Background: What Are The Facts?

There is growing evidence that foods can fight cancer by inhibiting new blood vessel growth, or angiogenesis. This evidence comes in two main forms: epidemiological and scientific.

EVIDENCE FROM EPIDEMIOLOGICAL STUDIES

What is epidemiology?

Epidemiology is the study of factors that influence health in real world populations. Typically, epidemiological studies try to find associations between dietary, behavioral, environmental or genetic factors and the development of diseases. These studies usually involved large numbers of people, sometimes tens of thousands, who are observed, or “followed”, for many years. The links between cigarette smoking and lung cancer and regular aspirin use and fewer heart attacks are two well-known findings from epidemiological studies.

In the area of diet, epidemiological studies have shown that consumption of certain foods containing naturally occurring angiogenesis inhibitors, such as tomatoes, soy, tea, and other fruits and vegetables, decrease the risk of angiogenesis-dependent diseases. This has been best demonstrated as a reduced risk for developing cancer among people whose diets contain large amounts of these foods. (Giovannucci J Natl Cancer Inst. 2002; Hadley Exp Biol Med 2002; Wright Am J Epidemiol 2008)

For example, multiple population studies have shown that high soy intake is associated with the reduced risk of different types of cancer in people, including: breast cancer, lung cancer, prostate cancer, and colon cancer (Wu Br J Cancer 2008; Lee Am J Clin Nutr 2009; Kourde, Cancer Epidemiol Biomarkers Prev 2009; Shu JAMA 2009; Guha Breast Cancer Res Treat 2009; Seow Cancer Epidemiol Biomarkers Prev 2009; Yan Am J Clin Nutr 2009; Yang Am J Clin Nutr 2009). Specifically, eating soy foods from an early age is correlated with a reduction of breast cancer risk by 60% (Kourde, Cancer Epidemiol Biomarkers Prev 2009); drinking green tea with the reduction of colon cancer risk by 37% (Yang, Cancer Epidemiol Biomarkers 2007); and drinking at least one glass of red wine a day with a reduction of lung cancer risk by 24% (Chao Epidemiol Biomarkers Prev 2007).

While epidemiological studies have yielded extremely valuable information about food and our health, they should be viewed with some caution. Many factors can influence how someone’s health is affected by his or her diet. For example, people digest and metabolize foods at different rates. And foods may affect people’s health in different ways based on their physical and genetic make-up and any pre-existing health conditions. Epidemiology tries to account for these differences, but it is always possible that some unforeseen factor could influence the results.

What is the difference between epidemiological studies and clinical trials?

Clinical trials are generally considered the “gold standard” of medical research because they generate the highest quality scientific evidence. Unlike epidemiological studies that follow real world populations, clinical studies use defined populations that are carefully selected. Participants in clinical studies are chosen for a specific disease or condition, and are randomly assigned to receive either an experimental treatment or a dummy treatment (placebo). Because clinical studies are carefully controlled, their results may not broadly applicable to the “real world” .

SCIENTIFIC EVIDENCE

Basic scientific research looks at the way substances in food affect our bodies on the molecular level. While foods contain hundreds of molecules that may impact on the body in different ways, an important common mechanism of the dietary products we study is that they all inhibit angiogenesis, or new blood vessel growth. Inhibiting angiogenesis cuts off a cancerous tumor’s blood supply, thus starving the cancer of oxygen and nutrients.

Cancer research pioneer Dr. Judah Folkman of Harvard Medical School first proposed the concept that blocking angiogenesis could keep microscopic early cancers dormant. (Folkman, N Engl J Med 1971). Since Dr. Folkman’s seminal discovery in the early 1970s, scientific research conducted in the laboratory has shown that dozens of foods and beverages contain potent, naturally occurring angiogenesis inhibitors. (Li, Cancer Chemoprevention, 2004). Adriana Albini of Italy coined the term ‘angioprevention’ in 1997 to describe cancer prevention by angiogenesis inhibition (Tosetti FASEB 2002).

Since 1999, the nonprofit Angiogenesis Foundation has researched dietary factors from more than 20 different foods, including fruits, vegetables, and herbs, and has identified potent anti-angiogenic effects. The Foundation has catalogued over 100 foods containing naturally occurring angiogenesis inhibitors, and is now studying the potency of specific food varieties and species. Here are just a few scientific facts about anti-angiogenesis foods:

The first study conducted in Germany showed that the soy bean-derived factor, genistein, can block angiogenesis (Fotsis, Proc Natl Acad Sci 1993).

A Harvard study showed that a soy diet reduced tumor growth and angiogenesis in prostate cancers growing in mice. (Zhou J Nutr 1999).

In people who ate plant-based diet high in soy, genistein is found 30-fold higher in their urine than in people who consume a traditional Western diet (Fotsis J Nutr 1995).

See list of foods containing naturally occurring angiogenesis inhibitory activity

Eat to Defeat is based on both scientific and epidemiological evidence.

