Antioxidants – Keeping Free Radicals at Bay

Antioxidants and free radicals are terms that come up often in the world of health and nutrition. Although some of us have heard these terms many times, very few know the importance of free radicals and antioxidants for our bodies and health. What exactly are antioxidants? Are free radicals bad? And how many antioxidants do I actually need to consume daily? In this article, we'll dive into all these questions, and explore the exciting world of antioxidants and free radicals with you. CARE educates about the role of free radicals in our bodies and how you can use antioxidants to optimize your health. Are you ready? Let's go!

Blog Author Elena Health Coach at CARE
Elena Iagovitina

Health Coach

Published in Nutrition
14 min read · Jan 05, 2024

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What Are Antioxidants?

Antioxidants are protective molecules and our natural defenders against free radicals, which is why they are also called radical scavengers. They can neutralize free radicals by donating an electron to them without becoming unstable themselves. [1]

This explanation didn't do much for you? That is quite understandable. To really comprehend antioxidants and free radicals, we first have to take a little detour into molecular biology and turn to the smallest units of life – the molecules.

Excursion Into Molecular Biology – Molecules

Let’s start this section with a little joke.

Never trust an atom. They make up everything.

While the biology enthusiasts of you might be howling, we’ll shed some light on this joke for all the other normal people among you. Molecules are the building blocks of our universe.  They are made up of atoms that are linked together by chemical bonds. They surround us everywhere and at all times – both in living organisms and in the inanimate world.

Some molecules are stable and do not change. Others, however, are extremely reactive and may be able to influence neighboring molecules – and this is where our antioxidants and free radicals come into play.

What Are Free Radicals?

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Free radicals are molecules that have one or more unpaired electrons in their outer electron shell and, in a sense, have a kleptomaniac tendency. The unpaired electrons in the electron shell of free radicals make them extremely reactive. They strive to balance their electrons by “stealing” electrons from other molecules.

This type of chemical activity can cause great damage in a cell or organism, such as your body. [1]

So, free radicals are bad, right?

No, not entirely. Free radicals are not bad per se. In fact, they play an important role in various biological processes, such as the immune system's fight against bacteria and viruses. They are even produced when you normally breathe. Free radicals become a problem when they get out of control and are produced in increased amounts, especially in response to external influences such as cigarette smoke, pollution, environmental toxins and UV radiation. [1]

Free radicals can damage your cells and DNA through a process called oxidative stress, which can lead to premature aging, inflammation, and various diseases. [1]

But what exactly was oxidative stress again?

Oxidation and Oxidative Stress

When free radicals come into contact with surrounding molecules to balance their own electrons, they can cause damage to cells, proteins, lipids (fats) and even DNA.

This damage is called oxidation, and the process by which the free radicals cause this damage is called oxidative stress. Therefore, it is crucial to maintain a balance in the body and avoid oxidative stress where it does not serve an important function of your body. [2]

Now, we can get back to antioxidants. Antioxidants defend our body against the negative effects of free radicals by donating an electron to the free radicals without losing their own stability. They neutralize free radicals by doing so. Pretty useful, isn't it?

The importance of antioxidants for our health is, therefore, enormous. They play a key role in the prevention of oxidative stress caused by the excess of free radicals. [1]

Oxidative stress is associated with a variety of health problems, including inflammation, premature aging, and increased susceptibility to chronic diseases. [2]

When you think of antioxidants, it is important to understand that several substances can act as antioxidants in your body. If a substance, such as a vitamin or a phytochemical, has an antioxidant effect, we call it an antioxidant.

And how exactly do antioxidants work in the body?

How Do Antioxidants Work, And How Do They Reduce Oxidative Stress?

Antioxidants act in the body by neutralizing free radicals and preventing their harmful effects on cells and tissues. The mode of action of antioxidants is a complex process that takes place in several steps.

