In addition to the eight essential B vitamins (B1, B2, B3, B5, B6, B7, B9, B12), there are vitamin-like compounds, or vitaminoids, that work closely with the B vitamins as cofactors and were therefore counted as B vitamins themselves until recently. In ideal conditions, these cofactors can be produced by the body itself. Particularly when taking high doses of B vitamins, it is important to ensure a parallel supply of these compounds to avoid nutritional imbalances:
- Choline (formerly vitamin B4) is mainly found in the form of phosphatidylcholine (lecithin) and acetylcholine.
- Betaine (in the form of trimethylglycine/TMG) is another activated form of choline which plays an important role in the methylation cycle as well as in homocysteine metabolism.
- Inositol (formerly vitamin B8) is found primarily in the brain, liver and kidneys.
- PABA (formerly vitamin B10) functions as a coenzyme and is involved in the formation of red blood cells via vitamin B9.