Folic acid is a part of the B complex of vitamins. It is vital for red blood cells and for many other cells in the body. The form of folic acid occurring naturally in food is called ‘folate’.
Functions of folic acid
Folic acid, along with vitamin B12, is important for formation of red blood cells. Lack of these two vital nutrients leads to variety of anemia called macrocytic anemia. This means the red blood cells appear bloated and large and have a reduced capacity to carry oxygen.
Folate along with other B vitamins are also vital for nerve function. Folate is essential for the formation of DNA (genetic material) within every body cell. This allows normal replication of cells.
Biochemically folates act as chemicals that medicate one-carbon transfer reactions. These are important for formation of purines and pyrimidines. These purines and pyrimidines form basic building blocks for DNA.
Most of the required folate in men and non-pregnant women are obtained from a healthy and well-balanced diet. Pregnant and breast feeding women and children during their growing years require folate in their diet. In pregnant women, for example, lack of folate in diet can lead to severe nerve defects like neural tube defects, spina bifida, anencephaly etc. in their unborn children.
Daily recommendations for folate (folic acid)
Adults and children over 11 years: 200μg
Any woman considering pregnancy: 200μg plus a folate supplement containing 400μg
Pregnant Women: 300μg plus a 400μg supplement during the first 12 weeks of pregnancy
Breast feeding women - 260μg
Folate deficiency occurs in two cases – excess demands of folate (e.g. during pregnancy and breast feeding) and excessive loss (e.g. Crohns disease or untreated coeliacdisease, alcoholism, use of medications like diuretics etc.).
Symptoms of folate deficiency
In cases of folate deficiency there may be some general symptoms of anemia like fatigue and tiredness. There may be features of diarrhoea, loss of appetite, weight loss, headaches, heart palpitations, sore tongue and behavioural disorders.
Folate deficiency during pregnancy
During pregnancy folate deficiency is associated with nerve defects in the fetus. The fetus develops rapidly and develops spine and nerve cells in the first few weeks of pregnancy. Inadequate blood levels of folate during this time increase the risk of the baby’s spine developing a ‘neural tube defect’. This may cause spinal malformation called spina bifida.
Folates also help in reduction of high levels of homocysteine. Homocysteine is a protein that irritates blood vessels. This leads to increased risk of heart attack or stroke.
Foods rich in folic acid
Folate is found naturally in dark green leafy vegetables. The word folate in fact comes from the word foliage. Folate is a water-soluble vitamin and is thus lost easily from vegetables during cooking. This can be prevented by avoiding over-cooking. Folate can also be preserved by steaming ormicrowaving vegetables rather than boiling them in open.
Folates are also present in foods fortified with folic acid. This is practiced in many countries since, despite recommendations, many women do not take folic acid supplements in early pregnancy. Foods commonly fortified with folic acid are breakfast cereals, flour etc.
Over dosage of folate in diet and as supplements
Routine fortifications may not be beneficial as folates need to be supplemented along with vitamin B 12 because if not administered together a vitamin B12 deficiency mediated nerve damage may be unmasked and this may lead to irreversible nerve damage. Elderly are most at risk as uptake of vitamin B12 from diet reduces with age.
Those over 50 are advised not to take folic acid supplements containing more than 200μg/day. For others, long-term intakes of folic acid from fortified foods and supplements should be below 1mg/day for adults (lower amounts for children).
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)