B Vitamins Complex Benefits

Vitamin B complex supplements provide all eight of the essential B vitamins. These are vitamins B1, B2, B3, B5, B6, B7, B9 and B12. Some of the numbers are missing because dietary substances originally though to be vital for life are no longer classified as such. These include choline (originally known as vitamin B4), inositol (once designated as vitamin B8) and para amino benzoic acid (PABA, which is still sometimes referred to as vitamin B10).

Some vitamin B complexes do still include these related nutrients, especially choline and inositol, as they are believed to be important for optimum health.

The benefits of a B vitamins complex

B complex vitamins are mainly involved in energy production in cells, and are used to help reduce tiredness and fatigue, improve brain and nervous system function, aid memory, support immunity, maintain normal heart health and red blood cell formation.

B vitamins have been used in high doses to lower levels of homocysteine, an amino acid that damages artery walls when allowed to accumulate. Normally, homocysteine is converted into other harmless substances by enzymes that need folic acid, vitamin B12 and vitamin B6 to work properly. Some people inherit versions of these enzymes which need higher levels of these vitamins to function properly. The clearance of homocysteine becomes less efficient with age – especially after the menopause in women. As a result, an estimated 10% to 15% of the population (and almost 30% of those with coronary heart disease) do not break down homocysteine at optimal efficiency.

B vitamins and stroke

Data from 14 trials involving over 54,900 people suggest that taking a high dose vitamin B complex to lower homocysteine levels reduced the overall risk of stroke by 7%. The greatest beneficial effects were seen after 3 years of treatment and in those with a systolic blood pressure (the higher reading) of greater than 130 mmHg.

An update involving 17 trials (86,393 people) compared 7 different B vitamin treatments against inactive placebo and confirmed that taking B vitamin supplements was associated with reduced risk of stroke. The risk of stroke was lowest with supplements that included folic acid plus vitamin B6, or folic acid plus vitamin B6 and vitamin B12. The researchers concluded that taking B vitamin supplements was associated with a reduced risk of stroke.

Other studies suggest this protective effect is partly due to the ability of folic acid to reduce the progression of hardening and furring up of the carotid arteries in people at high-risk of stroke. The carotid arteries supply blood to the brain and, when they become furred up, they can be a source of blood clots that break off and block a blood vessel in the brain to cause a stroke.

B vitamins and heart attack

A daily supplement with low-dose B vitamins complex was found to reduce cardiovascular risk factors in 390 healthy people over the age of 60. All participants received vitamin C (50mg) and half also received a B vitamin complex supplying 400 mcg folic acid, 2 mg vitamin B6, and 10 mcg vitamin B12. After 12 months, those taking the additional B vitamins showed significant improvements in heart disease risk factors such as cholesterol balance, homocysteine levels and blood pressure. An overall analysis of data from 23 trials involving 57,900 people found that taking a vitamin B complex reduced heart attacks by 2%, cardiac death by 4% and stroke by 6% which were not statistically significant.

B vitamins and dementia

Lack of folate (folic acid) is a risk factor for developing dementia. Scientists have found that taking high-dose B vitamins (800 mcg folic acid, 20 mg vitamin B6, 500 mcg vitamin B12 ) can slow cognitive decline in older people with an increased dementia risk by reducing shrinkage of whole brain volume over 2 years. In particular, taking these high dose B vitamins reduced shrinkage of brain gray matter by seven-fold in areas usually associated with Alzheimer’s disease such as the medial temporal lobe. Beneficial effects were most evident in people with a high homocysteine level.

The combination of omega-3 fish oils and B vitamins complex appears to be especially effective for reducing shrinkage of the brain and slowing the progression of memory impairment and Alzheimer’s dementia. here ple

Vitamin B complex doses

The dose of a vitamin B complex tablet is based on the recommended daily amount for each individual vitamin, which varies widely, with some needed in tiny microgram (mcg) amounts, and others needed in larger milligram (mg) amounts.

Some supplements just provide the basic RDA of each vitamin, while others provide B vitamin doses that are purely based on similar sounding quantities. These high-dose supplements revolve around numbers such as 20, 25, 50 or 100. A popular combination is a 25 based B vitamin supplement, which provides 25mcg of some B vitamins and 25mg of others, as appropriate.

Always read the manufacturer’s instructions as some high dose B Vitamin Complex products are only designed for short-term use.

The following vitamins are usually included in a good B vitamins complex.

Vitamin B1    

Thiamin is a water-soluble vitamin that is readily lost from the body. Most people only have stores sufficient to last one month. A regular dietary supply is therefore essential.

Vitamin B1 plays a central role in metabolism and the way nerves and muscle cells conduct messages. It is essential for the production of energy from glucose, and the more carbohydrate you eat, the more thiamin you need. It also helps to maintain feelings of calm, alertness and mental energy.

Vitamin B2

Riboflavin is a water-soluble vitamin that cannot be stored in the body, so a regular dietary supply is important.

