I used to see my multivitamin and mineral as good nutritional insurance. It certainly is a form of insurance, but there can be consequences with taking your daily supplement blindly.
The folic acid fortification program in the United States provides us with a very good example of why supplementation willy-nilly can have perverse consequences.
People do not get enough folate in their diets and a low folate status is associated with birth defects like spina bifida. Since many women do not plan their pregnancies and many who do plan them do not consume enough folate in preparation, the USDA decided to fortify grain-based foods with folic acid in the late 1990s.
Nearly a decade later, researchers are trying to determine the effect of this food fortification program. Neural tube defects like spina bifida are on the decline, but cognitive problems are on the rise in the elderly.
It appears that you can get too much of a good thing under certain circumstances.
Added folic acid in your diet should improve your cognition. It is even a depression-fighting nutrient. However, it appears that if you are low in vitamin B-12 (another depression-fighting nutrient), the added folic acid will worsen your cognitive state.
According to Morris et al. in a 2007 paper, the 60-plus year old study participants benefited from folic acid if their B-12 status was sound and actually had worse cognitive function if their B-12 status was low.
One reason the study focused on an older group of people is because as we age, we are more likely to be deficient in vitamin B-12. That leaves the older folks in our population at risk of facing cognitive impairment due to high folic acid intake.
In a review article published in the same issue of the American Journal of Clinical Nutrition, researcher A. David Smith calls for more research on the food fortification program and questions the ethics of saving a small number of babies from neural tube defects while putting at risk a large portion of the population.
What You Can Do
Consume Food Folate
The folic acid fortification example makes a case first for beginning to rely more on our food than on our supplements for the nutrients our bodies need. Food contains folate and very little of that folate is in the form of folic acid. There is no evidence that a lot of dietary folate will adversely affect our moods or cognition. In fact, it is difficult to get enough folate. It would be next to impossible to get too much in the natural form that our food contains.
Know Your Status
Ask your doctor for a plasma homocysteine test. An elevated level (above about 12) is associated with a poor status of B-12, B-6, folate (or some combination). If your levels are elevated, have your levels of each of those B-vitamins tested. If you are low in B-12, begin a supplementation program and add B-12 food sources to your diet. With an improved B-12 status, you will then benefit from folic acid rather than hurt by it.
Consider the Methylfolate Form as a Supplement
Smith offers this as a possible remedy to the problem – use methylfolate instead of folic acid. Folic acid is metabolized into methylfolate. Some researchers speculate that unmetabolized folic acid is part of the problem in this story. (And not everyone effectively metabolizes folic acid in the first place.)