Volume 6  Number 9  December 10, 2009
Second Opinions

Urban Myths: Food Facts and Fallacies

Edible: adj.: Good to eat, and wholesome to digest, as a worm to a toad, a toad to a snake, a snake to a pig, a pig to a man, and a man to a worm.
Ambrose Bierce

There is nothing to which men, while they have food and drink, cannot reconcile themselves.
George Santayana

Thanks to the wisdom of the cliché-laden dialect "Healthspeak," we all know the importance of lots of sleep, reduced stress, plenty of exercise, yearly checkups, and cancer screening. But towering above all these promised components of a long, healthy life, stands first and foremost, a "good diet," however one may define it.

Preventing Cancer with Diet: More Mythology

For the past few years the "battle against cancer" includes taking lots of fruits and vegetables-five servings a day is the latest propaganda from the Department of Agriculture and the food pyramid worshipers. They also tell us to ingest plenty of vitamins, especially vitamins E, C, A, beta carotene, and the mineral selenium. Yet these and many other measures that are often assumed — and marketed — as ways to prevent cancer are either wrong-headed or nonsensical according to researchers quoted in a recent issue of the New York Times.

The evidence about fruits and vegetables is vague, "far from definitive," and therefore unproven. Fiber, found in fruits, vegetables and grains, has been touted to prevent colon cancer, even though two large studies found no effect. As for low-fat diets, long advertised to prevent breast cancer, a large federal study randomizing women to a low-fat or normal diet and looking for an effect in breast cancer found nothing.

Then there's exercise and weight loss, always a good bet to achieve longevity and glowing health. Studies have associated strenuous exercise with less cancer. But that is the same sort of evidence that misled scientists about aspects of diet. "I think it's wishful thinking," said Dr. Susan Love, a breast surgeon, founder of her own research foundation. "We would like things to be more in our control. I think that's part of it. And in the absence of anything else, what do we tell women about how to prevent breast cancer? We tell them to exercise and eat a good diet."

Not long ago a proposed cancer prevention study would have been the largest such clinical trial ever attempted, involving 35,000 men 50 and older. This time the idea was that vitamin E and selenium might prevent prostate cancer. This study was ended early. Once again, there was no protection from cancer, and there were hints the supplements might be causing cancer. The great hope, after more millions spent on scientific imaginings, again turned into profound disappointment.

What about the Miracle of Antioxidants?

Because oxidative stress has been invoked in the pathogenesis of many human diseases, the use of antioxidants vitamin A (and its relative beta carotene), vitamins C, vitamin E (tocopherols), glutathione, etc. have been intensively studied. Yet to this day it is unknown whether oxidative stress is the cause or the consequence of such diseases. Despite the natural abundance of antioxidants in normal diets — they are present in a wide variety of fruits and vegetables, nuts, grains and some meats, poultry and fish — these compounds have become widely and uncritically used as ingredients in dietary supplements with the implication they prevent diseases such as cancer, coronary, and a host of other diseases. Almost overnight millions of consumers became antioxidant worshipers, and morphed into enthusiastic pill poppers while antioxidant vitamins were added to an astounding variety of foods.

In a study published Feb.28, 2007 in JAMA, researchers in Europe analyzed data from 68 large trials in which more than 232,000 adults were given antioxidant supplements. In a subset of those studies, the scientists concluded, subjects taking vitamins A and E and beta carotene saw a slightly increased risk of death compared with those who did not take supplements. (Vitamin C had no effect on mortality, the team found.) Final Conclusions: "Treatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles for vitamin C and selenium on mortality need further study." (Selenium and zinc are commonly referred to as antioxidant nutrients, but these chemical elements have no antioxidant action themselves.)

Other studies of healthy adults taking antioxidant vitamins have also proved disappointing. After tracking nearly 40,000 women for a decade, researchers at Harvard found that those taking vitamin E were just as likely as others to suffer cardiovascular disease and cancer. See this excellent article in the New York Times.

The Audacity of False Food Beliefs

As I've previously written, the public and the professions are increasingly seduced by hundreds of changing and contradictory pronouncements provided by Government, scientists, marketing hucksters, and ambitions amateurs. Potentiated by the Internet these myriad sources provide us with a toxic mixture of "truth," lies, and mythology, driving our food perceptions and nutritional orthodoxies. So let the striving for virtue begin, because most of us are true believers in what constitutes a "healthy diet," and everyone seems to know the deadly perils of "wrong" foods, including saturated fats one year, trans fats the next, and simple sugars the next.

It's obvious that bad luck, bad habits, and genetics have nothing to do with health and survival. It's all about what we eat and how we take care of ourselves. Let us try to forget Mother Nature's cruel decree that "health" remains capricious, and extreme longevity is imperiled by disease, disability, and dementia.

Martin F. Sturman, MD, FACP

Copyright 2009, Mathemedics, Inc.

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