Antioxidants: A comprehensive guide

Antioxidants: A comprehensive guide

23 Mar 2022

What are antioxidants?

Antioxidants are compounds, largely found in foods that neutralise free radicals (1).  They can be artificial ("man-made") or natural, and include certain nutrients and minerals found in food. They help delay or stave off cell damage (10). Thousands of substances can act as antioxidants.

The health benefits of antioxidants were first made public in the ‘90s. During this time, scientists were exploring free radical damage, specifically its link to various chronic conditions (11, 12).

Studies took a look at how certain substances, in supplement form, could help treat these chronic disorders. Primarily, vitamin E and beta-carotene came into focus.

This hailed the start of the media buzz around antioxidants and their many benefits. Specific antioxidant-containing foods then got singled out as disease-fighting "superfoods (11)." In some cases, they are referred to as "free-radical scavengers" or ROS (reactive oxygen species) (13, 14).

What is oxidation and why does it damage cells?

When the human body does certain activities, such as the body converting food into energy or a person exercising, highly unstable molecules are formed. These are called free radicals, which are problematic and pose a health risk. They are part of what can trigger "oxidative stress," which is a process that damages cells (2).

Other things that can trigger oxidative stress in the body include chemotherapy, excessive exercise, ozone exposure, radiation, and tissue trauma from injuries or inflammation (15).

Additionally, consumption of certain foods such as additives, artificial sweeteners, certain dyes, refined and processed foods, and trans fats can trigger oxidative stress (16).

Exposure to chemicals such as drugs, pesticides, and industrial solvents can also cause oxidative stress. Lastly, ischemia, reperfusion damage, and mitochondrial activity can also cause oxidative stress in the body (17).

These activities and forms of exposure result in cell damage (8), which may further lead to an excessive release of copper ions in the body, disruption of the electron transport chain, and increase of free radical-generating enzymes.

There is a limited extent to which the body can handle free radicals on its own. When there's an overabundance of it, the effects cannot be reversed over time. It can also lead to any number of diseases (18).

Things that can inadvertently speed up oxidation include sunlight, pollution, alcohol, stress and smoking. The latter includes mere exposure to cigarette smoke (1).

Oxidative stress plays a major role in diseases such as age-related macular degeneration, cardiovascular diseases, and others (2).


Benefits of antioxidants

While antioxidants are not the "be all and end all," they still play a key role in supporting human health. So much so, in fact, that they could have a modest protective quality for certain debilitating conditions, cognitive abilities, eye health, heart health, and lung health (3).

Here’s a closer look at the specific benefits of some of the most popular ones, as well as foods rich in antioxidants (3):


This carotenoid also supports heart health improvement, and helps with sun protection (19). Sources of carotenoids (which include lycopene and beta-carotene) include apricots, asparagus, beef, bell peppers, rockmelon, carrots, collard greens, kale, mango, orange, peaches, and pink grapefruit.


In addition to acting as an antioxidant, lutein helps Improve vision sharpness, lessens glare impairment, and helps lessen the effects of eye diseases (20). Lutein can be found in broccoli, collard greens, corn, papaya, peach, and boiled spinach.


Manganese helps the body form bones and connective tissues in the body (21).

Phenolic acids

These have anti-ageing, anti-inflammatory, and anti-proliferative qualities on top of being an antioxidant (22). Phenolic compounds can be found in apples, berries, onions, and red wine.


This helps with cardiovascular disease prevention, reduces cognitive disorder possibilities, and provides thyroid function support (23). Sources of resveratrol include berries, grapes, peanuts, red and white wine.


This supports asthma symptom reduction, boosts the immune system, and plays a key role in thyroid health (25). Selenium can be found in barley, beef, brazil nuts, brown rice, cheese, chicken, corn, eggs, and fish.

Vitamin A

In addition to acting as an antioxidant, vitamin A supports acne risk reduction, bone health support, and immune system support (24). Vitamin A can be found in carrots, mangoes, papaya, spinach, chard, liver, eggs and milk.

Vitamin C

Vitamin C helps reduce free radicals in the body and maintains general health and wellbeing (26). There are many sources of vitamin C, including beets, bell peppers, snow peas, strawberries, turnips, tomatoes, and sweet potatoes.

Vitamin E

Besides being an antioxidant, vitamin E helps with hair and skin health, including the scalp (27). Vitamin E can be found in almonds, avocados, beef, canola oils, corn, hazelnuts, mustard, soybean, boiled spinach, and turnip.

Other foods that are rich in antioxidants include alfalfa sprouts, beans, dark chocolate, eggplants, goji berries, onions, pomegranates, prunes, and raisins.

Plant-based foods in general have antioxidants like catechins, flavones, flavonoids, phytoestrogens (3,4,8). This is why a balanced diet including fresh vegetables and fruits is highly recommended by medical professionals.


How cooking affects antioxidants in food

Cooking can also make a difference in the antioxidant levels of food.

