Folic acid: when can a supplement hide a dangerous vitamin deficiency? | Dr. Itay Gal
Folic acid is one of the most important supplements in preventive medicine, especially for women before and during early pregnancy, because it reduces the risk of neural tube defects. But for specific people, uncontrolled intake can hide an important deficiency.
The important supplement that requires context: few supplements have saved as many babies as folic acid. It is essential for building DNA, proper cell division, and the creation of red blood cells. Taking it before pregnancy and in its early stages clearly reduces the risk of neural tube defects, such as spina bifida. Therefore, it is important to say at the outset: folic acid is not an enemy. On the contrary, it is one of the most important recommendations for women of childbearing age.
The problem begins when this important recommendation expands to uncontrolled use by people who do not need it, or when it hides another problem. Folic acid and vitamin B12 work together in pathways related to DNA production and nervous system function. A deficiency in either of them can cause megaloblastic anemia, a condition where red blood cells are large and abnormal. But B12 deficiency also causes nerve damage because it is essential for maintaining the myelin sheath that surrounds nerves.
Here lies the trap: a high dose of folic acid can improve the blood picture in a person suffering from B12 deficiency, that is, correct part of the anemia or make it less noticeable. The doctor sees a less dramatic blood count, the patient feels that everything is fine, but the B12 deficiency may continue to damage the nervous system. Symptoms can include tingling in the feet and hands, a burning sensation, decreased sensation, instability when walking, weakness, memory disturbances, confusion, depression, and sometimes prolonged neurological damage.
Who is at risk for B12 deficiency? Vegans and vegetarians who do not supplement B12, the elderly, people after bariatric surgery, patients with intestinal diseases or celiac disease, people with atrophic gastritis, patients on long-term metformin, chronic users of stomach acid-reducing medications, and people with unexplained anemia or neurological symptoms. For them, independent intake of folic acid without a B12 test can confuse the picture.
It is also important to distinguish between dosages. The recommended dose for women before and during early pregnancy is set for a clear reason, and sometimes higher doses are needed for women at high risk, according to a doctor. This is different from an adult who takes a high-dose supplement for months or years because it is "good for the blood." Not everything that is beneficial during pregnancy is suitable for everyone all the time.
Foods fortified with folic acid and supplements in multivitamins also contribute to total intake. A person may not know they are receiving folic acid from several sources simultaneously. In most cases, this will not cause harm, but in populations at risk for B12 deficiency, the question is not just excess folate, but what it is hiding.
The correct diagnosis is not complicated: a B12 test, a blood count, and sometimes methylmalonic acid and homocysteine as needed. If there are neurological symptoms, one should not settle for correcting anemia. B12 deficiency is treated quickly, sometimes with injections, depending on the severity and cause. The longer the nerve damage continues, the smaller the chance of full recovery.
Women of childbearing age should continue to listen to the recommendations for folic acid. This is important preventive medicine. On the other hand, adults, vegans, people after bariatric surgery, or those suffering from tingling and fatigue should not take folic acid as a general solution without checking B12. Sometimes a supplement that corrects a number in a blood test hides what is really important to see.