We have summarized these steps for you below:

  1. Presence of free radicals: Free radicals are unstable molecules that have one or more unpaired electrons in their outer electron shell. This unpaired nature makes them reactive, and they have a tendency to steal electrons from neighboring molecules to balance their own electron balance. This theft of electrons can damage cells and tissues. [3]
  2. Antioxidant intake: Antioxidants are molecules that are able to neutralize free radicals by donating an electron to them without becoming unstable themselves. Antioxidants can either be absorbed directly from the diet, for example by eating fruits, vegetables and nuts, or they are produced in the body itself. [3]
  3. Neutralization of free radicals: When free radicals encounter antioxidants, the antioxidants readily donate an electron to complement the unpaired electron of the free radical. This reduces the reactivity of the free radical and prevents it from causing (further) damage to cells and tissues. [3]
  4. Antioxidant remains stable or is regenerated: The molecular structure of antioxidants is designed to neutralize free radicals without becoming unstable themselves. They often have specific structural features that allow them to transfer electrons without triggering an unstable chemical reaction or becoming a free radical themselves. [3]

For example, they have a specific redox potential that indicates how easily they can donate or accept electrons to achieve a stable configuration. This potential is designed to neutralize free radicals effectively without significantly affecting the stability of the antioxidant.

Some antioxidants can even be regenerated after giving up an electron so that they never become a free radical themselves. For example, vitamin C, after giving up an electron, can be restored to its active antioxidant form by vitamin E or other antioxidants. This allows for a continuous protective function. [3]

Antioxidants can act in various forms in the body – as enzymes such as superoxide dismutase and catalase that break down free radicals, and as non-enzymatic antioxidants such as vitamin C, vitamin E, glutathione and other molecules that neutralize free radicals. These antioxidants can work in different parts of the body, including your cell membranes, in the nucleus, and in the mitochondria. [3]

Our body has its own mechanism for regulating the balance between free radicals and antioxidants. A certain amount of oxidative stress is normal and even necessary for some physiological processes, such as your immune defense, respiration, and cell signaling. The key is to maintain a balance and ensure that oxidative stress does not get out of control, as this can lead to damage to cells and tissues.

A balanced diet rich in antioxidants and healthy lifestyle habits will help maintain this balance and promote your health. [3]

How Can Antioxidants Actually Benefit Your Health?

Antioxidants Protect the Eyes

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Our eyes are particularly susceptible to damage from ultraviolet (UV) radiation, especially our cornea and lens. Antioxidants such as lutein and zeaxanthin can protect the eye from the harmful effects of UV radiation by acting as natural “sunglasses”.

They absorb harmful UV light, reducing the risk of eye damage and cataracts (clouding of the eye with loss of vision) that can be caused by long-term UV exposure. [4]

Did you know that age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly? Antioxidants, especially lutein and zeaxanthin, have been shown to be effective in slowing the progression of AMD. They protect the macular, the central part of the retina, from oxidative stress and inflammation that can promote or cause AMD. [4]

Antioxidants Protect the Brain

Some antioxidants, especially flavonoids and polyphenols, can reduce inflammation in the brain. Chronic inflammation in the brain is associated with neurodegenerative diseases such as Alzheimer's and Parkinson's. [5]

In addition, our blood-brain barrier is a barrier between the bloodstream and the brain that protects the brain from harmful substances. Antioxidants can help maintain the integrity of this barrier and prevent harmful molecules from entering the brain. [5]

Antioxidants Protect Cartilage Tissue

Cartilage is a specialized connective tissue that serves as a cushion and protection between bones. Cartilage is susceptible to damage from various factors, and oxidative stress plays a role in the development of cartilage diseases such as osteoarthritis. Antioxidants are also important in the protection and maintenance of cartilage tissue. [6]

This is because oxidative stress in the joint can be caused by the accumulation of free radicals and reactive oxygen species (ROS). Antioxidants neutralize these harmful molecules, thereby reducing cellular and tissue damage in your cartilage tissue. [6]

Antioxidants Protect Against Cancer

Antioxidants can protect against cancer by neutralizing free radicals that can cause DNA mutations and cell damage. Free radicals are involved in the development of cancer by disrupting normal cellular functions and promoting genetic abnormalities. [7]

Antioxidants can prevent free radicals from causing this cellular damage, helping to reduce the risk of cancer. [7]

Thus, a balanced diet with sufficient antioxidants from fruits, vegetables, and nuts can help to support cancer prevention. [1]

How Can Antioxidants Be Absorbed Through Food?

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By now, you know that antioxidants are essential for your health and that they can protect you from the harmful effects of free radicals.

But how can you naturally incorporate these protective compounds into your diet?

