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The Best Antioxidants to Protect Against Free Radicals

Have you ever wondered what the most effective antioxidants are?

What about how many types of antioxidants? There are possibly thousands of different types of antioxidants or compounds that act like antioxidants, with the major, or most familiar being vitamins C and E, beta-carotene, selenium and manganese.

But what is the most powerful source of antioxidant? This article will run through a comparison of antioxidants, touching on:

• What are Antioxidants?
• Sources of Best Natural Antioxidants
• Lines of Antioxidant Defence
• Best Antioxidant Supplement to Protect Against Free Radicals
• Interesting Studies About Antioxidants

What are Antioxidants?

In our bodies, reactive oxygen species (ROS) contribute to cellular aging, Antioxidants are compounds that help our bodies cope with oxidative stress, and these can be divided into two groups, preventive oxidants — metal chelators that move and store antioxidant enzymes — and chain-breaking oxidants — free radical scavengers that neutralise free radicals and help remove dead cells.

The latter are the ones that you generally hear about when you hear about antioxidants and their benefits. They include vitamins C and E, carotenoids and polyphenols. Polyphenols can be divided even further, the largest being flavonoids, which have beneficial health benefits.

So, in terms of what’s interesting to consumers and nutritionists, antioxidant function is the ability of a compound to reduce pro-oxidant agents.

They may:

• Reduce inflammation in the joints
• Reduce damage to cells in the brain
• Prevent deterioration in the eyes
• Prevent certain cancers
• Reduce the risk of coronary heart disease

Further Reading: How Do Antioxidants Help Us Live Longer?

Sources of Best Natural Antioxidants

It’s important to remember that there are different antioxidants and each one has unique benefits. Also, while some antioxidants may be powerful, they may come in a form that is hard to absorb or that requires large doses.

The best sources of some specific antioxidants include:

• Beta-carotene: pumpkin, apricots, mangoes, carrots and spinach
• Catechins: red wine and tea
• Flavonoids: tea, green tea, citrus fruits, red wine, onion and apples
• Polyphenols: berries, herbs and spices, cocoa powder, red wine, nuts, flaxseeds, vegetables, olives, chilli, coffee and tea
• Selenium: seafood, offal, lean meat and whole grains
• Vitamin A (retinol): liver, sweet potatoes, carrots, milk and egg yolks
• Vitamin C: oranges, blackcurrants, kiwi fruit, mangoes, broccoli, spinach and strawberries
• Vitamin E: vegetable oils, avocados, nuts, seeds and whole grains
• Zinc: seafood, lean meat, milk and nuts

While it’s always better to obtain antioxidants from whole foods, there are some supplements that have the added benefit of containing antioxidants. Just make sure to stay within your daily recommended dosage of the antioxidant and supplement you take.

Lines of Antioxidant Defence

There are different levels of defence that antioxidants play a role in when protecting against free radicals. These include:

First: this is where preventative antioxidants act, where they suppress the formation free radicals. These antioxidants reduce hydroperoxides and hydrogen peroxides, such as glutathione peroxidase, glutathione-s-transferase, phospholipid hydroperoxide glutathione peroxidase (PHGPX) and peroxidase.

Second: these antioxidants scavenge the active radicals to break their chain reactions. These include hydrophilic antioxidants like vitamin C, uric acid, bilirbun, albumin and thiols, and lipophilic antioxidants like vitamin E and ubiquinol.

Third: these are repairing antioxidants that find, degrade and remove oxidatively modified proteins and prevent the accumulation of oxidised proteins.

Best Antioxidant Supplement to Protect Against Free Radicals

To help you understand which is a highly powerful antioxidant against free radicals, you need to understand some differences between antioxidants, as some actively scavenge them while others have different benefits.

The major antioxidants found within our bodies that directly neutralise ROS and RNS are superoxide dismutase, catalase and glutathione peroxidase, but what about external sources we use as antioxidant supplements?

Vitamin E

• This is predominantly a chain-breaking antioxidant, in that it can shorten the oxidation chain length when exposed to free radicals.
• Vitamin E is the most potent radical-scavenging lipophilic antioxidant.
• Mainly protects against lipid peroxidation.
• Protects against oxidative stress and is a singlet oxygen quencher.
• It protects membranes from oxidation and removes free radicals, as well as prevents the propagation reaction from continuing.
• Can delay neuronal death caused by inflammation.
• It’s a fat-soluble antioxidant.

Vitamin C (ascorbic acid)

• It’s part of the second defence stage and it reduces and neutralises ROS.
• This is predominantly a free radical scavenger but also has the benefit of being a singlet oxygen quencher.
• One of the most important antioxidants in extracellular fluids.
• It’s needed for collagen, carnitine and neurotransmitter biosynthesis.
• It is also an anti-atherogenic, anti-carcinogenic and immunomodulator.
• Works with vitamin E to quench free radicals.
• A water-soluble antioxidant.

