10 Best Antioxidant Supplements of 2025
If you're looking for the ultimate health boost, you've probably heard about the wonders of antioxidants. But before you start stockpiling on supplements, it's important to separate fact from fiction. While antioxidants have become a popular marketing buzzword, the science behind them is complex, and their benefits are not as straightforward as they may seem. So, should you be taking antioxidant supplements? Let's delve deeper into the science to find out.
What are Antioxidants?
There are hundreds, probably thousands, of different substances that can act as antioxidants. The most familiar ones are vitamin C, vitamin E, beta-carotene, and other related carotenoids, along with the minerals selenium, manganese. They’re joined by glutathione, coenzyme Q10, lipoic acid, flavonoids, phenols, polyphenols, phytoestrogens, molecular hydrogen and many more. Most are naturally occurring, and the presence of antioxidants in food is likely to prevent oxidation or to serve as a natural defence against the local environment. Antioxidants tend to work best in combination with other antioxidants (Harvard).
In this Article:
- NAC and Glutathione
- CoQ10
- Vitamin C
- Vitamin E
- Melatonin
- Astaxanthin
- Molecular Hydrogen
- Curcumin (Turmeric)
- Carotenoids (Vitamin A, Lutein and Zeaxanthin)
- Resveratrol and Pterostilbene
Best Antioxidant Supplements
Despite the potential risk, antioxidant supplements are popular and commonly considered healthy. If you feel that your diet does not provide sufficient amounts of antioxidants, supplements can help to fill the gap. In order to help you with your research, let's examine some of the popular antioxidant supplements.
Can NAC cause cancer to grow? Check out "Antioxidants May Make Cancer Worse".
Glutathione is a key indirect antioxidant that both recycles vitamin E and supports antioxidant enzyme production. Unlike direct antioxidants, indirect antioxidants continue to boost their antioxidant activity for a longer duration.
It’s essential for immune health and fighting cellular damage. Some researchers believe it may even contribute to longevity (Source).
Its antioxidant properties are also important for combatting numerous other ailments caused by oxidative stress, such as heart disease, infertility and some psychiatric conditions (Source).
Research suggests that levels of CoQ10 decline as you age, and supplementing with it has been shown to improve certain aspects of health in older individuals.
For example, a study in 443 older adults demonstrated that supplementing with CoQ10 and selenium over 4 years improved their overall quality of life, reduced hospital visits, and slowed the deterioration of physical and mental performance (Source).
CoQ10 supplements help reduce oxidative stress, a condition characterized by an accumulation of free radicals and other reactive molecules that accelerates the aging process and onset of age-related disease (Source, Source).
Though CoQ10 shows promise as an anti-aging supplement, more evidence is needed before it can be recommended as a natural way to delay aging.
Be sure to consult a trusted healthcare professional before giving it a try.
Vitamin C is able to act as both an antioxidant and pro-oxidant, depending on what the body needs. This allows it to serve a variety of functions in the body. Like other antioxidants, it works by targeting free radicals in the body.
Vitamin C is found in high amounts in fruit and vegetables, particularly citrus fruits like oranges and dark green leafy vegetables like broccoli.
Vitamin C, through its antioxidant potential, has been shown to improve blood flow relative to placebo in healthy people (Source).
Studies have also shown that vitamin C supplementation can reduce the effect of free radicals produced from exercise (Source).
Due to its antioxidant activity, studies have demonstrated that vitamin C can upregulate antioxidant enzymes in the body, reducing oxidative stress and improves insulin sensitivity (Source).
It has also been shown to be effective in preventing bone loss associated with oxidative stress in the elderly (Source).
That said, vitamin C is a direct antioxidant. Direct antioxidants have a limited lifespan. After neutralizing a free radical, they may lose their capacity to neutralize another one.
*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion.
2022 - A meta-analysis to review the association between vitamins and brain cancer showed that intake of vitamin C, β-carotene, and folate can reduce the risk of brain cancer, while high serum α-tocopherol (vitamin E) concentration also has a protective effect on brain cancer.
2022 - A systematic review on the effect of vitamins C and E on cancer survival showed improvement of survival and progression rates of cancers by vitamins C and E. However, the authors concluded that more high quality trials with large sample sizes are required to confirm.
Similarly to vitamin C, vitamin E has also been shown to improve blood flow. Vitamin E supplementation as alpha-tocopherol at 1,000 IU for three months was found to increase the vitamin E content of LDL particles and reduce their oxidation susceptibility as well as improve blood flow (Source).
Studies have also shown that supplementation of vitamin E can reduce blood pressure, but only when taken in doses of 160mg or 320mg as 80mg failed to demonstrate a beneficial effect (Source). In addition, only the highest dose in this study (320mg) demonstrated an improvement in the antioxidant capacity of the blood. Effects on blood pressure, therefore, seem to be dose-dependent.
Vitamin E supplementation has also been found to lower oxidative stress but only when the supplement is taken over a longer period of time and a high dose is taken (Source). This study showed that a dose of between 1,600 and 3,200IU daily for 16 weeks was effective in reducing oxidative stress.
2022 - A systematic review on the effect of vitamins C and E on cancer survival showed improvement of survival and progression rates of cancers by vitamins C and E. However, the authors concluded that more high quality trials with large sample sizes are required to confirm.
The Mediterranean Diet (MD) dietary pattern is also rich in antioxidants, such as melatonin. A systematic review published in Antioxidants (Elena 2023) showed high melatonin contents in MD-related foods, such as tomatoes, olive oil, red wine, beer, nuts, and vegetables. The consumption of specific MD foods increases melatonin levels and improves the antioxidant status in plasma.
