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11. Dietary supplements and functional foods

Dietary supplementation

  • Definition: A manufactured product intended to supplement the diet when taken by mouth as a pill, capsule, tablet or liquid
  • Can provide natural or synthetic nutrients
  • $37 billion industry in 2015
  • 50% of Americans take dietary supplements
  • Common types
    • Multivitamins
    • Sport nutrition supplements
    • Calcium
    • B-vitamins
    • Vitamin C
    • Glucosamine
    • Fish oil
    • Collagen
    • Ginseng
    • Glucosamine
    • Probiotic
    • Folic acid
  • Medically indicated uses for dietary supplementation
    • Changing diet to treat nutrient deficiencies is always preferred to dietary supplementation
    • Folic acid in pregnancy
    • Fish oil (omega-3 fatty acids have cardioprotective effect)
    • In diseases with malabsorption (Crohn’s, chronic pancreatitis)
  • Supplementing nutrients in patients who are not nutrient deficient has no effect!
  • A balanced diet eliminates the need for dietary supplement! (which it’s required by law to be written on the nutritional label)
    • Dietary supplements can’t make up for poor eating habits
  • Food safety
    • Most supplements are safe even in case of overdose, but some (like fat-soluble nutrients) are not
    • Vitamin K supplementation can impair the function of blood thinners
    • St. John’s wort speeds up the metabolism of many drugs, decreasing their effectiveness
    • Antioxidants can reduce the effectiveness of chemotherapy
    • Overdosing iron causes severe intestinal bleeding
    • Overdosing vitamin A can cause birth defects

Functional foods

  • Definition: Foods that have a potentially positive effect on health beyond providing nutrition
    • Claimed to have health-promoting or disease-preventing effects
    • Fruits and vegetables are functional foods as they contain molecules that are not nutrients but still beneficial
  • Includes
    • Fortified foods – foods with nutrients added to them
      • Omega-3 added to butter
      • Vitamin D added to milk
      • Iodine added to salt
      • Probiotics added to yoghurt
    • Phytonutrients/phytochemicals = Molecules in fruits and vegetables that are not nutrients or vitamins
      • Lycopene
      • Anthocyanin
      • β-carotene
      • Lutein
    • Wild fish
      • Contains omega-3 fats
    • Grains
      • Contain dietary fibre