Experts Dispute Raw-Food Diet Benefits

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Knight Ridder Newspapers
Miami, Fl
July 1, 2003

Experts dispute raw-food diet benefits
By Shari Rudavsky

Until the death of a severely underweight infant whose parents followed a raw-food diet, the term "raw food" was more likely to conjure visions of sushi, oysters or carpaccio than of crunchy greens. Indeed, "going raw" has a certain cachet in quarters far from the modest apartment in Homestead, Fla., where 5-month-old Woyah Andressohn lived. (Woyah, born at 7 pounds, weighed one pound less when she was pronounced dead on May 15.)

Investigators said they believed Woyah may have died of malnutrition. The family's four other children, according to state authorities, were severely malnourished. [More info]

Celebrities such as Woody Harrelson swear by the diet's salutary effects. Restaurants featuring all-raw menus have opened in California, New York and, recently, Miami Beach, Fla.

Raw-foods proponents argue that a diet of uncooked vegetables, fruits and nuts reflects a natural way of eating. Fire changes the molecular structure of food. Heating food above 118 degrees will kill the enzymes in it, diminishing its nutritional value, the theory holds. Pointing to nature and how no animal cooks its food, the theory continues that raw food is more alive than its cooked counterpart and therefore better for us.

"This is about the understanding that if you eat more food that has its life force still intact, that's going to be better for us," says Fred Busch, a raw-foods adherent and co-owner of a raw market and deli in Miami Beach. "This means that there's life force in the cells and that's what's feeding us."

Not so, say many nutritionists and scientists. While some raw foods will enhance your diet, an eating plan consisting totally of uncooked foods puts anyone -- particularly young children -- at the risk of nutritional unbalance. Although raw fruits and vegetables are packed with vitamins, a raw diet, without dairy or meat, may provide too little protein and too few fatty acids, essential to growth and health, experts say. In addition, some vegetables offer more nutrients when cooked, nutritionists say, as the heat makes these nutrients more accessible to our bodies.

"The burden of proof is on them to show that it's a better diet," says Linda Bobroff, a professor of nutrition at the University of Florida in Gainesville, noting that years of research stand behind the USDA-recommended food pyramid and a solidly balanced diet with a mix of raw and cooked foods.

Stan Glaser, owner of Glaser Farms in the Redland, Fla., counters that science has yet to offer him definitive proof that the mainstream diet is better. Over the course of several years, Glaser experimented with different ways of eating, including raw foods.

At one point he subsisted only on green leaves and fruits, but now he has added raw vegan foods such as nuts and seeds. Glaser, who sells his fresh fruits and vegetables and prepared raw foods at a farmers market on Saturdays, scoffs at the standard nutrition line.

"They lead you to believe that you have to be a Ph.D. in nutrition to know what to eat. I find this ludicrous," he said.

Instead, he advocates a diet more akin to that followed by our ancestors and other species. By doing that, Glaser says we will hit upon a diet that not only worked well for our forebears but will work for us. "If you limit what you eat to the uncooked vegetables, foods which have always been available to us, then you can trust your taste," he says.

Early converts

Glaser's theories stem from more than a century's worth of alternative health teachings. The raw-foods concept dates back at least to the 1920s when German writer Arnold Ehret published his account of how a raw-foods diet helped restore him to health.

A few years later, Ann Wigmore, also an alternative healer, propounded her own theory of living foods, uncooked fruits, vegetables, beans, sprouts, nuts and wheat grass that she argued would detoxify the body. Her Hippocrates Health Institute, originally in Boston, helped spread the word.

While adherents attest the diet helps them shed pounds and energizes them, experts remain skeptical. "We don't have any research to indicate that this is a better way to eat," says Cynthia Sass, a spokesperson for the American Dietetic Association and a dietitian based in Tampa, Fla. "We don't have any concrete studies at this time."

