Overview. This application is a request to renew a productive regional project that has been in existence since 1971. Facilitated by comprehensive collaboration among participants, the overall goal of W-3122 is on improving food safety and human health worldwide. Research supported by W-3122 addresses the role that natural foodborne toxicants, cancer chemopreventives, botanical estrogens, dietary fiber, immune modulators and antimicrobials play in human health and disease. A particular strength of W-3122 is its dual focus on understanding the molecular basis by which dietary chemicals positively and negatively impact disease translating knowledge to improve human health by increased consumption of beneficial dietary chemicals and decreased intake of natural toxicants. These efforts cover a spectrum of cutting-edge scientific approaches that include gene expression, molecular signaling, genomics, tumor formation, and molecular biomarkers. The objectives of this renewal application continue W-3122's established emphasis on the role of natural dietary compounds in human health, while reflecting a continual evolution and refinement in the state-of-the-art. W-3122 has been highly successful in meeting its objectives, as measured by its numerous collaborative efforts, and it is anticipated that the renewal will be equally successful.

Issues related to food safety and to diet and health impact many stakeholders. Understanding the complex relationship between dietary chemicals and human health remains a paramount concern to public and agrifood industry stakeholders. These stakeholders include consumers, agricultural producers, food processors, health professionals, and policy makers charged with maintaining a safe and nutritious food supply. Dietary bioactive chemicals are defined in this proposal as naturally occurring substances produced by plants or microbes that exert beneficial or undesirable effects when they are consumed.

Excluding smoking, diet-related factors appear to account for over 50% of all remaining cancer deaths in this country, or 150,000 food-related cancer deaths per year in the U.S. alone (National Research Council, 1996).


There is also growing evidence that many dietary bioactive dietary chemicals can improve human health. For example, numerous epidemiologic studies indicate that regular consumption of several food commodities, especially fruits and vegetables rich in anticarcinogenic factors, and fiber-rich foods, correlate negatively with several human cancers. Thus, a more realistic view of the diet-cancer relationship is that variation in cancer rates reflects the presence or absence of natural chemoprotective factors in an individual's daily diet as well as the level of food-borne carcinogens and tumor promoters. A specific example studied by W-3122 is chlorophyll and its derivatives, which can function as anticarcinogens and block the action of genotoxic chemicals such as aflatoxin B1. Bioactive dietary chemicals can affect other chronic diseases. With some exceptions, W-3122 research maintains that bioactive chemicals are most beneficial when present in the food matrix. This whole foods approach to disease prevention has been advocated by leaders of cancer chemoprevention, for example Thomas Kensler of Johns Hopkins University, who stated: Although pharmacological approaches establish proof of principle and help identify key molecular targets for interventions, food-based approaches that also use these molecular targets may be the most practical for widespread application in high risk populations (Kensler, et al., 2004). While W-3122 investigators have expended considerable research efforts in purified bioactive chemicals, these have been proof-of-concept studies that are often expanded into investigations of their effect in food matrices.

Our emerging focus on whole-foods has been affirmed by growing clinical evidence that vitamin supplements may do more harm than good (More Evidence Against Vitamin Use, New York Times, October 11, 2011). For example, in the Select Trial, vitamin E and selenium supplementation among 35,000 men led to a higher risk in prostate cancer (Klein, et al., 2011). Another study involving 38,000 women in Iowa discovered a higher risk of dying during a 19-year period among older women who used multivitamins and other supplements compared with women who did not (Neuhouser, et al., 2009). The findings translate to a 2.4 percent increase in absolute risk for multivitamin users, a 4 percent increase associated with vitamin B6, a 5.9 percent increase for folic acid, and increases of 3 to 4 percent in risk for those taking supplements of iron, folic acid, magnesium and zinc. Based on existing evidence, we see little justification for the general and widespread use of dietary supplements, the authors wrote. This increase in risk due to multivitamin consumptions is counter intuititve because this type of dietary intervention was previously viewed and an insurance policy to good health and these new findings suggest a significant risk to a practice that has previously been assumed as safe.

A January 2009 editorial in Journal of the National Cancer Institute noted that most studies of vitamins had shown no cancer benefits, but some had shown unexpected harms. Two studies of beta carotene found higher lung cancer rates, and another study suggested a higher risk of precancerous polyps among users of folic acid compared with those in a placebo group (Albanes, 2009).

