Here's an example of what I've found on other forums...this from 2008:
"My doc said I was low in folate so I neede supplements but it is crucial when having B12 injections as they work together and
large doses of B12 can pull down the folate this works a treat for me I take one with my injections...."
And this study suggests that 'higher serum folate' can result in higher homocysteine and MMA levels, cognitive impairment, and anemia, if one is b12 deficient:
http://www.pnas.org/content/104/50/19995.full
"We recently examined the interaction between serum folate and vitamin B12 status in relation to anemia, macrocytosis, and cognitive impairment in older participants (age ?60 years) in the 19992002 United States National Health and Nutrition Examination Survey (NHANES) (11).
As expected, low vitamin B12 status was associated with all three abnormalities. Furthermore, when vitamin B12 status was normal, high serum folate was related to protection from cognitive impairment.
Among those with
low vitamin B12 status, however,
high serum folate was directly associated with both anemia and cognitive impairment. Consistent with our findings for subjects with normal vitamin B12 status, several cross-sectional studies (1215), as well as some prospective investigations (1619), have reported direct relations between folate status and cognition. On the other hand, Morris et al. (20)
found that higher folate intake was associated with more rapid cognitive decline in a cohort of ?4,000 community-dwelling elderly people whose vitamin B12 status was unknown."
"In vitamin B12 deficiency, high tHcy reflects impaired methionine synthase activity, whereas high MMA indicates impaired methylmalonyl-CoA mutase activity. Consequently, our findings suggest that
both pathways of vitamin B12 metabolism are adversely affected by high serum folate despite the direct involvement of folate only in methionine synthase activity."
So...do we first 'load up' on b12...and then slowly add folate? Or probably better, try and get a serum folate level tested? Not sure if medicaid would pay for that...
And/or...could this interaction perhaps explain why some have bad reactions to the methylfolate (or other folates as well)...because they're b12 levels are low or 'trapped' due to toxins??? So confusing...
Hopefully Rich can stop by and comment.
d.