Can you have too many antioxidants?
Hello everyone,
‘Antioxidants’ are one of the most used terms when referring to healthy eating, diets or wellness. Although this group of chemicals are found naturally in many food types, it is also possible to buy antioxidant supplements, which claim to prevent diseases and improve overall health. Is there any danger to these supplements, in that it is possible to take too many of them? We asked 4 nutrition experts, ‘Can you have too many antioxidants?’, here is what they said…
EXPERT CONSENSUS
Can you have too many antioxidants?
2 out of 4 experts say ‘Nearly Certain’
What are antioxidants?
Dr Tim Crowe, a nutrition expert from Thinking Nutrition, says “Antioxidants have been big news for many years. With promises of preventing and treating many diseases, it is no wonder that they get top billing when assessing the health merits of food. Berries, beans, green leafy vegetables, tea, pecan nuts and dark chocolate are common foods with some of the highest antioxidant values.”
Dr Crowe goes on to explain that “Antioxidants though are not just one molecule, they represent a property that is part of many vitamins and minerals such as vitamins A, C and E, and the minerals copper, zinc and selenium. But there are thousands of other chemicals that have some potential antioxidant activity and these compounds are called polyphenols. There are over 8,000 different types of polyphenols found in fruits, vegetables, grains, legumes, tea and coffee.”
What do antioxidants do?
Antioxidants are chemicals that protect against the effects of free radicals.
Dr Cornelie Nienaber-Rousseau, a nutrition expert from North-West University in South Africa, says “Our bodies use oxygen in metabolic reactions. Oxygen reacts with body compounds to form molecules known as free radicals. In addition to body processes, free radicals are generated during exposure to ultraviolet radiation, air pollution and tobacco smoke. Free radicals are unstable molecules with one or more unpaired electrons. Because free radicals can oxidize macromolecules (DNA, proteins and lipids) in the body, they have been linked to the onset of cancer, diabetes, and cardiovascular diseases.”
She goes on to explain that “Antioxidants are chemical compounds that protect us against the adverse effects of free radicals by donating an electron or two to neutralize them.” Dr Crowe adds that “antioxidants can short-circuit the damage caused by free radicals and prevent or reduce the damage caused by oxidation. So, it seems logical that the more antioxidants a person eats, the healthier they will be.”
Can you have too many antioxidants?
Too much of anything isn’t good for you. Too many antioxidants can be harmful depending on which antioxidant you are overdosing on.
Dr Crowe says “with antioxidants, more is not always better. There is increasing evidence that antioxidants are more effective when obtained from whole foods, rather than isolated from food and presented in tablet form. In fact, some antioxidant supplements have been found to actually increase cancer risk.”
Increasing cancer risk can sometimes occur because the antioxidant acts in the opposite way it usually does when in very high concentrations – instead of acting as an antioxidant it acts as a pro-oxidant.
Dr Crowe explains “For instance, vitamin A as beta-carotene when it is part of food has been associated with a reduced risk of certain cancers. But taken in a supplement form, there is clear evidence that it increases cancer risk in some people, especially lung cancer in smokers.”
Dr Nienaber-Rousseau adds “Vitamin A toxicity is a real possibility when concentrated amounts of preformed vitamin A in foods or supplements are consumed exceeding 3000 mg/day” She says “Whereas fruits and vegs containing beta-carotene prevent cancer, the researchers of the Beta-Carotene and Retinol Efficacy Trial (CARET) observed that smokers given beta-carotene and vitamin A supplements had increased rates of lung cancer. Results of the CARET was subsequent confirmed by others.”
Dr Nienaber-Rousseau gives another example: “Vitamin C is one of the water-soluble vitamins. Vitamin C is known as the bodyguard for water soluble substances in cells and body fluids… Also vitamin C protects iron from oxidation in the small intestine thereby enhancing iron’s absorption. Because vitamin C is water soluble, it is readily excreted and toxicity symptoms such as gastrointestinal distress and diarrhea are rare. However, excessive supplementation can lead to vitamin C quantities exceeding the body’s need. Vitamin C’s tolerable upper level for consumption is 2000 mg/day. Above this level the beneficial effects on iron absorption can become harmful - too much free iron can cause cellular damage typically inflicted by free radicals.”
Is there a healthy way to get enough antioxidants?
If it is possible to have too many antioxidants, is there a safe way to ensure healthy levels?
Dr Nienaber-Rousseau says “Plant-derived bioactive antioxidants seem to lower cancer in people whose diets include abundant vegs and fruits. Summaries of the scientific studies on antioxidant supplements (beta-carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium) for prevention of cancers found no evidence that they prevent cancers. In fact high doses of some antioxidants (beta-carotene, vitamin A, and vitamin E) may have harmful long-term effects, seem to increase overall mortality”
She summarises with: “Consuming foods rarely cause toxicities, but supplements can.”
Dr Crowe suggests to “Focus instead on eating a diversity of these plant foods and focus less on antioxidants. It is the diversity of foods, especially plant foods that matter most for good health, not their antioxidant content.”
The takeaway:
It might be possible to take too many antioxidants, getting them from foods rather than supplements is the best option!
May the facts be with you!
Eva
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