According to the American Institute for Cancer Research (AICR), a direct link exists between nutrition and certain types of cancer. In fact, AICR estimates that 1/3 of cancers can be prevented with diet and exercise. A healthy diet rich in antioxidants could aid in cancer prevention while diets rich in high fats and calories may increase the risk of developing cancer. In a previous Newark Cancer Examiner article, the connection between obesity and the risk of cancer was discussed. This article highlights a selected few examples of naturally occurring compounds with potential to prevent and/or treat cancer.
Turmeric is the commonly used term for curcumin, a polyphenol compound with tremendous potential to prevent and treat cancer. Curcumin is derived from the roots of a plant called Curcuma longa. For thousands of years, Asian cultures have used turmeric as a spice in cooking and for medicinal purposes. Interestingly, epidemiological studies have documented that the prevalence of certain cancer types (e.g. digestive tract cancers) are low in countries such as India where turmeric is commonly used. These studies are correlative, but given the fact that curcumin blocks multiple cellular signaling pathways involved in cancer development and progression, the ability of curcumin to prevent and/or treat cancer needs to be further evaluated. In fact, several clinical trials are currently examining whether curcumin has potential to prevent certain types of cancer (i.e. colon cancer).
With the exception of water, tea is the most widely consumed beverage around the world. The leaves of the Camellia sinensis plant are dried, and depending on the method of production, yield several types of tea (black, green or Oolong). Of these different varieties, green tea contains the highest amount of antioxidants called catechins (a group of polyphenol compounds). Green tea has several major polyphenols including, (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG) and (-)-epicatechin. Local researchers at Rutgers, The State University of New Jersey are studying the cancer preventative potential of these compounds. In a recent publication, the NJ scientists reviewed studies from over the past 40 years on how tea might help prevent cancer. For more details, please refer to the following article (Yang CS et al., Nature Reviews Cancer, June 2009).
Tocopherols and Tocotrienols (vitamin E)
Fresh fruits, vegetables, and nuts are a good source of vitamins. Tocopherols and tocotrienols are a class of organic, fat-soluble antioxidant compounds with vitamin E activity. In nature, vitamin E exists in four different tocopherol forms (alpha-, beta-, gamma-, and delta-tocopherol) and four different tocotrienol forms (alpha-, beta-, gamma-, and delta-tocotrienol). Of the eight different chemical forms, alpha-tocopherol is what human bodies preferentially absorb and accumulate. A number of studies have examined whether alpha-tocopherol can prevent the development of cancer but the results have been negative. Recently, local scientists at Rutgers University have found that a mixture of tocopherols rich in the gamma form can prevent the development of colon, lung, prostate, and breast cancer in animal models (Ju et al., Carcinogenesis, 2009) . Several clinical trials are underway to evaluate Vitamin E for prevention or treatment of human cancers, including prostate, colorectal, and head and neck cancers.
Other natural products
Evidence exists that several other antioxidant nutrients (vitamin A, vitamin C, beta-carotene and lycopene) have the potential to slow or prevent the development of cancer. Resveratrol, a phytoalexin found on the skin of grapes, is also being investigated in cancer clinical trials for prevention against colon and skin cancers.
Nature is abundant in anticancer agents. Fresh fruits, vegetables, whole grains, and beans are foods rich in compounds that could fight cancer. This article briefly reviewed a selected few examples of these natural products. Many of these natural products are safe for dietary consumption and are widely available. Consumption of a single natural dietary product alone may not be sufficient to prevent cancer but a healthy diet rich in a combination of these products will help protect against certain cancer types.
For more info:
1) National Cancer Institute, Antioxidants and Cancer Prevention Fact Sheet
2) National Cancer Institute, Obesity and Cancer Fact Sheet
3) National Cancer Institute, Tea and Cancer Prevention: Fact Sheet
4) National Institute of Health, Office of Dietary Supplements (vitamin E)
5) National Institute of Health, Clinical Trial Registry
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