Antioxidants

Overview

Antioxidants are natural substances found in many foods. They protect your cells from damage caused by unstable molecules called free radicals. Free radicals form naturally when your body changes food into energy, and also from things like smoke or too much sun. When there are too many free radicals and not enough antioxidants, it is called oxidative stress. Over time, oxidative stress can raise the risk of heart disease, diabetes, and other long-term conditions.

Antioxidant-rich foods are easy to find, but many people still don't eat enough fruit and vegetables. Health surveys in many countries show that most adults fall short of the recommended five portions a day.

Antioxidants matter for everyone. People who smoke, drink alcohol heavily, have a poor diet, or live with long-term health conditions such as diabetes may have higher oxidative stress and can benefit most from more plant foods.

Symptoms

Common symptoms

• Antioxidants don't cause symptoms — but a diet lacking them may leave you tired, prone to infections, or slow to heal.
• More specific signs, like bleeding gums, easy bruising, poor night vision, or cracks at the corners of the mouth, can appear with a severe vitamin deficiency.

Symptoms in children

• Children rarely have obvious symptoms. Look out for poor growth, frequent infections, or very low energy — but these can have many causes.
• If you're worried about your child's diet or weight, ask your health visitor, school nurse, or GP.

Symptoms in older adults

• Older adults might not notice specific symptoms either. Dry skin, tiredness, or a slower-healing wound could mean a nutritional gap, but they can also be signs of other conditions.
• If an older person is losing weight without trying or eating very little, they should have a medical check.

Causes

Main causes

• Free radicals are produced naturally as your body uses oxygen for energy. They also come from cigarette smoke, air pollution, ultraviolet light, alcohol, and unhealthy processed foods.
• When the body's antioxidant defences can't keep up with free radicals, oxidative stress occurs.
• Some health conditions — such as diabetes, heart disease, and chronic inflammation — increase oxidative stress.

Risk factors

• Eating few fruits, vegetables, nuts, or whole grains
• Smoking or heavy alcohol use
• Long-term stress or poor sleep
• A chronic condition like diabetes or inflammatory bowel disease
• Ageing, because the body's natural defences become less efficient

When to see a doctor

See a doctor urgently if:

• Any emergency symptoms listed above — don't wait.
• Unexpected chest pain or breathlessness.

Book a routine appointment if:

• If you are concerned about what you eat or want personalised dietary advice, book a routine GP or nurse appointment.
• Before starting any supplement, talk to your GP or pharmacist.

Diagnosis

Antioxidants are not measured in a standard health check. A doctor may test for specific vitamins or minerals only if your symptoms or medical history suggest a deficiency. The most important part of 'diagnosis' is looking at your diet and lifestyle.

Tests that may be done

• Blood tests for vitamin C, vitamin E, vitamin A, or selenium if deficiency is suspected
• A full blood count and iron studies to rule out anaemia and other causes of tiredness
• Measurement of HbA1c or cholesterol to check overall metabolic health

What to expect at your appointment

Your GP will ask about your meals, appetite, smoking, alcohol, and any supplements you take. They may arrange a blood test if needed. Results will help decide whether you need to change your diet or take a supplement under supervision.

Treatment

First-line treatment is always diet. Eat a rainbow of vegetables and fruits, include wholegrains, nuts, beans, and healthy fats. Supplements are not a quick fix and can be harmful in high doses.

Self-care at home

• Try to have at least five portions of fruit and vegetables a day — fresh, frozen, tinned, or dried all count.
• Add a handful of nuts or seeds to breakfast or salads.
• Use herbs and spices like turmeric, ginger, and cinnamon — they are rich in plant antioxidants.
• Swap refined cereals for wholegrain oats, brown rice, or wholemeal bread.

Medical treatments

In specific cases — for example, a confirmed deficiency or a condition that affects absorption — a doctor might recommend an individual vitamin or mineral supplement at a safe dose. Only take this under medical advice, because high-dose supplements can interact with medicines and may be harmful.

When is surgery considered?

Antioxidant supplements can affect bleeding or anaesthesia. If you are having surgery, tell your surgeon or anaesthetist about every supplement you take, and stop them if they advise you to.

Living with this condition

Think of antioxidants as a team you build at every meal. Start with vegetables on your plate, add fruit for snacks, and choose water, tea, or coffee instead of sugary drinks. Small daily habits matter more than occasional superfoods.

Lifestyle tips

• Cook more meals from whole ingredients at home.
• Shop seasonally and budget-friendly — frozen vegetables have just as many antioxidants as fresh.
• If you smoke, ask your GP about stop-smoking support.
• Limit alcohol to the recommended national guidelines, or avoid it.

Diet and exercise

Aim for at least 150 minutes of moderate exercise per week — like brisk walking or cycling. Combine that with a colourful, high-fibre diet, and your body's antioxidant defence system works more effectively.

Mental health and emotional wellbeing

Eating well supports your overall wellbeing, but it is not a treatment for mental health conditions. If you feel anxious about your health or food, or are struggling with low mood, speak to your GP. Support is available.

Prevention

You cannot prevent every free radical — they are part of normal life. But a healthy diet without smoking, with limited alcohol and protected skin, can greatly reduce the oxidative stress that contributes to disease.

Vaccines

Vaccines do not prevent oxidative stress, but staying up to date with your recommended vaccinations keeps your body free from infections that add extra stress.

Screening programmes

There is no routine screening test for antioxidant deficiency in healthy people. Your doctor will only test specific nutrients if they have a clinical reason.

Complications

If left untreated

• A severe lack of vitamin C causes scurvy, with bleeding gums, bruising, and poor wound healing — very rare but still possible.
• Long-term poor diets with low antioxidant intake are linked to a higher chance of cardiovascular disease and some cancers.
• Too much supplementation can cause toxicity, so 'treating' your own antioxidant levels is not safe.

Long-term outlook

The outlook is promising. Most people can meaningfully improve their antioxidant intake by making simple food changes. Even one extra portion of fruit or vegetables a day can lower risk over a lifetime.

Find support

International organisations

• World Health Organization ↗

Local organisations

• NHS ↗ · UK
• British Dietetic Association ↗ · UK

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.