Keep in mind that antioxidants refer to various substances that have an antioxidant effect. These include vitamins, minerals, trace elements and enzymes. So if you eat certain foods that contain one or more of these substances, you are providing your body with antioxidants. [1]

We have summarized several ways in which you can take in antioxidants through different food sources and categorized the antioxidants present in them:

Vitamins

Vitamins are one of the best known groups that can act as antioxidants in the body. [1]

Vitamin C: Vitamin C is known as a superhero when it comes to health benefits. The vitamin has earned this reputation, not least because it also acts as an antioxidant. Vitamin C is found in many fruits and vegetables, such as oranges, strawberries, peppers, and broccoli. [1]

It is a powerful antioxidant that helps protect cells from oxidative stress. [1]

Vitamin E: Found primarily in nuts, seeds, and vegetable oils, vitamin E is critical to the health of your cell membranes and protects against free radical damage. [1]

Vitamin A: This vitamin is abundant in carrots, sweet potatoes, and leafy greens, and not only is it an antioxidant, but it also supports the health of your skin and eyes. A win-win situation for your eyes and cells. [1]

Minerals & Trace Elements

Some minerals and trace elements can act as antioxidants in the body – these include selenium, copper and the mineral zinc. [1]

If you're wondering what the difference is between a mineral and a trace element, we have the answer. Minerals are needed by your body in relatively high concentrations for survival. Trace elements, on the other hand, are only present in your body in low concentrations.

Selenium: Selenium is a trace mineral found in foods such as Brazil nuts, salmon, and chicken. It plays a critical role in combating oxidative stress and supporting the immune system. [1]

Zinc: Zinc is necessary for the formation of superoxide dismutase, an important enzyme that neutralizes free radicals. Good sources of zinc are beef, nuts and seeds. [1]

Copper: Copper is necessary for superoxide dismutase activity and is found in foods such as nuts, legumes, and whole grains. [1]

Enzymes

Enzymes are protein molecules that play an important role in neutralizing free radicals. One example is glutathione peroxidase, which can be found in foods such as asparagus, avocado, and spinach. [1] [8]

Secondary Plant Metabolites

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Secondary plant metabolites are natural compounds in plants that are not basic nutrients such as carbohydrates, proteins, and fats, but nevertheless play an important role in plant physiology and also in human health.

Many secondary plant metabolites act as antioxidants because they have the ability to neutralize free radicals and thereby prevent cellular damage. [1]

These include flavonoids, polyphenols, resveratrol, carotenoids and glucosinolates, which are found in a wide variety of fruits, vegetables, nuts and spices and help reduce oxidative stress in the body. Even red wine contains various antioxidants. Resveratrol, for example, is a polyphenol found in the skin of red grapes. [1] It is associated with a variety of health benefits, including protection of the heart and blood vessels.

Which Food Groups Are Particularly Rich in Antioxidants?

The majority of antioxidants in your diet come from fruits, vegetables, nuts and herbs. [1]

We've rounded up some particularly antioxidant-rich foods for you, and grouped them together, so you can find some inspiration for a healthy diet rich in antioxidants:

Vegetables

Dark green leafy vegetables like spinach, kale and Swiss chard contain antioxidants like lutein, zeaxanthin and vitamin K that support the health of your eyes and cardiovascular system.

Salads

Mixing different vegetables and fruits in your salad provides a wide range of antioxidants. Be sure to supplement your salad with healthy dressings, nuts, and seeds to further enhance the antioxidant benefits.

Green leafy lettuces like spinach and romaine lettuce are a wonderful option because they contain the antioxidants lutein, zeaxanthin and vitamin C, which not only fight free radicals, but also support your eye health and immune system.

Fruits

Berries such as blueberries, raspberries and strawberries are not only particularly tasty, but also rich in antioxidants such as anthocyanins and vitamin C.

Of course, citrus fruits such as oranges, grapefruits and lemons are also particularly rich in antioxidants, because they contain vitamin C. However, they provide you not only with the well-known vitamin C, which acts as an antioxidant, but also with flavonoids such as hesperidin, which also has anti-inflammatory properties.

Herbs

Many spices and herbs not only add flavor and aroma to our food, but they are also rich in antioxidants. Oregano, rosemary and marjoram, for example, contain rosmarinic acid, an antioxidant that protects your cells.

Rosmarinic acid is not only a powerful antioxidant, but it also has neuroprotective, antimicrobial and anti-inflammatory effects.

How Many Antioxidants Do I Need Daily?

According to international nutrition expert Patrick Holford, you should eat foods with at least 3500 ORAC units a day, and 5,000 to 6,000 would be even better [9].

Antioxidants are present at the level of molecular biology or biochemistry and refer to substances that have the ability to have an antioxidant effect in the body. Accordingly, there is not one antioxidant that we can consume in certain gram quantities or that we can quantify and weigh, such as proteins.