Glutathione

• As part of the second defence stage, glutathione can reduce enzyme systems and reacts directly with oxidants.
• It’s one of the important cellular antioxidants.
• It scavengers a wide range of ROS.
• It can regenerate several important antioxidants, like vitamins C and E, back to their active, non-radical forms.

Flavonoids

• These have potent antioxidant activity and may prevent or delay chronic and degenerative diseases, like cancer, cardiovascular disease, inflammation, arthritis, aging, cataracts, memory loss, stroke, infections and Alzheimer’s disease.
• They do this by preventing the formation of damaging radicals and by terminating free radicals and metal ions.
• They can also activate the creation of antioxidant enzymes and regenerate vitamins, like vitamin E.
• Have weak prooxidant properties that may boost cellular antioxidant systems and, therefore, prevent anticancer agents.
• Curcumin is a flavonoid polyphenol with antioxidant, metal-chelating, anti-inflammatory and antiaggregating properties but doesn’t have much of an effect on free radicals.

Resveratrol

• A non-flavonoid polyphenol that has antioxidant and antitumor properties.
• Resveratrol’s main antioxidant activity is related to scavenging ROS and suppressing free radicals but may also prevent hypertension.
• Resveratrol also positively affects the synthesis of sirtuins, SIRT1 (helps create NAD+).
• Has anti-inflammatory properties and is able to suppress oxidative stress.
• Resveratrol can outperform vitamin C in the inhibition of lipid peroxidation and free radicals, as well as a range of other compounds.
• There are a range of other resveratrol benefits, like having anticarcinogenic, antiviral, neuroprotective and cardioprotective effects.
• It’s also been shown to mimic calorie restriction effects.

Melatonin

• Studies have found that melatonin is a very good scavenger of free radicals and can activate other antioxidant enzymes like catalase and glutathione peroxidase to boost the immune system.
• Easily crosses the cell membrane and blood-brain barrier, but is seen as a ‘suicidal’ antioxidant in that it can only be used once after being oxidised.
• Has neuroprotective properties.

Beta-carotene

• A strong antioxidant and the best quencher of singlet oxygen (damages DNA and can be mutagenic).
• Its main protective antioxidant activity is in its protection of membranes against ROS-induced damage.
• It has some benefits as a chain breaker antioxidant and free radical scavenger — it can scavenge certain radicals.
• Can be converted to vitamin A (retinol), which is needed for vision.
• Don’t take more than the daily recommended dosage as, under certain conditions, may behave as prooxidants.

Selenium

• Taken in low doses (don’t take more than 400ug per day), selenium has antioxidant, anti-carcinogenic and immunomodulatory benefits.
• It is predominantly known for its antioxidant activity against peroxides.
• It’s needed for thyroid function.
• Protects cells against ROS-induced damage and infections.

CoQ10:

• One of the most significant lipid antioxidants.
• Protects cell membranes from free-radical-induced damage and prevents peroxidation of lipids and DNA damage.

Interesting Studies About Antioxidants

A study tested the antioxidant capacity in selected vegetables and the amount of total polyphenols of these vegetables. The highest antioxidant function was found in the green parts of vegetables, with the exception of dill, with celery leaves and parsley leaves having the highest. The antioxidant function in root vegetables like carrot, celery, coriander, fennel and cumin was quite low, as were capsicum, tomato and cucumber.

A study tested a range of synthetic and natural antioxidants on lipid peroxidation of egg yolk and erythrocyte membranes caused by a free radical generator. While most were protective, some acted as prooxidants, inducing oxidation, showing how diverse antioxidants are in different systems. This means that a general statement or conclusion about antioxidants cannot be made without careful consideration.

A study looked into the antioxidant claims made about beverages and tested a range to determine which had higher antioxidant potency. From highest to lowest, it ranked as pomegranate juice, red wine (resveratrol), concord grape juice, blueberry juice, black cherry juice/acai juice/cranberry juice, orange juice/iced tea beverages/apple juice.

End Note

It’s also important to note that some antioxidant supplements can act as prooxidants at high dosages, so make sure to only take the recommended dosage and speak with your doctor before adding any new supplement to your diet.

Many natural antioxidants from the diet or supplements have very limited bioavailability that may not translate well in the human body. Flavonoids, for example, are very good antioxidants in vitro, or in the lab, whereas they undergo changes in vivo, in the body. It’s similar with melatonin, where levels in certain organs might not be high enough to exhibit antioxidant properties. Tea antioxidants, particularly EGCG, are great antioxidants for scavenging free radicals, but once again, have limited activity in plasma.

While these antioxidants are great for other activities, like preventing chronic diseases, they may not be the best for scavenging free radicals in the human body.

So, what is the strongest antioxidant? There are many, and it’s difficult to specify a single antioxidant as the best, as they each have different functions. It’s best to decide what you’re taking antioxidants for to determine which is best for you.

We hope you’ve learned a bit about some of the best antioxidants to protect against free radicals. Be sure to check out Xandro Lab’s dietary supplements high in antioxidants, including Curcumin, Trans-Resveratrol and POM-Q10!