7

• Vitamins


  Tasteless organic compounds required in small amounts, vitamin deficiencies may result in serious conditions
• Vitamin classification based on solubility

  • Nine (9) Water-Soluble: B group vitamins, Vitamin C
  • Four (4) Fat-Soluble: Vitamin A, Vitamin D, Vitamin E, Vitamin K

  
• Vitamin functions


  1. Digestion

  2. Absorption

  3. Transportation

  4. Storage

  5. Excretion
• Fat-soluble vitamins


  Generally less bioavailable than water-soluble vitamins
• Vitamins from plant foods


  Generally less bioavailable than those in animal foods
• Solubility


  Affects a vitamin's stability and susceptibility to destruction
• Some preparation and storage accelerate vitamin loss, but fat-soluble vitamins are more stable
• Retinoids


  Animal-based vitamin A
• Carotenoids


  Plant-based vitamin A, act as antioxidants
• Vitamin D


  • Fat-soluble, requires bile for absorption, plays an important role in calcium and phosphorus metabolism, bone and teeth health, immune system, and mood regulation

  
• Vitamin D deficiency can lead to rickets in children, osteomalacia in adults, and osteoporosis
• Vitamin E


  • Alpha-tocopherol is the most active form, sensitive to UV light, acts as an antioxidant to prevent oxidation of LDL cholesterol, protects cell membranes

  
• Vitamin E toxicity is very rare, but deficiency can result in anaemia, weakness, neurological problems, muscle cramps, and reduced immunity
• Vitamin K


  Fat-soluble, responsible for the production of prothrombin, a blood clotting factor

  
• Vitamin K deficiency and toxicity are both rare, but overuse of antibiotics and excessive bleeding can affect intestinal bacteria synthesis of vitamin K
• Food sources of vitamin K

  • Leafy green vegetables, cruciferous vegetables, liver, milk
• Water-soluble vitamins


  • Vitamin C, Vitamin B group (Thiamine, Riboflavin, Niacin, Pyridoxine, Folic Acid, Cobalamin, Pantothenic Acid, Biotin)

  
• Water-soluble vitamins


  • Subject to cooking losses, important roles as coenzymes, in energy metabolism, as antioxidants, and for supporting the nervous system
• Vitamin B12 is only found in animal foods, so vegans and breastfed infants of vegan mothers need alternative sources, usually supplements
• Primary functions of B complex vitamins

  • Energy metabolism, red blood cell synthesis, homocysteine metabolism
• Neural tube defects


  Occur when the neural tube fails to close properly in the first 28 days of pregnancy, leading to brain and spinal cord malformations
• Importance of folate before and during pregnancy to prevent neural tube defects
• Food sources of B vitamins

  • Meat, poultry, fish, eggs, dairy, legumes, whole grains, leafy greens

  
• Vitamin C


  Antioxidant, increases iron absorption, supports collagen synthesis, immunity, wound healing, growth and repair of tissues, higher needs for smokers

  
• Vitamin C deficiency can lead to scurvy, a disease characterized by fatigue, bleeding gums and joints, and other symptoms
• Food sources of vitamin C

  • Citrus fruits, kiwi, green peppers, cauliflower, broccoli, strawberries, leafy greens
• Industrial uses of vitamins

  • Vitamin A as a food dye, vitamin C as an antioxidant preservative, riboflavin as a yellow food dye, vitamin E as an antioxidant preservative

  
• Vitamins


  • Exposure to Oxygen

  • Exposure to ultraviolet (UV) light

  • Exposure to heat and pH changes

  • Subject to cooking losses

  • Cooking utensils and cutlery (Copper, iron...)
• * Some preparation and storage accelerate vitamin loss. Fat-soluble vitamins are more stable
• Vegetables and fruits begin to lose their vitamins almost immediately after being harvested
• Fat Soluble Vits ADEK

  lymph then protein carrier ( absorbtion)

  Long term ( Storage)

  Less readily extreced - remain fat storage sites (extrection)
• Water Soluble vits. B C

  Directly into blood (absorption)

  Shprt term ( storage)

  Kidneys detect and remove in urine ( extrection)
• Vitamin toxicity

  Very rare

  –Ingesting excess vitamins = tissue saturation

  –Can damage cells

  –From supplements (megadoses); cannot occur from eating whole foods
• Vitamin A


  Animal Foods = RETINOIDS

  Plant-based Foods = CAROTENOIDS
• Properties of Vitamin A

  • Fat-soluble • Needs bile to be absorbed

  • Usually resistant to heat

  • Carotenoids are anti-oxidant: • Against oxidation – prevent oxidation

  Have various functions in the body: • Prevents cell damage and death • Supports immunity • Vision • Embryonic development (Deficiency disrupts these functions)
• Vitamin D The “Sunshine Vitamin"

  Need two things to be activated: 1) UV light 2) The pro-hormone in skin
• Vitamin D


  Considered a prohormone-Found in two forms:

  1. Cholecalciferol(vitamin D3) = in our skin and in animal foods
  2. Ergocalciferol(vitamin D2) = in plants & dietary supplements
• Activation of Vitamin D *

  When skin comes in contact with the UV light within 15-30 mins, cholecalciferol becomes activated
• Activation of Vitamin D*

  Activation is easier when: • Exposed to perpendicular sun rays, • Having a light skin • Those at a younger age

  In bedridden individuals or in ladies with hijab = cholecalciferol formation drops
• Vitamin K


  • Overuse of antibiotics and excessive bleeding will kill off intestinal bacteria synthesising Vitamin K