Don't try overdosing on vitamin B - it's too difficult. (Photo by Auntie P)
It's time to end my vitamin B experiment. A week ago I increased my supplementation to see if it would make a difference. I can't say that it did. Or, at least, if there were any effects, they were not visible.
The amounts of vitamin B from the supplements and food combined were:
Vitamin B1 (thiamine) - 313 % of RDA
Vitamin B2 (riboflavin) - 362 % of RDA
Vitamin B3 (niacin) - 391 % of RDA
Vitamin B5 (panthotenic acid) - 334 % of RDA
Vitamin B6 (pyridoxine) - 360 % of RDA
Vitamin B7 (biotin) - 300 % of RDA*
Vitamin B9 (folic acid) - 330 % of RDA
Vitamin B12 (cobalamin) - 497 % of RDA
* The value for biotin is based on supplements alone, since nutritiondata.com doesn't show the amounts of biotin from food.
For B1, B2, B5, B7 and B12 there seem to be no tolerable upper levels established. For B3 it's 35 mg / day. I was eating about 60 mg / day, which is almost double that. For B6 it's 100 mg / day, which is considerably more than the 7 mg or so that I was eating. For B9 it's 1000 mcg / day, and I was eating about 650 mcg / day.
I noticed no side effects from consuming more niacin than the upper tolerable intake for adults. According to Wikipedia, symptoms such as facial flushing, dry skin and indigestion are associated with even higher intakes (1.5 - 6 mg / day).