SummaryRead the full fact sheet
- The B-group vitamins are a collection of 8 water-soluble vitamins essential for various metabolic processes.
- Most of these vitamins can’t be stored by the body and must be consumed regularly in the diet.
- Extended cooking, food processing and excess alcohol consumption can destroy or reduce the availability of many of these vitamins.
- It is important not to self-diagnose a vitamin deficiency, because some vitamins can be toxic if taken incorrectly and/or mask other vitamin deficiencies. See your doctor or dietitian for advice.
About B-group vitamins
naturally occur in food and are needed in very small amounts for various bodily functions such as energy production and making red blood cells. There are 13 vitamins that our body needs, 8 of which make up the B-group (or B-complex) vitamins.
The B-group vitamins do not provide the body with fuel for energy, even though supplement advertisements often claim they do. However, it’s true though that without B-group vitamins the body lacks energy. This is because the B-group vitamins are needed to help the body to use the energy-yielding nutrients (such as , and ) for fuel. Other B-group vitamins are needed to help cells to multiply by making new DNA.
Vitamin B in food
can also reduce the amount of B-group vitamins in foods – either by destroying them, or in white flours, white breads and white rice removing the parts that contain the most B-group vitamins. This is one of the reasons white flours, white breads and white rice are less nutritious than their wholegrain counterparts.
The body has a limited capacity to store most of the B-group vitamins (except B12 and folate, which are stored in the liver). A person who has a poor diet for a few months may end up with B-group vitamins deficiency. For this reason, it’s important that adequate amounts of these vitamins be eaten regularly as part of a well-balanced, nutritious diet.
Vitamin B supplements
Although are readily available and it might sound like a good idea to take them just in case, it’s important to always see your doctor or a dietitian for advice before starting. The body only needs small amounts of vitamins and most of these needs can be met by eating a .
Taking vitamins that your body does not need can mean, at a best-case scenario, that your body gets rid of the excess in your urine (so you waste your money). But some vitamins can also be toxic if taken incorrectly, so you could also be damaging your body instead of helping it.
Some B-group vitamins also work together in the body (for example, vitamin B12 and folate or folic acid). This means taking supplements can sometimes hide deficiencies of other vitamins, which can also lead to health problems.
Types of vitamin B
There are 8 types of vitamin B:
- thiamin (B1)
- riboflavin (B2)
- niacin (B3)
- pantothenic acid (B5)
- pyridoxine (B6)
- biotin (B7)
- folate or ‘folic acid’ when included in supplements (B9)
- cyanocobalamin (B12).
Thiamin is also known as vitamin B1. It helps to convert glucose into energy and has a role in nerve function.
Good sources of thiamin
Thiamin deficiency is generally found in countries where the dietary staple is white rice. Deficiencies in the Western world are generally caused by and/or a very poor diet. Symptoms include – confusion, irritability, poor arm or leg (or both) coordination, lethargy, and muscle weakness.
Beriberi is a condition caused by thiamin deficiency and affects the cardiovascular, muscular, gastrointestinal and nervous systems. It can be classified as ‘wet’ and ‘dry’ beriberi. ‘Dry’ beriberi affects the nervous symptom while ‘wet’ beriberi affects the cardiovascular system.
Wernicke-Korsakoff syndrome (also called ‘wet brain’) is another thiamin-deficiency disease linked to alcohol excess and a thiamin-deficient diet. Alcohol reduces thiamin absorption in the gut and increases its excretion from the kidneys.
Riboflavin is primarily involved in energy production and helps vision and skin health.
Good sources of riboflavin
- cottage cheese
- wholegrain breads and cereals
- egg white
- leafy green vegetables
Riboflavin deficiency (ariboflavinosis)
Riboflavin deficiency (or ariboflavinosis) is rare and is usually seen along with other B-group vitamin deficiencies. People at risk include those who consume excessive amounts of alcohol and those who do not consume milk or .
Niacin is essential for the body to convert carbohydrates, fat and alcohol into energy. It helps maintain skin health and supports the nervous and digestive systems. Unlike other B-group vitamins, niacin is very heat stable and little is lost in cooking.
Good sources of niacin
Niacin deficiency (pellagra)
People who drink excessive amounts of alcohol or live on a diet almost exclusively based on corn are most at risk of pellagra. Others causes are associated with digestive problems where the body does not absorb niacin efficiently.
Excessive niacin intake
Large doses of niacin produce a drug-like effect on the nervous system and on blood fats. While favourable changes in blood fats are seen, side effects include flushing, itching, nausea and potential liver damage.
Pantothenic acid (B5)
Pantothenic acid is needed to metabolise carbohydrates, proteins, fats and alcohol as well as produce red blood cells and steroid hormones.
Good sources of pantothenic acid
Pantothenic acid is widespread and found in a range of foods, but some good sources include:
Pantothenic acid deficiency
Because pantothenic acid is found in such a wide variety of foods, deficiency is extremely rare.
Vitamin B6 (pyridoxine)
Pyridoxine is needed for protein and carbohydrate metabolism, the formation of red blood cells and certain brain chemicals. It influences brain processes and development, and steroid hormone activity.
Good sources of pyridoxine
Excessive pyridoxine intake
Pyridoxine toxicity is mostly due to supplementation and can lead to harmful levels in the body that can damage the nerves.
Good sources of biotin
- egg yolks
Biotin deficiency is very rare – it’s widely distributed in foods and only required in small amounts. Over-consumption of raw egg whites over periods of several months (by bodybuilders, for example) can induce deficiency because a protein in the egg white inhibits biotin absorption.
Folate or folic acid (B9)
Folate, or folic acid (the synthetic form of folate which is used extensively in dietary supplements and ) is needed to form red blood cells, which carry oxygen around the body. It helps the development of the , as well as DNA synthesis and cell growth. Women of child-bearing age need a diet rich in folate for this reason.
Good sources of folate
- green leafy vegetables
- citrus fruits.
Since 2009, all bread sold in Australia (except organic) has been fortified with folic acid.
Excessive folic acid intake
Although folic acid is generally considered non-toxic, excessive intakes above 1,000mcg per day over a period of time can lead to malaise, irritability and intestinal dysfunction. The main risk with excessive folate intake is that it can mask a vitamin B12 deficiency, so it’s best to consume these 2 vitamins within the recommended amounts.
Cyanocobalamin (or vitamin B12) helps to produce and maintain the myelin surrounding nerve cells, mental ability, red blood cell formation and the breaking down of some fatty acids and amino acids to produce energy. Vitamin B12 has a close relationship with folate, as both depend on the other to work properly.
Good sources of B12
- almost anything of animal origin.