Antioxidants

Antioxidants are molecules that neutralize reactive oxygen species (ROS) and free radicals before they can damage DNA, proteins, lipids, and mitochondrial membranes. Some are synthesized by the body, others must come from food and supplements, and many work in linked networks — one antioxidant regenerating another in a continuous redox cycle. Oxidative stress underlies aging, cardiovascular disease, neurodegeneration, diabetes, cancer initiation, and most chronic illness, which is why antioxidant biochemistry sits at the center of integrative and functional medicine.

Table of Contents

  1. Endogenous & Mitochondrial Antioxidants
  2. Vitamin Antioxidants
  3. Mineral Cofactors
  4. Plant Polyphenols & Flavonoids
  5. Herbal Antioxidants
  6. Amino Acid Antioxidants
  7. Mushrooms, Algae & Marine Sources
  8. Antioxidant-Rich Foods
  9. How Antioxidants Work
  10. Connections
  11. Featured Videos

Endogenous & Mitochondrial Antioxidants

These are the molecules the body either synthesizes itself or relies on to keep the mitochondrial electron transport chain leak-free. They form the inner ring of the antioxidant network — the molecules that protect ATP production at its source.

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Vitamin Antioxidants

Several vitamins double as antioxidants. They occupy different physical compartments — water-soluble vitamins work in plasma and cytosol; fat-soluble vitamins protect cell membranes and lipoproteins.

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Mineral Cofactors

The body's three major antioxidant enzymes — glutathione peroxidase, superoxide dismutase, and catalase — cannot function without specific mineral cofactors. Deficiency in any of these collapses the enzymatic antioxidant defense even when dietary antioxidants are plentiful.

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Plant Polyphenols & Flavonoids

Polyphenols are the most diverse antioxidant class — over 8,000 identified compounds. They work by direct radical scavenging, by chelating pro-oxidant metals (iron, copper), and increasingly through epigenetic and signaling pathways (Nrf2 activation, NF-κB inhibition).

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Carotenoids

Fat-soluble pigments that quench singlet oxygen with unmatched efficiency and concentrate in the tissues most exposed to light and oxygen — the eye, skin, and vasculature.

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Herbal Antioxidants

Many traditional medicinal herbs owe their effects to a combined polyphenol-triterpenoid-saponin profile that delivers antioxidant action plus modulation of stress, immune, and detoxification pathways.

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Amino Acid Antioxidants

Sulfur-containing amino acids and the precursors to glutathione synthesis form the foundation of intracellular redox defense.

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Mushrooms, Algae & Marine Sources

Fungi and aquatic organisms produce unique antioxidant chemistries — ergothioneine, fucoxanthin, astaxanthin, and beta-glucans — that terrestrial plants do not.

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Antioxidant-Rich Foods

Whole foods deliver antioxidants in their natural matrix — fiber, cofactors, and accompanying phytochemicals that supplements cannot fully replicate.

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How Antioxidants Work

Reactive oxygen species (ROS) are a normal byproduct of mitochondrial respiration — roughly 0.1–2% of all oxygen consumed leaks from the electron transport chain as superoxide (O&sub2;−). Additional ROS arise from immune-cell respiratory burst, peroxisomal beta-oxidation, ionizing radiation, environmental toxins, and inflammation. At physiological levels ROS serve as signaling molecules; in excess they damage lipids (lipid peroxidation), proteins (carbonyl formation), DNA (8-OHdG adducts), and mitochondrial membranes.

The body's defense operates in three coordinated layers:

  1. Enzymatic defense — superoxide dismutase converts O&sub2;− to H&sub2;O&sub2;; catalase and glutathione peroxidase convert H&sub2;O&sub2; to water. These enzymes require selenium, zinc, copper, manganese, and iron as cofactors.
  2. Small-molecule antioxidants — vitamin C, vitamin E, glutathione, alpha lipoic acid, CoQ10, uric acid, bilirubin, and carotenoids donate electrons to neutralize free radicals directly. They operate in a redox-cycling network — each regenerates the others.
  3. Signaling and induction — the Nrf2/Keap1 pathway senses oxidative stress and upregulates more than 200 cytoprotective genes (glutathione synthesis, NQO1, HO-1, glutathione-S-transferases). Phytochemicals like sulforaphane, curcumin, and rosmarinic acid are powerful Nrf2 activators.

The redox-cycling network means that no single antioxidant works in isolation. Vitamin E quenches a lipid radical and becomes the tocopheryl radical — vitamin C donates an electron to regenerate vitamin E and becomes the ascorbyl radical — glutathione donates an electron to regenerate vitamin C — NADPH regenerates glutathione via glutathione reductase. Alpha lipoic acid uniquely participates in every step of this cycle and is the only antioxidant that can regenerate all of the others, which is why deficiencies anywhere in the network produce systemic oxidative load.

See the Oxidative Stress hub page for the full clinical picture and mechanistic detail.

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Connections

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