Vitamin B2 plays a crucial role in the production of energy and the metabolism of proteins, fats and carbohydrate. People who are physically active need more riboflavin than those who take little exercise. It also acts as an antioxidant, is involved in immunity and the production of antibodies and in the formation of hair, skin and nails.

Vitamin B3  

Niacin is a water-soluble vitamin that exists in two forms, as nicotinic acid and nicotinamide. Small amounts of vitamin B3 are made in the body, but not enough to meet your needs.

Vitamin B3 plays an important role in releasing energy from muscle energy stores (glycogen) and for processing fatty acids released from body fat stores. It works together with vitamins B1 and B3 to increase energy production in cells, and also works on its own to maintain healthy skin, nerves, intestines and thought processes.

Vitamin B3, together with mineral chromium, forms the Glucose Tolerance Factor (GTF) which is essential for the hormone, insulin, to regulate glucose uptake into muscle and fat cells.

Vitamin B5

Pantothenate (also known as pantothenic acid) is a water-soluble vitamin found in most animal and plant-based foods. Despite its wide distribution, it is easily destroyed by food processing and deficiencies can occur. A regular intake is therefore essential.

Vitamin B5 is vital for many energy producing reactions in the body involving carbohydrates, fats and protein. It is also necessary for making glucose, fatty acids, adrenal gland hormones, and for maintaining a healthy nervous system. Vitamin B5 stimulates cell growth in healing tissues, encourages stronger scar tissue formation, helps to rejuvenate ageing skin and to reduce skin mottling.

Vitamin B6  

Pyridoxine is the active form of vitamin B6. Small amounts are stored in the liver, normally amounting to one to two week’s supply. A regular intake is therefore important.

Vitamin B6 is needed for over 100 enzymes to work properly, and is involved in the synthesis of DNA, amino acids, proteins, brain chemicals and for metabolising carbohydrates and essential fatty acids.

Vitamin B7

Biotin is a water-soluble B group vitamin involved in the synthesis and metabolism of fatty acids, amino acids, genetic material, stress hormones and energy storage molecules. It is also essential for healthy hair, nails, skin and sweat glands.

Vitamin B9  

Folate and the more bioavailable synthetic form, folic acid, are involved in the synthesis and metabolism of proteins, glucose and nucleic acids and are especially needed by rapidly dividing cells such as those within the bone marrow. When folic acid is in short supply, dividing cells become larger than usual and, when red blood cells are affected, a form of anaemia can result. Folic acid is especially important during early pregnancy.

Vitamin B12

Cyanocobalamin is a water-soluble vitamin which can be stored in the liver, and supplies are often enough to last several years. Vitamin B12 is essential for the synthesis of DNA during cell division, healthy nerve function, immunity and healing. Vitamin B12 deficiency can lead to pernicious anaemia.


Some supplements also include choline, which was originally classed as vitamin B4, then demoted when it was decided we probably make enough to meed our needs. This is not always the case, however, especially in later life when good intakes are increasingly important for cognitive function – the ability to think straight, concentration and alertness. Choline is a component of phosphatidylcholine, which is vital for healthy cell membranes, cholesterol metabolism and for the production of brain chemicals such as acetylcholine and dopamine. If choline is in short supply, cells cannot function properly and enter a process known as apoptosis (programmed self-destruction).


Some supplements include inositol, a vitamin-like substance that was once known as vitamin B8. Inositol is needed to maintain healthy cell membranes, and for cells to send and receive signals between one another. Inositol helps to regulate mood, insulin sensitivity, fat metabolism and the switching on and off of genes.


Para amino benzoic acid, once known as vitamin B10, appears in some vitamin B complex formulas as it is crucial for the synthesis of co-enzyme Q10. PABA makes up the main ‘business end’ of a CoQ10 molecule which, like B vitamins, is involved in energy production in cells. PABA is believed to reduce fatigue, low mood, skin irritation and premature hair greying. PABA is also used topically as a sunscreen and is included in many sun creams.

Vitamin B complex side effects

Most B vitamins are water-soluble and do not build up in the body to cause side effects.

Some controversial research suggests that high doses of vitamin B6 may cause nerve damage. The European Food Safety Authority have suggested a tolerable upper intake level of 25mg vitamin B6 per day for long-term use from supplements. Higher doses of 50mg to 200mg are sometimes advised short-term to treat problems such as pre-menstrual syndrome.

Although vitamin B12 can be stored in the body, the doses found in vitamin B complex supplements are well below the suggested upper tolerable intake of 2000mcg (2mg) per day.

B vitamins do have a strong yeast-like odour with some supplements smelling stronger than others.

Click here to read my Expert Health Review of Multivitamin brands.

multivitamins cover
Do You Need A Multivitamin? My Quick Nutrition guide (46 pages) is currently free via this link
Vitamin coverMy Essential Guide to Vitamins, Minerals and Herbal Supplements offers a complete overview of each vitamin, mineral, dietary oils and herbal remedy.

Available from Amazon.co.uk and Amazon.com.

Image credits: pixabay

Please leave a comment or ask me a question ...