If anything, the concrete research that does exist pokes holes in the raw-foods diet. While cooking produces chemical changes in objects subjected to heat, it does not change the molecular structure completely, says Robert Wolke, emeritus professor of chemistry at the University of Pittsburgh. The claim that enzymes are destroyed at 118 degrees is similarly specious, he adds. More than 1,000 enzymes exist and each one has its own temperature at which it is denatured.

"It's like saying that all substances melt at 32 degrees Fahrenheit. It's nonsense. Ice does, but rocks don't and peanut butter doesn't," he said.

Even the notion that heat destroys enzymes in vegetables may not stand up, says Leslie Bonci, director of sports medicine at the University of Pittsburgh Medical Center. Vegetables do not contain that many enzymes to begin with, and our bodies can do an effective job of extracting those that do exist, she says. Not to say that there aren't some advantages to raw foods.

Overcooking vegetables can decrease their vitamin content, particularly vitamins B and C, which are volatile and susceptible to heat. Cooked vegetables may also come with excess salt or butter, while raw ones come with few extras and lots of fiber.

Cooked food, however, also has its advantages, the experts say. Heat kills microorganisms or other toxins lurking in food. Soybeans contain substances that in large quantities will interfere with digestion and the absorption of zinc and iron. Cooking disarms these blockers, the American Dietetic Association says.

Heat helps

Other foods just confer more benefits when cooked. Tomatoes do not release lycopene, a substance that appears to prevent disease and even cancer, unless cooked. Despite conventional wisdom that cooked carrots contain less beta carotene, scientists now say that we get more beta carotene from cooked carrots because the heat makes the nutrient more accessible. Beta carotene is thought by some to have a role in preventing cancers.

Mainstream nutritionists conclude the answer is not all-raw or all-cooked but a combination. "In an ideal world you're having a mix of both," Bonci says.

Even those who espouse living foods philosophy agree that it's not simply a matter of eating vegetables. "The key is not just to say raw food," says Brian Clement, director of the Hippocrates Health Institute in West Palm Beach, Fla., which continues to follow Wigmore's teaching. "If you say that to somebody without an education, they could be eating lettuce and apples. You have to be well-balanced."

Adults who avoid cooked foods and fail to eat nutritionally balanced diets may suffer fatigue, muscle injuries or decreased immune function. Children, who have even greater nutritional needs to spur their growth, can be at even higher risk, as they need high levels of protein to help them grow. They also require vitamin D, found in milk, which is forbidden in a raw-foods diet.

For infants, such a diet is even more ill-advised, the experts say.

"People think this is healthy. No, it's not healthy, certainly not for infants," UF's Bobroff says. "Anyone who tries to feed an infant that's under 1 year of age any diet meant for an adult is maltreating that infant." Compounding the challenge, raw foods tend to fill you up quickly, so you may stop eating long before you've met your nutritional needs.

"A cup of vegetables may only have 25 calories, but it's very filling. You can imagine how many cups of vegetables that are raw you would have to eat," Sass of the American Dietetic Association says, recommending that anyone who chooses a raw-only diet consult a nutritionist. "The total caloric intake could easily become inadequate."

Then, there's the simple notion of deprivation. The diet rules out piping hot soup, warm pastas and desserts featuring rivulets of melted chocolate.

Enthusiasts such as Busch, who went raw three years ago, say uncooked does not mean untasty. His deli features pizza made from nuts and flax bread, nori rolls (the seaweed wrappers often used in sushi) and ice cream from frozen bananas.

At Roxanne's, the raw-only restaurant in Larkspur, you can order fine wine to accompany your meal of lasagna terrine layered with roma tomato sauce, mushrooms, baby spinach, corn and herbed cashew cheese.

If you do opt for this, the experts say, don't point to science as your guide.

"Do anything you want," says chemist Wolke, author of "What Einstein Told His Cook: Kitchen Science Explained." "That's your personal choice. Just don't try to justify it by saying science proves it."