When eaten by crustaceans and other sea life, it tends to lend a reddish hue to the shells, or the flesh of salmon. Marine birds like flamingos also get their color from eating microalgae full of astaxanthin.
In the body it works as an antioxidant, helping to protect against reactive oxygen species and oxidation, which plays a role in aging, heart disease, Alzheimer's disease and Parkinson's disease (R). Studies have also shown astaxanthin works from the inside out to protect your skin from free radical damage.
One standout feature of astaxanthin is that it is 550 times stronger than vitamin E and 6,000 times more potent than vitamin C. In addition, it is 10 times more effective than zeaxanthin, lutein, canthaxanthin and beta-carotene (R).
Yes, we are referring to H2, which is the smallest molecule in the universe. Molecular hydrogen is a relatively recent addition to the wellness space, and it is rapidly gaining popularity.
They’re essential for many processes in your body, including maintaining healthy vision, ensuring the normal function of your immune system and organs and aiding the proper growth and development of babies in the womb.
Vitamin A compounds are found in both animal and plant foods and come in two different major categories: preformed vitamin A (retinoids) and provitamin A (carotenoids).
Preformed vitamin A is known as the active form of the vitamin, which your body can use just as it is. It’s found in animal products including meat, chicken, fish and dairy and includes the compounds retinol, retinal and retinoic acid.
Provitamin A (carotenoids) — alpha-carotene, beta-carotene and beta-cryptoxanthin — are the inactive form of the vitamin found in plants. Other carotenoids in food, such as lycopene, lutein, and zeaxanthin, are not converted into vitamin A and are referred to as non-provitamin A carotenoids; they might have other important activities not involving vitamin A formation [R].
Although the biological effects of retinoids are numerous, among the most important effect is that retinoids may exert some of their actions by virtue of their acting as lipid-soluble antioxidants.
1. NAC (N-Acetyl Cysteine) and Glutathione
Cysteine is a semi-essential amino acid. It’s considered semi-essential because your body can produce it from other amino acids, namely methionine and serine. It becomes essential only when the dietary intake of methionine and serine is low.
NAC exhibits direct and indirect antioxidant properties (European Respiratory Journal 2004).
Note: Direct vs Indirect Antioxidants, what's the difference? Direct Antioxidants become free radicals after they've neutralized a free radical. Consequently, they can cause DNA damage. Indirect Antioxidants do not become free radicals, and therefore do not inflict DNA damage.
Cysteine is found in most high-protein foods, such as chicken, turkey, yogurt, cheese, eggs, sunflower seeds and legumes.
N-acetyl cysteine (NAC) is a supplement form of cysteine.
Consuming adequate cysteine and NAC is important for a variety of health reasons — including replenishing the most powerful antioxidant in your body, glutathione. These amino acids also help with chronic respiratory conditions, fertility and brain health.
NAC is valued primarily for its role in antioxidant production. Along with two other amino acids — glutamine and glycine — NAC is needed to make and replenish glutathione.
Cysteine is found in most high-protein foods, such as chicken, turkey, yogurt, cheese, eggs, sunflower seeds and legumes.
N-acetyl cysteine (NAC) is a supplement form of cysteine.
Consuming adequate cysteine and NAC is important for a variety of health reasons — including replenishing the most powerful antioxidant in your body, glutathione. These amino acids also help with chronic respiratory conditions, fertility and brain health.
NAC is valued primarily for its role in antioxidant production. Along with two other amino acids — glutamine and glycine — NAC is needed to make and replenish glutathione.
In a controlled clinical trial in 262 individuals at high risk of influenza (flu) and flu-like illness, NAC supplementation at a dosage of 600 mg twice daily for six months resulted in a significant decrease in frequency and severity of flu and flu symptoms, such as cough, sore throat, headache, and muscle and joint pain. NAC’s ability to protect against flu symptoms was especially evident during the winter season. Of those who tested positive for influenza virus infection during the study, only 25% in the NAC group developed symptomatic illness compared with 79% in the placebo group (De Flora 1997).
This same NAC dosage in dialysis patients, over eight weeks, resulted in marked reductions in levels of inflammatory markers, including C-reactive protein, tumor necrosis factor-alpha, and IL-6 (Purwanto 2012).
NAC is likely safe for adults when provided as a prescription medication. However, high amounts may cause nausea, vomiting, diarrhea and constipation (Source).
When inhaled, it can cause swelling in the mouth, runny nose, drowsiness and chest tightness.
People with bleeding disorders or taking blood thinning medications should not take NAC, as it may slow blood clotting (Source).
NAC has an unpleasant smell that makes it hard to consume. If you choose to take it, consult with your doctor first.
When inhaled, it can cause swelling in the mouth, runny nose, drowsiness and chest tightness.
People with bleeding disorders or taking blood thinning medications should not take NAC, as it may slow blood clotting (Source).
NAC has an unpleasant smell that makes it hard to consume. If you choose to take it, consult with your doctor first.
Related: Best NAC Supplement
Glutathione
Glutathione is considered the body’s most important antioxidant because it’s found within the cells and helps boost activities of other antioxidants or vitamins. Glutathione is a peptide consisting of three key amino acids that plays several vital roles in the body, including helping with protein use, creation of enzymes, detoxification, digestion of fats and destruction of cancer cells.
Glutathione is considered the body’s most important antioxidant because it’s found within the cells and helps boost activities of other antioxidants or vitamins. Glutathione is a peptide consisting of three key amino acids that plays several vital roles in the body, including helping with protein use, creation of enzymes, detoxification, digestion of fats and destruction of cancer cells.
Glutathione peroxidase can also prevent lipid peroxidation, which can fight inflammation.
