Findings Cause Concern Among Cancer Scientists, Nutritionists

WASHINGTON,DC A new survey commissioned by the American Institute for Cancer Research (AICR) shows that as Americans grow older, they are much less likely to make the kind of dietary changes that can lower cancer risk. The survey also revealed that the percentage of Americans who turn instead to dietary supplements for cancer prevention rises sharply after age 65.

"These two trends are related, and theyre both disturbing," said Melanie Polk, M.M.Sc., R.D., Director of Nutrition Education at AICR. According to Polk, a wealth of consistent and convincing data argues that diets rich in a variety of fruits, vegetables, whole grains and beans can significantly lower cancer risk. But dietary supplements havent been subjected to the kind of testing that could determine their effectiveness and evaluate possible risks.

It is this lack of reliable information about supplements that concerns cancer experts, health professionals, and nutritionists, Polk said. In some studies, dietary supplements like beta-carotene have been linked to increased cancer risk.

"Weve known for some time that usage of dietary supplements is on the rise, but we still dont know a great deal about how, or if, these substances affect cancer risk. The fact that so many Americans especially older Americans are seeking cancer protection in pills and powders is alarming."

Surprising New Numbers in Ongoing Debate

Although several polls have been taken to date on the use of dietary supplements in this country, the AICR survey offers the first glimpse of American beliefs and behaviors specifically related to diet, supplement use, and cancer risk.

Overall, 39 percent of Americans say they have made changes to their diet to reduce their risk of getting cancer. Polk and her colleagues at AICR found this figure heartening.

"Keep in mind that just 20 years ago, only a handful of people knew about the link between healthy diets and lowered cancer risk. Today, two out of five Americans say they are taking the kind of simple, everyday steps that actively fight cancer."

Meanwhile, 43 percent of Americans say they take a daily multi-vitamin for cancer protection. 21 percent take some other form of nutritional or dietary supplement (i.e., concentrated doses of single vitamins, minerals or herbal substances) to lower their cancer risk. These figures, Polk said, are less encouraging.

"We know that consuming a healthy, varied diet offers more effective protection against disease than any pill could hope to," said Polk.

She stressed that although hundreds of vitamins, minerals and herbal compounds are now available in supplement form, food scientists estimate that fruits, vegetables, whole grains and beans could contain thousands of yet-to-be-identified substances. Further, the naturally occurring compounds within these foods interact in complex ways that science is only beginning to understand.

Polk was careful to point out that multi-vitamins are certainly useful for people who are having trouble meeting basic nutritional needs. She pointed out, however, that there is as yet no evidence of their effectiveness in the battle against cancer.

"As a nation, weve made tremendous progress. Many more of us are making positive, cancer-protective changes to our diets than ever before. But the fact that more Americans are taking multi-vitamins for cancer protection than are making simple dietary changes suggests that weve still got a long way to go."

A Series of Puzzling Results From Older Americans

Polk said that although the overall numbers are troubling, the trends that she and her colleagues find particularly puzzling emerge when survey respondents are grouped according to age.

"When we divide respondents into age groups, we would expect to see continuous, gradual increases in the number of people who are doing something about lowering their cancer risk," she said. "After all, people tend to become more mindful of health issues like cancer as they age."

And in fact, the number of Americans taking multi-vitamins for cancer prevention shows just such a gradual increase. Despite a lack of scientific evidence showing any real effect on cancer incidence, 33 percent of those respondents aged 18 to 34 said they used a daily multi-vitamin for cancer protection. Of those aged 35 to 44, the number is 42 percent; for ages 45 to 54, 48 percent; for those 55 to 64, 50 percent. More than half of Americans over 65 years old 54 percent said they take a multi-vitamin to help lower their cancer risk.

The two survey questions related to supplement use and dietary change, however, yielded more surprising results. 13 percent of Americans between 18 and 35 said they take supplements to help lower their cancer risk. The numbers rise gradually (20 percent of those aged 35 to 44; 23 percent of those 45 to 54; 24 percent of those 55 to 64) until the 65 and over age group.

"We see a sudden upsurge in use of supplements for cancer prevention among Americans 65 and over. The number jumps from 24% of those aged 55 to 64, to 36% of those 65 and over. And thats only half the story."

The AICR survey also showed that Americans between the ages of 45 and 54 are the only age group that is more likely to change their diets (53 percent) than to take multi-vitamins (48 percent) for lower cancer risk. "If that trend continued," said Polk, "it would be good news. It would mean that most older Americans are relying on a proven strategy for cancer protection, rather than the unproven claims of multi-vitamins and other supplements. Unfortunately, that trend doesnt continue."