In 2007, randomized trials of antioxidant supplements were extensively reviewed in a meta-analysis. In 47 trials involving 181,000 participants, the rate of dying was 5 percent higher among the antioxidant users. The main culprits were vitamin A, beta carotene and vitamin E whereas vitamin C and selenium seemed to have no meaningful effects Bjelakovic, et al., 2007).

Importance of Studying Dietary Bioactive Chemicals. Bioactive dietary chemicals are extraordinarily diverse with respect to chemical structures and biological activities. For example, aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin often found in U.S. foods such as corn, peanuts and milk. Recent studies indicate that contamination of the U.S. corn supply by another mycotoxin, fumonisin, may represent another hazard due to its carcinogenic and teratogenic properties. Mycotoxins are not only carcinogens, but can suppress growth and immune function, rendering the consumer more susceptible to adventitious infections. Wide-spread Fusarium mold contamination of wheat and barley and resultant vomitoxin contamination often occur prompting food/cereal companies and the brewing industry to stop purchasing these commodities from U.S. farmers. The presence of mycotoxins in agricultural crops is of further significance because of their transfer from feed to animal tissues used for food. Research by W-3122 members addresses mechansistic risk assessment of these mycotoxins that is being used by regulatory agencies in the U.S. and through the world. Other research deals with strategies for mitigating human health impacts of mycotoxins. In addition to the mycotoxins, the food supply can be contaminated with numerous other substances with significant toxicity, including bacterial toxins, industrial pollutants and carcinogens produced from cooking of meat.

Brassica indoles and chlorophyll are examples of beneficial dietary chemicals. These compounds can act as cancer preventative agents. Indoles are strong inhibitors of chemical-induced mammary tumors and spontaneous uterine tumors in rodents, and have become the preferred treatment for recurrent laryngeal papillomas in humans. One of these indole products, DIM, is undergoing clinical trials as a treatment against cancers of the breast, prostate and colon. Chlorophyll and its derivatives have the potential to reduce cancer risk by sequestering active carcinogens in the gastrointestinal tract which reduced carcinogen exposure. Results of a large human study in China showed that administration to humans of the chlorophyll derivative, chlorophyllin, could markedly reduce the level of DNA damage caused by AFB1. Risk of liver, colon, stomach, breast, prostate, and lung cancer, which include the leading causes of cancer death in the US and the world, may be significantly reduced by appropriate daily intake of simple, safe, inexpensive indole and chlorophyll derivatives, or foods rich in these chemicals. Whether synthetic analogues of the Brassica indoles will have improved protective activities, is a subject of our further investigations.

Other examples of beneficial dietary chemicals are the omega-3 fatty acids, certain herbal supplements and prebiotics which may affect the immune system and be particularly important in the prevention and treatment of autoimmune and inflammatory diseases. Potential target diseases include rheumatoid arthritis multiple sclerosis, immune-mediated or type 1 diabetes mellitus, inflammatory bowel diseases, systemic lupus erythematosus, psoriasis, scleroderma, and autoimmune thyroid diseases. These diseases can afflict millions of Americans. Typically autoimmune diseases strike women more often than men and notably, they impact women of working age and during their childbearing years. Certain autoimmune diseases occur more frequently in certain minority populations. Lupus is more common in African-American and Hispanic women than in Caucasian women of European ancestry. Rheumatoid arthritis and scleroderma impact a higher percentage of residents in some Native American communities than in the general U.S. population. Clearly, failure to exploit the potential for bioactive dietary chemicals to ameliorate such diseases would have far-reaching social, economic, and health impact.

W-3122 researchers have determined that, in some cases, bioactive dietary chemicals have paradoxical effects. For example, the soy phytoestrogen and dietary supplement genistein, has been shown to reduce the number of DMBA-induced mammary tumors when administered to young rodents, probably through its estrogenic effect. However, when genistein is administered to rodents with estrogen responsive tumors, genistein enhances tumor growth. W-3122 researchers have also shown that Brassica indole, indole 3-carbinol (I3C), is a tumor promoter in a multisite cancer model. Further studies of the beneficial and potentially hazardous effects of genistein and other soy products, as well as Brassica indoles, are being conducted by W-3122 researchers.