It’s essential for immune health and fighting cellular damage. Some researchers believe it may even contribute to longevity (Source).
Its antioxidant properties are also important for combatting numerous other ailments caused by oxidative stress, such as heart disease, infertility and some psychiatric conditions (Source).
Some supplement companies have developed 'liposomal glutahtione' so that glutathione can be directly absorbed into the cells. According to Dr Brad Stanfield (YouTube 05:00):
However, this is an huge issue as the cells will not be able to regulate the amount of antioxidants within the cells. It's critically essential to understand that each tissue maintains different amounts of glutathione based on its metabolic demands. This demand is dynamic and variable which is why the cells must be able to regulate their own glutathione synthesis and we absolutely need to make sure that glutathione supplements do not mess with this process.
Note: Glycine and NAC are different as they are building blocks for glutathione production and therefore, do not mess with the internal regulation of glutathione production.
2. CoQ10
Coenzyme Q10 (CoQ10) is one of the most studied antioxidant that your body produces. It plays essential roles in energy production and protects against cellular damage (Source).Research suggests that levels of CoQ10 decline as you age, and supplementing with it has been shown to improve certain aspects of health in older individuals.
For example, a study in 443 older adults demonstrated that supplementing with CoQ10 and selenium over 4 years improved their overall quality of life, reduced hospital visits, and slowed the deterioration of physical and mental performance (Source).
CoQ10 supplements help reduce oxidative stress, a condition characterized by an accumulation of free radicals and other reactive molecules that accelerates the aging process and onset of age-related disease (Source, Source).
Though CoQ10 shows promise as an anti-aging supplement, more evidence is needed before it can be recommended as a natural way to delay aging.
Be sure to consult a trusted healthcare professional before giving it a try.
Related: Best CoQ10 Supplements
3. Vitamin C
Vitamin C, also known as L-ascorbic acid, is a water-soluble essential vitamin and a direct antioxidant. This means that it must be taken in through food or supplements on a daily basis because it cannot be stored in the body.Vitamin C is able to act as both an antioxidant and pro-oxidant, depending on what the body needs. This allows it to serve a variety of functions in the body. Like other antioxidants, it works by targeting free radicals in the body.
Vitamin C is found in high amounts in fruit and vegetables, particularly citrus fruits like oranges and dark green leafy vegetables like broccoli.
Vitamin C, through its antioxidant potential, has been shown to improve blood flow relative to placebo in healthy people (Source).
Studies have also shown that vitamin C supplementation can reduce the effect of free radicals produced from exercise (Source).
Due to its antioxidant activity, studies have demonstrated that vitamin C can upregulate antioxidant enzymes in the body, reducing oxidative stress and improves insulin sensitivity (Source).
It has also been shown to be effective in preventing bone loss associated with oxidative stress in the elderly (Source).
PubMed has indexed more than 3,000 research studies on vitamin C and cancer.
Vitamin C and Cancer Prevention
2022 - An umbrella review* (Xu 2022) to assess the existing systematic reviews and meta-analyses for the association between vitamin C intake and multiple health outcomes; showed that vitamin C intake was associated with reduced risk of all-cause mortality, cardiovascular disease (CVD), oesophageal cancer, gastric cancer, cervical cancer and lung cancer with an increment of 50–100 mg per day.
Beneficial associations were also identified for respiratory, neurological, ophthalmologic, musculoskeletal, renal and dental outcomes. A total of 76 meta-analyses (51 papers) of randomised controlled trials and observational studies with 63 unique health outcomes were identified. Harmful associations were found for breast cancer and kidney stones for vitamin C supplement intake.
*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion.
2022 - Obese women who took vitamin C and B6 at amounts that exceeded the recommended daily intake levels were associated with a lower risk of breast cancer, according to a five-year long South Korean cohort study. 40,432 women without a history of cancer at baseline were included in this study.
Vitamin C and Cancer Treatment
2020 - Vitamin C is known as an antioxidant, but at high concentrations, vitamin C can kill cancer cells through a pro-oxidant property (Transl Oncol. 2020). This study has also demonstrated that vitamin C treatment with magnesium supplementation provided more effective anticancer therapy than vitamin C treatment alone.
Related: Best Vitamin C Supplement
4. Vitamin E
Vitamin E refers to eight molecules, which are divided into two categories: tocopherols and tocotrienols. Each of these categories is further divided into alpha (α), beta (β), gamma (γ), and delta (δ) vitamers.Vitamin E is found in high amounts in foods such as nuts, seeds, and vegetable oils.
Similarly to vitamin C, vitamin E has also been shown to improve blood flow. Vitamin E supplementation as alpha-tocopherol at 1,000 IU for three months was found to increase the vitamin E content of LDL particles and reduce their oxidation susceptibility as well as improve blood flow (Source).
Studies have also shown that supplementation of vitamin E can reduce blood pressure, but only when taken in doses of 160mg or 320mg as 80mg failed to demonstrate a beneficial effect (Source). In addition, only the highest dose in this study (320mg) demonstrated an improvement in the antioxidant capacity of the blood. Effects on blood pressure, therefore, seem to be dose-dependent.
Vitamin E supplementation has also been found to lower oxidative stress but only when the supplement is taken over a longer period of time and a high dose is taken (Source). This study showed that a dose of between 1,600 and 3,200IU daily for 16 weeks was effective in reducing oxidative stress.
Vitamin C, E and Cancer Treatment
PubMed has indexed more than 5,000 studies on vitamin E and cancer.
5. Melatonin
Melatonin is one of the most important antioxidant molecules. In the human body — aside from having direct antioxidant effects — it also stimulates the synthesis of glutathione and other important antioxidants like SuperOxide Dismutase (SOD) and catalase.
