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Dietary Antioxidants Notes

Dietary Antioxidants

  • Dietary antioxidants are substances in foods that reduce the negative effects of free radicals on the body's normal functions.
  • The body's defense and repair systems can sometimes struggle to control free radicals, especially with age or chronic disease, leading to oxidative stress.
  • Oxidative stress can lead to various health problems.
  • Antioxidants work by neutralizing free radicals through electron donation.

How Antioxidants Work

  • Antioxidants donate electrons to free radicals, neutralizing them.
  • Antioxidants may sacrifice themselves in the process of neutralizing free radicals.
  • Antioxidants can take electrons from other antioxidants or use phytochemicals to regenerate themselves (e.g., vitamin C).
  • Example: The phytochemical hesperitin, found in oranges and citrus fruits, restores vitamin C to its active antioxidant form.

Oxidative Stress and Chronic Conditions

  • Oxidative stress is considered a causative factor in the development of many chronic conditions.
  • Antioxidants are seen as a protective factor against these conditions.

Sources of Antioxidants

  • Many plant-derived foods contain a range of antioxidant compounds.
    • Vitamin C
    • Vitamin E
    • Polyphenols
    • Carotenoids
    • Ubiquinols

Types of Antioxidants

  • Vitamin C
  • Vitamin E and mixed tocopherols
  • Beta carotene and other carotenoids
  • Vitamin A (in animal foods)
  • Selenium
  • Zinc
  • Manganese
  • Glutathione
  • Triplet (a triple amino acid mixture of glutamic acid, glycine, and cysteine)
  • Lipoic acid
  • Methionine and cysteine (sulfur amino acids)
  • Glutamine
  • Many phytochemicals, e.g.:
    • Anthocyanins
    • Quercetin
    • Chlorogenic acid
    • Resveratrol