However, the so-called ORAC (Oxygen Radical Absorbance Capacity) value tells us how strongly a substance was able to neutralize free radicals in laboratory tests. [9]

A recommended daily requirement of ORAC is given as 3,500 to 6,000 units. However, you must know that ORAC values are determined in the laboratory and interpreting the laboratory results to the biological processes in the human body are purely indicative and not scientifically proven. Therefore, it is forbidden to advertise certain products or foods with ORAC values.

Nevertheless, the values can give us an approximate indication of what antioxidant potential a certain type of food may have. [9]

Therefore, we have collected some ORAC values of food for you:

  • Acai berries approx. 5,500 units
  • Pomegranate approx. 3,300 units
  • Blueberries approx. 2,200 units
  • Strawberries approx. 1,800 units
  • Raspberries approx. 1,700 units
  • Currants approx. 1,400 units
  • Cherries approx. 800 units
  • Broccoli approx. 890 units
  • Bell pepper approx. 840 units
  • Blue grapes about 730 units
  • Kale approx. 1,700 units
  • Spinach approx. 1,300 units
  • Beet approx. 900 units

How Can I Absorb More Antioxidants?

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It should be quite easy for you to incorporate the aforementioned foods with antioxidant effects into your diet, as there are numerous delicious and healthy options of foods that contain antioxidants.

Beyond food choices, however, there are a few other factors you might want to consider to benefit as much as possible from the antioxidants in your diet. [1]

Regional and Seasonal Food – Hit the Local Market

Did you know that vitamins and other nutrients lose bioactivity over time? The fresher a food is, the more likely it is to still contain a high amount of vitamins, such as vitamin C, which have antioxidant activity.

It is therefore recommendable that you buy your fruits and vegetables seasonally and regionally, so that the storage time of the food is as short as possible and you can benefit from the antioxidants and nutrients contained.

Always prepare fruits and vegetables promptly after purchase, and preferably buy food as fresh as possible from the weekly market.

Gentle Preparation of Food – Heat Is the Enemy

When preparing your food, remember that heat can destroy antioxidants, such as vitamins and enzymes.

So prepare your food gently: steam vegetables instead of boiling them, and don't add your honey to your tea until it's cooled. Better yet, eat your vegetables raw and fresh whenever possible.

Green Vegetables

Green vegetables are particularly rich in antioxidants. Due to their high content of chlorophyll, carotenoids such as lutein and zeaxanthin, and the important vitamins C and E, which contain or act as antioxidants, they protect your body from harmful free radicals and oxidative stress.

So when shopping, make sure you pack enough green foods in your basket.

Fruit and Vegetables With Peel

Many of us tend to get rid of the peel of certain fruits and vegetables. Vegetables and fruits with peel are rich in antioxidants due to the natural colorants in the peels, which contain powerful antioxidants such as anthocyanins.

The fiber in the peel also promotes the absorption of antioxidants and improves their absorption in the body.

The variety of antioxidants in the skins of fruits and vegetables can fight a wide range of free radicals and boost your health.

Antioxidants Effect & Supplements

Studies to date and the scientific consensus state that the effect of antioxidants, which are taken in naturally with food, is most efficient. A blood analysis with CARE and your regular health checks can provide you with information about how you can optimize your diet and the antioxidant effect of certain foods.

Find out with our health specialists how you can use antioxidants as an anti-aging method, so to speak, to keep the natural aging process or the destruction of your body cells in check.

As pioneers in preventative health care, we would love to guide you on your wellness journey to becoming the fittest and healthiest version of yourself.

List of References

Blog Author Elena Health Coach at CARE

Elena Iagovitina

Health Coach at CARE Zurich

About the author

Elena is an enthusiastic Health Coach and blog writer at CARE, with a passion for holistic medicine and health. Previously, Elena worked for almost five years as a coach leading retreats, workshops, and seminars. These included mind-body therapy: breath work, meditation, and massage; as well as energy force therapy: reiki, and qi gong; and third expressive therapy: movement, writing and support groups. Elena shares exciting articles on the blog, on the topic of where the alternative and traditional medicine intersect with Western Medicine. Elena is also the driving force behind the CARE community. In her spare time, she enjoys hiking, traveling to remote locations and dancing. You might also see her on the lake of Zurich as a coast guard. Join her on her journey to learn more about health and discover the world of preventive medicine! Visit all articles written by Elena!