New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Antioxidant

An antioxidant is a chemical that reduces the rate of particular oxidation reactions in a specific context, where oxidation reactions are chemical reactions that involve the transfer of electrons from a substance to an oxidizing agent, this generally results in different chemicals to the original ones.

Antioxidants are particularly important in the context of organic chemistry and biology. All living organisms maintain a reducing environment inside their cells, all cells contain complex systems of antioxidants to prevent chemical damage to the cells' components by oxidation. These antioxidants include glutathione and ascorbic acid and are substrates for enzymes such as peroxidases and oxidoreductases.

Antioxidants are widely used as ingredients in dietary supplements used for health purposes such as preventing cancer and heart disease. Studies have suggested antioxidant supplements has benefits for health, but several large clinical trials did not demonstrate a definite benefit for the formulations tested, and excess supplementation may even be harmful.

Dietary supplementation has few specific antioxidants compared to a broad diet rich in phytonutrients, which will yield thousands of different polyphenol antioxidants available for metabolism.

Related Stories
 


Health & Medicine News

July 9, 2026

Researchers found that mRNA cancer vaccines can recruit an unexpected immune cell to launch powerful tumor-fighting responses, overturning a long-held assumption about how the vaccines work. The discovery could lead to more effective cancer vaccines ...
A surprising discovery is reshaping scientists' understanding of how humans develop sharp central vision before birth. Instead of blue cone cells migrating away from the retina's center, the study found they transform into red and green cones under ...
Poison control calls involving semaglutide (Ozempic and Wegovy) soared after the drug was approved for weight management, with researchers linking the increase to accidental dosing mistakes rather than intentional misuse. Simple education about ...
Scientists have created a silicon chip that can write dozens of DNA sequences simultaneously using electricity and water-based enzymes, offering a cleaner alternative to conventional DNA manufacturing. The breakthrough could eventually support ...
Tiny silica nanoparticles engineered to seek out prostate cancer caused tumor cells to self-destruct and supercharged the immune system in preclinical mouse studies. Combined with immunotherapy, the treatment produced complete remissions in multiple ...
Researchers have cracked the code behind bacteria's ability to naturally manufacture multiple versions of powerful anti-cancer drugs. The discovery could make it much easier to engineer new cancer treatments inspired by nature, including improved ...
Scientists have discovered that creatine may strengthen one of the immune system's most important cancer-fighting pathways by energizing dendritic cells that activate killer T cells. The promising results could eventually help make immunotherapy ...
Intermittent fasting helped people lose as much weight as calorie restriction, but without the same feeling of constantly controlling their food intake. Researchers say that difference could make ...
A new once-daily weight-loss pill called orforglipron delivered better weight loss and blood sugar improvements for people with type 2 diabetes than the leading oral semaglutide in a major clinical trial. The tablet could offer a more convenient ...
Scientists at the University of Illinois Chicago have turned an unlikely source into a potential new weapon against cancer: bacteria that naturally live inside tumors. They developed a peptide called aurB, inspired by a bacterial protein, that ...
Almost half of the takeaway meals tested contained more salt than advertised, with some dishes delivering nearly twice the recommended daily limit in a single serving. Surprisingly, classic fish and chips ranked among the lowest-salt options, while ...
Scientists have identified a molecular switch that may help explain how colorectal cancer becomes deadly. When levels of a gene-regulating factor called GATA6 drop, cancer cells can shed their normal identity and transform into highly adaptable, ...

Latest Headlines

updated 12:56 pm ET