Vitamin B9 (folate)

In the 1920s, Lucy Willis, who was one of the first British women to become a med­ical doc­tor, start­ed study­ing a par­tic­u­lar­ly severe and often fatal form of ane­mia that often occurred in preg­nant poor women in India. As in cas­es of “per­ni­cious ane­mia,” the women didn’t have enough red blood cells, but the red blood cells they had were often abnor­mal­ly large.

Dr. Willis sus­pect­ed that this “per­ni­cious ane­mia of preg­nan­cy” was due to a dietary defi­cien­cy. In 1931, she found that a cheap yeast extract called Mar­mite quick­ly cured the prob­lem. Lat­er on, the sub­stance that was respon­si­ble for cur­ing the ane­mia was iso­lat­ed from spinach. It was named “folate,” after the Latin word foli­um, which means leaf. Folate is also called vit­a­min B9.

Folate is a per­fect exam­ple of why it is bet­ter to get your nutri­ents from food than from pills. The form of vit­a­min B9 that is found in foods is called folate. Unfor­tu­nate­ly, this form tends to be unsta­ble. The form of vit­a­min B9 that is used in processed foods and in vit­a­min sup­ple­ments is called folic acid. It’s much more sta­ble, and if you take a rea­son­able dose of it, it’s a good source of vit­a­min B9. Yet some food sci­en­tists and pub­lic health author­i­ties are con­cerned about the effects of tak­ing too much folic acid, from for­ti­fied foods or from vit­a­min sup­ple­ments.

The body has a com­pli­cat­ed sys­tem for con­trol­ling how much folate gets absorbed from the food into the blood­stream. As a result, peo­ple don’t get too much folate from eat­ing too many leaves. On the oth­er hand, if they take too much folic acid, the extra folic acid could bypass the sys­tems that the body usu­al­ly uses to con­trol folate lev­els. The extra folic acid in the blood­stream could be dan­ger­ous in some­one who has a defi­cien­cy of vit­a­min B12. It could cor­rect the ane­mia that is an impor­tant warn­ing sign of vit­a­min B12 defi­cien­cy, per­haps allow­ing the prob­lem to progress to the point that the per­son suf­fers per­ma­nent dam­age to the ner­vous system.[1] This is a seri­ous con­cern, con­sid­er­ing that so many elder­ly peo­ple are at risk for vit­a­min B12 mal­ab­sorp­tion. The have also been some reports that tak­ing too much folic acid could increase the risk of can­cer.

Women who have a folate defi­cien­cy are more like­ly to give birth to babies with severe birth defects, called neur­al tube defects. Exam­ples include anen­cephaly (absence of the brain) and spina bifi­da (open spine). In these cas­es, the dam­age is done at a very ear­ly stage of devel­op­ment, usu­al­ly before the woman even knows that she is preg­nant. That’s why it’s impor­tant to make sure that women who might become preg­nant have good folate sta­tus.

To help pre­vent neur­al tube defects, the U.S. Food and Drug Admin­is­tra­tion start­ed requir­ing food man­u­fac­tur­ers to add folic acid to sev­er­al dif­fer­ent kinds of food, includ­ing ready-to-eat cere­als and the enriched flour used to make baked goods. The food for­ti­fi­ca­tion pro­gram led to a sig­nif­i­cant drop in the risk of neur­al tube defects. Some researchers argue that this has been bal­anced by a rise in the risk of col­orec­tal can­cer. How­ev­er, it’s unclear whether that increase was real or sim­ply the result of an increased num­ber of patients receiv­ing colono­scopies.

Peo­ple who eat a health-opti­miz­ing diet will auto­mat­i­cal­ly get plen­ty of folate and are at low risk of get­ting too much folic acid in their food. That’s because they eat lots of fruit and veg­eta­bles, includ­ing plen­ty of leafy green veg­eta­bles. They also eat whole-grain prod­ucts, rather than the “enriched” white flour prod­ucts that have had folic acid added to them.

Reference List

  1. Quin­li­van EP, Gre­go­ry JF, III. Effect of food for­ti­fi­ca­tion on folic acid intake in the Unit­ed States. Am J Clin Nutr. 2003;77(1):221–225.