Folic acid is a nutrient generally thought to be good for brain health and better thinking, but new research indicates that too much folic acid in people who are deficient in vitamin B-12 can cause just the opposite.
Researchers at Tufts University in Boston using data from the two most recent National Health and Nutrition Examination Survey that had measured cognitive status, anemia, and vitamin B-12 and folate levels found that subjects (aged 60 and older) who had the highest levels of folate were protected against cognitive impairment, but those with low levels of vitamin B-12 and high levels of folate were 2.6 times more likely to show signs of cognitive impairment. And, surprisingly, anemia was 3.1 times greater in the low B-12, high folate group. The results of this study were published in the January American Journal of Clinical Nutrition (AJCN).
How did these subjects who had low vitamin B-12 levels and high folate levels end up with so much folate? In large part, thanks to the efforts of our government.
Over the years there have been a handful of studies showing that pregnant women who take folic acid early in their pregnancies markedly decrease the risk that their babies will be born with a neural tube defect (NTD). Several years back homocysteine was fingered as a risk factor for heart disease; folic acid, along with vitamin B-12 drives blood levels of homocysteine lower. As a consequence, in 1998 the US Food and Drug Administration (FDA) mandated that flour products in this country be fortified with folic acid (actually, pteroylglutamic acid, an extremely minor component of the folates in unfortified food). The thinking of the bureaucrats in the FDA was that since flour is a primary component of the American diet, fortifying cereals, breads, and other flour products would ensure that all Americans got plenty of folic acid whether they wanted it or not. The desired outcome would be a drop in the number of babies born with NTDs and the incidence of heart disease would decrease. As an editorial accompanying the AJCN article points out that
The consequence was, however, that for each NTD prevented, several hundred thousand people were to be exposed, without choice, to extra folic acid. Despite this concern, no studies have been carried out in nonchildbearing subsets of the population to see whether they might also benefit from, or could even be harmed by, exposure to folic acid. The prevailing view was that it must be “a good thing” to give extra folic acid, not only to prevent NTDs but also to lower plasma homocysteine concentrations and perhaps prevent cardiovascular disease. Although folic acid fortification has reduced the number of NTDs, recent trials suggest a limited effect, or no effect, of folic acid intervention on cardiovascular disease, although the outcome may not be entirely negative.
So, once again, the law of unintended consequences asserts itself. In an effort to reduce NTDs and heart disease, the government has spawned what could be an epidemic of slow thinking in the population of folks over 60, the very people who are already worried about Alzheimer’s. And the very same folks who are worried about their cholesterol, and who, thanks to the government food pyramid, have been scared off of eating meat.
Since MD and I and most readers of this blog follow low-carb diets, all the folic acid added to flour-based products shouldn’t affect us. If we’re following a good-quality, whole-food, low-carb diet, we should be getting plenty of green leafy and colorful vegetables, all of which contain folic acid. If we’re really good, we eat liver – a great source of folic acid – from time to time. And since the vast majority of us eat a fair amount of meat, we all will have plenty of vitamin B-12 – which is only found in foods of animal origin, primarily meat. (There is some in eggs and dairy, but not nearly as much as in meat.)
We low-carbers will have good levels of vitamin B-12 and good levels of folate, so we should be well armed to maintain our ability to think well into our dotage.
Given the results of this study, a mystery that I have posted about several times lately can finally be solved.
Let’s look at a list of foods other than liver (which I’ve discovered from many commenters that very few people eat) that contain high levels of folic acid:
Fortified breakfast cereals
Bread, pasta and other whole wheat products
Green leafy vegetables
Cantaloupe and other melons
Now let’s look at the list of foods that contain high levels of vitamin B-12:
The above study showed that high levels of folic acid combined with low levels of vitamin B-12 leads to cognitive impairment. Given this fact, looking at the above lists of foods, it’s pretty easy to connect the dots and suddenly realize why members of PETA are so stupid. They can’t help it. They all have too much folic acid and not enough vitamin B-12.
Readers of this blog who eat primarily meat (but who don’t like liver) and who eat few vegetables might want to consider a folic acid supplement. See my previous post on the best folic acid supplement.