A vitamin is the name given to nutrients (chemical compounds) vital to health and well-being that cannot be produced (synthesised) by the body.

Such nutrients therefore have to be ingested in the form of food or supplements. Unlike dietary minerals, which are elements on the periodic table, vitamins are molecules made from the elements.

Vitamin C (ascorbic acid), for example, is made of carbon, oxygen and hydrogen. It is found naturally in nature and can be produced by many animals – but not humans, fruit bats or guinea pigs. What may be a vitamin to a human may not be a vitamin to other animals; dogs need ascorbic acid but have a gene that can make it – this is why you rarely see dogs eating oranges!

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The human body needs thirteen different vitamins. Each one is described briefly below, along with a list of foods containing the vitamin.

A Distinction: Water- and Fat-Soluble Vitamins

Vitamins are often divided into two groups: water- and fat-soluble vitamins. Vitamins B and C are the main water-soluble vitamins. Vitamins A, D, E, and K are fat-soluble.

The water-soluble vitamins are not stored in the body, and you therefore need a regular supply. However, the fat-soluble vitamins can be, and are stored in the body, in fat cells.

This means that your body always—or usually—has access to a store of these vitamins, and you do not need to eat them every day or even that often. It is also possible to consume too much of these vitamins, and this can have an adverse effect on health. It is therefore not recommended to take a very high dose supplement of any of the fat-soluble vitamins unless advised to do so by a doctor. Taking a high dose supplement of the water-soluble vitamins is less likely to be harmful—but it is also unlikely to be very useful. Indeed, the evidence suggests that all you are doing is making your body work harder to excrete it.

You can find out more about the science behind supplements (or rather, its absence) in our page on Supplements.

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Vitamin A (Retinol)

Vitamin A is often associated with vision. It helps us to see in dimly-lit conditions and is important for colour vision. Vitamin A also helps strengthen the immune system and is useful for healthy skin.

In high levels, Vitamin A can damage unborn babies; pregnant women are therefore advised to avoid foods known to be high in Vitamin A.

We get Vitamin A from:

• Liver (including pâté made from liver)
• Milk and dairy products
• Oily fish (salmon, trout, mackerel etc.)
• Vegetables, especially carrots, sweet potatoes, butternut squash, kale and lettuce
• Herbs and dried herbs
• Some red spices including paprika and cayenne pepper

Vitamin B1 (Thiamine)

Thiamine is not stored by the body so needs to be replenished every day. Vitamin B1 is common in many foods and most people consume enough. The vitamin works with other vitamins in the B group to help in the production of glucose and other essential substances by breaking down food. Thiamine also keeps muscles and nerves healthy.

We get Vitamin B1 from:

• Nuts (especially pecans, pine nuts and pistachios)
• Pork
• Many fruits and vegetables
• Milk and other dairy products
• Whole grain foods
• Fortified breakfast cereals

Vitamin B2 (Riboflavin)

Vitamin B2 or riboflavin helps to keep the skin and eyes healthy and is also important for the production of steroids and red blood cells in the body. Riboflavin also helps to keep the nervous system in good working order. It perishes if exposed to direct sunlight.

We get Vitamin B2 from:

• Liver (including pâté made from liver)
• Fortified breakfast cereals
• Cheese
• Wheat bran
• Oily fish (salmon, trout, mackerel etc.)
• Mushrooms

Vitamin B3 (Niacin)

Niacin helps in breaking down food and producing energy. Vitamin B3 is also vital to healthy digestive and nervous systems.

We get Vitamin B3 from:

• Liver (including pâté made from liver)
• Bacon
• Sundried tomatoes
• Fortified breakfast cereals
• Wheat and rice bran
• Oily fish (salmon, trout, mackerel etc.)
• Milk and eggs

Vitamin B5 (Pantothenic Acid)

Pantothenic Acid or Vitamin B5 is used to process protein, carbohydrates and fat in our diets. Vitamin B5 is found in most foods in low levels.

We get Vitamin B5 from:

• Most meats including chicken and beef and liver
• Vegetables including potatoes, tomatoes, broccoli, and mushrooms
• Whole grains
• Avocados
• Eggs
• Fish

Vitamin B6 (Pyridoxine)

Vitamin B6 is used to break down and extract energy from the food we eat. It is important for the proper functioning of the nervous and immune systems. Pyridoxine is also involved in the body’s creation of hormones and red blood cells.

