Myth: Food products with antioxidants are superior. Truth: Browse any grocery store and you'll find dozens of products that market antioxidant activity as a selling point.
Some even use bar graphs to compare their antioxidant activity against other foods. The ORAC measures a food's ability to neutralize free radicals in a test tube—and antioxidants behave very differently in our bodies than they do in test tubes.
That's why, in , the USDA completely shut down its public database of ORAC values, citing "evidence that the values indicating antioxidant capacity have no relevance to the effects of specific bioactive compounds…on human health. Myth: All free radicals, which antioxidants fight, are evil and dangerous. Truth: Oxidative stress causes the body to be flooded with free radicals, which research has linked to diseases like cancer, diabetes, Alzheimer's, and Parkinson's.
But correlation is not causation, friends—and newer research shows that you can actually have too few free radicals. The bottom line: Even if we don't know exactly why they're beneficial, experts agree we still need to get antioxidants from our diet especially vitamins C and E, which are essential nutrients. So how to make sense of the madness? As always, you should consult with your healthcare provider about your specific health needs. Can I take too many antioxidants?
Before we start discussing amounts of antioxidants, we need to define free radicals since they go hand in hand. A basic definition of free radicals is unstable compounds that are looking to react with anything in its presence. Free radicals are needed for normal functioning of our bodies. However, if our bodies produce or are exposed to too many free radicals, then our cells can be damaged. The general faith toward the health benefits of products containing antioxidants is partly because of misinformation conveyed by industries manufacturing these food products, which promoted putative overuse of these products as dietary supplements.
However, the harmful effects of these products have remained obscured for unknown reasons Lu et al. It is crucial to emphasize the harmful effects of the chronic consumption of antioxidants, including potential toxicity, in addition to promotion of potential benefits.
In this article we have tried to discuss probable mechanisms by which chronic antioxidant consumption provokes adverse effects. We have attempted to depict the role of antioxidants in a comprehensive model of inflammation, oxidative stress, and cancer. From an evolutionary point of view, oxygen was a toxic component which turned into one of the most important molecules essential for life and a vital agent after millions of years of evolution. However, in certain conditions, its toxic effects still continue to protect more evolved organisms against certain pathogens.
Reactive oxygen species ROS which play an important role in the innate immune response are a group of molecules and reactive ions and radicals derived from oxygen. Phagocytes mainly comprised of macrophages and neutrophils release a variety of molecules including toxic oxygen radicals in a process undergoing respiratory burst upon activation in response to infectious agents and pathogens.
It has been observed that patients with impaired ROS production are critically immune suppressed i. Toxic oxygen-derived products such as superoxide, hydrogen peroxide, singlet oxygen, and hydroxyl radical play a critical role in oxygen-dependent intracellular killing of pathogens, and hence, are key factors within the immune system. ROS could be toxic to both normal and abnormal cells infected by intracellular pathogens and malignant cells.
It has been shown that increased oxidative stress could enhance prevalence of malignancies by direct cellular damage, Seifirad et al. Reductive stress concept has been recently introduced. It seems that although reducing agents provoke many adverse effects and cause damages, this phenomenon has been obscured in the shadow of oxidative stress.
Antioxidants could also be categorized as reducing agents. Antioxidants are rich in weakly-bound electrons and could cause direct DNA damage Lu et al. Recent studies demonstrate that ROS detoxication and enhanced intracellular antioxidant might be pro-tumorigenic DeNicola et al. It has been shown that high intake of tea or coffee that are rich in flavonoids in pregnant women might increase the risk of central nervous system tumors and childhood leukemia Strick et al.
In a very recently published study, Lu et al. By means of femtomedicine, they compared the toxic effects of green tea extract GT epigallocatechin gallate EGCG as the main flavonoid in green tea, H 2 O 2 , and Cisplatin on human lung and skin normal cells.
This observation was also in accordance with the previous findings Yang et al. In another words, antioxidants may diminish the ability of an exogenous reducing agent in killing tumor cells Watson, A comprehensive model for oxidative stress, antioxidants, inflammation, and carcinogenesis: oxidant-antioxidant equilibrium, cancer protection, and carcinogenesis equilibrium are described as determinant balancing points between health and disease states in this model.
Red: Antioxidants as reductive agent. Yellow: Oxidative stress carcinogenesis pathway. Green: Antioxidant as immunosuppressant. Antioxidants decrease oxidative stress and oxidative damage and subsequently diminish likelihood of developing malignancies due to oxidative stress.
This pathway has been the foundation of current thoughts leading to the antioxidant general administration and usage in common belief. Antioxidants could impair function of immune system by means of decreased oxidative stress. Since antioxidants are rich in weakly-bound electrons, they could cause direct DNA and cell damage.
Traditionally disequilibrium in natural homeostasis is defined as disease state. In traditional medicine, diagnosis and treatment of disorders was based on managing equilibrium Shahabi et al. There is no unit and all figures are representing increase and decrease in parameters, curves, and arrows are representing hypothetical relationship between parameters. But crucially, it maintains a balance. One has to do with that balance we talked about: You need a certain supply of reactive molecules in order to maintain your immune system.
Plus, researchers are now realizing that some signaling pathways inside cells are only activated by free radicals. Increasing evidence suggests that lung cancer and certain types of melanoma are actually made worse by excess antioxidants. That seems to be because free radicals are, in some ways, actively protecting cells from becoming cancerous. Exercise also seems to rely somewhat on some free radicals to induce a little cellular stress. Preliminary studies now show that taking high levels of antioxidants interferes with the health benefits you get from exercise.
There are many types of both molecules, and each seems to act in a slightly different capacity. Vitamins E and C, for instance, are both antioxidants, but they seem to fill different roles in your body. So just getting more antioxidants as a broad category is kind of meaningless. Now they can behave like a free radical.
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