B vitamins at a glance: B12, B6, folate and what they do

"B vitamins" sounds like a homogeneous group, but it's actually a family of eight rather different relatives. They share a letter and a rough playing field — energy metabolism, nervous system, blood formation — but their roles differ markedly. Once you have an overview, you make better decisions. Especially with fatigue, it's worth a parallel look at iron — B12, folate and iron work hand in hand in blood formation.

The eight at a glance

Vitamin	Other names	Focus
B1	Thiamine	Energy from carbohydrates
B2	Riboflavin	Energy metabolism, vision
B3	Niacin	Energy metabolism, nervous system
B5	Pantothenic acid	Energy metabolism, hormone synthesis
B6	Pyridoxine	Protein metabolism, nervous system
B7	Biotin	Skin, hair, energy metabolism
B9	Folate / folic acid	Blood formation, cell division
B12	Cobalamin	Blood formation, nervous system

Apart from B12, all are water-soluble and need to be replenished more or less regularly. B12 is the odd one out: it's stored in the liver, often for years, which keeps shortages invisible for a long time.

B12 is the special case

There is one B-family member that really deserves your particular attention: B12. The reason — B12 occurs naturally only in animal-source foods: meat, fish, eggs, dairy. Plant-based sources contain no B12 by nature. Fortified products (plant drinks, some nutritional yeast varieties, breakfast cereals) are the exception — and you have to check the label to confirm fortification.

In the EU list of authorised health claims (Regulation 432/2012), B12 is listed for several functions, three of which are particularly relevant:

• Vitamin B12 contributes to the normal function of the nervous system.
• Vitamin B12 contributes to normal energy-yielding metabolism.
• Vitamin B12 contributes to the reduction of tiredness and fatigue.

DGE recommends 4 µg of B12 per day for adults. Anyone eating strictly plant-based should always supplement B12 deliberately — that's the explicit recommendation of DGE in its updated position on vegan nutrition (2020). A blanket reluctance toward B12 supplements is out of place here: on a vegan diet, B12 is simply part of routine provision.

Folate (vitamin B9)

Folate is the natural form, folic acid is the synthetic one — both count as vitamin B9. Folic acid has better bioavailability in the body, which is an advantage in supplements.

Daily intake according to DGE — given as folate equivalents, i.e. natural folate plus synthetic folic acid converted:

• Adults: 300 µg folate equivalents / day
• Pregnant: 550 µg / day
• When trying to conceive: an additional 400 µg of folic acid per day, starting at the latest 4 weeks before conception until the end of the 1st trimester
• Breastfeeding: 450 µg / day

Folate-rich foods: spinach, broccoli, chickpeas, lentils, whole grains, egg yolk. Folate is heat-sensitive — gentle cooking or raw consumption in salads preserves more.

Folate contributes to normal blood formation and to amino acid synthesis (EFSA, Regulation 432/2012). In the context of pregnancy, deliberate folic acid intake has a recognised role — talk to your gynaecologist before and during pregnancy.

Vitamin B6

B6 — as pyridoxine, or as pyridoxal phosphate (PLP) in the body — is a co-factor for over 100 enzymes. Focus areas: protein and amino acid metabolism, nervous system.

The following statements are authorised from the EU positive list:

• B6 contributes to normal protein and glycogen metabolism
• B6 contributes to the normal function of the nervous system
• B6 contributes to the reduction of tiredness and fatigue
• B6 contributes to normal red blood cell formation

DGE recommendation: 1.4 mg (women) or 1.6 mg (men) per day. B6 is in meat, fish, bananas, potatoes, legumes and whole grains — with a balanced diet, deficiency is rare.

An important warning about B6: long-term intake well above the recommended level from supplements has been linked in the literature to sensations in hands and feet — sensory symptoms that usually subside after stopping. EFSA lowered the tolerable upper intake level to 12.5 mg per day (adults) in 2023; Germany's BfR updated its supplement upper-limit recommendation in 2024. Highly dosed B6 products without medical guidance are not a good idea — refer to the current BfR document for the daily upper limit from supplements.

Who has higher needs?

There are classic life situations in which individual B vitamins deserve particular attention:

• Pregnancy and breastfeeding: practically all B vitamins, especially folate and B12.
• Vegan or strictly vegetarian: B12 deliberately and without exception; B2 is also often lower.
• Older adults: B12 absorption via the gastrointestinal tract decreases with age. That's not an intake question but an absorption one and belongs in medical advice.
• High stress or sustained strain: B vitamins act as co-factors in energy metabolism, which runs hot under chronic stress.
• Endurance sports: slightly higher needs from increased energy turnover.

Complex or single-nutrient product?

Both have their place. A B-complex covers a broad range — sensible if you suspect a general gap without knowing a specific shortfall. A single-nutrient product (typically B12 on a vegan diet, folic acid before and during pregnancy) makes sense when you want to dose deliberately.

For B12, by the way, retail dosages are far higher than the DGE daily requirement of 4 µg — typically 5 µg to 500 µg per tablet. There's a reason: with oral intake, only a fraction is absorbed via the natural pathway, the rest goes through passive diffusion. Higher doses compensate for the poorer absorption.

B vitamins, iron and energy

B vitamins don't act in isolation. In red blood cell formation, B12, folate and iron work together. Anyone who looks at a single substance "because of fatigue" often misses the interplay. More on the iron side in the article Iron and tiredness.

If you're not sure which B vitamins are relevant in your everyday life and where an adjustment would be worthwhile, the free Vital-Check helps with an initial assessment. For clear symptoms, clarification belongs in medical hands.