What is the long term effects of to much vitamin b?

Nerve issues. Vitamin b6 is the one to watch as it can be . Toxic in overdoses. "adverse effects have only been documented from vitamin b6 supplements and never from food sources." b vitamins are water soluble and we usually pee out what we do not need. It is ok to take breaks from supplementation. You can also monitor your levels periodically with blood tests. www.spectracell.com is worth looking at.