Vitamin B: What you need to know about the eight B vitamins

Figure 1: The B vitamins form a strong team involved in many vital processes in the body. Because they cannot be produced by the body or are produced only insufficiently, B vitamins must be supplied through the diet.

Vitamin B is not, as one might initially think, a single vitamin. Rather, it refers to a group of eight water-soluble vitamins that fulfil a variety of functions in the body. You can read in this blog article how the individual B vitamins work and what roles they play in the organism. We also reveal which foods are particularly rich in B vitamins, how to recognise a vitamin B deficiency, and what you should pay attention to when choosing a vitamin B supplement.

The B vitamins: a strong team for many functions

In medicine, the term "vitamin B" denotes a group of eight essential vitamins that perform numerous vital tasks in the body. Because the body cannot produce them itself, B vitamins must be obtained from the diet.

Among other things, the B vitamins are involved in energy metabolism, brain function, cell division, and the formation of blood and hormones. Although each B vitamin has its own chemical structure and performs different roles in the body, they work closely together in their functions. A good example is the role of each B vitamin as a cofactor in energy metabolism processes. This was demonstrated, among other studies, in a randomised, double-blind crossover trial that investigated the anti-fatigue effects of vitamin B supplementation. The combined intake of the B vitamins B1, B2, B6 and B12 over 28 consecutive days led to a significant improvement in endurance performance and reduced fatigue after physical activity in the study participants.[1]

Another common feature of the B vitamins is their water solubility. In the event of an overdose, excess vitamins are simply excreted in the urine. The reason the numbering of the B vitamins is not continuous is that some substances were initially mistakenly classified as vitamins. Substances such as pangamic acid ("vitamin B15") or choline ("vitamin B4") are now considered vitaminoids (vitamin-like substances) and therefore no longer appear on the list of B vitamins.

What roles do the individual B vitamins play in the body?

Figure 2: In many bodily processes the B vitamins work closely together. Among other things, they jointly ensure optimal utilisation of macronutrients (carbohydrates, fats and proteins).

The eight B vitamins are involved in a wide range of important metabolic processes in the body and often work closely together. For a functioning organism, all B vitamins are therefore required in sufficient amounts. However, each vitamin performs different tasks, which are briefly summarised below.

Vitamin B1 (Thiamine)

Vitamin B1, also known as the "nerve vitamin" or "mood vitamin", contributes to normal nervous system function, normal psychological function, normal heart function and normal energy metabolism. One of the most important roles of vitamin B1 is converting nutrients from food, especially carbohydrates, into energy. Vitamin B1 is also involved in collagen formation, which is important for the health of hair, skin, bones, cartilage and ligaments.

Vitamin B2 (Riboflavin)

Vitamin B2 is also essential for human energy metabolism and protects cells from oxidative stress. By supporting the maintenance of red blood cells, the vitamin helps reduce tiredness. In addition, versatile riboflavin contributes to the breakdown of fats and proteins and to the maintenance of normal nervous system function.

Vitamin B3 (Niacin)

Alongside vitamin B12, vitamin B3 is the only B vitamin that can be partly stored by the body. Vitamin B3 is essential for the regenerative capacity of nerves, muscles, skin and mucous membranes. It is also involved in the repair of human DNA and contributes to the reduction of tiredness and fatigue. Niacin also plays an important role in immune system function.

Vitamin B5 (Pantothenic acid)

Vitamin B5 is needed for the maintenance of normal mental performance as well as for the production of certain neurotransmitters and the synthesis of vitamin D. Pantothenic acid counteracts tiredness and fatigue. Vitamin B5 is also credited with positive effects on wound healing and the regulation of fat metabolism.

Vitamin B6 (Pyridoxine)

Pyridoxine is a true generalist among the B vitamins: among other things, it contributes to normal energy metabolism, normal nervous system function, normal psychological function and normal homocysteine, protein and glycogen metabolism. In addition, vitamin B6 supports the immune system and plays an important role in the regulation of hormonal activity.

Vitamin B7 (Biotin)

Biotin, the "beauty vitamin", is a particularly popular representative of the B vitamins. Because it contributes to the maintenance of healthy skin and hair, biotin is often included in cosmetic products. In addition, vitamin B7 supports normal energy metabolism and the normal utilisation of macronutrients.

Vitamin B9 (Folic acid)

Folic acid will also be familiar to many people. The vitamin is necessary for cell division and contributes to the growth of maternal tissues during pregnancy. Pregnant and breastfeeding women should particularly monitor their folic acid supply, as a deficiency can lead, among other things, to malformations and growth disorders of the unborn child. Folic acid also makes an important contribution to blood formation, homocysteine regulation and DNA synthesis.

