In short:
- Antioxidants are compounds that neutralize the harmful effects of free radicals on body cells.
- The main dietary antioxidants are vitamins C and E, beta-carotene, selenium and polyphenols.
- A varied, plant-rich diet ensures an adequate antioxidant intake — supplements are usually not necessary.
Antioxidants are compounds that protect body cells from oxidative stress by neutralizing the harmful effects of free radicals. Every day, our bodies are exposed to free radicals — both as a by-product of normal metabolism and through external factors such as ultraviolet radiation, cigarette smoke and air pollution. Substances your body needs cover a lot of ground, but antioxidants are among those without which cell damage quietly accumulates.
What are antioxidants and how do they work in the body?
Free radicals are unstable molecules missing one electron in their outer shell. To make up for this shortfall, they snatch an electron from neighboring molecules — setting off a harmful chain reaction that can damage cell membranes, proteins and DNA (Valko et al., 2007). Antioxidants step into this process: they donate an electron to the free radical without becoming unstable themselves, ending the harmful chain reaction before it reaches critical cell structures.
The body also produces endogenous, or internal, antioxidants — enzymes such as superoxide dismutase (SOD), catalase and glutathione peroxidase. These form the first line of defense. Antioxidants from food complement this system, especially during periods of high training load. Your overall physical condition also affects mental clarity and work capacity — as Art and the body discusses — and adequate cellular protection is its quiet foundation.
What are the main antioxidants and which foods contain them?
Among dietary antioxidants, there are several well-studied groups:
- Vitamin C — found in citrus fruits, peppers, strawberries and broccoli; acts as a water-soluble antioxidant and also helps regenerate vitamin E (Pisoschi & Pop, 2015)
- Vitamin E (tocopherol) — in nuts, seeds and vegetable oils; protects cell membranes from lipid peroxidation
- Beta-carotene — in carrots, sweet potatoes, spinach and apricots; the body converts it into vitamin A
- Selenium — in whole grain products, fish, eggs and meat; important as a component of glutathione peroxidases
- Polyphenols — a broad group of compounds (flavonoids, resveratrol, anthocyanins) found in tea, coffee, berries and legumes (Halliwell, 2012)
EFSA (the European Food Safety Authority) has confirmed that vitamin C and vitamin E protect cells from oxidative stress — a scientifically substantiated effect that may be claimed for foods (EFSA, 2010). You can find more information about healthy eating on the WHO healthy eating page.
Why is oxidative stress dangerous and how do antioxidants help?
Oxidative stress — a state in which free radical production exceeds the body’s capacity to neutralize them — is linked to a number of chronic diseases: cardiovascular disease, type 2 diabetes, neurodegenerative diseases (e.g. Alzheimer’s disease) and certain forms of cancer (Valko et al., 2007). Long-term oxidative stress also affects the functioning of the immune system and the ability of cells to regenerate (Lobo et al., 2010).
In autumn, the body needs more conscious care, because limited sunlight and the intense virus season put extra strain on the immune system. This is exactly the time to make sure your nutrition includes enough antioxidants — varied, plant-rich food is the best choice here.
That said, it must be stressed: antioxidants are not medicines and do not replace a doctor. Their role is preventive and supportive, not curative.
How many antioxidants does the body need per day?
There is no single recommended daily amount for all antioxidants, as they are a very diverse set of compounds. According to the dietary recommendations of the National Institute for Health Development (TAI), eating 500 g of fruit and vegetables every day ensures an adequate antioxidant intake for most adults. The recommended daily intake of vitamin C for an adult in Estonia is 80–110 mg, and for vitamin E 10–15 mg of tocopherol equivalents.
Caution is needed with supplements: studies have shown that taking isolated antioxidants in large doses may not deliver the expected benefit, and synthetic beta-carotene may increase the risk of certain cancers in smokers (Lobo et al., 2010; Halliwell, 2012). Listen to your body… reminds us that fatigue, frequent illness and slow recovery can be signals worth paying attention to — but the answer is usually a varied diet, not large extra doses.
The best way to get antioxidants is a plant-rich, colorful diet — not isolated megadoses of individual compounds.
References
- Valko M, Leibfritz D, Moncol J, Cronin MT, Mazur M, Telser J. (2007). Free radicals and antioxidants in normal physiological functions and human disease. International Journal of Biochemistry & Cell Biology, 39(1), 44–84. PMID: 16978905
- Lobo V, Patil A, Phatak A, Chandra N. (2010). Free radicals, antioxidants and functional foods: Impact on human health. Pharmacognosy Reviews, 4(8), 118–126. PMID: 22228951
- Pisoschi AM, Pop A. (2015). The role of antioxidants in the chemistry of oxidative stress: A review. European Journal of Medicinal Chemistry, 97, 55–74. PMID: 26036425
- Halliwell B. (2012). Free radicals and antioxidants: updating a personal view. Nutrition Reviews, 70(5), 257–265. PMID: 22676009
- EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). (2010). Scientific Opinion on the substantiation of health claims related to vitamin C and vitamin E. EFSA Journal, 8(10), 1688. DOI: 10.2903/j.efsa.2010.1688
Frequently asked questions
Do antioxidants protect against cancer?
Studies show that getting enough antioxidants from food is linked to a lower risk of some types of cancer, but antioxidants are not anti-cancer drugs. The role of a healthy, plant-rich diet is preventive; it doesn’t mean that supplements cure cancer or prevent it completely.
Are antioxidant supplements necessary?
Most healthy adults don’t need antioxidant supplements as long as their nutrition is varied and includes plenty of fruit and vegetables. In some cases (certain medical conditions, restricted diets), a doctor may recommend supplements, but that should be an individual decision.
Which foods contain the most antioxidants?
The foods with the highest antioxidant content are berries (bilberries, chokeberries, strawberries), dark green vegetables (spinach, kale), nuts and seeds, red bell peppers, citrus fruits and green tea. A colorful plate is a good rule of thumb, since different plant pigments point to different antioxidants.
Is it possible to overdo antioxidants?
It is practically impossible to overdo antioxidants from food. High doses of isolated compounds from supplements, however, can have negative effects. For example, synthetic beta-carotene in high doses is harmful for smokers. So: variety in your diet, caution with supplements.
Do antioxidants help athletes recover faster?
Intense training increases oxidative stress and the production of free radicals. Moderate amounts of antioxidants from food support recovery. However, very high doses of antioxidants from supplements may interfere with the beneficial adaptations that come from training (the so-called hormesis effect), which is why food sources are recommended first.
Come and train! ArtGym
