FolateVitamin B9 · Folic acid
A B-vitamin that partners with B12 for healthy blood and nerves.
Folate is vitamin B9, needed for DNA synthesis and repair, for making red blood cells, and for the metabolism of amino acids. Folate is the form found naturally in food, chiefly leafy greens, pulses and liver; folic acid is the stable synthetic form used in supplements and fortification.
Its best established use is one of the strongest cases for any supplement anywhere. Folic acid taken before conception and in early pregnancy substantially reduces the risk of neural tube defects such as spina bifida, and because the neural tube closes in the first few weeks, often before a pregnancy is known, the recommendation is to start before conceiving rather than after.
Deficiency otherwise causes a macrocytic anaemia, with large red cells and a raised MCV, alongside fatigue and mouth ulcers. Poor diet, alcohol, coeliac disease, some medications and pregnancy itself all increase the risk.
The interaction with vitamin B12 is the point most worth remembering. High dose folic acid can correct the anaemia of B12 deficiency while the neurological damage continues underneath, which is why the two are always checked together and why a large red cell anaemia should never be treated with folate alone.
Methylated forms are heavily marketed on the basis of MTHFR gene variants. Those variants are common and, in people who are not deficient, of far less clinical significance than the marketing suggests; ordinary folic acid is effective for the great majority.
Very high intakes are not obviously beneficial and have been debated for other risks, which is another argument against megadosing something a varied diet supplies.
In practice: eat greens and pulses, take folic acid if you are planning a pregnancy or could become pregnant, and have B12 checked alongside folate if either is low.
Where your own result would sit
Most people reading this page are holding a blood-test report with this marker on it, and the question they arrived with is whether their number is normal. A reference interval says where most results from a healthy population fall; a guideline threshold is where a clinical body draws a line for a decision. Neither is a target, and a result on the wrong side of one is not a diagnosis: the same number can be unremarkable in one person and worth looking into in another, which is why the clinician who ordered the test reads it against your history rather than against a list.
Folate has no published interval on this page yet. We hold one, and the dashboard draws it beside a reader’s own result, but it has not been read back against the laboratory’s own page since it was collected. A figure printed beside somebody’s blood result has to have been seen at its source, not remembered, so this one waits.
On your own blood test?
Folate is one of the markers FitTools can read from an uploaded blood-test report. You confirm every value before anything is saved, and your results are explained together in one place.