Antioxidant Rich diet by Sue Kira

by sue

Antioxidant Rich diet

by Sue Kira, Naturopath & Clinical Nutritionist

Introduction to antioxidants

Important benefits of antioxidants

Different types of antioxidants

Antioxidant food sources

The best antioxidant rich foods to eat

Introduction to antioxidants

The word anti-oxidant can conjure up all sorts of meanings, but basically the word ‘anti’ means against and ‘oxidant’ is something that creates oxidation. This means that an anti–oxidant stops things from oxidizing e.g. rust is the oxidation of metal when exposed to oxygen.

We think of oxygen as a good thing, which it is, but it does depend on what it is bound to and how many molecules of oxygen there are. For example, oxygen is bound to 2 hydrogen atoms, giving us H2O, otherwise known as water.

Oxidation occurs when oxygen molecules are not bound or paired to another electron.

Antioxidants are naturally occurring compounds found in many foods and plants. They help to prevent cellular damage done by oxidisation and free radicals (FR).  A good example of oxidisation in food is when you cut an apple and it goes brown. This is the oxygen reacting to the iron-containing phenols in the apple. However, if you put lemon juice on the apple it prevents it from going brown, which is the anti-oxidant effect. This reduces the amount of available oxygen to oxidise.

You can think of antioxidants as protectors against oxidisation, and to neutralise free radicals.

What are Free Radicals?

The process of oxidation in the human body damages cell membranes and other structures, including cellular proteins, lipids (fats) and DNA. When oxygen is metabolized, it makes other molecules which are unstable called ‘free radicals’, which take electrons from other molecules, causing the damage to DNA and other cells.

The effect of Free Radicals

The body can cope with a small degree of free radicals and needs them to function effectively. However, damage can be caused by an overload of free radicals over time, which can be irreversible and lead to a host of different disease pathologies, including liver disease and some cancers. Oxidation can be accelerated by stress, cigarette smoking, alcohol, excessive sunlight, pollution and other factors.

Some examples of free radical damage in the body

  • Eye lens deterioration, contributing to blindness
  • Inflammation of joints such as arthritis
  • Nerve cell damage in our brains, which can contribute to conditions like Parkinson’s disease or Alzheimer’s disease
  • Acceleration of the ageing process and wrinkling of our skin
  • Increased risk of coronary heart disease, because free radicals create the low-density lipoprotein (LDL) cholesterol that sticks to artery walls

Important benefits of antioxidants

Repair damaged molecules
Some specialised antioxidants can actually repair the damage to our molecules by donating  one of their hydrogen atoms, which is quite critical when that molecule is an important one, like your DNA.

Block toxic metal free radical production
Some antioxidants have a chelating effect, which means they can bind to toxic metals like mercury and arsenic causing free radical formation. This binding process helps prevent any damaging chemical reactions from taking place. Water-soluble chelating agents can also clear toxic metals out of your body via the urine.

Stimulate gene expression
Antioxidants can help to stimulate gene expression and internal antioxidant production. Some antioxidants can stimulate your body’s genes and increase your natural defenses.

Provide a protective effect
Antioxidants such as flavonoids from many fruits, can act as a type of shield by attaching to your DNA to protect it from free radical attack.

Promote apoptosis of cancer cells (apoptosis means self-destruction)
This basically causes a self-destruction of cancer cells. Some antioxidants provide anti-cancer chemicals that stop cancer growth and force them to self-destruct.

Different Types of Antioxidants

There are different types of antioxidants which have different jobs or roles to play in your body, so just having one or two types of antioxidants eaten or taken by supplement may not be enough.

Antioxidants often work together to help recycle each other so that their effect lasts longer in your body. Pretty cool hey?

Anti-oxidants can be classified by their solubility. They can be either soluble in lipids/fat (hydrophobic) or water (hydrophilic). Both are required by your body to protect your cells, as the inside and outside of your cells are composed of water, while the cell membranes (lining) are mostly made of fat.

Because free radicals can attack the watery cell contents or the fatty cell membranes, you need both types of antioxidants to have full protection from oxidative damage.

