Vitamin B1

["Barbara B. Peck" <bpeck@together.net>]

There could be a few problems with feeding an excess

just one of the B vitamins long term.

There are several B vitamins, that are present together and in a specific ratio in foods. 

B vitamin supplements are usually taken as "B-complex"  with B1,2,3,6 in lesser amounts than B12.

 

If just one is over supplemented for an extended period, the body may respond as if there is a deficiency in the others, and symptoms of deficiency may appear (even though they are in adequate levels).

Most people don't get enough B vitamins anyway, so this is rare,

but can happen.

 

I don't know about horses, but in people an over dose of B1 can cause drowsiness in some people.

 

B vitamins are water soluble, and excess is eliminated via the kidney's .

 

Barb