For practical reasons, most research to date on the relation between diet and health has relied on epidemiological studies. This is not surprising, as it would be extremely difficult to have people to eat one food every day for months or years. Because of the challenges in conducting controlled, blinded food studies, the Angiogenesis Foundation’s Eat to Defeat campaign gathers evidence from both scientific and epidemiology sources.

By combining basic science research on “anti-angiogenesis” foods with real world data showing that consumption of certain foods reduces cancer risk, we are creating a powerful case for incorporating these foods into one’s everyday diet. The goal of the Foundation’s Eat to Defeat campaign is to identify the most potent anti-angiogenesis food, based on the best available research, and to disseminate this knowledge to people around the world for their benefit.

SUPPORT OUR RESEARCH

Much more research is needed, both on the scientific and epidemiological fronts. The Angiogenesis Foundation is conducting scientific research comparing the anti-angiogenesis potency of foods, including specific varieties fruits and vegetables. We are also looking at how the cooking, processing and preparation of foods affects their cancer fighting properties.

As part of our research, we are assigning the foods we study a specific anti-angiogenesis profile. This system will make it easy for the general public to identify and select foods based on their ability to fight cancer. We are the only non-profit organization taking this approach.

In the next phase of our research, we plan to conduct larger, prospective studies using foods we have identified as having the most potent anti-angiogenesis profiles. We rely on the generous contributions from the general public to fund our research. Please support us.

References:

Giovannucci E, Rimm EB, Liu Y. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst. 2002;94(5):391-398.

Guha N, Kwan ML, Quesenberry CP, et al. Soy isoflavanones and risk of cancer recurrence in a cohort of breast cancer survivors: the Life After Cancer Epidemiology study. Breast Cancer Res Treat 2009;118(2):395-405.

Korde LA , Wu AH , Fears T, et al. Childhood soy intake and breast cancer risk in Asian American women. Cancer Epidemiol Biomarkers Prev 2009 Apr;18(4):1050-1059.

Folkman J. Tumor angiogenesis: therapeutic implications. N Engl J Med, 1971;285:1182-86

Fotsis T, Pepper M, Adlercreutz H et al. Genistein, a dietary-derived inhibitor of in vitro angiogenesis. Proc Natl Acad Sci USA 1993;90:2690-2694.

Fotsis T, Pepper M, Adlercreutz H et al. Genistein, a dietary ingested isoflavanoid, inhibits cell proliferation and in vitro angiogenesis. J Nutr 1995;125:790S-797S.

Hadley CW, Miller EC, Schwartz SJ, et al. Tomatoes, lycopene, and prostate cancer: progress and promise. Exp Biol Med 2002;227(10):869-80.

Lee SA, Shu XO, Li H, et al. Adolescent and adult soy food intake and breast cancer risk: results from the Shanghai Women’s Health Study. Am J Clin Nutr 2009;89(6):1920-1926.

Li WW. Tumor angiogenesis as a control point for early intervention and cancer prevention. In: Kelloff GJ, Hawk ET, Sigman CC, eds. Cancer Chemoprevention, Vol. 1: Promising Cancer Chemopreventive Agents, New Jersey: Humana Press; 2004: p.611-633.

Seow A, Koh WP, Wang R, et al. Reproductive variables, soy intake, and lung cancer risk among nonsmoking women in the Singapore Chinese Health Study. Cancer Epidemiol Biomarkers Prev 2009;18(3):821-27.

Shu XO, Zheng Y, Cai H, et. al. Soy food intake and breast cancer survival. JAMA 2009;302(22):2437-2443

Tosetti F, Ferrari N, De Flora S, et al. Angioprevention: angiogenesis is a common and key target for cancer chemopreventative agents. FASEB J 2002;16:2-14.

Wright ME, Park Y, Subar AF, et al. Intakes of fruit, vegetables, and specific botanical groups in relation to lung cancer risk in the NIH-AARP Diet and Health Study. Am J Epidemiol 2008;168(9):1024-1034.

Wu AH, Yu MC, Tseng CC, et al. Epidemiology of soy exposures and breast cancer risk. Br J Cancer 2008;98(1):9-14.

Yan L, Spitznagel EL. Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis. Am J Clin Nutr 2009;89(4):1155-63.

Yang G, Shu XO, Li H, et al. Prospective cohort study of soy food intake and colorectal cancer risk in women. Am J Clin Nutr 2009;89(2):577-583.

Yang G, Shu XO, Li H, et. al. Prospective cohort study of green tea consumption and colorectal cancer in women. Cancer Epidemiol Biomarkers Prev. 2007;16(6):1219-1223.

Zhou JR, Gugger ET, Tanaka T, et. al. Soybean phytochemicals inhibit the growth of transplantable human prostate carcinoma and tumor angiogenesis in mice. J Nutr 1999;129(9):1628-1635.

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