The Antioxidant Paradox: Should You Really Be Taking Supplements?

Antioxidants have long been hailed as magic bullets against ageing, cancer, heart disease, and just about every modern health complaint. From vitamin C capsules to acai powder, the promise of neutralising dangerous “free radicals” seemed too good to ignore.

But as the dust of decades of research has settled, a more complex — and more fascinating — picture has emerged. Antioxidants are neither simply good nor bad. In fact, under certain circumstances, antioxidant supplements might even hinder health rather than help it.

So, where does the truth lie?

The Rise (and Fall) of the Antioxidant Hype

In the early 1990s, a flood of observational studies suggested that diets rich in fruits and vegetables were linked to lower rates of chronic diseases. The natural assumption was that antioxidants like vitamins A, C, and E were the protective agents — and if a little was good, a lot must be better.

The supplement industry exploded. Global sales of antioxidant supplements rose into the billions. But when scientists rigorously tested these supplements in large, randomised trials, the results were disappointing — and occasionally alarming.

• The Physicians’ Health Study II (over 14,000 male doctors followed for over a decade) found that vitamin C and E supplements offered no protection against major cardiovascular events or cancer.

• The ATBC Trial (Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study) shockingly found that beta-carotene supplements increased lung cancer risk among smokers.

• A major Cochrane Review, analysing data from 78 trials, concluded that antioxidant supplements not only failed to prolong life but were associated with higher mortality in some groups — especially with high doses of beta-carotene, vitamin A, and vitamin E.

Clearly, antioxidants were not the one-size-fits-all panacea we had hoped for.

Antioxidants and Oxidative Stress: A Delicate Dance

To understand why antioxidant supplements often fall short, we need to reframe how we think about oxidative stress.

Free radicals (reactive oxygen species) are not just accidental by-products of metabolism; they play critical roles as signalling molecules in the body:

• Directing immune responses

• Regulating blood vessel tone

• Triggering beneficial cellular adaptations (like mitochondrial repair and biogenesis)

• Supporting controlled cell death to prevent cancer spread

In fact, small, well-regulated amounts of oxidative stress are essential for health.

This phenomenon, where low-level stress makes us stronger, is called hormesis — and it’s why exercise, fasting, and even certain plant compounds are so beneficial.

Over-suppressing free radicals with high doses of antioxidant supplements can disrupt these vital processes, leading to blunted immune function, impaired mitochondrial adaptation, and potentially poorer long-term health.

For instance:

• Studies show that taking high-dose vitamin C or E after exercise blunts the body’s ability to build new mitochondria and adapt to training.

• Excess antioxidants can interfere with cellular “cleanup” processes (autophagy) needed for healthy ageing.

In short:

Not all oxidative stress is bad — and not all antioxidants are good.

The Body’s Built-in Antioxidant System

Fortunately, the body is equipped with an elegant, powerful antioxidant network, including:

• Glutathione (the body’s master antioxidant)

• Superoxide dismutase (SOD)

• Catalase

• Peroxiredoxins

Rather than flooding the system with external antioxidants, a better strategy is to support and enhance these natural defences through smart lifestyle practices:

• A colourful, plant-rich diet full of polyphenols and micronutrients

• Regular physical activity

• Intermittent fasting and metabolic switching

• Mild stressors like sauna, cold therapy, and exercise (“good stress”)

This approach triggers Nrf2, a master regulator of antioxidant gene expression, naturally strengthening the body’s resilience over time.

When Antioxidant Supplements Might Still Have a Role

While the general evidence warns against indiscriminate antioxidant supplementation, there are specific circumstances where targeted, evidence-based use of antioxidants can offer real benefits.

Correcting Deficiencies

In cases of true vitamin deficiencies, supplementation can be lifesaving. Severe deficiencies of vitamins like C, A, or E — although rare in developed countries — still occur in certain populations and can lead to serious health problems such as scurvy, impaired vision, and immune dysfunction. In these cases, supplementation is not only appropriate but essential.

Supporting Mitochondrial Health

In individuals with mitochondrial dysfunction — seen in conditions like heart failure, neurodegenerative diseases, or rare mitochondrial disorders — supplementation with Coenzyme Q10 has shown clear benefits. CoQ10 plays a critical role in the production of cellular energy, and supporting its levels can help improve energy metabolism and overall cellular function.

Managing Diabetes Complications

For people with diabetes, oxidative stress plays a significant role in the progression of complications like neuropathy. Alpha-lipoic acid, a potent antioxidant that also improves insulin sensitivity, has been shown in several studies to reduce symptoms of diabetic neuropathy and improve quality of life.

Cognitive Support in Ageing

Emerging evidence suggests that certain polyphenol-rich antioxidants, such as resveratrol and flavonoids found in berries and green tea, may help support cognitive function by improving blood flow to the brain and reducing neuroinflammation. While more research is needed, these findings are promising in the context of brain ageing and dementia prevention strategies.

Protecting Skin from Environmental Damage

In the realm of skin health, both oral and topical antioxidants have shown benefit. For example, astaxanthin, a carotenoid found in marine algae, and vitamin C serums have been demonstrated to protect against UV-induced skin damage, improve skin elasticity, and reduce signs of photoageing.

Intense Physical Stress

In athletes undergoing extremely high oxidative stress from intense training or competitions, targeted use of antioxidants such as N-acetylcysteine (NAC) may help support recovery and reduce exercise-induced oxidative damage. However, it is crucial to time supplementation carefully to avoid blunting the natural adaptive benefits of exercise.

Counteracting Environmental Pollution

For individuals living in highly polluted environments, where exposure to airborne toxins leads to chronic oxidative stress, supporting the body’s detoxification systems with nutrients that enhance glutathione production — the body’s master antioxidant — may offer additional protection.

In each of these scenarios, the key is precision:

• The right antioxidant,

• At the right dose,

• For the right person,

• At the right time.

Blanket use of antioxidant supplements without a clear clinical reason remains unsupported by evidence — and may even disrupt the body’s own finely tuned balance.

Important note:

• These uses are targeted, time-limited, and preferably guided by a clinician.

• Mega-dosing indiscriminately is still discouraged.

Final Thoughts: Choose Wisely

In the story of health and ageing, antioxidants are not simple heroes. They are part of a delicate communication network between cells, mitochondria, and the environment.

Flooding your body with high-dose antioxidant supplements is neither natural nor universally safe.

Instead, nourishing your own internal antioxidant systems through whole foods, movement, and adaptive stresses offers a far better blueprint for long-term resilience.

When used judiciously — correcting deficiencies, supporting recovery, or targeting specific conditions — antioxidant supplements can still play a supporting role. But in most cases, your best defence lies not in a bottle, but on your plate.

How to Boost Your Natural Antioxidant Power

• Eat the rainbow: Aim for 6–10 servings of colourful fruits and vegetables daily.

• Move your body: Exercise naturally strengthens antioxidant defences.

• Fast smartly: Occasional fasting boosts autophagy and resilience.

• Use spices and herbs: Turmeric, rosemary, and oregano are antioxidant powerhouses.

• Protect your sleep: Poor sleep increases oxidative stress dramatically.

• Minimise toxins: Avoid smoking, excessive alcohol, and processed foods.