There may be no disease Americans fear more. Sure, there's been progress in treating cancer and death rates continue to decline, yet it remains the illness whose name we fear to speak.
Once it strikes, the road to survival is costly, physically, psychologically and financially. Beating cancer can mean surgery, painful chemotherapy and other treatments, and the constant dread of recurrence for many years later. No wonder tens of millions of Americans are focusing more attention on cancer prevention as a way to live to a healthy old age.
In fact, anxiety over the 'C' word, along with other diseases associated with aging, has helped turn the dietary supplement industry into an $18 billion a year business. An estimated 150 million Americans have taken a supplement in the last year, according to the Council for Responsible Nutrition, a Washington-based trade association for the supplement industry.
Baby boomers in particular are popping vitamins, minerals and other herbal concoctions in the hopes of warding off not only cancer, but heart disease, osteoporosis and other maladies as well.
"Cancer and aging go side by side," says Dr. Benjamin Paz, medical director of the City of Hope Breast Center in Duarte, Calif., noting that on average, one in two men and one in three women will develop a major cancer during their lives.
While we do have some power to avoid cancer, Paz believes, "it has to be a lifetime commitment."
In general, people can help lower their risk of developing some cancers by not smoking, maintaining a moderate weight, eating lots of fruits and vegetables and exercising regularly, doctors say.
But for many consumers, the "eating right" message isn't enough.
In addition to fueling the growth of dietary supplements, "prevention" is also the driving force behind the fast-growing $4.6 billion functional food industry, also known as nutraceuticals. Functional or super-fortified foods are the cereals, energy bars and beverages pumped with extra vitamins and minerals and promoted for their cancer- and other disease-fighting properties.
Evidence lacking
However, scientific evidence proving that dietary supplements are effective in preventing cancer is far from conclusive.
In reviewing studies on the effects of vitamins A, C or E, multivitamins with folic acid or combinations of antioxidants, the U.S. Preventive Services Task Force, an independent panel convened by the Public Health Service, concluded in 2003 that there was insufficient evidence to recommend vitamin supplements as a way to prevent cancer.
"Vitamins and minerals are probably more or less worthless as far as cancer prevention is concerned," says Dr. Daniel W. Nixon, president of the Institute for Cancer Prevention in New York. "The American public is not vitamin-deficient. Does adding vitamins to their diet do anything? Probably not."
Part of the problem with trying to prevent cancer is that it's not just one disease but rather more than 100 distinct diseases, experts note.
"What's effective for one form of cancer may not be effective for others," says John Hatchock, a nutritionist with the Council for Responsible Nutrition, acknowledging that there have been "disappointments and successes" in the nutritional dietary supplement industry when it comes to fighting cancer.
"Supplements aren’t meant to be a substitute for traditional medicine; they provide extra insurance," says a spokeswoman for the industry council. "They’re not taking the place of drugs or eating right or exercising. They’re one more piece of what you should do as part of a healthy lifestyle."
While a controlled lab test may indicate that a substance offers some protection against tumors or damaged cells, researchers might not know what form of the substance — in foods or via pills — makes the ingredient most useful.
For example, the antioxidant lycopene, found in tomato-based foods, has been linked to a reduced risk of prostate cancer. But nutrition experts say it's not clear whether pills containing the nutrient would have the same effect as getting it from food.
Still, as the country's 76 million boomers become more anxious about their health, cancer prevention as a marketing strategy could get a boost.
From Cheerios to Diamond Walnuts, food products promoting "heart-healthy" goodness are already a big trend. Reducing cancer risks could be next.
Last September, the Food and Drug Administration loosened the rules about what health claims could be promoted on food labels. The new program allows certain foods to make "qualified" disease-fighting health claims.
As a result, the St. Louis company Solae petitioned the FDA to allow the soy food manufacturer to tout its supposed cancer-fighting abilities on packaging. The Solae Company, a joint venture between DuPont and Bunge Limited, refers to 58 studies showing a relationship between soy protein foods and reduced incidence of some cancers, including those of the breast, colon and prostate.
"The FDA labeling will definitely have a big effect," says David Lockwood, market researcher with consulting firm Mintel Reports. "Everyone will want to make a claim as fast as possible and it will definitely lead to consumer confusion."
Indeed even if the FDA allows Solae to promote soy's cancer-fighting abilities, consumers may find themselves perplexed and angry if future research shows the food to be harmful.
The idea of soy and soy products as a cancer-fighter comes from international comparisons showing Asian women, who consume a lot of soy, have lower rates of breast cancer than women in the West.
However Dr. Graham Colditz, director of the Center for Cancer Prevention at the Harvard School of Public Health in Boston, says the benefits of soy are far from certain.
Because soy foods contain plant-like estrogens called phytoestrogens, some scientists worry that soy might cause recurrence in women who had already had breast cancer.
"There are studies looking at the impact of soy on breast cell proliferation that do not suggest protection against breast cancer," says Colditz. "That’s an example of everyone getting on the bandwagon that soy must be good, when slowly, but surely, studies come along that may question the overall benefit of it as a magic bullet."
In any case, soy may find itself edged out by the next big trend on grocery store shelves and supplement aisles — omega-3 fatty acids, Lockwood predicts. Found in fatty fish such as salmon, omega-3s can reduce heart disease, research indicates. Because of their antioxidant properties, omega 3s are also associated with protection against cancer.
"Omega-3 ingredients are going to be put in everything," says Lockwood. "As long as manufacturers can make it so it doesn't taste or smell nasty and doesn't raise the cost [of the product] dramatically, people will go for it."
Green tea has already reaped the rewards of being linked to lower cancer risk. The grassy-tasting beverage has exploded in popularity as its antioxidant properties have been shown in human studies to protect the body from some cancers and heart disease.
Green tea contains catechins, a group of chemicals that have been found to inhibit early damage to DNA that is thought to be a precursor to cancer.
The lure of good health from gulping down pots of the world's most popular drink have helped drive sales from $2 billion a year in 1990 to over $5 billion in 2003, according to the Tea Council.
False sense of security?
While studies may eventually prove that particular supplements offer some cancer-fighting benefits, the largely unregulated industry remains controversial. A prescription or over-the-counter drug must be proven safe and effective before it can sold. But that's not the case with vitamins, minerals or herbal remedies, so different brands of the supposedly same substance aren't always standardized and might not contain the same ingredients.
Doctors also express concern about the lack of large studies on human subjects using dietary supplements. These products simply may not work, or they could cause harm.
"The problem with mega-vitamin therapy is people take them way beyond what we know are safe volumes," says Dr. Tausef Ahmed, chief of oncology and hematology at Arlin Cancer Institute at Westchester Medical Center in New York. "They can cause certain undesired side effects."
Another concern is that supplements and super-foods could give consumers the wrong idea about their health, says Colditz.
"The bigger question is whether by taking a supplement we in essence have a false sense of security that we're doing the right thing so we don't need to worry about our weight or activity levels," he says.
According to research, only 60 percent of women follow breast cancer screening guidelines, 30 percent of men and women follow colon cancer screening recommendations, and only 40 percent of men regularly get tested for prostate cancer.
"There's plenty to do before you take anything," says Paz.