While there are many ways to describe what antioxidants do inside the body, one definition of antioxidants is any substance that inhibits oxidation, especially one used to counteract the deterioration of stored food products or removes potentially damaging oxidizing agents in a living organism.
Antioxidants include dozens of food-based substances you may have heard of before, such as carotenoids like beta-carotene, lycopene and vitamin C. These are several examples of antioxidants that inhibit oxidation, or reactions promoted by oxygen, peroxides and/or free radicals. (1) Research suggests that when it comes to longevity and overall health, some of the benefits of consuming antioxidant foods, herbs, teas and supplements include:
- Slower signs of aging, including of the skin, eyes, tissue, joints, heart and brain
- Healthier, more youthful, glowing skin
- Reduced cancer risk
- Detoxification support
- Longer life span
- Protection against heart disease and stroke
- Less risk for cognitive problems, such as dementia
- Reduced risk for vision loss or disorders like macular degeneration and cataracts
- Antioxidants are also added to food or household products to prevent oxidation and spoilage
Why do we need antioxidants, and what do specific antioxidants do inside the body once consumed?
Antioxidant sources, like antioxidant foods, herbs, spices and teas, reduce the effects of free radicals, also called oxidative damage/stress, which plays a major role in disease formation. The leading health problems facing us today — including conditions like heart disease, cancer and dementia — have been linked to increased levels of oxidative damage and inflammation. In simplest terms, oxidation is a chemical reaction that can produce free radicals, leading to other chemical chain reactions that damage cells.
Sources of antioxidants in your diet offer much-needed help in counteracting the damage done by things like blue light or sun exposure, a poor diet, smoking or using other drugs, taking medications, toxicity or chemical exposure, even high amounts of stress and other natural factors that increase the risk of age-related problems. In the process of fighting free radical damage, antioxidants protect healthy cells while halting the growth of malignant or cancerous cells.
History of Antioxidants Knowledge and Their Usage
It’s not exactly agreed upon who first “discovered” antioxidants. Antioxidants have been dated in medical literature to the early 19th and 20th centuries, but researchers and health experts have been discussing them for much longer. Each antioxidant has its own unique history of discovery. Some, such as vitamin C and vitamin E, were first researched by doctors, such as Henry A. Mattill during the 1920s–1950s, used to explain why animals fed whole foods lived longer and remained healthier. (2)
Joe McCord is another researcher credited with discovering the function of antioxidant enzymes like superoxide dismutase, mostly by mistake, and noting how all organisms held these beneficial compounds inside their bodies but less so as they aged. (3)
Today, the level of antioxidants in any substance or food is evaluated with an ORAC score, which stands for “oxygen radical absorption capacity. ORAC tests the power of a plant to absorb and eliminate free radicals. These measurements were developed by the National Institute of Aging and are based on 100 grams of each food or herb.
Most common fruits, vegetables and herbs in the diet that contain antioxidants include forms like vitamin E, lutein, vitamin C, beta-carotene, flavonoids and lycopene. While there is currently no official recommended daily allowance for antioxidants or antioxidant foods, generally speaking the more you consume each day from real foods in your diet the better.
Top 10 High Antioxidant Foods List
Antioxidants may be easier to add to your diet than you might think. Based on ORAC scores provided by the Nutrient Data Laboratory, Beltsville Human Nutrition Research Center and Agricultural Research Service of the U.S. Department of Agriculture, below are some of the top antioxidant foods by weight:
- Goji berries: 25,000 ORAC score
- Wild blueberries: 14,000 ORAC score
- Dark chocolate: 21,000 ORAC score
- Pecans: 17,000 ORAC score
- Artichoke: 9,400 ORAC score
- Elderberries: 14,000 ORAC score
- Kidney beans: 8,400 ORAC score
- Cranberries: 9,500 ORAC score
- Blackberries: 5,300 ORAC score
- Cilantro: 5,100 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. Other high antioxidant foods not listed above, which are still great sources and highly beneficial, include common foods like tomatoes, carrots, pumpkin seeds, sweet potatoes, pomegranates, strawberries, kale, broccoli, grapes or red wine, squash, and wild-caught salmon. Try to consume at least three to four servings daily of these high antioxidant foods (even more is better) for optimal health.
