By: Jean Johnson for Reflux1Papers across the country heralded in early February that low fat diets have little effect on breast cancer, colorectal cancer, heart disease and stroke. Yet some remain skeptical. In a comparative study of 20,000 women on reduced-fat diets and 29,000 women eating regularly, researchers found only very slight differences in correlating rates of cancers and diseases associated with the cardiovascular system.
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Harvard School of Public Health’s nutrition source Web site summarizes their take on low-fat diets:
The message ‘eat a low fat, low cholesterol diet’ is out of date. What matters is the type of fat in the diet.
The key is to substitute good fats for bad fats. When in doubt choose olive, canola, safflower, sunflower, and corn oils.
The biggest influence on blood cholesterol level is the mix of fats in the diet.
Moderate consumption of eggs – up to one a day – does not increase heart disease.
Hard stick margarine is worse for the heart than butter.
Fish is an important source of polyunsaturated fat know as omega-3 fatty acid.
To lower trans fat intake: Choose liquid vegetable oils, avoid products with hydrogenated or partially hydrogenated oils, and reduce the amounts of commercially prepared baked goods, snack foods and fast foods.
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The Large and Expensive Study Is Definitive, Say SomeUsing $415 million in taxpayer dollars, the National Institutes of Health embarked on the large trial. Forty-nine thousand women ages 50 to 79 were tracked over eight years in part of the ongoing work known as the Women’s Health Initiative – the same program that produced unexpected and alarming conclusions related to the effects of estrogen replacement therapy.
The results of the expensive low-fat study were published in a recent issue of the Journal of the American Medical Association. According to the director of epidemiological research for the American Cancer Society, Michael Thun, M.D., the massive undertaking was “the Rolls-Royce of studies. We usually have only one shot at a very large-scale trial on a particular issue.”
Physician and chief emeritus at Rockefeller University in New York City, Jules Hirsch, M.D., expert on diet, weight and health was stunned. “These studies are revolutionary. They should put a stop to this era of thinking that we have all the information we need to change the whole national diet and make everybody healthy.”
A Berkeley statistician who specializes in study designs, David A. Freedman, Ph.D., agrees that the research approach was sound enough to accept the conclusions. “The studies were well designed, and the investigators tried to confirm popular hypotheses about the protective effect of diet against three major diseases in women,” Freedman said, adding, “but the diet studied here turned out not to be protective after all.”
Design Has Flaws, Say Others
“In the mid-1990s, when my mother first became a subject of the Women’s Health Initiative study, of which the low-fat diet was a part, she complained after her first orientation session, ‘They make no distinction between lard and olive oil!’” In her letter to the editor of the New York Times, Gigi Edwards of Saunderstown, Rhode Island, continued, “It would be highly irresponsible of the American medical community if, as Dr. Michael Thun of the American Cancer Society suggests, this were to be the last word. The study was flawed from the get-go.”
Cardiologist and professor at Harvard Medical School, Peter Libby, M.D. gave a nod to Edwards’ observation. He noted that the study’s concept of fat intake “had an antique patina” since more recently many Americans have focused on the type of fat people eat rather than total quantities.
Others take issue with not the quality, but with the amount of fat the women in the trial consumed. “Reports on the study of a low-fat diet on breast cancer would have more appropriately stated that the study was flawed in implementation since participants were unable to maintain a low-fat diet,” wrote David J. Goldstein, M.D. in another letter to the New York Times.
Goldstein refers to the fact that while trained nutritionists working with the women asked them to eat only 20 percent of their calories in fat, by the end of the study, most participants were getting 28 percent of their total intake from fats.
“As a consequence, wide reporting of this study as if it had been properly executed could have widespread health consequences, like reducing the availability of lower and no-fat foods,” Goldstein went on. “This study provides no new information except confirmation that maintaining a diet is difficult and a hint that reducing ‘extremely high’ levels of fat intake to ‘high’ levels may be beneficial.”
While not as resoundingly oppositional as Goldstein, epidemiologist at the nonprofit hospital group MedStar Research, Barbara V. Howard, M.D. shares the physician’s concerns.
“We are not going to reverse any of the chronic diseases in this country by changing the composition of the diet,” Howard said “People are always thinking it’s what they ate. They are not looking at how much they ate or that they smoke or that they are sedentary.”
The Mediterranean Diet – Focus on Quality Not Quantity
Harvard’s Libby agrees that more contemporary approaches to healthy eating like the Mediterranean diet, which draws most of its fat from heart healthy olive oil, have not been clinically scrutinized in similar fashions. “If they did a study like that and it was negative,” Libby said, “then I’d have to give up my cherished hypothesis for data.” Clearly Libby thinks following a food plan rich in vegetables, fruits, whole grains, legumes, and olive oils, graced sparingly with wine, dairy products, fish and meats is a hit.
Libby need not worry says K. Dun Gifford, founder of Oldways Preservation Trust, a food issues think tank running since 1993.
“Looking back after 15 years, it feels really good to say that we brought olive oil into the American mainstream, and people aren’t eating some fake salad oil and fake butter de rigueur,” said Gifford. “Now people are enjoying olive oils with all their great tastes and colors – green ones, tart ones, very deep yellow ones. That was a big success.”
“But then the problem was what to do about the low-fat diets – silly things to foist off on the human race,” Gifford said. “So we created the Mediterranean pyramid diet in answer since the best science said it is the healthiest way to eat.”
Longtime friend of Gifford’s, the late Julia Child shared his philosophy. “Water pack tuna?” Child once said on a National Public Radio interview. “That’s ridiculous. All the flavor’s in the oil. Just eat less and enjoy each bite.”
Child was famous for similar rifts about the Thanksgiving meal, and argued that good food enjoyed moderately was the key to health. So when it comes to the question of spending $415 million studying low fat diets in which all fats were considered equal, Child most likely would politely suggest we follow her into the kitchen while she whips up some nice pasta primavera and a lovely green salad decked out in a gorgeous golden olive oil.