Lipid or fat-soluble antioxidants are mostly located in your cell membranes and protect the membranes from what is termed lipid peroxidation (the breakdown of the fatty layer by the process of oxidation). Lipid-soluble antioxidants include the carotenoids, vitamins A and E and lipoic acid.

Water-soluble antioxidants are commonly found in fluids like blood and the fluids within and around your cells, called the cytosol or the cytoplasmic matrix. Water-soluble antioxidants include the well known vitamin C as well as polyphenols and glutathione.

Solubility is not the only way to classify antioxidants as antioxidants can also be classified as enzymatic or non-enzymatic antioxidants.

The enzymatic antioxidants help you by breaking down and removing the damaging free radicals. They can remove dangerous oxidative products by converting them into hydrogen peroxide (H2O2) then further break them down to water (H2O). This is done through a multi-step process that requires various trace mineral cofactors, such as zinc, copper, manganese, and iron. Enzymatic antioxidants are produced in your body with the co-factors of the minerals just mentioned.

The main enzymatic antioxidants

  • Superoxide dismutase (SOD) is an antioxidant that can break down superoxide into hydrogen peroxide and oxygen with the help of copper, zinc, manganese, and iron. It is found in almost all aerobic (oxygen carrying) cells and extracellular fluids (fluids around the cells).
  • Catalase (CAT) works by converting hydrogen peroxide into water and oxygen, using iron and manganese as the cofactors. It basically finishes up the detoxification process that was started by SOD.
  • Glutathione peroxidase (GSH) and glutathione reductase are selenium-containing enzymes that help to break down hydrogen peroxide and organic peroxides into types of alcohols. They are most abundant in your liver and the main enzyme antioxidant used by the liver to detoxify. It is also the one most depleted by our diet and lifestyle choices.

Non-enzymatic antioxidants

Most antioxidants found in food and supplements are the non-enzymatic types and these antioxidants provide support to enzymatic antioxidants by doing a ‘first sweep’ and disabling the free radicals. This prevents the enzymatic antioxidants from being depleted. Some examples of these non-enzymatic antioxidants are carotenoids in carrots, vitamin C in oranges, vitamin E in nuts, and plant polyphenols like resveratrol in grapes.

Antioxidants can be classified in terms of their molecular size

  • Small-molecule antioxidants work by clearing or ‘scavenging’ the reactive oxygen species and carry them away through a type of chemical neutralization. The main players in this category of antioxidants are glutathione, lipoic acid, vitamins C and E, as well as the carotenoids and CoQ10.
  • Large molecular sized antioxidants tend to be the enzymatic enzymes outlined above, as well as ‘sacrificial proteins’ that absorb reactive oxygen species (ROS) and stop them from attacking your essential proteins. One example of these sacrificial proteins is albumin (found in egg whites) which ‘takes the bullet’ for crucial enzymes and DNA.

Some antioxidants that are produced by your body

One of the antioxidants mentioned above (in the enzymatic section) that your body can produce with the help of certain foods, is Glutathione. Glutathione is known as your body’s most powerful antioxidant, often called the ‘master antioxidant’ because it has the unique ability to maximize the performance of all other antioxidants in the body such as vitamins C and E, CoQ10, alpha-lipoic acid, as well as the antioxidants found in fresh fruits and vegetables that we eat.

Roles of glutathione:

  • protect our cells and mitochondria from oxidative and peroxidative damage
  • essential for detoxification, energy utilization, and preventing diseases we associate with aging
  • eliminates toxins from your cells
  • provides protection from the damaging effects of radiation, chemicals and environmental pollutants

Your body’s ability to produce glutathione decreases with age, but there are nutrients which can promote glutathione production, such as curcumin (turmeric), eggs and grass-fed meat.

Alpha-Lipoic Acid (ALA)
ALA is another powerful antioxidant with the following benefits…

  • ALA has strong free radical scavenging ability
  • Is great at great modifying gene expression to reduce inflammation
  • A potent heavy metal chelator (binder)
  • Enhances insulin sensitivity to protect against diabetes
  • One of only two antioxidants that can cross the blood brain barrier (the other one being glutathione) offering protection to the brain.
  • Recycles and regenerates other antioxidants, like vitamins C and E and glutathione.

