Fat soluble vitamins are obtained through fat containing foods such as meats, oils, nuts, seeds and avocados. Fat soluble vitamins are absorbed in the small intestine and can be stored in the liver or adipose tissue for long periods of time. This is beneficial as daily amounts are not required with dietary averages being sufficient. The down side is that too much of these vitamins can lead to toxicities and that if deficiencies occur, they can take a long time to manifest.

  • Fat soluble vitamins are as the name implies soluble in fat
  • Relatively stable in heat (cooking)
  • Are organic (contain carbon)
  • Do not contain nitrogen
  • Absorbed in the small intestine
  • Can be stored for long periods of time hence deficiencies are less common

Vitamin A: Retinal and the precursor, Beta carotene

  • Healthy vision Vitamin A (Retinal) got its name from its role in distinguishing light at the retina of the eye. It also allows humans to see in colour and if dim/night light.
  • Regulates gene expression- genes direct the synthesis of specialize cells including enzymes, proteins (including immune cells) and in breakdown of old bone, sperm production and fertility in women
  • Cell differentiation- body’s ability to develop a certain type of cell for a specific function.
  • Beta carotene (a carotenoid) is found in orange, yellow and red fruits and vegetables. The body can produce vitamin A from beta carotene so it is known as a provitamin or precursor. Carotenoids such as beta carotene appear to have many protective roles in the body including protecting against sun damage, enhances the immune system and prevent age related vision changes.
  • Vitamin A is primarily stored in the liver

Vitamin D:  Vitamin D can be classified as a hormone ( a substance that is secreted by one cell that has an impact on another cell)

Skin cells are able to synthesize most of the Vitamin D needed in the presence of sunlight (UV light) . Vitamin D is also added to milk and some other dairy products.

  • Involved in calcium and regulation and phosphorous levels to maintain bone integrity (bone health)
  • When calcium is needed by the body for proper functioning of nerve, muscle and the glands, vitamin D can act to 3 locations to release the needed calcium; skeleton, digestive tract (absorption) and the kidney ( re-absorption)
  • Vitamin D stimulates maturation of cells including cells of the immune system
  • Current BC physician guidelines recommend that breast fed infants receive 10 micrograms (400 IU) of Vitamin D /day by droplet. In addition, adults over the age of 40 are recommended to take 1000 IU/day (due to decreased sunlight in BC) to maintain bone health

Vitamin E

Vitamin E is an important antioxidant that defends the body against oxidative damage. This damage occurs when free radicals formed through normal essential metabolism or from external sources such as xrays, ozone, smoking, air pollutants exceed the body’s ability to scavenge and remove them.  Vitamin E removes the free radicals protecting vulnerable cells and membrane particularly in the lungs. Vitamin E is readily available in foods such as wheat germ, oils, nuts, seeds and fruits and vegetables.

Vitamin K

Vitamin K is involved in the conversion  of clotting factors II, VII, IX and X to the active form needed for blood clotting. Vitamin K also assist in the maintenance of adequate bone density. Vitamin K can be produced by bacteria in the gut (intestinal microflora) and is found in broccoli, cabbage, spinach, tomatoes and blueberries.