Many people are not aware that only 5% of your body’s melatonin — which is also a potent anticancer agent — is produced in your pineal gland. The other 95% is produced inside your mitochondria — provided you get sufficient near infrared exposure which is typically from sun on your bare skin. This is why vitamin D is more than likely a biomarker for sun exposure, which is intricately involved in melatonin production. (R)
6. Astaxanthin
Astaxanthin is a red pigment molecule belonging to the carotenoid family. It is produced in marine algae when the algae become stressed.When eaten by crustaceans and other sea life, it tends to lend a reddish hue to the shells, or the flesh of salmon. Marine birds like flamingos also get their color from eating microalgae full of astaxanthin.
In the body it works as an antioxidant, helping to protect against reactive oxygen species and oxidation, which plays a role in aging, heart disease, Alzheimer's disease and Parkinson's disease (R). Studies have also shown astaxanthin works from the inside out to protect your skin from free radical damage.
One standout feature of astaxanthin is that it is 550 times stronger than vitamin E and 6,000 times more potent than vitamin C. In addition, it is 10 times more effective than zeaxanthin, lutein, canthaxanthin and beta-carotene (R).
In part, this additional protection may be related to the molecular structure that enables it to reside inside and outside the cell membrane (R).
From an anti-aging standpoint, researchers (R) have found 6 mg of astaxanthin taken over six to eight weeks may reduce the appearance of crow's feet and age spots while enhancing elasticity and skin texture.
From an anti-aging standpoint, researchers (R) have found 6 mg of astaxanthin taken over six to eight weeks may reduce the appearance of crow's feet and age spots while enhancing elasticity and skin texture.
7. Molecular Hydrogen (H2)
For starters, H2 is a potent selective antioxidant. This is important, as many other antioxidants, such as vitamin C and E are not selective, and when taken in excess, can be counterproductive.
Hydrogen doesn't have that downside. Now, when we talk about molecular hydrogen, we are talking about the gas, the H2 molecule, which is two hydrogen atoms bound together.
The H2 molecule is the smallest in the universe, which allows it to diffuse through all cell membranes, including the blood-brain barrier and subcellular compartments, and into the mitochondria. It doesn't need any transporter protein. It is 'the one and only' antioxidant that can both penetrate the mitochondria and neutralize the reactive oxygen species (ROS) (Med Gas Res. 2020).
The publication of a landmark study in 2007, reported in a reputable journal (Nature Medicine) by a team in Japan, discovered that inhaled hydrogen gas could act as an antioxidant and protect the brain from free radicals. This sparked the interest in its potential health benefits worldwide and led to many published and on-going clinical research.
Following the landmark publication in Nature Medicine in 2007, many other studies regarding the potential application of hydrogen therapy on various conditions were subsequently published.
Since the Japanese discovery, the effects of hydrogen have been researched in 63 diseases [R]!
It’s less known that hydrogen was therapeutically used for the first time in humans in the early 90s. It was given to 3 divers to successfully help them overcome the effects of high pressure on the brain in deep-sea diving [Source, Source].
Hydrogen is the smallest existent gas molecule. Because of this unique property, molecular hydrogen could penetrate into virtually every organ and cell in the body (including the brain) where it may have antioxidant, anti-inflammatory, weight-loss, and anti-allergy activity. Molecular hydrogen seems like the perfect therapeutic the world has been eagerly searching for – with very few known side effects and such wide-ranging action [Source, Source].
Hydrogen water is loaded with hydrogen molecules. It was formulated as the most practical and easy way to get hydrogen into the whole body. But it’s not the only way – hydrogen can also be inhaled, injected, or absorbed through a bath [Source].
Hydrogen doesn't have that downside. Now, when we talk about molecular hydrogen, we are talking about the gas, the H2 molecule, which is two hydrogen atoms bound together.
The H2 molecule is the smallest in the universe, which allows it to diffuse through all cell membranes, including the blood-brain barrier and subcellular compartments, and into the mitochondria. It doesn't need any transporter protein. It is 'the one and only' antioxidant that can both penetrate the mitochondria and neutralize the reactive oxygen species (ROS) (Med Gas Res. 2020).
The publication of a landmark study in 2007, reported in a reputable journal (Nature Medicine) by a team in Japan, discovered that inhaled hydrogen gas could act as an antioxidant and protect the brain from free radicals. This sparked the interest in its potential health benefits worldwide and led to many published and on-going clinical research.
Following the landmark publication in Nature Medicine in 2007, many other studies regarding the potential application of hydrogen therapy on various conditions were subsequently published.
Since the Japanese discovery, the effects of hydrogen have been researched in 63 diseases [R]!
It’s less known that hydrogen was therapeutically used for the first time in humans in the early 90s. It was given to 3 divers to successfully help them overcome the effects of high pressure on the brain in deep-sea diving [Source, Source].
Hydrogen is the smallest existent gas molecule. Because of this unique property, molecular hydrogen could penetrate into virtually every organ and cell in the body (including the brain) where it may have antioxidant, anti-inflammatory, weight-loss, and anti-allergy activity. Molecular hydrogen seems like the perfect therapeutic the world has been eagerly searching for – with very few known side effects and such wide-ranging action [Source, Source].
Hydrogen water is loaded with hydrogen molecules. It was formulated as the most practical and easy way to get hydrogen into the whole body. But it’s not the only way – hydrogen can also be inhaled, injected, or absorbed through a bath [Source].
The ability of molecular hydrogen (H2) to protect the DNA and the mitochondria from oxidative damage may have beneficial effects on chronic diseases and cancer. But perhaps it could help slow down or reverse the aging process itself. A couple of cellular studies give us some interesting clues [Ref, R].
