To decide if a higher dose of folic acid supplementation is needed, care providers should assess whether the woman has personal characteristics or health conditions linked with a heightened risk of having a baby with neural tube defect (NTD).
It recommends a rate of more than 400mcg (0.4mg) of folic acid per day for women who have a low dietary intake of folate, an elevated folate requirement or an altered folate metabolism.
Dietary factors linked to a heightened risk of NTD are: A poor quality diet, chronic dieting and avoiding folic acid fortified foods such as low carbohydrate diets.
In addition to smoking, a woman’s ethnic group may also have an influence. The organization highlights Hispanic-Canadians’ preference for non-fortified rice as a staple and the use of maize flour (masa) versus folic acid fortified wheat flour.
It picks out prolonged stewing too; a common practice among some South Asian-Canadians that destroys naturally occurring folate.
Risk factors associated with elevated folate requirements include:
Personal or family history of NTDs, congenital anomalies and medications that interfere with folate metabolism such as methotrexate.
Other factors that warrant higher folic acid intake are: Malabsorption and gastric bypass surgery, liver disease and kidney dialysis.
Women with altered folate metabolism should receive supplementation at rates higher than 400mcg of folic acid, recommends Health Canada. That applies to women who are obese or who have diabetes, impaired glucose metabolism and hyperinsulinemia.
If a higher rate of folic acid proves necessary women can either:
- Consume a multivitamin supplement and add single folic acid tablets as necessary to achieve the recommended daily dose of folic acid.
- Or consume a multivitamin containing more than 1 mg of folic acid.
Health Canada advises that with both options, the multivitamin supplement should contain vitamin B12. Most multivitamin supplements available in Canada contain vitamin B12, it adds.
But the organization cautions against taking more than one multivitamin supplement each day in an attempt to consume a higher dose of supplemental folic acid.
In large doses, some substances, such as Vitamin A in the retinol form, could be harmful.
If a woman doesn't conceive after 3 or 4 months of taking daily supplements, a lower level of folic acid supplementation of 0.4 to 1.0 mg should be considered.