Skip Your Vitamins and Face Cancer Risk, Experts Say

Skip Your Vitamins and Face Cancer Risk, Experts Say

RESTON, Va (October 29, 1998 12:56 p.m. EST http://www.nandotimes.com) - Americans' proclivity for junk food could be causing more than obesity, heart disease and diabetes. It could be causing cancer, too, experts say.

They say overfed Americans may be fat but they are not getting the proper nutrition -- and they may pay for their bad eating habits with cancer. Poor diet could damage cells in much the same way radiation does, said Bruce Ames of the University of California at Berkeley.

"Deficiency of vitamins folic acid, B12, B6, C, or E, iron or zinc, and probably selenium mimics radiation in damaging DNA," Ames told this week's conference of the Society of Toxicology in Reston, Virginia, near Washington.

"The percentage of the U.S. population that is deficient in these eight micronutrients ranges from 5 percent to 20 percent for each. We're talking about a sizable percentage of the population," he added.

Ames said 15 percent of the population is estimated to be deficient in vitamin C and 20 percent in vitamin E, despite recent government findings that 55 percent of the adult population is overweight.

Poor have most unhealthy diets

The trouble is the food that puts on a layer of blubber is not the food the body needs to prevent cancer, Ames said. And the fattest people, with the worst diets, are the poorest.

"Micronutrient deficiency may explain why the quarter of the population that eats the fewest fruits and vegetables -- five portions a day is advised -- has about double the cancer rate of the quarter that eats the most," Ames said.

Such nutrients, known as antioxidants, work to cancel out the effects of so-called free radicals, which damage cell DNA. Free radicals are charged ions generated by chemicals, radiation such as sunlight and even the oxygen we breathe. To explain their effects on the body, scientists often point to rust, which is the damage cause to iron by oxidation.

Ames said the body, if given the right tools, can very effectively fight off such damage. Fears about pollution and chemical dumps are a distraction, he said, because poor diet is a much bigger cause of cancer.

"Nutrition is where it's at," he said. "I am convinced that if we got a multivitamin-mineral pill into the poor, we'd have an enormous increase in health."

But Ames said the contents of the vitamins should be controlled because too many vitamins can be as bad as too few. Most men already get too much iron, found in red meat and vegetables such as spinach, he noted.

Eating better, and eating less, could be the key not only to avoiding cancer but to living longer, other experts told the conference.

Dr. Ron Hart of the U.S. Food and Drug Administration's National Center for Toxicological Research in Arkansas said dozens of animal tests have shown that staying a little hungry is an important key to long life.

'Lower the calories, longer the life span'

"The lower the calories, the longer the life span," Hart told the conference. "Our studies have clearly shown that the greater the body weight, the higher the incidence of spontaneous tumor occurrence, the greater the susceptibility to chemical carcinogens and the shorter the life span."

This is not true in cases of real malnutrition. Underfed animals have to get all the right nutrients, Hart said. "In the absence of proper nutrition, sensitivity to carcinogens appears to be enhanced."

Hart said some animals seemed to have evolved a response to famine conditions. When they have to go hungry for a while, the body shuts down stressful reproductive functions, freeing up more energy for survival, and steps up activity against other outside stresses such as exposure to cancer-causing agents.

"It is our belief that during periods of environmental stress these systems may be key to perpetuation of the species and the gene pool of the individual," Hart said.

He thinks a combination of factors is at work -- the body is putting its resources into repairing damage to DNA, doing more to kill off damaged cells that can become cancerous, and cells start growing more slowly.

Colleagues on his team have found similar responses in humans and several teams told the conference they have found strong evidence that monkeys on restricted, but balanced, diets live longer and have less disease.

A National Institute of Aging study is finding that monkeys on calorie-restricted diets have lower levels of harmful cholesterol and healthier levels of glucose and insulin. Not surprisingly, they also have lower blood pressure and less body fat.

Biosphere 2, the glass-enclosed greenhouse built to test humanity's ability to live in space, showed similar effects, a team from the University of California Los Angeles said. The biosphere included a simulated rain forest, marshland, ocean and desert, but the men inside lost on average 18 percent of body weight and the women 10 percent because they could not grow enough food.

Medical tests, however, showed they were very healthy and responded to a low-calorie diet much as rats and monkeys did.

So dies the secret to eternal life lie in a strict diet and a few vitamin pills? Hart offers hope to gluttons, who seem to make up the majority of the U.S. population, saying drugs perhaps could mimic healthful effects of low-calories diets.

"Our next step now is to identify the genes which are responsible," he said. Drugs that have similar effects could help humans survive famine, disease and other stresses better and, perhaps, live longer.

By MAGGIE FOX, Reuters