Antioxidantia

Antioxidantia, in a broad sense, are substances that inhibit oxidation and neutralize reactive oxygen species, helping to maintain cellular redox balance. They can act directly by scavenging free radicals or indirectly by supporting the body's own antioxidant defenses. The term covers both non-enzymatic compounds and enzymatic systems that protect cells from oxidative damage.

In nutrition and biology, antioxidants include vitamins such as vitamin C and vitamin E, carotenoids like beta-carotene and lycopene, polyphenols such as flavonoids, and minerals such as selenium and zinc. Enzymatic antioxidants include superoxide dismutase, catalase, and glutathione peroxidase, which catalyze reactions to neutralize reactive species and repair oxidized molecules.

Common dietary sources of antioxidants are fruits and vegetables, nuts and seeds, whole grains, tea and coffee, and herbs and spices. A diet rich in plant-based foods generally provides a broad mix of antioxidant types that can work synergistically to support health.

Mechanistically, antioxidants act through direct scavenging of free radicals, chelation of metal ions that catalyze oxidative reactions, regeneration of other antioxidants, and modulation of cellular signaling pathways that regulate stress responses, such as Nrf2.

Health implications are complex. Observational studies associate higher dietary antioxidant intake with reduced risk of some chronic diseases, but randomized trials of isolated supplements have produced mixed or null results, and high-dose antioxidant supplements can be harmful. Current guidance favors dietary patterns rich in diverse antioxidants over high-dose supplementation. Research continues into roles for antioxidants in aging, inflammation, and disease prevention.