We get Vitamin B6 from:

• Bran and whole grains
• Nuts, especially pistachios and hazelnuts
• Liver (including pâté made from liver)
• Dried herbs and spices
• Raw garlic
• Seeds especially sunflower seeds

Vitamin B7 (Biotin)

Extra biotin is required in the human diet, but only in certain circumstances. Intestinal bacteria usually produce more Vitamin B7 than the body needs on a daily basis. Vitamin B7 helps the body break down proteins, carbohydrates and fats, and aids in the production of glucose. Biotin also helps move carbon dioxide around the body. It may help to keep skin, hair and nails healthy and is found in many cosmetic products.

We get Vitamin B7 from:

• The bacteria in our intestines
• Egg yolks
• Oats
• Nuts
• Fish

Vitamin B9 (Folic acid)

Folic acid is crucial to many functions of the body. It is needed to produce and repair DNA. It is vital in supporting rapid cell division and growth, such as in infancy and pregnancy (and for this reason, a folic acid supplement is recommended during and before pregnancy). Folic acid plays an important part in the fertility of both men and women. It is also used to produce healthy red blood cells, preventing anaemia.

We get Vitamin B9 from:

• Spinach, broccoli and Brussels sprouts
• Liver (including pâté made from liver)
• Bean-sprouts
• Brown rice
• Fortified breakfast cereals
• Asparagus

Vitamin B12 (Cobalamin)

Vitamin B12, also known as cobalamin, performs key functions in the body, including production and regulation of DNA, fatty acid creation and the production of energy. It also performs key roles in the normal operation of the brain and nervous systems. Vitamin B12 has a complex molecular structure and cannot be synthesized by plants or animals.

We get Vitamin B12 from:

• Seafood including fish, shellfish, crabs and lobster
• Liver (including pâté made from liver)
• Meat
• Cheese
• Eggs
• Fortified breakfast cereals

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Vitamin C (Ascorbic acid)

Vitamin C is a vitamin for humans, but not for most other animals. Animals still need Vitamin C but have genes capable of producing it. Vitamin C plays an important role in the body, including maintaining the health of connective tissue, which supports the body’s organs and other tissue. It is essential in the production of certain hormones and a powerful antioxidant. However, contrary to popular myth, taking it does not stop you catching colds.

We get Vitamin C from:

• Citrus fruit, such as oranges, lemons, limes, and grapefruit
• Other fruits, especially, blackcurrants, kiwi fruit and strawberries
• Vegetables, including peppers, chilli peppers, broccoli, spinach and cauliflower

Vitamin D (Calciferol)

Vitamin D is unusual and required in the human diet only in certain circumstances, because we can make most of our Vitamin D from the action of sunlight on the skin. In certain climates or at certain times of year, we may not get much exposure to sunlight and therefore may need to include some dietary Vitamin D. Vitamin D is important in the body for regulating the amount of calcium and phosphate, which both contribute to healthy bones and teeth.

In the UK, the Royal College of Paediatrics and Child Health (RCPCH) estimates that up to 25% of UK children are Vitamin D-deficient. These figures may be due in part to changing lifestyles. Young people spending longer indoors and not being exposed to natural sunlight may help to explain the problem. The USA, Canada and Finland have introduced schemes where more Vitamin D is available in diets by fortification of food and drink. Children lacking adequate Vitamin D can suffer from rickets. Rickets is a condition that affects bone development, making bones soft and malformed, which can lead to deformities.

We get Vitamin D from:

• Sunlight (10–20 minutes a week for people with light skin; 30+ minutes a week for dark skin)
• Oily fish such as salmon, trout, and mackerel
• Eggs
• Fortified breakfast cereals

Vitamin E (Tocopherol)

There are many different forms of Vitamin E and it is common in a wide variety of foods. Vitamin E can help protect the body against inflammation by acting as an antioxidant.

We get Vitamin E from:

• Vegetable based oils: sunflower oil, olive oil and peanut oil
• Seeds and nuts
• Fruit and vegetables

Vitamin K1 (Phylloquinone)

Vitamin K is required for the modification of proteins in food and also for blood clotting and probably for development of strong, healthy bones. It may play a role in helping to prevent heart disease and cancer, although there is very little hard evidence on that, and most studies seem to conclude that further research is needed.

We get Vitamin K from:

• Most fresh vegetables especially broccoli, spinach and kale
• Cereals
• Vegetable-based oils: sunflower oil, olive oil and peanut oil

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