Apple Peels Turn On Anticancer Genes

June 25, 2013 by Michael Greger M.D.

A new study calculated that if half the U.S. population ate just one more serving of conventional fruits and vegetables, 20,000 cases of cancer could be prevented. At the same time the added pesticide consumption could cause up to 10 extra cancer cases. So by eating conventional produce we may get a tiny bump in cancer risk, but that’s more than compensated by the dramatic drop in risk that accompanies whole food plant consumption. Even if all we had to eat was the most contaminated produce the benefits would far outweigh any risks. Having said that, why risk any bump at all? That’s one of the reasons I encourage everyone to choose organic whenever one can, but we should never let concern about pesticides lower our fruit and vegetable consumption.

Washing fruits and vegetables can decrease pesticide residues (see my video Can Pesticides Be Rinsed Off?), and peeling even more so, but the skin is often where the nutrition is most concentrated. As you can see in my 3-min. video Apple Skin: Peeling Back Cancer, within the last year half a dozen studies have touted the benefits of apple peels.

We’ve known the more apples we eat, the lower our apparent risk of several cancers and scientists are just starting to unravel why. In the video I profile a study from the University of Wisconsin, where researchers pitted two lines of human prostate cancer and two of human breast cancer against the peels of organic gala apples. The cancer was not very happy about that (see the before and after here).

To figure out the mechanism by which apple peels cleaned cancer’s clock, the researchers measured the effect of apple peels on the tumor suppressor protein maspin inside the cancer cells. Maspin is a tumor suppressor gene that has been shown to have cancer suppressing, anti-angiogenic and anti-metastatic properties in both breast and prostate cancer cells. The tumor cells found a way to turn this gene off. Amazingly, the apple peels turned it back on. For the first time, the researchers showed an upregulation of this tumor suppression gene as they added more and more of the blended apple peels to each of the cancer types. They concluded that apple peels “possess strong antiproliferative effects against cancer cells, and apple peels should not be discarded from the diet.”

If that’s what one plant can do, what might a whole diet full of plant foods do to prostate and breast cancer cell growth? See Ex Vivo Cancer Proliferation Bioassay and The Answer to the Pritikin Puzzle, respectively.

More on the wonders of apples in Dried Apples Versus Cholesterol and Apples & Breast Cancer.

Apple juice, on the other hand, may not be health-promoting for reasons I explained in my last post Uric Acid Caused by Meat and Sugar. See my 3-min video Apple Juice May Be Worse Than Sugar Water to learn more.

Conventional apple juice may also contain contaminants (Fungal Toxins in Apples), though there is actually a fruit that’s healthier in juice form. See The Fruit Whose Juice is Healthier.

The antioxidant comparison in the Apple Skin: Peeling Back Cancer video is taken from Antioxidant Power of Plant Foods Versus Animal Foods. The comparison among juices is from Best Fruit Juice.