It was already discovered that hydrogen can prolong the life of stem cells by reducing oxidative stress [Ref].
A hydrogen-rich environment reduced both oxidative stress and aging in cells. Some scientists think
that drinking hydrogen water could increase longevity in humans (Circ J. 2016).
It was already discovered that hydrogen can prolong the life of stem cells by reducing oxidative stress [Ref].
A hydrogen-rich environment reduced both oxidative stress and aging in cells. Some scientists think
that drinking hydrogen water could increase longevity in humans (Circ J. 2016).
Related: Best Molecular Hydrogen Tablets
8. Curcumin (Turmeric)
Curcumin — the main active compound in turmeric — has been shown to possess powerful anti-aging properties, which are attributed to its potent antioxidant potential. Turmeric also has one of the highest anti-oxidant ORAC score: 102,700.Cellular senescence occurs when cells stop dividing. As you age, senescent cells accumulate, which is believed to accelerate aging and disease progression (Source, Source).
Research demonstrates that curcumin activates certain proteins, including sirtuins and AMP-activated protein kinase (AMPK), which helps delay cellular senescence and promotes longevity (Source, Source).
Plus, curcumin has been shown to combat cellular damage and significantly increase the lifespan of fruit flies, roundworms, and mice. This compound has been shown to postpone age-related disease and alleviate age-related symptoms as well (Source, Source).
This may be why turmeric intake has been associated with a reduced risk of age-related mental decline in humans (Trusted Source).
You can increase your curcumin intake by using turmeric in recipes or taking curcumin supplements.
Research demonstrates that curcumin activates certain proteins, including sirtuins and AMP-activated protein kinase (AMPK), which helps delay cellular senescence and promotes longevity (Source, Source).
Plus, curcumin has been shown to combat cellular damage and significantly increase the lifespan of fruit flies, roundworms, and mice. This compound has been shown to postpone age-related disease and alleviate age-related symptoms as well (Source, Source).
This may be why turmeric intake has been associated with a reduced risk of age-related mental decline in humans (Trusted Source).
You can increase your curcumin intake by using turmeric in recipes or taking curcumin supplements.
9. Carotenoids (Vitamin A, Lutein and Zeaxanthin)
Vitamin A is the generic term for a group of fat-soluble compounds highly important for human health.They’re essential for many processes in your body, including maintaining healthy vision, ensuring the normal function of your immune system and organs and aiding the proper growth and development of babies in the womb.
Vitamin A compounds are found in both animal and plant foods and come in two different major categories: preformed vitamin A (retinoids) and provitamin A (carotenoids).
Preformed vitamin A is known as the active form of the vitamin, which your body can use just as it is. It’s found in animal products including meat, chicken, fish and dairy and includes the compounds retinol, retinal and retinoic acid.
Provitamin A (carotenoids) — alpha-carotene, beta-carotene and beta-cryptoxanthin — are the inactive form of the vitamin found in plants. Other carotenoids in food, such as lycopene, lutein, and zeaxanthin, are not converted into vitamin A and are referred to as non-provitamin A carotenoids; they might have other important activities not involving vitamin A formation [R].
There are more than 600 different types of carotenoids found in nature, but only about 20 make their way into the eyes.
Of those 20, lutein and zeaxanthin are the only two (macular carotenoids) that are deposited in high quantities into the macular portion of the eyes, which is one of the earliest to be damaged during aging. Research shows that high-lutein sources like spinach are proven to help decrease eye-related degeneration and improve visual acuity.
Carotenoids are converted to the active form in your body. For example, beta-carotene is converted to retinol (an active form of vitamin A) in your small intestine (Source).
Of those 20, lutein and zeaxanthin are the only two (macular carotenoids) that are deposited in high quantities into the macular portion of the eyes, which is one of the earliest to be damaged during aging. Research shows that high-lutein sources like spinach are proven to help decrease eye-related degeneration and improve visual acuity.
Carotenoids are converted to the active form in your body. For example, beta-carotene is converted to retinol (an active form of vitamin A) in your small intestine (Source).
Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. Though its exact cause is unknown, it’s thought to be the result of cellular damage to the retina, attributable to oxidative stress (Source).
The Age-Related Eye Disease Study (AREDS) found that giving people over the age of 50 with some eyesight degeneration an antioxidant supplement (including beta-carotene) reduced their risk of developing advanced macular degeneration by 25% (Source).
However, a recent Cochrane review found that beta-carotene supplements alone won’t prevent or delay the decline in eyesight caused by AMD (Source).
The Age-Related Eye Disease Study (AREDS) found that giving people over the age of 50 with some eyesight degeneration an antioxidant supplement (including beta-carotene) reduced their risk of developing advanced macular degeneration by 25% (Source).
However, a recent Cochrane review found that beta-carotene supplements alone won’t prevent or delay the decline in eyesight caused by AMD (Source).
Lutein and zeaxanthin are powerful antioxidants that defend your body against unstable molecules called free radicals.
In excess, free radicals can damage your cells, contribute to aging and lead to the progression of diseases like heart disease, cancer, type 2 diabetes and Alzheimer’s disease (R).
Lutein and zeaxanthin protect your body’s proteins, fats and DNA from stressors and can even help recycle glutathione, another key antioxidant in your body (Source).
In excess, free radicals can damage your cells, contribute to aging and lead to the progression of diseases like heart disease, cancer, type 2 diabetes and Alzheimer’s disease (R).
Lutein and zeaxanthin protect your body’s proteins, fats and DNA from stressors and can even help recycle glutathione, another key antioxidant in your body (Source).