According to the AICR survey, the number of Americans between 55 and 64 who say they have changed their diet for cancer protection decreases sharply, dropping to 39 percent from a high of 53 percent for those aged 45 to 54. The numbers rise only slightly for Americans 65 and older (43 percent), making healthy diets an overall downward trend among those over 54.

"The AICR survey raises important questions that health professionals need to focus on," said Polk. "For example, why this drop? Why do so many Americans over 54 stop making the kind of dietary changes that can lower risk? For that matter, why do Americans between 45 and 54 seem to understand the importance of diet more than any other age group?"

Experts Offer Several Theories

Dr. Ritva Butrum, Vice-President for Research at AICR, believes the answers to the questions raised by the survey may be complex. "American diets, and the attitudes that shape them, reflect a broad range of tastes, knowledge and influences," she said.

Some health experts believe the observed drop-off in healthy diets among seniors is attributable to misguided perceptions about the role of diet itself. Many Americans may regard diet simply as a strategy for weight management, not a plan for overall health and disease prevention. As they grow older and their metabolism slows, however, they may find it more difficult to effectively manage their weight. They may then become frustrated and give up on healthy diets.

"People should know that diets high in plant foods contain less fat and more fiber than the typical American diet," Polk explained. "Thats an often-overlooked bonus of eating plenty of vegetables, fruits, whole grains and beans it makes watching your weight that much easier."

Older Americans may also be turning away from healthy diets due to concerns about convenience. They may mistakenly believe that healthy meals require too much time and effort, and instead seek out pills and multi-vitamins as a "quick-fix."

"People have to understand that a healthy meal isnt necessarily an elaborate meal. A quick veggie stir-fry, or a simple salad, can get you in and out of the kitchen in minutes," said Polk.

Another theory is that the spike in healthy diets among Americans aged 45 to 54 is purely generational in origin. This group, the so-called "Baby-Boom" generation, is highly informed on health issues, and is now at an age when concerns about cancer and other chronic disease become more pressing.

Thus, a survey done ten years from today might show a similar spike among people aged 55 to 64, as the "Baby-Boomers" continue to follow healthy diets as they age.

"It may not be that older Americans are turning away from healthy diets," said Butrum. "Sadly, the truth may be that most Americans now over 55 simply never ate them in the first place."

Additional Findings of the AICR Survey

Respondents to the survey were asked which specific dietary and nutritional supplements, if any, they took to lower their risk of cancer. Vitamin C was the most commonly used supplement, reported by 17 percent of Americans. Vitamin E came in second, at 16 percent. A surprising 9 percent of respondents said they took garlic supplements for lower cancer risk. Folic acid came in fourth, at 8 percent, and beta-carotene was the fifth most popular dietary supplement used to fight cancer, taken by 7 percent of Americans.

Vitamin C, vitamin E and beta-carotene are widely known antioxidants, substances that protect the body from the kind of cellular damage that can lead to cancer. "We know that antioxidants are important protective compounds in the diet," said Polk. "But we certainly dont know whether or not they are protective against cancer as supplements."

There is some concern among scientists that very large doses of single anti-oxidants may have a promotional effect on cancer growth. In a series of studies, beta-carotene supplements were linked to increased lung cancer incidence among smokers.

"When it comes to folic acid, its certainly true that a lack of folic acid in the diet may increase the risk of certain cancers and birth defects as well. But so far there is no evidence that oversupplementation offers any protection."

Garlic supplements provide many of the phytochemicals that have shown the ability to protect against cancer, but most are missing the compounds that convert those substances into their active, cancer-fighting forms.

"The bottom line is this: a diet that contains these nutrients, as well as a host of additional phytochemicals, is the surest way to achieve real, enduring cancer protection."

Just over half of the surveys respondents (51 percent) said they take neither multi-vitamins nor supplements for the purpose of lowering their cancer risk. About one in four (27 percent) said they take a multi-vitamin for this purpose. 16 percent said they take both multi-vitamins and supplements, and 6 percent said they take only supplements to lower their cancer risk.

Conducted for AICR by International Communications Research (ICR), the survey involved 1,010 adults, 18 years or older, chosen at random. Respondents were interviewed by telephone during a five-day period in late July.

The American Institute for Cancer Research is the nations third largest cancer charity and focuses exclusively on the link between diet and cancer. The Institute provides a wide range of consumer education programs that have helped millions of Americans learn to make changes for lower cancer risk. AICR also supports innovative research in cancer prevention and treatment at universities, hospitals and research centers across the U.S. The Institute has provided over $55 million in funding for research in diet, nutrition and cancer. AICRs web address is http://www.aicr.org