A Simple Guide to Antioxidants and Their Benefits

Article by Charlotte Burnett-Armstrong

Eating a healthy, balanced diet while trying to include antioxidants can feel overwhelming, but you’re likely consuming more than you realise! This article will help you understand where antioxidants come from and reassure you that increasing your intake doesn’t require drastic changes - just a few simple, mindful choices.

What are antioxidants?

An antioxidant is a substance in some foods that decreases the negative effects of free  radicals on normal body functions. Vitamin A, C and E as well as phytochemicals such  as carotenoids and polyphenols and minerals such as zinc are examples of  antioxidants. It is also a substance that preserves foods by delaying discolouration or rancidity due to oxidation.

What are free radicals and where do they come from?

Free radicals are by-products of oxidation, a key process in human metabolism. These free radicals are highly reactive molecules that are missing an electron, so they "move around" in search of another electron. In this process, they can cause damage to cells. One example of this is when free radicals “steal” electrons from lipids in cell membranes, leading to a process called lipid peroxidation. This is where antioxidants come in—they carry extra electrons and donate them to free radicals, helping to stabilise them.

If free radicals are not neutralised by antioxidants, they can accumulate and cause oxidative stress, which can lead to inflammation. This increases the risk of degenerative diseases such as Alzheimer's disease, various cancers, and cardiovascular diseases. Additionally, when free radicals damage a cell, they can also harm its genetic material, leading to mutations. These mutations can cause cells to grow abnormally and rapidly, which may contribute to the development of some cancers. 

What are the best food sources for antioxidants?

Most of us will already be consuming plenty of antioxidant-rich foods without even  realising, as they’re mainly found in plant foods - there is no need to drastically  change your diet! The antioxidant vitamins are A, C and E.

Vitamin A

Vitamin A is fat soluble and  helps our immune system work as it should, as well as helping with vision, and keeping  our skin and the lining of some parts of our body, such as our nose, functioning  properly.  Vitamin A can be found in: 

  • Cheese,

  • Eggs,

  • Dark green leafy vegetables,

  • Orange fruits and vegetables e.g. carrots, sweet potato, butternut squash and  papaya.

Vitamin C

Vitamin C is water soluble and helps to protect cells from damage, it also helps with the  formation of collagen – this is important for normal bones, gums, teeth and skin. Vitamin C also helps the immune system and nervous system function normally, and can be found in:

  • Fruit, especially citrus fruits, blackcurrants, strawberries, papaya and kiwi

  • Green vegetables 

  • Peppers 

  • Tomatoes

Vitamin E

Vitamin E helps to protect the cells in our body against damage and is also fat-soluble, like vitamin A. This can be found in: 

  • Vegetable and seed oils such as olive, rapeseed, sunflower and peanut • Nuts and seeds such as sunflower seeds and almonds,

  • Olives, 

  • Avocados.

Polyphenols

Polyphenols are a category of compounds naturally found in plant foods. Polyphenols have antioxidant as well as anti-inflammatory properties. It has been found  that polyphenols may improve blood sugar levels by potentially slowing down the  conversion of carbohydrates into simple sugars after eating. They can also help lower  the risk of heart disease and protect the body against cancers, as they are antioxidants  and therefore stabilise free radicals, as mentioned above. Polyphenols can be found in: 

  • Dark chocolate (opt for 75% and up!)

  • Fruits (blackberries, strawberries, raspberries),

  • Herbs and spices (thyme, basil, ginger),

  • Nuts (hazelnuts, almonds, pecans), 

  • Vegetables (Onions, spinach, chicory, olives, artichokes),

  • Even red wine!

What about antioxidant supplements?

There is not enough evidence to support the consumption of antioxidant supplements  as a means of disease prevention or cure. In some cases, Vitamin E and A  supplementation has even been found to increase mortality. For certain groups,  supplements may be necessary, for example if they are diagnosed with a deficiency.  However, for the general population, it is much more beneficial to reap the rewards of  consuming real food containing antioxidants.  

Summary

Antioxidants are an essential part of our diet to prevent cell damage and keep our bodies functioning properly. Great sources of antioxidants include colourful fruit and vegetables, beans and pulses, and herbs and spices. Foods such as red meat, refined carbohydrates, added sugar, and those high in saturated fats can contribute to the production of free radicals and increase oxidative stress in the body. However, everything can be consumed in moderation as part of a healthy, balanced diet! Consider what you can add into your current diet to up your antioxidant intake. Remember to include a range of sources, because they all carry different benefits - chances are, it’ll be easier than you think!

References

  1. .Everything You Need To Know About Antioxidants (2021) Cleveland Clinic.  Available at: https://health.clevelandclinic.org/what-do-antioxidants-do  (Accessed: 26 February 2025). 

  2. Poljsak, B., Kovač, V. and Milisav, I. (2021) ‘Antioxidants, Food Processing and  Health’, Antioxidants, 10(3), p. 433. Available at:  https://doi.org/10.3390/antiox10030433. 

  3. Prior, R. and Wu, X. (2013) ‘(PDF) Diet Antioxidant Capacity: Relationships to  Oxidative Stress and Health’, ResearchGate [Preprint]. Available at:  https://doi.org/10.5099/aj130200126. 

  4. Vitamins and Minerals - Nutritional Information (2023) British Nutrition  Foundation. Available at: https://www.nutrition.org.uk/nutritionalinformation/vitamins-and-minerals/ (Accessed: 26 February 2025). 

  5. Polyphenols: Facts, Benefits, and Foods (2024). Available at:  https://zoe.com/learn/what-are-polyphenols (Accessed: 26 February 2025). 

  6. Bjelakovic, G. et al. (2012) ‘Antioxidant supplements for prevention of mortality in  healthy participants and patients with various diseases’, The Cochrane Database  of Systematic Reviews, 2012(3), p. CD007176. Available at:  https://doi.org/10.1002/14651858.CD007176.pub2. 

  7. Donnelly, J.K. and Robinson, D.S. (1995) ‘Invited Review Free Radicals in Foods’,  Free Radical Research [Preprint]. Available at:  https://doi.org/10.3109/10715769509147536.

Charlotte is currently studying for her MSc in Human Nutrition. She has always worked in the food industry, having been a freelance chef, a customer service and design assistant at Detox Kitchen, and a Social Media Manager at Gladwin Brothers restaurants. However, her primary interest lies in nutrition. She is excited to be pursuing this passion and looks forward to using the knowledge gained from her studies to help others.

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