Folate is short in a striking number of diets: research published in The Lancet Global Health estimates around 54% of people don't get enough to meet the recommended intake.
Its central job is helping your body make DNA and form new cells, which is why it matters most during periods of rapid growth. It also works alongside B12 to make healthy red blood cells. When intake stays low over time, that's associated with tiredness, weakness, and a particular type of anaemia.
Adults need around 400 mcg a day, from dark leafy greens, legumes, citrus fruits, and fortified grains. The name hints at the best sources, since "folate" shares a root with "foliage."
There's an upper limit of 1,000 mcg a day, but it applies specifically to folic acid, the synthetic form in supplements and fortified foods, rather than the folate naturally in vegetables. The reason is worth knowing: a high folic acid intake can hide the early signs of a low B12 level, letting it go unnoticed for longer.
The at-risk group really stands out here. Folate is especially important for women who are pregnant or may become pregnant, since adequate intake in early pregnancy is strongly associated with healthy fetal development, which is why it's so often recommended in that window. Anyone in that situation is best guided by their doctor on the right amount.