B.5 – Vitamins

What are Vitamins?

Vitamins are micro-nutrients that we generally get through our diet that often act as enzymes and co-factors in metabolic reactions.

Properties of vitamins:

  • Heat sensitive
  • Different vitamins are soluble in fat or water

Vitamin A

  • Contains a conjugated double and single bond system
    • Absorbs light giving vitamin A an orange colour
  • Fat soluble
    • Largely non polar
    • Contains few H bonds
    • Therefore not excreted in urine
  • Found in carrotsmangoes and sweet potatoes
  • Stored in the liver and fatty tissues
  • Used mainly in vision and sight

Deficiency

  • Called Nycatalopia or night blindness
    • Reduces sight (basically you can’t see)

Vitamin C

  • Water soluble
    • Contains many polar groups and hydrogen bonds
    • Excess Vit. C is excreted in the urine.
  • Found in citrus fruits e.g. orangeslemonslimes etc.
  • Used as an antioxidant
    • Quenches reactions involving free radicals
      • Acts as a reducing agent by giving electrons to free radicals
  •  Used to maintain general health and prevent scurvy

Deficiency

Vitamin C deficiency, called scurvy, causes gum diseaseweakness and fatigue. It occurred frequently in sailors back in the day on long distance travels as they were unable to store fresh citrus fruits.

Vitamin D

  • Fat soluble
    • Mainly non-polar
  • Synthesised in the skin from cholesterol in a reaction catalysed by light
  • Used to help absorb microminerals such as calciumzinc and magnesium

Deficiency

Vitamin D deficiency or rickets causes soft and weak bones as well as stunted growth.

Tackling Vitamin Deficiency

Vitamin deficiency often occurs due to malnutrition in developing nations. Preventative measure include:

  • Providing diverse vegetables and foods
  • Eating plenty of fruit and vegetables (eat your peas?!?!)
  • Maintaining a balanced diet