For a good multi-vitamin, I consider the minimum to be at least 25 milligrams of each of the main Bs (B-1, B-2, B-6, e.g.). I also consider more to be better as far as the water-soluble vitamins go (the Bs, vitamin C, and some others are water-soluble, while A, D, E, and K are fat soluble).
'Bear in mind that the RDI (recommended daily intake), DV (daily value), or whatever, is calculated to be the dose that keeps you from overtly DYING of a nutrient deficiency.
'I believe that the state of optimal health is unattainable at doses approximating our RDIs. There are just too many stresses out there: bad food, bad soil, bad water, air pollution, pesticide sprays, weed killers, car exhaust, genetic manipulation, etc., etc., ad nauseum.
'But the dose is not necessarily the most important factor. Delivery system is key, too. I'd prefer 50 milligrams in a non-time-release capsule over 100 milligrams of a time-release hard pill - I just don't believe many people absorb all of the latter.'
How much is too much?
Can you get too much vitamin B?
Knowing that large doses of vitamin C can cause loose bowels (sending a warning that you've reached your personal upper limit of vitamin C dosage), Do any of the Bs create an easy-to-read reaction like that, indicating that you're getting too much.
'There aren't any that I'm aware of specifically concerning the Bs, at least at doses any normal individual would consider.
'Vitamin B-6, in doses over 1000 milligrams/day for 6 months or more (usually far more) can cause numbness and tingling of the extremities (the same as a deficiency). But that's just not going happen with a B-100 type supplement.
One exception might be a reaction to B-3 if it's real niacin. That's the best form, by far, but higher doses can cause the infamous niacin flush, where you get a 20-minute sunburn-like redness and itching sensation.
For the record, vitamin B-2 is wonderful for oily hair, as higher doses dry it up (don't ask me why). However, I have NOT heard anyone ever complain that normal hair gets too dry, so I don't think that's a problem.'
Overdoing the dosage of vitamin B-12 is generally not a problem for vegetarians, according to a study in the American Journal of Clinical Nutrition (AJCN) that carries an important warning about cardiovascular health.
A study tested the effects of B vitamin supplements on more than 500 patients who had undergone coronary angioplasty. Half of the group received a supplement of folic acid, vitamin B6 and B12, while the other half received a placebo. Following up on the patients for a full year, the researchers found that the B supplement not only slowed the development of plaque build up in the arteries, but actually prevented it from occurring. Their conclusion: B vitamin and folate supplements may significantly lower homocysteine levels.
This AJCN study takes that research a step forward with an examination of vitamin B-12 levels in 174 subjects - 29 vegetarians, 66 lactovegetarians (vegetarians who eat dairy products, but not eggs), and 79 meat eaters. Of the three groups, the vegetarians had the lowest B-12 levels (low enough to be considered a deficiency), and the highest levels of homocysteine (one of the primary markers indicating a risk of cardiovascular disease).
The researchers concluded with a recommendation that vegetarians should be monitored by health professionals to check both vitamin B-12 status, as well as homocysteine levels. And while supplements of B-12 might help bring down the homocysteine, Remember that vitamins are not food, or a replacement for it. But it's a nice trick to mix more nutrients into the food we eat as health insurance.