Is Folic Acid Safe For Seniors?

Folic acid, also known as folacin, folate or vitamin B-9, is a member of the B complex family. Like many B vitamins, folic acid works best when it cooperates with other nutrients, especially vitamin B-12. Folate plays a vital role in several metabolic processes in your body, so daily consumption of folate-containing foods is important for your health. Although folate is an essential nutrient at all stages of life, elderly people should use folic acid supplements with caution.

Functions

According to nutritionist Elson Haas, M.D., folate's functions support those of vitamin B-12 in your body. Once absorbed from your intestine, folate is converted to its active form, called tetrahydrofolic acid, or THFA, which assists in the production of red blood cells. THFA and B-12 are instrumental in the synthesis of hemoglobin, the oxygen-carrying protein in your red blood cells, and both participate in the manufacture of DNA, which is needed to form new cells. Folate cooperates with vitamin B-12 in converting homocysteine, an amino acid implicated in heart disease, to methionine. During this conversion, B-12 helps to regenerate folic acid.

Anemia

One important consequence of folic acid deficiency is a decline in your ability to produce red blood cells. Without sufficient supplies of DNA and hemoglobin, your bone marrow forms red corpuscles that are abnormally large and less numerous, leading to a condition called megaloblastic anemia. Vitamin B-12 deficiency also causes megaloblastic anemia, and your doctor cannot distinguish between B-12 and folate deficiency by examining your blood under a microscope. Folic acid supplementation "cures" the anemia caused by B-12 deficiency, but it does not replace all of vitamin B-12's functions.

Trapped Folate

If you are vitamin B-12 deficient, folic acid is not regenerated at its usual rate during the homocysteine-to-methionine conversion. This leads to "trapping" of folate in an inactive state, where it cannot fulfill its metabolic functions. Increasing your folic acid intake overcomes this deficit, but it does not address the underlying B-12 deficiency, and vitamin B-12 performs one critical task that folic acid cannot: It helps to manufacture myelin, the protective coating that surrounds and insulates your nerves. If unrecognized, vitamin B-12 deficiency can cause irreversible damage to your brain, spinal cord and peripheral nerves.

Differential Absorption

Once consumed, folic acid is readily absorbed from your intestine and transported into your bloodstream. In contrast, vitamin B-12 absorption requires a complex interaction among stomach acid, protein factors and specialized receptors in your intestine. As you age, your ability to absorb vitamin B-12 diminishes, while folic acid absorption remains relatively stable. According to the Linus Pauling Institute at Oregon State University, up to 30 percent of people over age 60 suffer from atrophic gastritis, a condition that impairs vitamin B-12 absorption.

Precaution

Deficiencies of folic acid and vitamin B-12 produce similar problems. Supplementation with folic acid can address some, but not all, of the issues caused by B-12 deficiency. In elderly individuals who may already be B-12-deficient due to impaired absorption, supplementation with folic acid alone can "mask" B-12 deficiency and allow serious nerve damage to progress. Both folic acid and vitamin B-12 are essential nutrients for seniors, just as they are for younger people, but older people should not take extra folic acid without first checking with their physicians.