Of particular relevance to this project, there is a burgeoning herbal product and food supplement industry in the U.S., recently estimated at $28 billion-a-year (Business Wire August 2011). The Dietary Supplement Health and Education Act by the U.S. Congress in October 1994 has blurred the distinction between functional foods, food supplements (vitamins, antioxidants, etc.) and medicinal herbs have sometimes allowed toxic substances to enter the human food chain. In addition to individual toxicity problems, these occurrences may reflect negatively on truly useful products. Additionally, such agents have the potential to interfere with successful therapies or medications. For example, genistein, can negate the inhibitory effect of tamoxifen on estrogen-stimulated breast cancer growth. Other examples include the ability of Saint Johns wort to act in an additive manner with anti-depressant drugs.

The primary foci of W-3122 are plant products, compounds derived from the growth of microbes on foodstuffs, and substances created (induced) during food processing. An additional category of induced bioactive components is substances that may appear inadvertently in genetically manipulated plant materials, which result from efforts to alter plant quality. Proposed work will continue to focus attention on the role of food-related anticarcinogens as chemopreventive agents for reducing human cancer, and also on natural beneficial compounds which improve health and reduce the incidence of other chronic diseases. This proposal also seeks to identify, understand, and eliminate, in so far as practicable, the specific toxicants in the food supply that contribute to health deficits.

Technical Feasibility of Studying Dietary Bioactive Chemicals. The research proposed herein is unique because exploits recent technical and conceptual advances in biomedicine within the context of agrigoods. New knowledge of the regulatory pathways for cell cycle, cell differentiation and programmed cell death and their relationship to disease now allows the identification and exploration of cellular control mechanisms. W-3122 members have established an international reputation in research into mechanisms and hazards of dietary toxicants as well as exploitation of beneficial natural dietary compounds to improve human health. We have extensive experience in a variety of model systems (plants, human subjects, human and animal cell cultures, transgenic and knockout mice, rats, poultry, rainbow trout) with which to pursue this work. Using these models, members have established the benefits of chlorophylls, indoles, anti-oxidants, omega 3 fatty acids, fiber, various antimicrobials and plant growth factors. These models have also been used by W-3122 investigators to identify potential adverse effects of mycotoxins, indole-3-carbinol, phytoestrogens, and induced toxicants, demonstrating that the effects of natural dietary compounds are sometimes double-edged.

Advantages of Multi-state Study of Bioactive Dietary Chemicals. Defining the role of bioactive dietary chemicals in cancer and chronic disease is an exceedingly complex undertaking. The problems to be addressed and benefits to be achieved are region- or nation-wide and not confined to a single state. No single research group or experiment station has all the expertise and facilities to fully address the issues involved for even one protective or risk factor. The proposed work requires collaboration from those with diverse academic backgrounds (toxicology, molecular biology, genomics, nutrition, food science and risk assessment) as well as geographic diversity due to the wide range of food crops that may be involved. W-3122 members have collaboratively studied bioactive dietary chemicals and continue to make great progress. Since several of the issues are being addressed in different ways among researchers in several states, information exchange and collaborations will both facilitate goal achievement and limit duplication of effort among members respective units. Their positions as faculty at major land-grant universities and USDA facilities ensure that data arising from W-3122 collaborative activities will be disseminated to the greatest extent possible among stakeholders and will thus provide maximum benefits to the U.S. public. W-3122's efforts and focus are not duplicated in any other regional project.

Impacts of Studying Dietary Bioactive Chemicals. There are a number of positive impacts that will result from this work. First, and foremost, this research will directly result in an improved understanding of the mechanisms responsible for the beneficial and detrimental effects of dietary bioactive chemicals. This knowledge will then help form the basis for an informed evolution of dietary habits to enhance or reduce the levels of these compounds thereby improving human health. Second, this research will result in the identification of new specialty crops and stimulation of the small farm economy. Third, biotechnology firms may he able to engineer increased production of bioactive agents in the patent crop or introduce these agents into different more palatable crops. Fourth, pharmaceutical firms may discover more active derivatives and more effective means of administering the active substances in pure form.