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Pernicious Anaemia Society
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High folic acid intake in aged mice causes a lowered immune response

Yet another "too much isn't good for you" story - with particular relevance to anyone taking folic acid and (maybe) folates.

High folic acid intake in aged mice causes a lowered immune response


    January 11, 2016


    Tufts University, Health Sciences Campus


    A study in aged mice shows that excess folic acid intake causes lowered immune function because important immune cells, called natural killer cells, are less effective. These results build upon the findings of a previous study in 2005 by the same lab that found that 78 percent of healthy postmenopausal women had unmetabolized folic acid in their blood plasma, which is indicative of excess folic acid intake.


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Thank you for a stimulating read though I'm not convinced that the title of the article isn't misleading

This is a link to an interesting article on NK (natural killer) cells that provides a bit more background for anyone that might be interested in following up a bit more


The study showed that high levels of folic acid affect cause reduced effectiveness in one small part of a rather large system - making NK cells slightly less toxic to cells they identify as threats - but doesn't look at the immune system as a whole.  The article itself is actually contradictory reporting one member of the team as saying it shows an adverse effect on immunity and another - more senior- saying that more research was required to see if high folic acid intake actually reduced the effectiveness of the immune system - which is much more complex so something that makes one part less effective doesn't necessarily make the whole system less effective as it might make other parts more effective.

The study did seem to have identified the mechanism which resulted in NK cells becoming less effective - lowered production of another chemical - so another part of the research puzzle would be understanding more about the interaction between high levels of folic acid and reduce levels of IL-10 by splenocytes


Yes - identification of mechanism seemed the most important single feature. Once that is properly known, everything else can be related to that and appropriately considered - we hope.


It's a good job not many aged mice are members of this community... :D


I had a terrible time when my doctor gave me excess folate, and I still don't understand why. That's when my neurological symptoms worsened, and I stopped all supplements thinking that would help, and then the Neuro symptoms really started to get bad.

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An interesting article that sums up the concerns, I think.

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