Vitamin B12

Vitamin B12 has a significant impact on our physical and mental performance. Together with folate, the vitamin and coenzyme are involved in DNA synthesis and blood formation. Vitamin B12 deficiency is widespread in this country. In Germany alone, about one in ten people is insufficiently supplied with vitamin B12. Risk groups for vitamin B12 deficiency particularly include older people and those who eat exclusively vegan diets.

These foods are especially rich in B vitamins

B vitamins occur in many plant and animal foods. However, there is no single natural food that contains all B vitamins in the amounts recommended for a healthy adult. A varied and wholesome diet is therefore crucial to ensure comprehensive supply of all B-group vitamins. To preserve B vitamins as effectively as possible, you should prepare your dishes gently and, for example, cook vegetables only briefly.

The table below provides an exemplary selection of foods that contain a notable amount of the respective B vitamin.

How does a vitamin B deficiency manifest?

If the body is not adequately supplied with at least one of the eight B vitamins, this is referred to as a vitamin B deficiency. However, the symptoms of deficiency are often quite general and nonspecific at first. Because the B vitamins work closely together in their functions, it is often difficult to determine which B vitamin is present in insufficient amounts.

A long-term vitamin B deficiency can sometimes lead to serious diseases. For example, a deficiency in vitamin B6 can lead to an elevated homocysteine level in the blood, which in turn increases the risk of vascular calcification, heart attack and stroke.[2] If symptoms such as exhaustion, difficulty concentrating, digestive complaints or skin changes persist over a longer period, it is worth having a blood test to check your vitamin B levels.

Figure 3: A varied diet provides an important foundation for ensuring supply of all B vitamins. In some cases it may also be sensible to use dietary supplements containing vitamin B.

Who might benefit from vitamin B supplementation?

In general, adequate supply of all B vitamins can be ensured through a balanced diet. However, there are certain groups of people whose requirement for B vitamins is increased due to factors such as age, illness or an unfavourable lifestyle.

As many older people find it increasingly difficult to eat a balanced, vitamin-rich diet, this group is particularly often affected by vitamin B deficiency. Pregnant and breastfeeding women should also pay particular attention to adequate B vitamin intake, as nutrient and vitamin requirements are increased during pregnancy and lactation. To prevent a vitamin deficiency, it may be advisable in these cases to supplement vitamin B in the form of dietary supplements.

Groups at increased risk for various forms of vitamin B deficiency include:

• Older people
• Pregnant and breastfeeding women
• People with chronic illnesses (e.g. Crohn's disease, gastritis)
• People following vegan or vegetarian diets
• People taking certain medications (e.g. acid blockers)
• Physically active individuals
• People following a strict diet
• People with alcohol dependence
• Smokers

Tips for choosing a dietary supplement with B vitamins

Figure 4: In addition to the composition of the vitamin B product, you should also check when buying whether the included B vitamins are present in a highly bioavailable form.

Dietary supplements containing vitamin B are usually taken as capsules or, less commonly, as powders. So-called vitamin B complexes offer the advantage that they typically contain all eight essential vitamins of the B group.

How to take and dose vitamin B supplements correctly

How vitamin B supplements should best be taken depends, among other things, on the chosen product, the aim of the intake and your personal preferences. Vitamin B complex capsules are usually taken once daily. However, fatty meals can impair the utilisation of B vitamins, so taking them on an empty stomach is recommended. Some people tolerate vitamin B better when they take the capsules with a meal. It is also advisable to take vitamin B supplements in the morning, as some B vitamins, particularly vitamin B6 and vitamin B12, can have a stimulating effect.

What side effects can vitamin B have?

Vitamin B supplements are generally well tolerated. Because all eight B vitamins are water-soluble, the body normally excretes any excess. Accordingly, overdosing on B vitamins is extremely rare and, according to the German Nutrition Society, cannot be achieved through natural food intake. Only when dietary supplements containing vitamin B are taken in very high doses can side effects such as hot flushes, itching or nerve damage occur in rare cases. 

[1] Lee MC, Hsu YJ, Shen SY, Ho CS, Huang CC. A functional evaluation of anti-fatigue and exercise performance improvement following vitamin B complex supplementation in healthy humans, a randomized double-blind trial. Int J Med Sci. 2023 Aug 15. https://pubmed.ncbi.nlm.nih.gov/37786445/.

[2] Kaplan P, Tatarkova Z, Sivonova MK, Racay P, Lehotsky J. Homocysteine and Mitochondria in Cardiovascular and Cerebrovascular Systems. Int J Mol Sci. 2020 Oct 18. https://pubmed.ncbi.nlm.nih.gov/33080955/.

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