What are B vitamins?
A dietitian explains what the different B vitamins are, which functions they are responsible for within the body, and good food sources for each B vitamin.
'Vitamin B' is actually eight different vitamins, and each plays a different role in many functions in the body.
Always speak to your GP or healthcare provider before taking a new supplement or if you are concerned about nutritional deficiencies.
What are B vitamins – what are the different types?
Vitamin B is not a single vitamin it's an umbrella term that includes eight vitamins: thiamin, riboflavin, niacin, pantothenic acid, B6, biotin, folate and B12. They have very important roles in the body and are involved in many metabolic processes. They are all water soluble, which means they cannot be stored in the body.
Why do we need B vitamins?
The different B vitamins have different functions within the body:
- Thiamine (B1) plays a role in carbohydrate metabolism, muscle contraction and conduction of nerve signals
- Riboflavin (B2) plays a role in carbohydrate, fat and protein metabolism and is involved in the production of B3 and B6
- Niacin (B3) plays a role in carbohydrate, fat and protein metabolism, DNA production, and is involved in the function of the digestive system, skin and nerves
- Pantothenic acid (B5) plays a role in carbohydrate, lipid and amino acid metabolism, production of hormones, cholesterol and bile acids
- Pyridoxine (B6) plays a role in the production and use of protein and glycogen as well as haemoglobin formation in the blood
- Biotin (B7) plays a role in carbohydrate and fat utilisation
- Folate (B9) plays a role in DNA synthesis, cell division and red blood cell formation
- Cobalamin (B12) plays a role in DNA reproduction, cell formation and nerve function
How much of the different B vitamins do we need?
AgeB1B2B3B6B9B12Male 19-501mg1.3mg17mg1.4mg200mcg1.5mcg50+0.9mg1.3mg16mg1.4mg200mcg1.5mcgFemale 19-500.8mg1.1mg13mg1.2mg200mcg1.5mcg50+0.8mg1.1mg12mg1.2mg200mcg1.5mcgPregnant0.9mg1.4mg13mg1.2mg400mcg*2mcgBreastfeeding1mg1.6mg15mg1.2mg260mcg2mcg
*300mcg in second and third trimester
There are no set recommendations for B5 and B7.
What are the effects of consuming too much?
As B vitamins are water soluble, they are unable to be stored in the body and are instead excreted in the urine. Therefore, if the recommended daily dose is exceeded, the body will naturally get rid of the excess.
However, this is slightly different where niacin is concerned. Taking high doses of nicotinic acid supplements has been reported to cause liver damage.
Which foods are good sources of the different B vitamins?
- Thiamine (B1) can be found in wholegrain bread, fruit, liver, peas and some fortified breakfast cereals
- Riboflavin (B2) can be found in some fortified breakfast cereals, eggs, milk and rice
- Niacin (B3) can be found in meat, fish, wheat flour, milk and eggs
- Pantothenic acid (B5) can be found in meat, tomatoes, porridge and potatoes
- Pyridoxine (B6) can be found in meat, fish, organ meats, some fortified breakfast cereals, peanuts, lentils, eggs, potatoes, banana and avocado
- Biotin (B7) can be found in a wide range of foods but in very small amounts
- Folate (B9) can be found in green leafy vegetables, liver, some fortified breakfast cereals and chickpeas
- Cobalamin (B12) can be found in meat, eggs, cheese, milk, fish, shellfish and some fortified breakfast cereals
B-vitamin rich recipes
More on vitamins and minerals
This article was published on 6 August 2019.
Emer Delaney BSc (Hons), RD has an honours degree in Human Nutrition and Dietetics from the University of Ulster. She has worked as a dietitian in some of London's top teaching hospitals and is currently based in Chelsea.
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