Vitamin B9 (Folate)

What it does

Vitamin B9, or folate, is essential for making and repairing DNA and for the process of cell division. Any tissue that produces large numbers of new cells depends heavily on it, which is why folate is so important during pregnancy, infancy and any time the body is growing or healing. It works as a carrier of "one-carbon" units, the small chemical building blocks the body needs to construct the genetic material inside new cells.

Folate is critical for making healthy red blood cells. A shortage disrupts cell division in the bone marrow, producing large, immature red cells that carry oxygen poorly — a condition called megaloblastic anaemia, which folate shares with vitamin B12. It also works with B12 and vitamin B6 to keep homocysteine, an amino acid linked to cardiovascular risk, at a healthy level.

Its role in early development is why folic acid (the synthetic, well-absorbed form) is recommended before and during early pregnancy: adequate folate at the time the neural tube forms substantially reduces the risk of serious birth defects such as spina bifida. Folate occurs naturally in green leafy vegetables, pulses and liver, and many countries fortify flour or cereals to help ensure a reliable supply.