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