Nothing is ever simple! Of course, this is just one study that raises questions rather than provides answers, but it's interesting and....
Questioning the safety of certain 'healthful' plant-based antioxidants
Scientists are calling for more research on the possibility that some supposedly healthful plant-based antioxidants — including those renowned for their apparent ability to prevent cancer — may actually aggravate or even cause cancer in some individuals. Their recommendation follows a study in which two such antioxidants — quercetin and ferulic acid — appeared to aggravate kidney cancer in severely diabetic laboratory rats. The study appears in ACS' bi-weekly Journal of Agricultural and Food Chemistry.
Kuan-Chou Chen, Robert Peng, and colleagues note that vegetables, fruits, and other plant-based foods are rich in antioxidants that appear to fight cancer, diabetes, heart disease, and other disorders. Among those antioxidants is quercetin, especially abundant in onions and black tea, and ferulic acid, found in corn, tomatoes, and rice bran. Both also are ingredients in certain herbal remedies and dietary supplements. But questions remain about the safety and effectiveness of some antioxidants, with research suggesting that quercetin could contribute to the development of cancer, the scientists note.
They 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.
ARTICLE FOR IMMEDIATE RELEASE
"Quercetin and Ferulic Acid Aggravate Renal Carcinoma in Long-Term Diabetic Victims"
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I don't think that the problem would be with vegetables and fruits themselves, more likely supplemental doses of antioxidants. We are endogenous antioxidant machines and make our own if given the proper nutrition, but when you use big doses of exogenous antioxidants you down-regulate endogenous antioxidant production and likely maintain a net-loss due to the transient nature of exogenous antioxidants besides those like vitamin c and e that the body has learned to incorporate into its synergistic network. That is my interpretation.
Oh but it does look like they may be instrinsically harmful
Quercetin was shown to be a potent insulin secretagogoue; it effectively elevated the serum insulin level to 2.2 μg/L compared to 1.25, 1.20, and 0.9 μg/L of the normal, EGCG-, and glibenclamide-treated groups, respectively (Figure 3). Interestingly, the serum insulin of ferulic acid-, rutin-, and gallic acid-treated rats remained at levels only comparable to the DM control (0.40 μg/L) (Figure 3)."
Stabbing conventional wisdom in its face.
Anyone who wants to talk nutrition should PM me!