CoQ10 (Ubiquinone)
Used by every cell in your body, CoQ10 is converted by your body to its reduced form, called ubiquinol, to maximize its benefits. Apart from naturally protecting you from free radicals CoQ10 can also:

  • help to produce more energy for your cells
  • provide support for your heart health, immune and nervous systems
  • helps to reduce the normal signs of aging
  • helps to keep blood pressure levels within the normal range

If you are under 25 years old, your body can convert CoQ10 to ubiquinol without any difficulty, but as you get older, your body finds it harder to convert the oxidized CoQ10 to ubiquinol. Therefore you may need to take a ubiquinol supplement (check with your practitioner).

Antioxidant food sources

There are many antioxidants that can’t be manufactured within your body and therefore must be obtained from antioxidant-rich foods or potent antioxidant supplements.

Let’s look at these foods and substances…

Many have heard that resveratrol is found in grapes, which is why some are told to drink red wine. In truth there isn’t much resveratrol in red wine but it makes a good excuse for many to drink it, even though the amount of damaging alcohol counters the positive effects of the antioxidant. Grape juice may be more powerful as it hasn’t got the alcohol to damage the liver at the same time. Resveratrol can also be found in many vegetables as well as cocoa. This antioxidant can cross the blood-brain barrier to help protect your brain and nervous system. Resveratrol can also help:

  • prevent the spread of cancer (promising studies have been done on prostate cancer)
  • lower elevated blood pressure
  • improve elasticity of your blood vessels and keep your heart healthy
  • normalize anti-inflammatory responses
  • prevent Alzheimer’s disease by protecting the brain

These are the antioxidants that give foods their vibrant colours. There are over 700 naturally-occurring carotenoids; you probably have at least 10 different kinds circulating through your bloodstream right now (if you eat your fruits and vegetables).

Carotenoids can be classified into two groups:

  • Carotenes – which do not contain oxygen atoms. Some examples are lycopene (found in red tomatoes); and also beta-carotene (found in orange carrots) which is converted by your body into vitamin A.
  • Xanthophylls – which contain oxygen atoms. Examples include lutein, anstaxanthin and zeaxanthin. Zeaxanthin is the most common carotenoid that naturally exists in nature and is found in peppers, kiwi-fruit, maize, grapes, squash and oranges.

Astaxanthin is a very special type of a carotenoid antioxidant (and good fat) which is produced by the marine microalgae Haematococcus pluvialis to protect itself from the sun’s ultraviolet radiation when the water it grows in dries up. It is what gives the pink colour in salmon (and other pink fish like trout) and one of the reasons why salmon is so good for us.

Astaxanthin is the most powerful carotenoid in terms of free radical scavenging. It is 65 times more powerful than vitamin C, 54 times more effective than beta-carotene, and 14 times stronger than vitamin E.

Like resveratrol, astaxanthin can also cross the blood-brain barrier, as well as the blood-retinal barrier, something that beta-carotene and lycopene from tomatoes cannot do.

Benefits of Astaxanthin:

  • helps to support your immune system
  • helps to improve your cardiovascular health by reducing C-Reactive Proteins (CRP) and triglycerides and increases beneficial HDL
  • helps to protect your eyes from cataracts, macular degeneration and blindness
  • helps to protect your brain for prevention against dementia and Alzheimer’s
  • reduces your risk from different types of cancer
  • promotes recovery from spinal cord and other central nervous system injuries
  • reduces inflammation from many causes, including asthma and arthritis
  • improves endurance, exercise performance and recovery time
  • relieves indigestion and reflux
  • helps to stabilize blood sugar levels, thereby protecting your kidneys
  • helps to increase sperm strength and sperm count, improving fertility
  • helps to protect you from the damaging effects of radiation from the sun
  • helps to reduce oxidative damage to your DNA
  • helps to reduce the symptoms of diseases, such as pancreatitis, multiple sclerosis, carpal tunnel syndrome, rheumatoid arthritis, Lou Gehrig’s disease, Parkinson’s disease, and neurodegenerative diseases

