When cells divide, they need to make copies of DNA—the chemical that carries all the genetic information in a cell. Folic acid is a crucial building block for DNA and is thus vital for cell division. Since blood cells are produced by arguably the most fearsome rate of cell division in the human body—more than 300 billion cells a day—the genesis of blood is particularly dependent on folic acid. In its absence (in men and women starved of vegetables, as in Bombay) the production of new blood cells in the bone marrow halts.
