Photograph of Peapod Courtesy of Catherine Merulpie
How Antioxidant Foods Affect your Epigenetics
You are your genes. Better stated, you are your epigenetics. If you have DNA that may increase the risk of certain cancers, can you change your own risk? Epigenetics refers to the cellular environment of our genes—how the expression of the genes are affected without changing the underlying DNA sequences.
How do broccoli and other cruciferous vegetable such as Brussels sprouts or cauliflower decrease the risk of cancer? Certain nutrients, such as sulforaphanes in broccoli and diallyl in garlic affect epigenetics by activating genes involved in the development of cancer (tumor promoters, tumor suppressor genes, DNA repair genes). Selenium, vitamin A, folate and vitamin D are also believed to impact on the development of cancer by affecting epigenetics.
Could it really be that easy? Just eat a lot of broccoli? More coldwater fish? Grape Juice? Dark chocolate? Green tea? Vitamin D supplements?
Actually, at least four factors—Timing, Quantity, Combination and Organ Exposure—play a role in how phytonutrients (beneficial food substances) affect the development of certain cancers.
Timing
The actual timing of a body organ’s exposure to a cancer fighting substance makes a difference. For example, taking folic acid when there are underlying pre-cancerous colon cancer cells in the body actually increases the risk of developing colon cancer.
Regular soy intake (preferably whole soy products such as miso) by adolescent and young women decreases their risk of breast cancer by about 15 %. Isoflavones in soy attach to the estrogen receptor and block the body’s intrinsic estrogen from attaching to estrogen receptors. By blocking estrogen from attaching to receptors, isoflavones may prevent development of breast cancer.
However, in women who already have estrogen positive breast cancer or who are on tomoxifen, soy intake is generally not recommended. In these women with current or previous history of breast cancer, isoflavones are believed to attach to estrogen receptors and mimics the effect of estrogen to promote the development of breast cancer. (But even that conventional wisdom is evolving! Stay tuned for several recent studies in breast cancer survivors that suggest that soy intake is safe, even in women who are taking anti-estrogen/progesterone receptor therapy.)
In general, whole soy foods rather than soy supplements or powders are recommended. This is an active area of breast cancer research, so hopefully the true effects of soy in women at risk for breast cancer or who have had breast cancer can be more clearly understood.
Quantity of Antioxidants Ingested
The total amount of a potential cancer preventing nutrient that is ingested is also important. In general, increasing vitamin D intake decreases the risk of certain cancers, especially breast and prostate cancer. But more is not always better! Patients who have very high blood levels of vitamin D actually increase their risk of prostate cancer. Very high intake of the combination of selenium, beta carotene and vitamin E has been shown to increase the risk of death in patients with esophageal cancer. So be cautious in your intake of supplements –more is not always better, and it is possible to have toxicity from high levels of supplements.
Combination
Combining an antioxidant with other substances makes a difference. The prime example is the use of beta carotene supplements in smokers, which actually increases the risk of lung cancer more than in smokers who did not take beta carotene. Of course we all know that quitting tobacco makes the biggest difference in decreasing lung cancer risk.
Combining fruits and vegetables with unhealthy fats (such as trans fats) rather than olive and canola oils eliminate many of their beneficial antioxidant effects.
The Organ Exposed
Finally, the organ that is exposed to the antioxidants in foods is affected in different ways. For example, the calcium in milk is believed to decrease the risk of colon cancer but may increase the risk of prostate cancer. The effects of calcium in milk cannot be explained just by the fat content of milk because in general, high fat intake increases the risk of both colon and prostate cancer.
In summary, antioxidants in food can decrease the risk of cancer by affecting the epigenetics of DNA susceptible to promoting cancer, but attention must be paid to other factors that can affect these phytonutrients.
This post is not meant to diagnose, treat or recommend any course of therapy. It provides general information on cancer genetics and nutrition. Check with your physician how these factors may impact on your health.
Last updated by Dr. Vee on August 6, 2011
