Lots of talk about B folate lately -- how much is best to take and is it based on weight, height, gender?

Dosage -
For overall good health and the prevention of heart disease: 400 to 800 mcg of folic acid a day.

For women who might become pregnant:
a total of 800 mcg a day.
(Adequate folic acid stores are important because the vitamin plays a role in a baby's development from conception.)

For people with depression: 400 mcg a day, as part of a vitamin B-complex supplement.

Guidelines for use -
Folic acid can be taken at any time of the day, with or without food. When taking individual folic acid supplements for any reason, combine it with an additional 1,000 mcg of vitamin B12 to prevent a B12 deficiency.

Buy a folic acid supplement that also contains vitamin B12 (too much of one can mask a deficiency in the other). A combination supplement may be less expensive than buying each vitamin separately.

Prevention -
Adequate folic acid at conception and for the first three months of pregnancy greatly reduces the risk of serious birth defects, including spina bifida.
This B vitamin also appears to regulate the body's production and use of homocysteine, an amino acid-like substance that at high levels may damage the lining of blood vessels, making them more susceptible to plaque buildup. This makes folic acid an important weapon against heart disease.
In addition, it may be useful in warding off certain cancers, including those of the lungs, cervix, colon, and rectum.

400 mcg is the RDA for Folic Acid (Folate), but 800 mcg is the normal dose in a standalone supplement.

Height/weight/gender doesn't really make any difference, really.... except that women who plan on becoming pregnant or are pregnant should definitely get supplemental Folic Acid in their diet because it helps to prevent birth defects. Most multivitamins and B-Complexes have 400 mcg of Folic Acid, but the general population doesn't take a B-Complex and are actually deficient (which is why more doctors are recommending a Folate/Folic Acid be taken supplementally).