10. Resveratrol and Pterostilbene
Resveratrol is the beneficial compound found in red wine, which is produced on grapes as a defense against toxins and is found within the skins of grapes. It is also in berries and peanuts. Resveratrol shares many benefits with bioflavonoids, a group of plant-derived compounds with antioxidant properties.In addition to being an antioxidant, resveratrol is also an anti-inflammatory, anticarcinogenic, cardioprotective, vasorelaxant, phytoestrogenic and neuroprotective agent (Source).
As with other antioxidant supplements, resveratrol reduces oxidative stress. Taking 10mg of resveratrol daily (in two doses) for four weeks was shown to reduce markers of oxidative stress, as well as improve insulin sensitivity (Source).
However, some of the biggest hurdles for reaping the benefits of resveratrol in humans appear to be its limited bioavailability and rapid elimination from the body. But those hurdles might be overcome by a compound that has more recently gained some notice.
About 10 years after the discovery that resveratrol activated a longevity gene, researchers began to take interest in its molecular cousin, pterostilbene. Although it is present in a higher concentration in blueberries than in red wine, pterostilbene is nearly identical in chemical structure to resveratrol.
The first human-safety study of pterostilbene was published in 2013, and investigations have intensified since then. Pterostilbene is now championed as a more potent form of resveratrol. It’s said to offer all of the previously known benefits of resveratrol but with superior bioavailability. Are these claims true?
About 10 years after the discovery that resveratrol activated a longevity gene, researchers began to take interest in its molecular cousin, pterostilbene. Although it is present in a higher concentration in blueberries than in red wine, pterostilbene is nearly identical in chemical structure to resveratrol.
The first human-safety study of pterostilbene was published in 2013, and investigations have intensified since then. Pterostilbene is now championed as a more potent form of resveratrol. It’s said to offer all of the previously known benefits of resveratrol but with superior bioavailability. Are these claims true?
When it comes to pterostilbene, the evidence is much sparser. Aside from a safety study published in 2013, there have been very few trials conducted in humans. There was one study, conducted at the University of Mississippi in 80 adults, which found that pterostilbene supported healthy blood pressure and lipid metabolism.
The vast majority of research on pterostilbene is in the experimental and preclinical phase. Researchers have found that pterostilbene supports many of the same cellular pathways as resveratrol—including supporting antioxidant defenses (R) and modulating pathways involved in healthy inflammatory balance, apoptosis, and autophagy. Most experts agree that the molecular mechanisms of pterostilbene should be considered equivalent to those of resveratrol.
The vast majority of research on pterostilbene is in the experimental and preclinical phase. Researchers have found that pterostilbene supports many of the same cellular pathways as resveratrol—including supporting antioxidant defenses (R) and modulating pathways involved in healthy inflammatory balance, apoptosis, and autophagy. Most experts agree that the molecular mechanisms of pterostilbene should be considered equivalent to those of resveratrol.
Pterostilbene vs Resveratrol
PubMed has indexed more than 12,000 research studies on resveratrol, but only 500 on pterostilbene. However, the sheer number of scientific studies on a compound doesn’t necessarily mean the compound is superior. It’s also important to note that pterostilbene research lags about 10 years behind resveratrol research.
The slight difference in molecular structure between resveratrol and pterostilbene provides a sound rationale for the superiority of pterostilbene. Pterostilbene should be more stable and bioavailable in theory, and preclinical studies so far validate the assumption.
The slight difference in molecular structure between resveratrol and pterostilbene provides a sound rationale for the superiority of pterostilbene. Pterostilbene should be more stable and bioavailable in theory, and preclinical studies so far validate the assumption.
Antioxidant Benefits
1. Slow the Effects of Aging by Reducing Free Radical DamageAs described above, the single most important benefit of antioxidants is counteracting free radicals found inside every human body, which are very destructive to things like tissue and cells. Free radicals are responsible for contributing to many health issues and have connections to such diseases as cancer and premature aging of the skin or eyes.
The body uses antioxidants to prevent itself from the damage caused by oxygen. Electrons exist in pairs; free radicals are missing an electron. This is their weapon of sorts. They “react” with just about anything they come into contact with, robbing cells and compounds of one of their electrons.
This makes the effected cell or compound unable to function and turns some cells into “electron-seeking muggers,” leading to a chain reaction in the body and the proliferation of free radicals. Free radicals then damage DNA, cellular membranes and enzymes.
2. Protect Vision and Eye Health
The antioxidants vitamin C, vitamin E and beta-carotene have all been shown to have positive effects on preventing macular degeneration symptoms, or age-related vision loss/blindness. Many foods that provide these nutrients also supply antioxidants called lutein and zeaxanthin, nicknamed the eye vitamins, found in brightly colored foods like fruits and vegetables — especially leafy greens and types that are deep orange or yellow.
These antioxidants are believed to be easily transported around the body, especially to the delicate parts of the eyes called the macula and the lens. In fact, there are more than 600 different types of carotenoids found in nature, but only about 20 make their way into the eyes.
Of those 20, lutein and zeaxanthin are the only two (macular carotenoids) that are deposited in high quantities into the macular portion of the eyes, which is one of the earliest to be damaged during aging. Research shows that high-lutein sources like spinach are proven to help decrease eye-related degeneration and improve visual acuity.
Similarly, flavonoid antioxidants found in berries, such as bilberries or grapes (also great sources of the antioxidant resveratrol), may be especially beneficial at supporting vision into older age.
3. Reduce the Effects of Aging on the Skin
Perhaps most noticeably, free radicals speed up the aging process when it comes to the appearance and health of your skin. Using antioxidants for skin may help combat this damage, especially from eating sources high in vitamin C, beta-carotene and other antioxidants.
