Learn about the classifications, functions, and requirements for these vital nutrients.
What is a vitamin?
A vitamin is an organic compound, essential in very small amounts for supporting normal physiological function. Vitamins occur naturally in all living things, plants and animals alike. They regulate a variety of bodily functions, are essential for building bodily tissues such as bones, blood, glands, nerves and skin, and assist in metabolising (digesting) proteins, carbohydrates and fats to produce energy. As vitamins cannot generally be biosynthesised quickly enough to meet the needs of the body, most need to be ingested through the food we eat.
How are vitamins classified?
Vitamins are classified into two groups based on their solubility: the fat-soluble vitamins (A, D, E and K) and the water-soluble vitamins (B vitamins, vitamin C and folate, to name a few). Fat-soluble vitamins are usually absorbed passively and must be transported with dietary lipids. They tend to be found in the lipid portion of the cell, such as the membrane and lipid droplets, and are generally excreted from the body in the faeces. Water-soluble vitamins are absorbed by passive and active mechanisms, transported by carriers and are not stored in appreciable amounts in the body. Water soluble vitamins are generally excreted through the urine.
What vitamins does your body need?
Your body needs at least 11 specific vitamins: vitamin A, vitamin D, vitamin E, vitamin K, vitamin C, and the members of the B vitamin family: thiamin (vitamin B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folate and vitamin B12. Other vitamins important for your health include pantothenic acid (B5) and biotin (B7).