidence suggests that limiting nut consumption to 1 or 2 ounces of plain nuts on a daily basis does not cause weight gain. In a study published last year, Richard Mattes, a professor of foods and nutrition at Purdue University, instructed volunteers to eat about 500 calories a day in peanuts.
One group cut 500 calories from their diet and replaced those calories with peanuts. A second group was told to consume their regular diet and add 500 calories a day in peanuts. A third group was allowed to consume peanuts in any way it chose. None of the groups gained weight.
A study from researchers at Loma Linda University in California found that a pecan-enriched diet did not cause study participants to gain weight when compared with a control group eating a much lower-fat diet. And a Harvard study found that people following a moderate-fat, Mediterranean-style diet that contained nuts maintained their weight loss better than people following a traditional low-fat diet.
"One could not, in good faith, recommend nuts if they posed a threat to body weight," says Mattes. "But a line of evidence shows that isn't a concern. When you purposefully increase nut consumption, it does not promote weight gain. ... In our study, people spontaneously adjusted their diet to offset about two-thirds of the calories from nuts."