Of course there is a down side. There's always a down side. It's just not as well publicized as the up side.
In the case of excess folic acid intake, possible adverse outcomes include B12 deficiency, immune suppression, and a laundry list of other issues in people with particular genetic susceptibilities.
The recent increase in the intake of folic acid by the general public through fortified foods and supplements, has raised safety concern based on earl…
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Selhub et Al, Excessive folic acid intake and relation to adverse health outcome