Tomatoes, for example, contain the antioxidant lycopene. Getting treated with heat will then make lycopene more accessible to the body for processing and use (28).

On the other hand, the cooking process depletes plenty of antioxidant activity in peas, zucchini and cauliflower (29).

Contrary to popular belief, however, it's not all about salad. It can be a matter of smoothies, soups, juices and even creative ways of preparing foods like carrots.

All of that being said, it's important that a person strikes a balance between raw and cooked foods that are rich in antioxidants. Many people achieve this through lightly steaming their vegetables, like broccoli and carrots.

Improving antioxidant intake can be done in a number of ways (8), such as adding sugar-free, salt-free dried fruit, nuts, and seeds to your snacks, like Brazil nuts and sunflower seeds. You can also drink matcha or green tea daily, eat foods with vibrant colors like beets, berries, and kale.

You can also have vegetables and fruits during meals and snacks. Additionally, you can use spices to further enrich your meals with antioxidants. You can use cinnamon, clove, cumin, ginger, oregano, or turmeric.

A good rule of thumb is to find supplements which can fill the gaps especially in terms of antioxidants the body needs.

Dangers of too many antioxidants

One of the things that scientists looked into is the counterintuitive effects of too many antioxidants (9). What are the antioxidants that can cause issues when taken excessively? The answer: all of them.

It is very important to have a clear sense of balance. Moderation is the key.

Antioxidants through supplementation

Realistically, getting enough nutrients from eating doesn't always happen. A good way to ensure you try to meet your daily requirements of nutrients with antioxidant properties is through taking supplements. They tend to have concentrated antioxidant forms in them, contributing to the overall daily value (DV) the body needs as a whole.

Some of the main antioxidants that can be incorporated into your diet incude:


Aside from being an antioxidant, it also has anti-inflammatory properties. It's very potent and serves to provide the reddish hue seen in the likes of trout, salmon and shrimp.

Astaxanthin maintains and supports skin elasticity and skin integrity by protecting skin elastin from breaking down. Astaxanthin when consumed, decreases or reduces skin irritation and itching.


This antioxidant and anti-inflammatory substance goes a long way in cell-mediated immunity. It helps to address a wide range of health issues.

Studies have shown that zinc supplementation amongst older adults helps to decrease inflammatory cytokine generation, lessen infection incidents and oxidative stress (6).

Zinc also helps to maintain and support immune system health.

Vegan Omega

The commonly-known source of omega-3 fatty acids is from consuming fish oil. An underrated vegan alternative is omega-3 which is sourced from algae oil. This means that people who have a preference for being vegan will be able to take it just fine (7).

Omega-3 plays a major role in maintaining and supporting general health and well being.

Antioxidants help protect the body against debilitating conditions. In excess, it can even damage the body. However, when taken in moderation, it can help a person be healthy for a very long time. Moderation is the key and making it a daily habit to take antioxidants in amounts the body needs can help keep major diseases at a distance.

When you sign up for a supplement subscription with Vitable Australia, you’ll have a wide range of antioxidants to choose from. You will also be guided on how to take them, so as not to cause oxidative stress. Try our vitamin subscription to get your personalised vitamins delivered to your doorstep, using our vitamin delivery service. Sign up now for the best vitamin packs in Australia

Find out more about other supplements that can support immunity:

Zinc | Iron | Astaxanthin | Ashwagandha | Probiotics SB | B complex | Vitamin C | Vitamin D | Daily probiotics | Vitamin B12 | Fish oil | Biotin

*Always read the label. Follow the directions for use. If symptoms persist, talk to your health professional. Vitamin and/or mineral supplements should not replace a balanced diet.


  1. National Center for Complementary and Integrative Health. “Antioxidants: In Depth”. Published on Accessed on 13 January 2022.
  2. Victoria State Government/Department of Health/Deakin University. “Antioxidants”. Published on Accessed on 13 January 2022.
  3. Harvard School of Public Health. “Antioxidants”. Published on Accessed on 13 January 2022.
  4. “Antioxidants: What You Need to Know”. FamilyDoctor.Org. Published on Accessed on 13 January 2022.
  5. Vitable. “Astaxanthin”. Vitable. Published on Accessed on 14 January 2022.
  6. Journal of Trace Elements in Medicine and Biology. “Zinc: An antioxidant and anti-inflammatory agent: Role of zinc in degenerative disorders of aging” Amanda  S. Prasad. Published on Accessed on 14 January 2022.
  7. International Journal of Preventive Medicine. “The Effect of Omega-3 Supplements on Antioxidant Capacity in Patients with Type 2 Diabetes”. Hossein Hajianfar, Zamzam Paknahad, Ahmad Bahonar. Published on Accessed on 14 January 2022.
  8. Medical News Today. “How can antioxidants benefit our health?” Megan Ware, RDN, L.D. Published on Accessed on 14 January 2022.
  9. MedlinePlus. “Antioxidants”. MedlinePlus. Published on Accessed on 29 January 2022.
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