Vitamin A and C have been connected to a decrease in the appearance of wrinkles and skin dryness. Vitamin C, specifically, is a powerful antioxidant that can help reduce the effect of oxidative damage caused by pollution, stress or poor diet.
Vitamin A deficiency has also been linked to skin dryness, scaling and follicular thickening of the skin. Similarly to how free radicals damage surface skin cells, keratinization of the skin, when the epithelial cells lose their moisture and become hard and dry, can occur in the mucous membranes of the respiratory, gastrointestinal tract and urinary tract.
4. Help Prevent Stroke and Heart Disease
Since antioxidants help prevent damage of tissues and cells caused by free radicals, they’re needed to protect against heart disease and stroke. At this point, the data does not show that all antioxidants are effective in protecting against heart disease, but some, such as vitamin C, do seem to be.
The American Journal of Clinical Nutrition featured a study that found those with high levels of vitamin C in their blood had almost a 50 percent decreased risk of stroke. Countless studies also have found that people who consume highly plant-based diets — loaded with things like fresh veggies, herbs, spices and fruit — have a better chance of living longer and healthier lives with less heart disease.
However, when it comes to heart health, certain studies have found that using vitamin E or beta-carotene supplements should be “actively discouraged” because of the increase in the risk of heart-related mortality, so consult a health professional when it comes to vitamin E or carotene supplementation.
5. May Help Reduce Risk of Cancer
Some research has unearthed a potential connection between antioxidants and cancer. In fact, studies have found that high intakes of vitamin A, vitamin C and other antioxidant foods could help prevent or treat several forms of cancer thanks to their ability to control malignant cells in the body and cause cell cycle arrest and apoptosis (destruction) of cancer cells.
Retinoic acid, derived from vitamin A, is one chemical that plays important roles in cell development and differentiation, as well as cancer treatment.
Lung, prostate, breast, ovarian, bladder, oral and skin cancers have been demonstrated to be suppressed by retinoic acid. Another study collected numerous references demonstrating the findings of retinoic acid in protection against melanoma, hepatoma, lung cancer, breast cancer and prostate cancer.
However, there’s evidence indicating that the benefits of chemicals like retinoic acid are safest when obtained from cancer-fighting foods naturally, rather than supplements.
As a rule, antioxidant supplements (vitamins A, C, and E; coenzyme Q10, and N-acetyl cysteine) should be avoided in patients undergoing chemotherapy and radiotherapy, as these interventions act largely by increasing oxidant injury (SWOG S0221, published in 2020). Paradoxically, while oral vitamin C is a potent antioxidant (Marik 2018), high-dose intravenous vitamin C generates reactive oxygen species that potentiates the effects of chemotherapy and radiation therapy.
6. Can Help Prevent Cognitive Decline
Oxidative stress is believed to play a central role in the pathogenesis of neurodegenerative diseases, but a nutrient-dense diet full of brain foods seems to lower one’s risk. The Journal of the American Medical Association of Neurology reports that higher intake of foods rich in antioxidants, such as vitamin C and vitamin E, may modestly reduce long-term risk of dementia and Alzheimer’s.
Many studies have found that people eating plant-based diets high in antioxidants, such as the Mediterranean diet, have better protection over cognition.
7. May Protect Against Diabetes
In addition to improving heart health and cognitive function, some research suggests that antioxidants could aid in the prevention of type 2 diabetes. For example, one animal model out of Japan showed that administering antioxidants to mice helped preserve the function of beta cells in the pancreas, which are responsible for the production of insulin.
Another large review of 12 studies found that vitamin E helped reduce blood sugar levels, while vitamin C was effective at decreasing levels of oxidative stress.
Best Antioxidant Foods and Herbs
Antioxidants may be easier to add to your diet than you might think.Based on ORAC scores provided by Superfoodly (based on research from a broad number of sources), below are some of the top antioxidant foods by weight:
- Dark chocolate: 20,816 ORAC score
- Pecans: 17,940 ORAC score
- Elderberry: 14,697 ORAC score
- Artichokes (boiled): 9,416 ORAC score
- Wild blueberries: 9,621 ORAC score
- Cranberries: 9,090 ORAC score
- Kidney beans: 8,606 ORAC score
- Blackberries: 5,905 ORAC score
- Cilantro: 5,141 ORAC score
- Goji berries: 4,310 ORAC score
The ORAC scores above are based on weight. This means that it might not be practical to eat high amounts of all of these antioxidant foods.
Try to consume at least three to four servings daily of these antioxidant-rich foods (even more is better) for optimal health.
Along with antioxidant foods, certain herbs, spices and essential oils derived from nutrient-dense plants are extremely high in healing antioxidant compounds. Here is another list of the herbs you can try adding to your diet for increased protection against disease.
Many of these herbs/spices are also available in concentrated essential oil form. Look for 100 percent pure (therapeutic grade) oils, which are highest in antioxidants:
Many of these herbs/spices are also available in concentrated essential oil form. Look for 100 percent pure (therapeutic grade) oils, which are highest in antioxidants:
- Clove: 314,446 ORAC score
- Cinnamon: 267,537 ORAC score
- Oregano: 159,277 ORAC score
- Turmeric: 102,700 ORAC score
- Cocoa: 80,933 ORAC score
- Cumin: 76,800 ORAC score
- Parsley (dried): 74,349 ORAC score
- Basil: 67,553 ORAC score
- Ginger: 28,811 ORAC score
- Thyme: 27,426 ORAC score
Different Types of Antioxidants
The science of antioxidants can be quite complex, and this often causes people to be confused about what types they should be taking. Each type of antioxidant has its own special function.
