FOLIC ACID (VITAMIN B9)

What is folic acid?

Folic acid is a water-soluble B vitamin. It is also known as vitamin B9 [^[1]].

What does folic acid do in the body?

Folic acid belongs to the B vitamin family. All B vitamins help the body break down and derive energy from macromolecules such as carbohydrates, proteins, and fats. B vitamins also play a role in nervous system function [^[2]].

Folic acid has many functions in human biochemistry. It is essential for proper balance in our cells [^[3]].

Folic acid helps the body grow new cells and prevent changes in DNA that may cause cancer. Deficiency in folic acid is associated with a variety of health conditions, including cancer [^[4]].

Folic acid works with vitamins B6 and B12 to regulate the levels of homocysteine in the blood [^[5]]. Homocysteine is an amino acid linked to arteriosclerosis, cancer, aortic aneurysm, hypothyroidism, and end-renal stage disease, among other conditions [^[6]].

How can folic acid help alleviate certain Long COVID symptoms and pathophysiology? 

Folic acid can help curb inflammatory processes in Long COVID by regulating homocysteine levels.

Low levels of folic acid can also predispose to Long COVID [^[7]]. Folic acid may also help reduce respiratory involvement in the acute phase of COVID-19, especially in the early phase [^[8], ^[9]]. Folic acid blocks the function of a protein called furin, which is involved in the viral replication of SARS-CoV-2, the virus that causes COVID-19 [^[10]]. Decreased folic acid levels are expected in hospitalized COVID-19 patients, and scientists believe that lower folic acid levels are seen in more severe patients [^[11], ^[12]]. Since more severe COVID-19 patients are more likely to develop Long COVID, folic acid levels should be measured in the acute phase of COVID-19 [^[13]].