What do some of the healthiest foods on earth, such as berries, spinach, cacao, and green tea, all have in common? They’re full of antioxidants, which are natural substances that can prevent or mitigate cellular damage.
Antioxidants are incredibly valuable in our diets and supplement routines—especially as we age—because they help counteract the effects of free radicals, which are unstable molecules produced by the body in response to exposure to harmful factors like pollution, UV radiation, chemical and alcohol consumption, and tobacco inhalation.
The damage that free radicals can cause has been associated with inflammation and chronic disease, including higher risks for cancer, heart disease, and neurological diseases.
Antioxidants work by neutralizing free radicals and preventing them from causing damage to cells. In fact, diets that include lots of antioxidants (think fruits, vegetables, herbs, and spices) are believed to be protective against the aforementioned diseases.
While your diet is your first line of antioxidant defense, you can also increase your intake of these beneficial compounds by adding certain supplements to your routine. Here’s what to know about the most popular types of antioxidant supplements, including who they’re best suited for and how to properly give them a go.
Why Consider An Antioxidant Supplement?
There are thousands of different antioxidants in existence, and foods that naturally contain them usually contain many types that work together synergistically. For that reason (amongst others), you’ll be hard-pressed to find a health or nutrition expert that doesn’t emphasize the importance of a balanced, whole foods diet for getting enough antioxidants to support overall wellbeing.
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That said, there are circumstances in which supplementing with specific types of antioxidants has been proven beneficial. Some of the biggest reasons people may choose to supplement with certain antioxidants:
- Immune function: Antioxidants such as vitamin C and vitamin E are important for immune function and may help support the body’s ability to fight off certain illnesses.
- Anti-inflammatory support: Some antioxidants help the body manage inflammation and ultimately avoid its long-term effects.
- Skin and eye health: Healthy skin and eyes (including normal vision) rely on antioxidants, such as vitamins C, A, and E, to protect them against damage from UV radiation and other environmental factors.
- Thyroid and hormonal health: Selenium is a popular antioxidant that’s taken to support the thyroid gland’s ability to make hormones that regulate metabolic functions. Research also suggests that antioxidants are important for women’s reproductive hormone health.
The Most Popular Antioxidant Supplements
When it comes to antioxidant supplements, you’ve got plenty of options—and which you ultimately opt for depends on your unique health status and needs. Here are five to prioritize.
1. Vitamin C
Vitamin C is an essential nutrient that plays a crucial role in many biological processes in the body. Some potential benefits of vitamin C supplements include:
- Supporting immune function: Vitamin C is important for the immune system and helps it respond as needed.
- Supporting skin and joint health: Vitamin C is involved in the production of collagen, a protein that is essential for skin health. Higher vitamin C intake may help protect against photoaging (signs of aging on the skin) caused by UV radiation and other environmental factors.
- Enhancing iron absorption: Vitamin C can enhance the absorption of iron from plant-based foods, which can be especially important for vegetarians and vegans.
According to nutritionist Rebecca Fallihee, C.N.S., L.D.N., vitamin C is one of your best antioxidant options for immune health, since it helps decrease oxidative stress and antioxidant depletion.
The recommended daily intake of vitamin C for adults is 75 to 90 milligrams per day, which can be obtained from a healthy diet rich in fruits and vegetables. It’s important to note that high doses of vitamin C supplements can cause side effects such as digestive upset, headaches, and kidney stones, so be sure to stick to recommended doses.
2. Vitamin E
Vitamin E supplementation is sometimes used for cognitive, cardiovascular, and skin health support, as well as for supporting fertility and reproductive health. These supplements are particularly helpful for people who don’t absorb vitamin E from foods well (typically those with fat-absorption issues).
Some benefits associated with vitamin E supplements include:
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- Protecting memory: According to dietitian Lisa Andrews, R.D., owner of Sound Bites Nutrition, along with omega-3 fatty acids and carotenoids, vitamin E may help improve memory in older adults. A study in healthy adults over the age of 65 found that two years of supplementation helped with working memory tasks. (In the study, participants took 15 milligrams of vitamin E, 1,000 milligrams of omega-3 fatty acids, and 22 milligrams of carotenoids per day.)
- Promoting long-term cardiovascular health: Vitamin E may be beneficial for supporting healthy cholesterol, triglyceride, and insulin levels, although more research is needed.
- Supporting reproductive health and fertility: Research suggests that selenium (200 milligrams per day) and vitamin E (400 IU per day) may be useful to women struggling with fertility, since this combo seems to positively impact ovarian reserve and healthy ovulation, as well as other reproductive processes. Similarly, a combination of vitamin E and omega-3 fatty acids may support balance in overweight women experiencing reproductive irregularities, according to Andrews.
