Understanding:
• Vitamins are chemically diverse carbon compounds that cannot be synthesised by the body
Vitamins are organic molecules with complex chemical structures that are quite diverse and hence categorised by groups
- Water soluble vitamins need to be constantly consumed as any excess is lost in urine (e.g. vitamins B, C)
- Fat soluble vitamins can be stored within the body (e.g. vitamins A, D, E, K)
The functions of vitamins are as diverse as their structure, although many function as cofactors, antioxidants or hormones
- Many vitamins are essential as they cannot be synthesised by the body and their absence may cause a deficiency disease
Application:
• Production of ascorbic acid by some mammals, but not others that need a dietary supply
Ascorbic acid is a form of vitamin C that is required for a range of metabolic activities in all animals and plants
- In mammals it functions as a potent antioxidant and also plays an important role in immune function
- It is also involved in the synthesis of collagen (a structural protein) and in the synthesis of lipoproteins
Ascorbic acid is made internally by most mammals from monosaccharides – but it is not produced by humans
- Consequently, human must ingest vitamin C as part of their dietary requirements in order to avoid adverse health effects
A deficiency in vitamin C levels will lead to the development of scurvy and a general weakening of normal immune function
- Common food sources of vitamin C include citrus fruits and orange juice
Common Symptoms of Vitamin C Deficiency (Scurvy)
Application:
• Lack of Vitamin D or calcium can affect bone mineralisation and cause rickets or osteomalacia
Vitamin D is involved in the absorption of calcium and phosphorus by the body – which contribute to bone mineralisation
- In the absence of sufficient amounts of this vitamin, these elements are not absorbed but instead excreted in the faeces
- This can lead to the onset of diseases such as osteomalacia (where bones soften) or rickets (where bones are deformed)
Vitamin D can be naturally synthesised by the body when a chemical precursor is exposed to UV light (i.e. sunlight)
- The vitamin D may be stored by the liver for when levels are low (e.g. during winter when sun exposure is reduced)
- Individuals with darker skin pigmentation produce vitamin D more slowly and hence require greater sun exposure
Vitamin D deficiencies are usually restricted to individuals with highly limited sun exposure (e.g. elderly, certain ethnicities)
- While excess sun exposure is beneficial for vitamin D production, it also increases the risks of developing skin cancers
Common Symptoms of Vitamin D Deficiency (Rickets)
