January 18, 2007
Folic Acid Slows Brain Aging Unless B-12 Deficient

In a January 2007 edition of the American Journal of Clinical Nutrition, A David Smith of University of Oxford surveys recent reports on the health effects of higher folic acid consumption. In a nutshell: Folic acid appears to slow brain aging for those who have lots of B-12 but for those with B-12 deficiency higher folic acid consumption makes the brain decline more rapidly.

Interestingly, Morris et al report both a "good" and a "not-so-good" side of folate. In agreement with current knowledge, they found that a low vitamin B-12 status is associated with macrocytosis, anemia, and cognitive impairment. The key finding in this report concerns interactions between folate status and vitamin B-12 status. The "good news" is that, in subjects with a normal vitamin B-12 status, high serum folate (>59 nmol/L) was associated with protection from cognitive impairment. This finding is remarkable in a population with a much higher mean folate concentration (39 nmol/L) than that seen in countries where there is no mandatory folate fortification. A similar result was reported for Latinos living in California, where higher red blood cell folate concentrations after fortification were associated with protection from cognitive impairment and dementia (11). Simply put, if your vitamin B-12 status is good, folate supplementation is good for you!

So good so far. But there's a gray lining in that silver cloud. Higher folic acid consumption appears to lower cognitive function in those with low B-12 in their blood serum.

The "not-so-good" news from the study by Morris et al is that the relation between high serum folate and cognitive impairment was reversed in subjects who had a low vitamin B-12 status. Those with a low vitamin B-12 status (serum cobalamin <148 pmol/L) and high serum folate (>59 nmol/L) had an odds ratio for cognitive impairment of 5 compared with those whose vitamin B-12 status and folate status were both normal. This group, which had a low vitamin B-12 status and a high serum folate concentration also had an odds ratio close to 5 for anemia. Thus, the simple interpretation is that the cognitive impairment and anemia usually associated with low vitamin B-12 status are made much worse by a high folate status.

This result supports the theory of some nutrition researchers that folic acid supplementation doesn't just mask B-12 deficiency. Folic acid makes the damaging effects of B-12 deficiency worse. One of the effects of B-12 deficiency is neurological damage.

You might think you are not at risk of B-12 deficiency because you eat lots of meat or perhaps you take a B-12 supplement. You might be right. But some people have an impaired ability to absorb B-12. So without a blood test you can't be absolutely sure that your B-12 status is fine.

4% of the elderly in this one study had both high folic acid and low B12.

Morris et al found that {approx}4% of the elderly persons they studied had a combination of low vitamin B-12 status and high folate status. If the same proportion of all elderly persons in the United States is affected, then {approx}1.8 million elderly might be at increased risk of cognitive impairment and anemia because of an imbalance between folate and vitamin B-12.

If you are deficient in B-12 you are at increased risk of neural damage already. The inability to absorb B-12 rises with age. But periodic B-12 injections can restore B-12 levels. So those with B12 deficiency are best off treating their problem with diet and with injections if necessary.

Dr Jane Durga of the University of Wageningen in the Netherlands just published a paper in :Lancet finding late middle age and early elderly people who take daily folic acid have higher performing brains.

Researchers found that men and post-menopausal women aged between 50 and 70 who took daily doses had the mental abilities of those almost five years their junior.

The supplements also helped maintain speed of information processing, reactions involving movement and overall brain power. These abilities decline with age, and their loss has been linked to a higher risk of dementia.

Another study just published in Archives of Neurology found those with higher folic acid consumption have reduced risk of Alzheimer's Disease.

The study, led by Dr. Jose Luchsinger of Columbia University Medical Center in New York, looked at 965 people age 65 and older in Manhattan. Those with higher levels of folate through diet and supplements were less likely to get the devastating brain ailment, the study found.

In an attempt to reduce the incidence of neural tube defects the US Food and Drug Administration mandated the fortification of many grains with folic acid in 1998. But since whole grains used in whole grain breads are not fortified a popular shift toward the use of whole grains and the attempts by many women to reduce carbohydrate consumption to control weight have reduced the concentration of folic acid in the blood of American women since 2000.

Now, it seems, even that first sign of progress is eroding an apparent victim of dietary shifts, obesity and the stubborn resistance of women in their childbearing years to taking a multivitamin. In a report issued Jan. 5, the CDC found that among women in their childbearing years, blood folate levels had declined 16% by 2004 from the levels recorded in 2000.

The March of Dimes is calling for a doubling of grain folic acid fortification. But as the first article above shows, some scientists are afraid higher folic acid consumption will cause net harm to millions who do not absorb enough B-12.

It might be a good idea to get your blood B-12 tested. If you are deficient then you can change your diet or get a periodic B-12 shot or try taking a B-12 supplement. Once you have enough B-12 then boosting your folic acid is probably a good idea. My advice: Get the folic acid from beans and greens. You'll derive numerous other benefits that way. If you avoid animal products in your diet then get B-12 in a supplement or in highly fortified foods (e.g. Total cereal).

Share |      Randall Parker, 2007 January 18 09:29 PM  Aging Diet Brain Studies

jim said at January 19, 2007 9:32 AM:

i wish somebody would invent a simple, blood analysis on a chip for a variety of compounds..... like the simple blood sugar one for people with diabetes.

not simple to make, but i'll bet it would have big pay-offs

Char Baker said at January 20, 2007 2:19 PM:

I am on 2MG of folic acid because of a homocyctene problom. Is that to much for my brain? As far as I know all my B12 blood tests have come back good,

Doug said at January 23, 2007 11:19 AM:

I take vitamin B-12 as methylcobalamin instead of cyanocobalamin, at the advice of the Life Extension Foundation (who, it's best to keep in mind, do have something to sell). My understanding is that methylcobalamin is already available for absorption; it doesn't have to be converted to an absorbable form by the digestive tract. So absorbable is methylcobalamin said to be, that the supplement offered by LEF is cherry-flavored and intended for oral dissolution and absorption. The point of oral absorption, as I recall, is to allow the B-12 to be circulated throughout the body without first passing through the liver, which I understand would filter much of the B-12, were one to swallow the tablet and allow absorption entirely through the stomach and intestines.

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