Did You Know... I’m back! And with a twist to my usual posts! I’m going to do a series of Did You Know… I’m starting with vitamins and today let’s start at the very beginning! VITAMIN A

Did You Know… Biochemist Casimir Funk coined the term vitamins in 1911. He is credited with being the first to have formulated the concept of vitamins which he called vital amines or vitamines. Vita is Latin for life.

There are 13 vitamins – vitamins A, C, D, E, K and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, B6, B12, and folate).

They are either water or fat soluble:

Fat-soluble vitamins are soluble in fats. They are absorbed with fat in the small intestine into the lymphatic capillaries and then into the blood. They are readily stored.  

Water-soluble vitamins are soluble in water. They are absorbed with fat in the small intestine directly into the blood. They are easily excreted (except for B12) if in excess.

Their key functions include:

  • Supporting the immune system
  • Regulating gene expression-Supporting neurological activity
  • Facilitating ATP production
  • Manufacturing of blood cells
  • Regulation of hormones

The body cannot produce vitamins (except vitamin D) so it is essential to get them from whole foods.

Vitamin A:

This was the first vitamin to be discovered hence ‘A’.

The active forms which complete the functions of vitamin A are:

Retinol, Retinal and Retinoic Acid.

Depending on what the body requires, retinol will be oxidised to the different forms (retinol → retinal → retinoic acid). If the body doesn’t need it, it will remain as retinol and be stored in the liver.

There are two forms of vitamin A: Pro-vitamin A & Pre-formed vitamin A.

Pro-vitamin A: converted into the active (usable) form of vitamin A (retinol) in the small epithelium and liver. Carotenes are examples of pro-vitamin A and the most active ones are α- (alpha); β- (beta) and γ- (gamma). Found in plant foods only (non-animal foods).

Pro-vitamin A is produced by plants, algae, fungi and bacteria.

Rich food sources: Dark green, yellow / orange vegetables and fruit, e.g. carrots, squash, mango, spinach, sweet potatoes.

As carotenoids are fat-soluble it is essential to optimise their absorption so ensure you are consuming adequate healthy fats in the diet. Drizzle food with coconut oil or olive oil.

Pre-formed vitamin A: this is active vitamin A that the body can use as is. Found in animal foods only.

Pre-formed vitamin A is only found in animal foods e.g. liver, fish liver oils, egg yolk, mackerel, salmon.

Pro-vitamin = a substance that can be converted into a vitamin.

Pre-formed vitamin = a vitamin that is already formed so don’t overindulge in animal food sources!

Vitamin A functions:

  • Vision & eye health
  • Immunity
  • Gene expression#
  • Reproduction
  • Antioxidant properties

Zinc and protein are required to transport vitamin A from liver storage to tissues for utilisation. Without zinc vitamin A is trapped! Don’t forget to optimise gut health for optimal vitamin A absorption!