Nutrition and Cancer Prevention: New Insights into the Role of PhytochemicalsAmerican Institute for Cancer Research For two days in September, leading researchers will gather in Washington, DC to debate and discuss a subject that is fast gaining the attention of the worldwide scientific community. Phytochemicals (phyto = plant) are the natural substances within fruits, vegetables and grains that, we are now learning, seem to do more than merely protect against many chronic diseases: There is increasing evidence that these substances actively fight cancer.  Past epidemiological studies - which investigate rates of disease among well-defined groups or populations - have strongly suggested that certain plant foods possess anti-cancer effects. Scientists today are following up these findings with laboratory and clinical trials that seek not merely to verify this hypothesis, but to identify the exact mechanisms involved. Many nutrition scientists have hailed the current research climate as a boom period in which our knowledge is expanding rapidly, but caution that much difficult work lies ahead. Thousands of phytochemicals have been identified to date, they point out, and many more still wait to be discovered. What's more, few of these substances seem to function simply or in isolation; most produce their disease-fighting benefits only by working in concert with other phytochemicals. Puzzling out the complex interactions that occur as the human body processes fruits, vegetables and grains will take time. At the American Institute for Cancer Research 9th Annual Research Conference on September 2 and 3, prominent scientists will report on the state of current research into the cancer-fighting components of such everyday foods as garlic, tea, grapes, wine, and soy. "Vitamins of the 21st Century" "Phytochemicals are, in a sense, the vitamins and minerals of the 21st Century," says soyfoods expert Mark Messina, Ph.D. He believes we now stand at the threshold of a "Second Golden Age of Nutrition." The first "Golden Age," he explains, took place in the first half of this century, when most of the vitamins and minerals we know today were discovered, classified, and first brought to bear against diseases like rickets and scurvy. "It's an exciting time to be doing this work," agrees Dr. Vay Liang W. Go, of the UCLA Center for Human Nutrition. "We're filling in the gaps left by the initial research. Those first population studies, for example, involved overall, big-picture kind of data like national cancer rates and average regional diets. "Now," he continues, "we're starting to pin down the specific cellular mechanism in the laboratory research. And in clinical trials with human subjects, we're piecing together practical, useable information, like the bioavailability of certain phytochemicals - how much of a given substance the body can get through diet, and how much of it the cells need for the anti-cancer benefits we're talking about." The State of Research Past, Present and Future Most panel presentations will be devoted to discussions of the cancer-fighting properties of particular foods. Each of these panels will combine an overall research history with the results of new clinical and laboratory studies that bring to light the phytochemical mechanisms involved in combating cancer. In addition, one panel will investigate the role of herbal or "alternative" medicine, and discuss how new information on phytochemicals and cancer relates to growing interest in dietary supplements. The final panel of the conference will be devoted exclusively to considering the impact of current knowledge on the future. Scientists will propose new directions for research to undertake and discuss how today's findings shape the real-world strategies that will be used to combat cancer in the coming decades. The Promise of Soy Low incidences of prostate, breast and colon cancers are seen in Asian countries, where soy and soy products are staples of the diet. The exact mechanism by which soy exerts this influence is the subject of considerable debate. This panel will examine the anti-cancer effects of soy from several perspectives. An overview of the population studies that first argued for soy as an anti-cancer agent will be presented. Two papers based on laboratory studies will propose different methods by which soy acts to fight cancer at a cellular level. A final paper will describe the results of both population studies and clinical trials, comparing groups of human subjects who were given diets high in soy to groups whose diets contained very little. Tempest in a Teacup Through different mechanisms, both black tea and green tea seem to suppress cancer development and slow or reverse the growth of tumors in animal studies. Papers presented in this panel will investigate whether such findings can be applied to humans with any confidence, and propose several methods used by tea phytochemicals to protect against cancer. The Pungent Power of (Real) Garlic Tracing the anti-cancer potential of garlic has posed a problem to researchers. Population studies seem to indicate a definite link between consumption of garlic and lower cancer risk, but in clinical trials, garlic supplements have shown no effect against the disease. This panel will investigate this seeming contradiction, and present several mechanisms by which allyl sulfides - the phytochemicals found in garlic - work to neutralize carcinogens and block tumor growth. Selenium: How Much is Enough? Selenium is not, strictly speaking, a phytochemical, but a mineral the body requires in trace amounts to survive. Once ingested, it takes several forms in the body, many of which seem to play a role in protecting against cancer. Exactly how much selenium is required for these anti-cancer benefits to manifest themselves remains an open question. Papers presented in this panel will present methods by which selenium in its several forms displays anti-cancer functions. Two papers in particular will debate the issue of bioavailability, and what effect it should have on recommended daily amounts of selenium. Wine, Grapes and Spices - The Resveratrol Connection Resveratrol, whose chief dietary source is red wine, has been linked to lower risk of heart disease for more than a decade, but research into its anti-cancer benefits has only begun very recently. To date, it has been difficult to determine how much resveratrol the body can readily absorb, but new tests promise more exact results in the future. The results of laboratory studies will be presented, in which resveratrol showed the ability to inhibit the kind of enzyme activity known to lead to cancers. Alternative Medicine and Dietary Supplements As we learn more about the disease-fighting power of substances within fruits and vegetables, many experts believe that traditional medicine and "alternative" medicine may be headed toward détente. This panel will trace the history of many important phytochemical discoveries, and explore the different attitudes of US and European medical professionals toward herbal or "alternative" solutions. In addition, the promise and dangers of dietary supplements will be examined. Strategies for the Future . . . The final panel will present scenarios for future phytochemical research, offer caveats about the way such research progresses, and suggest practical applications for the knowledge we acquire. One paper will present a history of research on beta-carotene as a cautionary tale, outlining the promise and limitations of the scientific process. Other papers will discuss various cancer-treatment models suggested by what we have learned thus far. ... And Guidelines for the Present As the research continues, a clear set of dietary guidelines can been derived from what science has established to date. In 1997, AICR published Food, Nutrition and the Prevention of Cancer: A Global Perspective, which reviewed 4,500 studies around the world. The report includes a series of fourteen recommendations and six dietary guidelines based on its conclusions. AICR estimates that as many as 40% of all cancers worldwide - approximately 4 million cases each year - are preventable by following these six simple guidelines: 1. Choose a diet rich in a variety of plant-based foods.
For more information, or to contact American Institute for Cancer Research, see their website at: www.aicr.org |
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