Top 10 Antioxidant Herbs List
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.
- 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
Other antioxidant-rich herbs include garlic, cayenne pepper and green tea. Aim to consume two to three servings of these herbs or herbal teas daily.
Top 10 High Antioxidant Supplements
The American Heart Association, along with the Mayo Clinic and Cleveland Clinic, recommend getting antioxidants from whole foods and a wide variety of foods. While it’s always ideal, and usually more beneficial, to get antioxidants or other nutrients directly from real food sources, certain types may also be helpful when consumed in supplement form.
There’s still debate over which antioxidants may offer help preventing or treating diseases when consumed in concentrated dosages. Some research has shown that antioxidants like lutein and glutathione may be beneficial when taken in supplement form — for example, in preventing vision loss, joint problems or diabetes. But other research doesn’t always show the same results and sometimes even that certain supplements like vitamin A or vitamin C may be harmful in high amounts.
So just remember that while they might help you in certain instances, overall it doesn’t seem that consuming supplemental antioxidants help you live longer. That’s where your diet and lifestyle come in. Bottom line: We should never rely on supplements to counteract unhealthy lifestyles and poor nutrition.
If you’re generally healthy and eat a varied diet, you might not benefit much from taking antioxidants supplements. However, if you’re at risk for something like vision loss or heart disease, talk to your doctor about whether the following antioxidant supplements in proper doses (and with a healthy lifestyle) might be helpful:
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.
Derived naturally from foods like berries and leafy greens, quercetin seems to be safe for almost everyone and poses little risks. Most studies have found little to no side effects in people eating nutrient-dense diets high in quercetin or taking supplements by mouth short term.
Amounts up to 500 milligrams taken twice daily for 12 weeks appear to be very safe for helping manage a number of inflammatory health problems, including heart disease and blood vessel problems, allergies, infections, chronic fatigue, and symptoms related to autoimmune disorders like arthritis.
Lutein has benefits for the eyes, skin, arteries, heart and immune system, although food sources seem to be generally more effective and safer than supplements. Some evidence shows that people who obtain more lutein from their diets experience lower rates of breast, colon, cervical and lung cancers.
4. Vitamin C
Known for improving immunity, vitamin C helps protect against colds, the flu, and potentially cancer, skin and eye problems.
Resveratrol is an active ingredient found in cocoa, red grapes, and dark berries, such as lingonberries, blueberries, mulberries and bilberries. It’s a polyphonic bioflavonoidantioxidant that’s produced by these plants as a response to stress, injury and fungal infection, helping protect the heart, arteries and more.
Astaxanthin is found in wild-caught salmon and krill and has benefits like reducing age spots, boosting energy levels, supporting joint health and preventing symptoms of ADHD.
Selenium is a trace mineral found naturally in the soil that also appears in certain foods, and there are even small amounts in water. It supports the adrenal and thyroid glands and helps protect cognition. It may also fight off viruses, defend against heart disease and slow down symptoms correlated with other serious conditions like asthma.
8. Lavender Essential Oil
Lavender oil reduces inflammation and helps the body in many ways, such as producing important antioxidant enzymes – especially glutathione, catalase and superoxide dismutase.
Chlorophyll is very helpful for detoxification and linked to natural cancer prevention, blocking carcinogenic effects within the body, and protecting DNA from damage caused by toxins or stress. It’s found in things like spirulina, leafy green veggies, certain powdered green juices and blue-green algae.
10. Frankincense Essential Oil
Frankincense oil has been clinically shown to be a vital treatment for various forms of cancer, including breast, brain, colon and prostate cancers. Frankincense has the ability to help regulate cellular epigenetic function, which positively influences genes to promote healing. Rub frankincense essential oil on your body (neck area) three times daily, and take three drops internally in eight ounces of water three times daily as part of a natural prevention plan.
