Antioxidants: what they do and the shortlist that earns its price

Antioxidants started as a specific term in chemistry and ended up as marketing shorthand for everything from blueberries to £60 supplement blends. The underlying biology is real and interesting; most of the marketing around it is not. Here's the practical version — what antioxidants do, where they matter, where more isn't better, and the specific nutrients with authorised EU claims for oxidative-stress protection.

The biology in one page

Your cells produce energy by burning glucose and fats with oxygen. The process isn't clean — it generates free radicals (also called reactive oxygen species), molecules with an unpaired electron that grab electrons from whatever's nearby. Over enough time, they damage cell membranes, proteins, lipids and DNA.

Antioxidants are molecules that donate an electron to neutralise a free radical before it can do damage. Your body makes some of its own (glutathione, superoxide dismutase, catalase) and gets others from food (vitamins C and E, carotenoids, polyphenols, selenium, zinc).

When antioxidant defences can't keep up with free-radical load, the imbalance is called oxidative stress. Chronic oxidative stress is part of the physiology of ageing, cardiovascular disease, neurodegeneration and metabolic disease. That's the honest biology.

What raises oxidative load

Free radicals aren't villains in themselves — your immune system uses them to kill pathogens, and ordinary metabolism produces them as a byproduct. The problem is chronic excess load, which in modern life comes mostly from:

• Smoking (the single biggest individual contributor).
• Excess alcohol.
• Ultra-processed food — oxidised fats, artificial additives, low micronutrient density.
• Chronic poor sleep.
• Chronic high stress.
• Air pollution and UV exposure.
• Sedentary living plus excess body weight.

What lowers it: the opposite list, plus an antioxidant-rich diet.

The antioxidants with authorised EU health claims

Under EU/UK law, only a handful of nutrients carry authorised claims specifically for protection of cells from oxidative stress^[1]:

• Vitamin C
• Vitamin E
• Vitamin B2 (riboflavin)
• Selenium
• Zinc
• Copper
• Manganese

Beyond that, vitamins A, C, E, zinc, selenium, copper and manganese contribute to various other authorised functions (immune system, skin, hair, nails, bones, normal vision) — the "protects cells from oxidative stress" claim is the pure antioxidant wording.

Other compounds widely marketed as antioxidants — carotenoids, polyphenols (flavonoids, curcumin, resveratrol, quercetin), CoQ10, astaxanthin, glutathione — are real antioxidants biologically but do not carry authorised EU cholesterol/oxidative claims at supplement level. They can be described factually; they cannot be given direct health claims on packaging.

Foods that deliver the most

Food beats supplements in almost every antioxidant category. The polyphenol and carotenoid densities in real plant foods are hard to match with capsules, and food gives you the co-factors alongside.

High-density sources:

• Berries — blueberries, blackberries, raspberries, strawberries, cherries. Anthocyanins and flavonoids.
• Cruciferous vegetables — broccoli, cauliflower, cabbage, Brussels sprouts, rocket. Glucosinolates plus vitamin C.
• Leafy greens — spinach, kale, chard. Lutein, zeaxanthin, folate, vitamin C.
• Coloured vegetables — red peppers, beetroot, tomatoes, carrots. Lycopene, beta-carotene, vitamin C.
• Herbs and spices — turmeric, rosemary, oregano, cinnamon, ginger. Concentrated polyphenol load per gram.
• Extra virgin olive oil — oleocanthal and related polyphenols.
• Green tea and coffee (unsweetened) — catechins, chlorogenic acid.
• Dark chocolate (70%+) in modest amounts — flavanols.
• Nuts and seeds — walnuts, pecans, sunflower seeds (vitamin E), Brazil nuts (selenium, with a two-nut daily cap).
• Fatty fish — not "antioxidants" in the classic sense, but omega-3 EPA and DHA modulate oxidative signalling.

The Mediterranean diet gets its reputation largely because it layers all of these together — the PREDIMED randomised trial reported around a 30% reduction in major cardiovascular events over 4.8 years on a Mediterranean diet supplemented with EVOO or nuts versus a low-fat control^[2].

Why "more is better" doesn't work with antioxidant supplements

This is where the marketing and the science diverge. Large randomised trials of single high-dose antioxidant supplements — beta-carotene, vitamin E, vitamin A, selenium — have repeatedly failed to show cardiovascular or cancer-outcome benefits in generally healthy populations. Some (beta-carotene in smokers, vitamin A at high doses) showed the opposite.

