Antioxidanty

Antioxidanty, or antioxidants, are molecules that slow or prevent oxidation, a chemical process that can generate free radicals and damage cells. By donating electrons or hydrogen atoms, they neutralize reactive species and help protect lipids, proteins, and DNA from oxidative injury.

The body produces some antioxidants endogenously through enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. Non-enzymatic antioxidants include vitamins C and E, carotenoids (such as beta-carotene, lycopene, and lutein), and polyphenols found in fruits, vegetables, tea, coffee, and grains. A varied diet provides the widest range of antioxidant compounds and supporting nutrients.

Oxidative stress arises when free radicals exceed the body's antioxidant defenses and is linked to aging and several chronic diseases. Despite this association, evidence that increasing antioxidant intake directly prevents disease is mixed; results from observational studies and randomized trials are not consistently favorable, and benefits may depend on context, dose, and bioavailability.

Dietary patterns rich in fruits, vegetables, and whole grains are associated with health benefits, while high-dose antioxidant supplements have not shown clear advantages and may carry risks for some individuals, such as smokers or people taking certain medications. The quality of evidence varies by antioxidant type and outcome.

Antioxidant capacity is measured in laboratory tests, but such assays do not directly translate to health effects. ORAC values are commonly used in marketing, yet they do not reliably predict benefits in humans once bioavailability and interactions are considered.