When classified according to their solubility, antioxidants can be categorized as either soluble in fat (hydrophobic) or soluble in water (hydrophilic). Both of these forms are required by your body in order to protect your cells, since the interior of your cells and the fluid between them are composed of water, while the cell membranes themselves are mostly made of fat.
Since free radicals can strike either the watery cell contents or the fatty cellular membrane, you need both types of antioxidants to ensure full protection from oxidative damage. Some examples of lipid-soluble antioxidants are vitamins A and E, carotenoids and coenzyme Q10 (CoQ10).
Water-soluble antioxidants are found in aqueous body fluids, like your blood and the fluids within and around your cells (cytosol or cytoplasmic matrix). Some examples of water-soluble antioxidants are vitamin C, polyphenols and glutathione.
When classified according to their solubility, antioxidants can be categorized as either soluble in fat (hydrophobic) or soluble in water (hydrophilic). Both of these forms are required by your body in order to protect your cells, since the interior of your cells and the fluid between them are composed of water, while the cell membranes themselves are mostly made of fat.
Since free radicals can strike either the watery cell contents or the fatty cellular membrane, you need both types of antioxidants to ensure full protection from oxidative damage. Some examples of lipid-soluble antioxidants are vitamins A and E, carotenoids and coenzyme Q10 (CoQ10).
Water-soluble antioxidants are found in aqueous body fluids, like your blood and the fluids within and around your cells (cytosol or cytoplasmic matrix). Some examples of water-soluble antioxidants are vitamin C, polyphenols and glutathione.
Direct vs Indirect Antioxidants, what's the difference? Direct Antioxidants become free radicals after they've neutralized a free radical. Consequently, they can cause DNA damage. Indirect Antioxidants do not become free radicals, and therefore do not inflict DNA damage.
Should I Take Antioxidant Supplements?
The oxidative stress caused by free radicals to the body’s cells is thought to be a major contributor to the development of cancer (R).
Since antioxidants neutralize free radicals, taking antioxidant supplements have been speculated to decrease the risk of developing or dying from cancer (Source).
Several meta-analyses, however, have shown that taking antioxidant supplements does neither reduce the risk of many types of cancers nor reduce the risk of dying from them once diagnosed, In fact, they may even increase the risk of certain cancers (Source, Source, Source, Source).
In addition, several meta-analyses have found that beta-carotene supplements, a precursor of vitamin A, increases the risk of bladder cancer, and, in people who smoke, the risk of lung cancer as well (Source, Source, Source, Source).
Vitamin A is important for fetal growth and development, but at high doses, vitamin A supplements can increase the risk of birth defects (Source, Source).
Therefore, women who might be or are pregnant should not take high doses of vitamin A supplements (Source).
These supplements are only recommended for pregnant women in areas where vitamin A deficiency is prevalent, such as in Africa and Southeast Asia (Source, Source).
Beta-carotene, the precursor of vitamin A, is not shown to lead to birth defects. But since taking the supplement long-term is associated with cancer, pregnant women should consult with their physician before taking beta-carotene supplements (Source, Source).
As for Vitamin C, all the adverse effects, including digestive distress and kidney stones, appear to occur when people take it in mega doses greater than 2,000 mg on a long term basis (Source).
Since antioxidants neutralize free radicals, taking antioxidant supplements have been speculated to decrease the risk of developing or dying from cancer (Source).
Several meta-analyses, however, have shown that taking antioxidant supplements does neither reduce the risk of many types of cancers nor reduce the risk of dying from them once diagnosed, In fact, they may even increase the risk of certain cancers (Source, Source, Source, Source).
In addition, several meta-analyses have found that beta-carotene supplements, a precursor of vitamin A, increases the risk of bladder cancer, and, in people who smoke, the risk of lung cancer as well (Source, Source, Source, Source).
Vitamin A is important for fetal growth and development, but at high doses, vitamin A supplements can increase the risk of birth defects (Source, Source).
Therefore, women who might be or are pregnant should not take high doses of vitamin A supplements (Source).
These supplements are only recommended for pregnant women in areas where vitamin A deficiency is prevalent, such as in Africa and Southeast Asia (Source, Source).
Beta-carotene, the precursor of vitamin A, is not shown to lead to birth defects. But since taking the supplement long-term is associated with cancer, pregnant women should consult with their physician before taking beta-carotene supplements (Source, Source).
As for Vitamin C, all the adverse effects, including digestive distress and kidney stones, appear to occur when people take it in mega doses greater than 2,000 mg on a long term basis (Source).
Conclusion
Excessive free radicals contribute to chronic diseases including cancer, heart disease, cognitive decline, and vision loss. Abundant evidence suggests that eating whole in fruits, vegetables and whole grains—all rich in networks of naturally occurring antioxidants and their helper molecules—provides protection against free radicals.
If you feel that your diet does not provide sufficient amounts of antioxidants, supplements can help to fill the gap. However, it's recommended that you inform your doctor or medical specialist if you are starting any form of supplements. It's also advisable that you are monitored by a qualified medical doctor.
Monitoring might include common baseline tests such as liver and kidney function tests, blood cholesterol, blood sugar and blood pressure. This is to ensure that the antioxidant supplements that you are taking are beneficial to you and not causing any harm. It will also provide objective evidence to you and your doctor that you are going in the right direction.
*********************
Online Shopping Guide
Before adding a new supplement to your routine, discuss its use with your healthcare provider, especially if you have an underlying health condition or are taking medication.
While many of the anti-oxidant supplements may be available in your local stores, it may be more convenient or affordable to shop for them online on Amazon (US):
Related: Best Vitamin Brands
Comments