Taking a folic acid supplement has long been recommended to pregnant women to lower the risk of low birth weight, preterm delivery, and defects in the development of the baby’s neurologic system.  In fact, in 1998, the U.S. required that flour and other whole grains be fortified with folic acid for this very reason.

 Taking it as a supplement is also recommended to adults in midlife and older for specific medical problems in which folic acid deficiency is playing a role. Some of these include: 1) a certain type of anemia (low red blood cell count)  related to Vitamin B12 deficiency;  2) liver disease; 3) alcohol abuse or overuse;  4) kidney dialysis;  5) problems with absorption in the gastrointestinal tract; and 6) in people on certain drugs such as antiseizure medications, among others.

In recent years, folic acid supplementation for older adults has been in vogue for prevention of heart disease, though no studies have shown such a benefit, and more recently, for stroke prevention. In fact, a study showing that folic acid was effective in preventing strokes was released just as we were writing our book, although appropriate dosages were unknown.

 Now comes research from Norway (Ebbing M et al. JAMA 2009 Nov 18.)* in which the results of two separate trials of folic acid supplementation were combined, and included nearly 7000 people.  (Of note, Norway does not mandate folic acid fortification of foods.) Study participants received either folic acid plus Vitamins B12 and B6; folic acid plus B12 only; B6 alone ; or placebo.

After following the patients for an average of 6 years, it was found that those who took folic acid had a 21% greater risk for developing cancer than those who did not take folic acid.  Interestingly in another study in 2009, it was shown that folic acid supplementation increased the risk of prostate cancer.  Since it is known that folic acid can impair the immune system’s surveillance of cancer cells, and may even stimulate growth of already established cancer cells,  these findings are not all that surprising from a biologic point of view.

So, where does that leave us adults in midlife and older with respect to folic acid supplementation? Do we take it and possibly prevent heart disease or strokes, but risk an increased chance of cancer? The answer is not simple; as with all good medicine, it involves taking a personal approach and weighing the risks vs. the benefits in terms of  your particular case given your health profile.  The best answer is definitely not the same one for everyone.

Since we now know that there may be a risk in taking folic acid in amounts over what we get in our diets, and the benefits of it in terms of cardiovascular disease and strokes are not definite, the safest approach – based on our CURRENT knowledge – is NOT to take extra, or supplements of, folic acid unless you have a specific medical reason, or a folic acid deficiency. Unless you have one of the conditions that lead to folic acid deficiency mentioned above, you should be able to get all you need in your diet. 

What foods naturally contain folic acid? Leafy green vegetables (like spinach and turnips), citrus fruits, and dried beans and peas. Should you avoid whole grains and foods containing flour since they are fortified with folic acid – so that you can avoid getting too much? Most experts believe that even with the fortification in these foods, the American population is still within safe limits in terms of the amount of folic acid in the diet.

There’s a good lesson in all this. Trends in nutrition and vitamin supplementation come and go. New information and scientific studies are constantly coming out. Speak to your clinician before you take supplements of folic acid, or anything else for that matter.  Remember: vitamin and herbal supplements can have negative effects too. Don’t go buying lot of vitamins and herbs in hopes of staying healthy or living forever. You will probably do better in the long run to simply eat a healthy diet.

*(Ebbing M et al. Cancer incidence and mortality after treatment with folic acid and vitamin B12. JAMA 2009 Nov 18; 302:2119)