The biochemical functions of folic acid are very closely related to those of Vitamin B12, being similarly involved the formation of ‘active methyl groups’, and through this role, with protein metabolism, purines, nucleic acids and with the synthesis of the haem of haemoglobin, the blood pigment. The most commonly recommended allowance is 400mcg per day, 800mcg during pregnancy and 600mcg during lactation (note these are again in micrograms). Our suggestion is to use around 100mcg of folic acid per day, a suitable range of intakes being in from 40 up to 200mcg per day. Note that this is markedly different from the practice with the other B Vitamins discussed so far, where we generally wish to suggest using well in excess of the RDA or RNI levels to everyone. This is really the result of official discouragement from giving more significant amounts of folic acid on account of its ability to mask symptoms of any co-existing Vitamin B12 deficiency. Covering up the effects with folic acid can lead to nervous system damage. Note, however, that we always advise in addition a diet rich in leafy vegetables, which are an excellent source of folic acid. Conditions for which folic acid is recommended naturally include the anaemias. It is usually recommended in alcoholism (which depletes all micro nutrients anyway) and in stress and adrenal exhaustion (in common with most other B vitamins). Because deficiency of folic acid may cause hair deterioration and gastro intestinal disturbances, it gets recommended for baldness and indigestion even though these can happen from several other causes. Studies have related folic acid to arterial disease, so it may be recommended for that. The comments we have made above regarding the limitations of disease of symptom-orientated prescription apply. These recommendations are a little superficial and the best policy is to make a modest supplementary contribution to folic acid supply in all subjects and to ensure at the same time a folic acid-rich diet. >>Source
Uses in the body: essential for growth and development of cells and normal function of nervous system (in conjunction with vitamin B12). Also helps to regulate histamine levels and is vital for normal neural tube development in the foetus.
Signs of deficiency: lethargy, anaemia, shortness of breath, cracking of the corners of the mouth and sore tongue (although these two symptoms can also be due to iron or B vitamin deficiency), depression, nerve damage, neural tube defects (such as spina bifida) in babies.
Therapeutic uses: essential for all women planning pregnancy, during pregnancy and when breastfeeding, for dairy allergic infants fed on goats’ milk (which is very low in folic acid), for people suffering from irritable bowel problems, depression, alcoholism, mental illness or the early stages of Alzheimer’s disease.
Dietary sources: leafy green vegetables (especially spinach and curly kale), sprouts, broccoli, brewer’s yeast, wholegrain cereals, liver, kidney, pulses, oranges.
Recommended daily allowance: 200µg
Typical therapeutic daily dose: 400µg is advised for all women planning pregnancy and up to the end of week 12 of pregnancy.
Daily intake shouldn’t exceed: 400µg, although women who’ve already had a child with a neural tube defect and who wish to become, or are already, pregnant, may be advised to take 5mg (5000µg). Consult your GP for further advice.
Cautions: large intake (400µg a day over many months) can mask symptoms of a vitamin B12 deficiency and anaemia.
Best taken: daily with food, together with a B12 or B-complex supplement and with iron