What Are Antioxidants? Simply Explained

Antioxidants are substances that intercept reactive molecules – known as free radicals – and thereby help maintain a balance within the body. For six nutrients (vitamin C, vitamin E, zinc, selenium, copper, manganese), the claim “contributes to the protection of cells from oxidative stress” is officially approved in the EU. Plant-based antioxidants such as OPC or resveratrol, by contrast, are described in neutral terms – no claims are approved for them.

Few words come up as often in the world of nutrition as “antioxidants” – on juice bottles, berry packaging, cosmetics. But what exactly do these substances intercept, and which ones live up to what the marketing promises? The answer is refreshingly concrete once you picture an apple.

The simple explanation: the browning apple

Cut an apple open and leave it out – it turns brown. That is oxidation: oxygen reacting with the flesh of the fruit. Drizzle some lemon juice over it and it stays lighter for longer; the vitamin C counteracts the oxidation. This very same principle plays out millions of times over inside your body. Metabolism continuously produces free radicals – highly reactive molecules. Antioxidants (“anti” = against, “oxidation”) intercept them and keep the balance. Importantly, the body needs a certain amount of free radicals, for instance for immune defence. It is not about switching them off, but about balance. For a deeper look at what oxidative stress actually means, see Free Radicals and Oxidative Stress.

These six nutrients may advertise cell protection

For six vitamins and minerals, the cell-protection role is scientifically recognised and approved as a claim in the EU. That is a genuine difference from a general “rich in antioxidants”:

You can read more about the individual nutrients in Vitamin C: Effects & Daily Requirement, Vitamin E as an Antioxidant, Zinc: Effects & Daily Requirement and Selenium: Effects & Form. The decisive point: only for these substances is the claim tested and permitted. When a product merely promises a blanket “rich in antioxidants”, that alone says nothing about a proven benefit.

Water-soluble or fat-soluble – why it matters to you

Antioxidants are broadly classified by whether they dissolve in water or in fat. This determines which areas of the body they preferentially move through – and how best you take them in:

• Water-soluble (vitamin C, many polyphenols) – act in the watery environment of the blood and the spaces between cells.
• Fat-soluble (vitamin E, carotenoids such as astaxanthin) – embed themselves in cell membranes and are absorbed better when you consume them with a little fat.

In practice this means: take the fat-soluble ones ideally with a meal that includes a little oil. Why this improves absorption is explained in Bioavailability Simply Explained. A vivid example of a fat-soluble plant carotenoid is Astaxanthin from Microalgae.

The antioxidant network: team players, not lone fighters

One detail that often gets lost in advertising: antioxidants work in the body as a network, not as lone fighters. When vitamin E intercepts a reactive molecule within a cell membrane, it is itself “used up” in the process – and can subsequently be restored to its active state by vitamin C. The body’s own systems, too, such as glutathione and enzymes that require selenium, zinc, copper or manganese as a component, mesh together. This is precisely what explains why the six approved nutrients are so different (three vitamins, three minerals) and why broad coverage is usually more sensible than a mega-dose of a single substance. Anyone wishing to explore the body’s own glutathione system will find background in Glutathione as an Antioxidant, and how selenium acts as an enzyme building block is put into context by Selenium: Effects & Form.

What about OPC, quercetin & resveratrol?

Alongside the six nutrients, there are countless secondary plant compounds that show antioxidant properties in the laboratory – polyphenols and flavonoids, for instance. These include OPC from grape seed and pine bark, quercetin and resveratrol from the grape. No health claims are approved for these plant compounds in the EU. We therefore describe them neutrally: as substances that occur in foods and extracts – without any promise of effect. This very honesty is what sets us apart from advertising that lumps everything together.

What research is investigating

Recognised and part of textbook knowledge is the role of the six named nutrients in cell protection. In the case of the secondary plant compounds, research is investigating whether and how their antioxidant activity measured in the test tube can be transferred to the living organism – an important point, because absorption, metabolism and actual availability in the body often differ greatly from the laboratory situation. This is precisely why no claims have been approved here to date. It is an open, active field of research, not a proven benefit.

The simplest approach: eat the rainbow

The most straightforward source of substances with antioxidant activity is a colourful, plant-focused diet. Many of the intense colours in fruit and vegetables come from secondary plant compounds – the deep red of the tomato (lycopene), the violet of the blueberry (anthocyanins), the green of kale. Anyone who gets as many colours onto their plate as possible over the course of the week covers a wide range. Nuts and oils supply vitamin E, citrus and bell peppers supply vitamin C, and Brazil nuts supply selenium. If you eat little vegetables, Nutrients When You Eat Few Vegetables offers guidance. Whether additional supplements make sense is honestly assessed by Worthwhile or a Waste of Money? – and the legitimate question of overdosing is addressed by Can You Take Too Many Vitamins?.

More is not better: the matter of dosage

One persistent fallacy goes: if antioxidants intercept reactive molecules, then a lot of them is automatically good. It is not that simple. The body needs a certain amount of free radicals – for immune defence and for signalling processes within the cells, for example. Very high doses of isolated single substances can disrupt this finely tuned balance rather than support it. For fat-soluble vitamins and some trace elements there are also upper limits that should not be exceeded on a lasting basis. That is why broad, moderate coverage through a varied diet is superior to “mega-dosing” a single substance. How much makes sense for individual nutrients and at what point it becomes too much is put into context by Can You Take Too Many Vitamins? and High-Dose Vitamin C: How Much?.

Honestly put into context

The cell-protection role of vitamin C, E, zinc, selenium, copper and manganese is established. Not established – and therefore to be described neutrally – are specific health effects of plant-based antioxidants such as OPC or resveratrol. It is also important to note: more is not automatically better. Isolated single substances in very high amounts are rarely the key; the interplay of many substances from a varied diet is the proven path. Supplements can top up this foundation in a targeted way, but they do not replace it.

Matching products from Scheunengut

You will find nutrients with an approved cell-protection claim in Vitamin C, Vitamin E, Zinc and Selenium. Plant-based antioxidants such as OPC we carry in the category OPC, and related plant compounds in Astaxanthin.

Frequently Asked Questions (FAQ)

What are antioxidants, simply explained?

Antioxidants are substances that intercept reactive molecules – free radicals – and thereby help maintain a balance within the body. You can picture them as “catchers”. The same principle that makes a cut apple turn brown (oxidation) takes place in the body, and antioxidants counteract it.

Which antioxidants are scientifically recognised?

In the EU, the claim “contributes to the protection of cells from oxidative stress” is approved for six nutrients: vitamin C, vitamin E, zinc, selenium, copper and manganese. For plant-based antioxidants such as OPC or resveratrol, by contrast, no approved health claims exist.

Are plant-based antioxidants ineffective?

No, that cannot be said – they do show antioxidant properties in the laboratory. For humans, however, their health effects are not yet proven to the extent that claims would be approved. This is why OPC, quercetin, resveratrol and the like are described neutrally.

Is it better to eat antioxidants or take them as a supplement?

The simplest and proven source is a colourful, plant-rich diet along the lines of “eat the rainbow”. It supplies many substances in their natural interplay. Supplements can top up this foundation in a targeted way when there is an individual need, but they do not replace it.