Vitamin C
The well known and loved vitamin C has a wide range of amazing health benefits. Vitamin C is in raw organic fruits and vegetables, but you can also take vitamin C as a supplement or have it even have it administered intravenously. As an antioxidant, vitamin C can:

  • support oxidation by acting as a major electron donor
  • maintain optimal electron flow in your cells
  • protect proteins, lipids (fats) and other vital elements in your body
  • be essential for collagen production, which is an important structural component of your bones, blood vessels, tendons and ligaments

Vitamin E
Natural vitamin E is a family of eight different compounds, four of these are called ‘tocopherols’ and four are called ‘tocotrienols’. You can obtain all of these vitamin E compounds from a balanced diet composed of wholesome foods. However, if you take a synthetic vitamin E supplement, you will usually only get one of the eight compounds.

The best antioxidant rich foods to eat

When trying to obtain any nutrients, antioxidants included, it is best to get them from your diet as they are definitely more bio-available (absorbable) for your body than from supplements. Speak to your health practitioner to clarify what’s best for your requirements.

By consuming a balanced, unprocessed diet rich in high-quality, raw organic foods, especially vegetables and fruits, your body will have the essential nutrients and antioxidants needed to achieve or maintain optimal health.

Fresh, organic vegetables.
Green leafy vegetables and many other vegetables are loaded with phyto-chemicals, which are antioxidants from plant compounds. Phyto-chemicals can help eliminate carcinogens and reduce inflammation. To get the most antioxidants from our produce it is better to eat them raw or blended in smoothies, as antioxidants can be easily destroyed by heat.

These are also powerful sources of antioxidants, minerals, vitamins, and enzymes that promote optimal health. Sunflower sprouts and broccoli sprouts provide you with the highest-quality protein you can eat in an easy to digest form. They are easy to grow in a tray like an old strawberry punnet – just fill with seed raising mix, sprinkle with seeds, lightly cover with a little more seed raising mix and water well. Put the lid down, keep warm and watch them grow within a few days, then cut them off with scissors as needed.

Fruits such as fresh berries like raspberries, blueberries, blackberries and cranberries are the best antioxidant fruits you can consume, as they contain powerful phyto-chemicals that prevent the DNA binding to certain carcinogens. Berries are some of the best sources of antioxidants like carotenes and carotenoids, as well as vitamin C and minerals such as zinc, potassium, iron, calcium and magnesium. Berries have very little sugar, so they really are the perfect fruit.

Most other fruits should be consumed in moderation due to their high fructose content (a type of sugar).

Nuts such as pecans, almonds, macadamia, brazil nuts, walnuts and hazelnuts are excellent antioxidant foods that can boost your heart health and overall health. Look for nuts that are organic and raw, rather than those that have been irradiated or pasteurized. Peanuts are not recommended as they are often pesticide-laden and can be contaminated with a carcinogenic mould called aflatoxin (and are not a nut but a legume, so it is also good to avoid cashews for the same reason).

Herbs and spices
Aside from being an abundant source of antioxidants, these can have potential anti-cancer benefits. Herbs typically come from plants’ leaves, while spices come from the bark, stem and seeds. Both have been used for thousands of years to flavour foods and treat illness. Best choices include parsley, coriander (cilantro), ground cloves, ground cinnamon, oregano, turmeric, ginger and garlic. Fresh is always best.

How much do you need to get enough antioxidants?

If you eat a wide range of fruits and vegetables, especially the colourful vegetables, green veggies and bright coloured fruits like berries, plus some nuts and seeds and wild caught salmon, you will get enough of the different types of antioxidants needed to keep you healthy. Sprinkle your food with some sprouts and herbs and spices for extra antioxidant defence against free radicals.


Before you commence a new diet, see your medical or health care professional for qualified guidance about what foods and supplements are best for your body. While on the diet do not stop any medications or supplements previously prescribed unless advised otherwise by your medical or health care professional.

During the early stages of a new diet, you may experience symptoms such as fatigue, headaches or body aches, which may occur because your body is detoxifying. However, if you are unsure about a symptom at any time, check immediately with your medical or health care professional.


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