Vitamins are organic substances - this means they're found in plants and animals.

Most vitamins can't be made by your body, so they must be sourced from your diet. Vitamin D and the B vitamin niacin are exceptions to this.

Nutritionists have divided vitamins into two groups: fat-soluble and water-soluble.

The fat-soluble vitamins - A, D, E and K - are transported through your body by fat. They can also be stored in your fat and liver cells for a limited period of time.

The water-soluble vitamins - B and C - are absorbed by and transported through your body in water. They need to be eaten every day, as you can't store them for any length of time.

Vitamin A

It looks after your eyes, the lining of your nose, throat and lungs, and your skin cells.

Carrots, sweet potatoes, pumpkins, red chillies, tomatoes, 'orange' fruits, such as apricots and mango, and dark green leafy vegetables.

600µg for females, 700µg for males.

Vitamin D

It helps your body to absorb calcium, needed to ensure strong bones and teeth.

The most important source is the sun, but it's also found in tiny amounts in dairy products, cod liver oil and oily fish.

No recommendations as sunlight is the main source.

Vitamin E

It fights free radicals - unbalanced molecules that can cause damage to your cells. It also contributes to the healthy condition of your skin.

Vegetables, poultry, fish, fortified breakfast cereals, vegetable oils, nuts and seeds.

Up to 4mg for adult males and up to 3mg for adult females is considered a safe intake.

Vitamin K

It helps your body to make a number of proteins, one of which helps your blood to clot.

Dark green leafy vegetables such as Brussels sprouts, broccoli, cabbage, spinach and asparagus. It's also found in soya oil and margarine.

1µg for every kg of body weight is considered a safe intake for both men and women.

B-complex Vitamins

They help you to metabolise your food and help your blood cells to form and flow.

Green vegetables, whole grains, meat, such as liver, kidneys, pork, beef and lamb, vegetable extracts, nuts and fortified breakfast cereals.

Eight vitamins make up the B-complex family:
B1 (Thiamin) - Adult male, 0.9mg. Adult female, 0.8mg.
B2 (Riboflavin) - Adult male, 1.3mg. Adult female, 1.1mg.
B3 (Niacin) - Adult male, 17mg. Adult female, 13mg.
B5 (Pantothenic Acid) - 3 to 7mg is considered a safe intake for both sexes.
B6 (Pyridoxine) - Adult male, 1.4mg. Adult female, 1.2mg.
B9 (Folate) - 200 mcg for both adult males and females.
B12 (Cobalamin) - 1.5 µg for both adult males and females.
Biotin - 10-20 µg is considered a safe intake for both sexes.

Vitamin C

It helps your body to produce collagen (important for skin and bone structure) and to absorb iron.

A wide variety of vegetables and fruit, including spinach, broccoli, tomatoes, strawberries, citrus fruit and potatoes.

40mg for both adult male and female.