Top Health Benefits of Antioxidant Foods
1. Slow the Effects of Aging by Reducing Free Radical Damage
As 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.
What do free radicals do exactly, and why are they so destructive? 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 affected 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 enzym
2. Protect Vision and the Eyes
The antioxidants vitamin C, vitamin E and beta-carotene have all been shown to have positive effects on preventing macular degeneration, or age-related vision loss/blindness. Many foods that provide these nutrients also supply antioxidants called lutein and zeaxanthin, nicknamed the eye vitamins, and 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. (4) Of those 20, lutein and zeaxanthin are the only two that are deposited in high quantities into the macular portion of the eyes, which is one of the earliest to be damaged during aging.
Based on concentrations of things like lutein and other carotenoids, examples of antioxidant foods that protect vision include spinach, kale, berries, broccoli and even egg yolks. Research shows that high-lutein sources like spinach are proven to help decrease eye related degeneration and improve visual acuity. (5) Similarly, flavonoid antioxidants found in berries, such as bilberries or grapes (also a great source 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. Antioxidants 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. (6)
The Department of Preventive Medicine & Public Health at University of Navarra states, “Fruits and vegetables are dietary sources of natural antioxidants and it is generally accepted that antioxidants in these foods are key in explaining the inverse association between fruits and vegetables intake and the risk of developing a cardiovascular event or having elevated levels of cardiovascular risk factors.” (7) 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. (8)
5. May Help Decrease Risk of Cancer
Studies have found that high intakes of vitamin A, vitamin C and other antioxidants 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. (9) 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 food naturally, rather than supplements.
6. Can Help Prevent Cognitive Decline, Such as Dementia or Alzheimer’s Disease
Oxidative stress is believed to play a central role in the pathogenesis of neurodegenerative diseases, but a nutrient-dense diet 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. (10)
Are There Any Antioxidant Precautions or Side Effects?
Just like any other supplement, it doesn’t seem that it’s beneficial or even necessarily safe to consume high doses of antioxidants in supplement form. For example, because during exercise oxygen consumption can increase by a factor of more than 10, taking high doses of antioxidants might interfere with proper exercise recovery. (12) Other research has shown that high-dose antioxidant supplementation may interfere with the cardiovascular benefits of exercise, have negative effects on the body’s natural anti-cancer activities, and affect how the body balances levels of different chemicals and nutrients on its own. (13, 14)
When it comes to protection against things like cancer or heart disease, overall the medical literature seems conflicting. Although some studies found a positive relationship between antioxidant supplementation and risk reduction, others have not found such positive effects. (15) To be safe, always follow directions carefully and speak with your doctor if you’re unsure of whether or not a supplement is right for you. And to remain your healthiest into older age, aim to reduce free radical load in your body by practicing things like:
- avoiding environmental pollutants in water
- reducing chemical exposure in household and cosmetic products
- limiting intake of processed and refined foods
- limiting intake of pesticide and herbicide-laden foods
- limiting intake of antibiotic and hormone-laden foods
- avoiding overuse of medications
- reducing stress
- getting moderate amounts of exercise
- using natural, cold-pressed oils (heat oxidizes fats in refined oils)
Final Thoughts on Antioxidants and High Antioxidant Foods
- Antioxidants inhibit oxidation in the body, also called free radical damage, which is tied to stress.
- We get most antioxidants from our diets, which help counteract effects of an unhealthy lifestyle, such as accelerated aging, damaged or mutated cells, broken-down tissue within the skin or eyes, the activation of harmful genes within DNA, and low immunity.
- Some noteworthy high antioxidant foods, herbs and supplements include leafy green veggies, artichokes, cocoa, wild berries, green tea, cinnamon, clove, sea vegetables like kelp, spirulina, quercetin or lutein supplements, and essential oils like lavender and frankincense.