‘Healthful’ Antioxidants That May Cause Cancer

In what may be yet another case of eat-this-oh-wait-don’t-eat-this, the safety of several plant-based antioxidants are being called in to question.

Scientists are suggesting more research on the possibility that some plant-based antioxidants–including some commonly touted as healthful and renowned for their cancer-fighting ability–may actually aggravate or cause cancer in people with diabetes. The recommendation was made after a study in which two antioxidants, quercetin and ferulic acid, appeared to aggravate kidney cancer.

The plant-based antioxidants looked at in this study are quercetin, which is abundant in onions and black tea, and ferulic acid, found in corn, tomatoes, and rice bran. Both also are used in a number of herbal remedies and dietary supplements.

The study found that diabetic laboratory rats fed either quercetin or ferulic acid developed more advanced forms of kidney cancer, and concluded the two antioxidants appear to aggravate or possibly cause kidney cancer. “Some researchers believe that quercetin should not be used by healthy people for prevention until it can be shown that quercetin does not itself cause cancer,” the report states. “In this study we report that quercetin aggravated, at least, if not directly caused, kidney cancer in rats,” it adds, suggesting that health agencies like the U. S. Food and Drug Administration should reevaluate the safety of plant-based antioxidants.

Until further studies are performed, it seems prudent to limit intake of these antioxidants to their natural food forms, and to not consume extra doses in the form of remedies or supplements.

The study, “Quercetin and Ferulic Acid Aggravate Renal Carcinoma in Long-Term Diabetic Victims” appears in ACS’ bi-weekly Journal of Agricultural and Food Chemistry.

Related: Cancer-Fighting Foods, Top 10 Food and Drinks for Cancer Prevention


Emma S.
Emma S3 years ago

It's hard to keep up with it all...

Anteater Ants
Anteater Ants3 years ago

As an anteater, I don't eat onions anyway. Ants rule!

Harriet Brown
Harriet Brown3 years ago

would need to read the study before cutting these items out of diet. If you feed outrageously large amounts of anything to an animal, it can have dire consequences. moderation and commons sense should guide us. poor little rats. are there other ways to test?

Nimue P.

Good yesterday, bad today, yada yada....and stop testing things on animals! Grrr!

Azaima A.
Azaima A3 years ago


Winn Adams
Winn Adams3 years ago


LMj Sunshine

Thank you.

LMj Sunshine

Thank you.

Siti R.
Siti R3 years ago

antioxidants Does not turn back the clock so moderation in natural foods is far better plus exercise. antioxidants in supplements is hardly advisable. keep it simple. i love onions, chillies and tomatoes. our grandparents didn't know the existence of quercetin but their food was simply made and less preservatives.

Dale O.

Agreed, Jane R. I will never give up tea, onions or tomatoes. Agreed with some of the previous comments that rats don't normally consume these things, so it isn't surprising that tests on them can cause such a result and one feels lucky not to be born a lab rat given all the things they are always subjected to.

There is such a thing as moderation. In some cases simply being alive will cause cancer. I suppose someone has already or soon will come up with a study saying that even small amounts of dark chocolate causes cancer. Oh well, I guess they'll have to remove the chocolate from my cold dead hands because I'm not giving that up either. At least I will have died happy.