The honest read: dietary antioxidants work in networks, not in isolation. Pulling one out and dosing it in mega-amounts is not biologically what the research on "diets high in antioxidants" was describing. For most adults, the rational supplement plan for oxidative protection is:

• A varied, plant-forward diet.
• Correct deficiencies if present.
• Modest doses of vitamins and minerals in food-level ranges.
• Specific research-backed compounds where the bioavailability is actually solved.

Where supplements fit sensibly

Vitamin E. Contributes to the protection of cells from oxidative stress (authorised claim)^[1]. Natural mixed tocopherols preferred over synthetic alpha-tocopherol. Most well-nourished UK adults meet vitamin E from nuts, seeds and olive oil.

Vitamin C. Contributes to the protection of cells from oxidative stress, normal collagen formation, normal function of the immune system, reduction of tiredness and fatigue, and helps regenerate reduced vitamin E (authorised claims). NHS guidance on dietary vitamin C is at the low end^[3]; 200–1000 mg daily from supplements is the reasonable range, megadoses don't add benefit and give most people loose stools.

Selenium. Contributes to the protection of cells from oxidative stress, normal thyroid function, normal function of the immune system and normal spermatogenesis (authorised claims). UK soil is selenium-poor — about 60–75 µg daily is a sensible ceiling. Two Brazil nuts daily is a famous food workaround.

Zinc. Contributes to the protection of cells from oxidative stress, normal immune system function, maintenance of normal skin, hair and nails, and more (multiple authorised claims).

Curcumin. Not EU-claim authorised at the supplement level, but one of the more actively researched polyphenols for markers of oxidative stress and inflammatory signalling. The long-standing challenge is bioavailability — a head-to-head comparison reported the liquid micellar form up to 185× more bioavailable than native curcumin powder^[4]. Our Licur 7000 uses NovaSOL® micellar curcumin alongside vitamin D.

Vitamin D. Not an "antioxidant" in the classic sense, but modulates immune and inflammatory signalling, and UK adults sit below optimal through winter. Our D3+K2 covers that case.

Omega-3 EPA and DHA. Not classic antioxidants either, but modulate inflammatory pathways that intersect with oxidative biology. 250 mg+ daily contributes to normal function of the heart (authorised claim). Our Omega-3 fish oil and life'sOMEGA algae oil both comfortably clear that.

Magnesium, B-Complex, iron (if tested), iodine. Round out the cofactor side of the antioxidant enzymes your body makes. Magnesium is involved in over 600 enzymatic reactions^[5].

The antioxidant stack for most adults

Food-first, then a small and sensible supplement set:

1. Plant-forward, Mediterranean-style eating.
2. A varied diet rich in berries, leafy greens, cruciferous vegetables, herbs, olive oil, nuts and seeds.
3. A broad-spectrum B-complex with vitamin C.
4. Vitamin D year-round (more in winter).
5. Omega-3 to clear the 250 mg EPA+DHA threshold.
6. Bioavailable curcumin if the polyphenol research interests you.

Skip: mega-dose single antioxidants, proprietary "detox" blends, the more-is-better premium "antioxidant capsules" market.

In practice

Antioxidants are real biology. Oxidative stress is real physiology. The best way to support both is to eat plants, sleep properly, move regularly, stop smoking, limit alcohol, and manage visible sources of oxidative load (UV, pollution) where you can. A rational supplement baseline — B-complex, vitamin D, omega-3, bioavailable curcumin — covers the high-ROI side. The "anti-ageing antioxidant complex" that costs £60 a month almost certainly does not outperform that. Save your money; spend it on better berries.

References

1. European Commission. EU Register of Nutrition and Health Claims Made on Foods. ec.europa.eu
2. Estruch R, Ros E, Salas-Salvadó J, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med. 2018;378(25):e34. PubMed: 29897866
3. NHS. Vitamin C. nhs.uk
4. Schiborr C, Kocher A, Behnam D, et al. The oral bioavailability of curcumin from micronized powder and liquid micelles is significantly increased in healthy humans and differs between sexes. Mol Nutr Food Res. 2014;58(3):516–527. PubMed: 24402825
5. de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev. 2015;95(1):1–46. PubMed: 25540137

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