The RDA for vitamin E is 15 mg/day (or 22.4 IU/day) for adults. Andrews points out, “Vitamin E can thin your blood. If you take blood thinners, additional vitamin E could thin your blood too much, so use caution.”
3. Vitamin A/Beta Carotene
Vitamin A plays a key role in many bodily functions, including vision, immune system function, and cell growth and differentiation. It can be obtained from a variety of food sources, including liver, fish, dairy products, and some fruits and vegetables. However, in some cases, vitamin A supplements may be recommended for these purposes:
- Eye health: Vitamin A can help maintain healthy vision, and a deficiency can lead to night blindness and other eye problems. The Age-Related Eye Disease Study found that a combination of antioxidants (vitamin C, vitamin E, carotenoids) plus zinc and copper supported long-term eye health and function.
- Skin health: Low levels of vitamin A can contribute to dry, rough skin and other skin problems, so taking vitamin A may help improve the skin’s barrier and microbiome, as well as its appearance.
- Reproductive health: Both men and women need enough vitamin A for reproductive health, as a deficiency can lead to infertility and other reproductive problem.
Something to keep in mind when it comes to vitamin A is that we typically get it from two sources: active or preformed vitamin A (which is the type found in fish, organ meats, dairy products, and eggs) or provitamin A carotenoids (which are turned to vitamin A by the body and are found in fruits, vegetables, and other plant foods), explains The Vitamin Shoppe nutritionist Brittany Michels, R.D.N., L.D.N., C.P.T. While there’s no recommended upper limit for those carotenoids (which include beta-carotene), there is an upper limit of 3,000 micrograms per day for preformed vitamin A. That means you’ll need to be aware of how much preformed vitamin A you supplement with, as well as how much you get from food, so that you don’t go overboard. (FYI: The RDA for vitamin A for adults is 700 to 900 micrograms per day (1,300 micrograms per day for nursing women.)
4. Selenium
As an essential mineral, selenium is needed for reproduction, metabolism, and immune system functions. It’s naturally found in whole grains, nuts like Brazil nuts, seeds, and poultry, and according to Andrews, most people get enough from their diets and true deficiencies aren’t common. (However, women are more likely to lack dietary selenium than men.)
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That said, supplementing with selenium can also potentially help ward off oxidative stress and an out-of-balance inflammatory response, helping the immune system respond to pathogens effectively, and support thyroid function (particularly in those experiencing issues). Michels recommends trying to meet your needs via food (the RDA for adults is 55 micrograms per day) and considering a supplement if you’re struggling to hit that mark. “There are no concerns with going slightly over daily needs, but be mindful that the daily upper limit for selenium is considered 400 micrograms per day,” she says.
5. Quercetin
Quercetin, a type of bioflavonoid antioxidant, is naturally found in many brightly-colored fruits, vegetables, and teas, such as onions, apples, grapes, berries, cherries, scallions, kale, and tomatoes. “Quercetin may decrease levels of an inflammatory marker called CRP,” says Michels. “Other research suggests that quercetin may reduce the build-up of uric acid in those with gout, and may offer some cardiovascular benefits related to blood pressure and cholesterol.” Get this: One study showed quercetin boosted antioxidant status and quality of life in adults with a history of heart problems.
“Many people take quercetin supplements along with vitamin C for their synergistic effects,” Michels shares. There isn’t a standard RDA of quercetin, however, about 500 milligrams per day is a common supplement dosage (and the amount used in the study mentioned above).
Other Antioxidants Worth Noting
Though the antioxidants listed above are certainly some of the heaviest hitters, there are a few others going mainstream these days worth keeping on your radar.
- N-Acetyl Cysteine (NAC): “NAC is a precursor to glutathione that may offer immune support,” explains Fallihee. She recommends it for immune-associated respiratory issues.
- Lutein and zeaxanthin: Two carotenoids that are commonly taken in supplement form, these may help enhance immunity, contribute to healthy reproduction, and protect vision and skin health by working against age-related macular degeneration.
Best Practices For Supplementing With Antioxidants
Again, it’s generally recommended to obtain antioxidants from a balanced diet rather than relying on supplements alone. When you do incorporate supplements, always follow dosage directions to avoid side effects. While the right dose of antioxidants can be beneficial, high doses may actually be harmful by interacting with other nutrients and even prevent the body from recovering properly from exercise, according to Fallihee.
“I always advise clients to ask their doctor or pharmacist about drug-nutrient interactions that could occur when they take supplements, especially if they have an existing condition, such as issues with blood clotting, nutrient absorption, or kidney stones, for example,” suggests Andrews. Selenium, in particular, may do more harm than good in people with prediabetes or high risk for diabetes, while excess beta-carotene can contribute to disease risk, especially in smokers, she says. That’s why it’s always worthwhile to check in with a health professional before updating your regimen to make sure you’ll actually reap the benefits you’re looking for.