The vitamin B-complex refers to all of the known essential water-soluble vitamins except
for vitamin C. These include thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), pyridoxine (vitamin B6), biotin,
folic acid and the cobalamins (vitamin
"Vitamin B" was once thought to be a single nutrient that existed in extracts of rice,
liver, or yeast. Researchers later discovered these extracts contained several vitamins,
which were given distinguishing numbers. Unfortunately, this has led to an erroneous belief
among non-scientists that these vitamins have a special relationship to each other. Further
adding to confusion has been the "unofficial" designation of other substances as members of
the B-complex, such as choline, inositol, and para-aminobenzoic acid (PABA), even though they are not essential
Each member of the B-complex has a unique structure and performs unique functions in the
human body. Vitamins B1, B2, B3, and biotin participate in different aspects of energy
production, vitamin B6 is essential for amino
acid metabolism, and vitamin B12 and folic acid facilitate steps required for cell
division. Each of these vitamins has many additional functions. However, contrary to popular
belief, no functions require all B-complex vitamins simultaneously.
Human requirements for members of the B-complex vary considerably—from 3 mcg per day
for vitamin B12 to 18 mg per day for vitamin B3 in adult males, for example. Therefore, taking
equal amounts of each one—as provided in many B-complex supplements—makes little
sense. Furthermore, there is little evidence supporting the use of megadoses of B-complex
vitamins to combat everyday stress, boost energy, or control food cravings, unless a person
has a deficiency of one or more of them. Again, contrary to popular belief, there is no
evidence indicating people should take all B vitamins to avoid an imbalance when one or more
individual B vitamin is taken for a specific health condition.
Most multivitamin-mineral products contain
the B-complex along with the rest of the essential vitamins and minerals. Since they are more
complete than B-complex vitamins alone, multiple vitamin-mineral supplements are recommended
to improve overall micronutrient intake and prevent deficiencies.
Are there any side effects or interactions?
Vitamin B-complex includes several different components, each of which has the potential to
interact with drugs. It is recommended that you discuss the use of vitamin B-complex and your
current medication(s) with your doctor or pharmacist.