Folate is a vitamin that's good for us and needed in our system, especially women of child-bearing age. Also a factor with those with anemia (good to know: folate and vit. B12 are needed together; in the absense of B12, folate stays unactive thus both becoming deficient causing anemia. One or both of the vitamins are needed to help said anemia, but B12 is especially important due to nerves/nerve damage). But 377%?? That's a lot. Can there ever be a toxic overdose of folate?
Folate is part of the B vitamins. It helps activate vitamin B12, it metabolizes homocysteine* and helps with the synthesization of cell division & new cell growth. As far as "too much", the UL (Tolerable Upper Intake Level) is 1000 micrograms/day. My studies tell me toxic symptoms are that it masks vitamin B12 deficiency.
The fact that it masks itself as a vitamin B12 deficiency is interesting; when my B12 is low (I'm anemic) and I haven't gone for my shot for a while, I can tell because I get more heart palpitations (among other symptoms). Homocysteine is related to the heart (see * below). Is that why I get more palpitations? When folate and/or B12 levels are low, it raises homocysteine. Hmm. Food for thought.
Anyways, my point being - it's better to eat raw if possible and definitely un-processed foods. It's best to get ones folate needs naturally (avacado, beans, lentils, spinach, oranges, cantaloupe, etc) than through fortified foods, or things like this can happen.
* homocysteine is an amino acid used by the body in cellular metabolism and the manufacture of proteins. Elevated levels are thought to increase risk for heart disease, damaging the lining of blood vessels and increasing the risk of blood clotting. High levels are associated with vitamin deficiencies.