By Refine Nutrition. Sources checked October 6, 2026. This article is educational and does not recommend, review, or sell any product.
The short answer
Eating plenty of fruits and vegetables is associated with lower risks of some chronic diseases. Taking high-dose antioxidant pills has not been shown to prevent those diseases. The National Center for Complementary and Integrative Health (NCCIH) says that, apart from age-related macular degeneration (AMD), there is currently no evidence that antioxidant supplements help with the diseases studied: cancer, heart disease, eye diseases and Alzheimer's disease. It also says high doses of some antioxidants can cause harm.
One exception exists. People who already have AMD may be told by an eye doctor to take a specific antioxidant-and-zinc formula. That is a medical decision, not a general wellness habit.
Why food and pills can behave differently
The food findings show an association, not proof that food causes the lower risk. NCCIH points to a 2017 review of 95 observational studies with more than 2 million participants. People who ate more fruits and vegetables had lower risks of cardiovascular disease and cancer. A 2023 UK study that followed 72,160 people for about 9 years linked higher fruit and vegetable intake to a lower risk of cataracts.
NCCIH lists three possible reasons pills don't match that result:
- Other substances in these foods, or other habits of people who eat this way, may explain the benefit.
- Purified antioxidants may act differently from the complex mixtures in food.
- The high doses in supplements may have different effects than the smaller amounts in food.
The Office of Dietary Supplements (ODS) puts the practical point plainly: supplements can't take the place of the variety of foods that are important to a healthy eating routine.
Evidence comparison: food-rich eating vs high-dose antioxidant pills
Where food and pills can be compared
Heart disease and cancer
- Food-rich eating: Higher fruit and vegetable intake was associated with lower risk in the 2017 review described by NCCIH.
- Antioxidant pills: NCCIH says the evidence does not support them for prevention. In 2022 the U.S. Preventive Services Task Force recommended against beta-carotene or vitamin E supplements for preventing cardiovascular disease and cancer. For other single nutrients or pairs, including vitamin C and selenium, it found the evidence insufficient to recommend either way.
Cataracts
- Food-rich eating: Higher fruit and vegetable intake was associated with a lower cataract risk in the 2023 UK study.
- Antioxidant pills: A 2012 review of 9 high-quality studies (117,272 participants) found no effect on the occurrence or progression of cataracts.
Where only pills were studied
- Age-related macular degeneration (AMD): Antioxidant pills haven't been shown to prevent AMD in people who don't have it. For people who already have AMD, certain antioxidant-and-zinc formulas may slow progression. In the AREDS trial, the formula reduced the risk of advanced AMD by about 25 percent among people with intermediate AMD.
- Memory and thinking: Two 2018 reviews found mixed results. One found low-certainty evidence of small benefits for beta-carotene taken for about 18 years and vitamin C taken for 5 to 10 years. High-dose vitamin E did not slow the progression from mild cognitive impairment to dementia in one study.
Safety limits of high-dose pills
More is not always better. NCCIH reports these risks:
- Beta-carotene: High doses may raise the risk of lung cancer and of death from cardiovascular disease, mostly in people at high risk, such as smokers.
- Vitamin E: High doses may increase bleeding risk and may interact with anticoagulant or antiplatelet medicines.
- Vitamin C: High doses can cause diarrhea, nausea and stomach cramps. They may interact with cancer treatments and can worsen iron overload in people with hemochromatosis.
- Combinations: In one study, a mix of vitamin E, vitamin C, selenium and beta-carotene reduced the cholesterol-lowering effect of two drugs taken together.
ODS adds that side effects are most likely at high doses, instead of prescribed medicines, or when taking many supplements. It also notes that the U.S. Food and Drug Administration (FDA) does not determine whether supplements are effective before they are marketed. Independent quality-testing seals indicate a product was properly manufactured, contains the ingredients listed on the label and has no harmful levels of contaminants. They do not guarantee a product is safe or effective.
Who should talk to a professional first
- Anyone in cancer treatment. Some treatments work partly by generating reactive oxygen substances, and antioxidants might weaken them. NCCIH describes a study of 1,134 women with breast cancer in which antioxidant supplement use during chemotherapy was linked to higher risks of recurrence and death. People chose their own supplements, so the result may be biased. Ask your cancer care team before taking any.
- Anyone taking blood thinners or other prescription medicines. Ask a doctor or pharmacist about interactions.
- Anyone with AMD. Ask your eye care provider whether an AREDS-type formula fits your stage. Our article on who the AREDS2 eye supplements were studied for explains who was in those trials.
- People who are pregnant or nursing, and parents considering supplements for a child. ODS advises caution and a provider's guidance.
- Anyone having surgery. Talk with your surgical team about every supplement you take.
What you can do next
- Build meals around fruits, vegetables and grains, the foods NCCIH names as antioxidant sources. ODS points to the Dietary Guidelines for Americans and MyPlate for what a healthy eating routine looks like.
- Write down every supplement and medicine you take, with the dose and the reason. ODS offers a printable record form for this.
- If a product says it prevents or treats a disease, remember that ODS states dietary supplements are not intended to treat, diagnose, mitigate, prevent or cure diseases.
- Bring your list to a doctor, pharmacist or registered dietitian before you start or stop anything.
The two federal pages below were last updated in 2023, and newer research may exist. Our earlier article on antioxidants and men's health covers this topic from a supplement angle. Its statements about preventing disease are stronger than the evidence summarized here, so weigh it against the sources below.
This article is for general education and is not medical advice. Talk with your doctor or another qualified health care provider before starting, changing or stopping any supplement.
Sources
- National Center for Complementary and Integrative Health, Antioxidant Supplements: What You Need To Know (page last updated July 2023; checked October 6, 2026). Supports the findings on food versus pills, the Task Force recommendations, cataracts, AMD, cognition, safety, and cancer treatment.
- National Institutes of Health Office of Dietary Supplements, Dietary Supplements: What You Need to Know (page updated January 4, 2023; checked October 6, 2026). Supports the statements on food variety, FDA oversight, quality seals, who should seek advice, and what supplements are not intended to do.