Folate is a water soluble B-vitamin present naturally in foods such as wholemeal bread, legumes, green leafy vegetables (e.g. broccoli, lettuce and cabbage) and liver. Folate is responsible for many processes in the body, including fertility, foetal development and the prevention of anaemia. Consuming adequate folate also substantially reduces the risk of neural tube defects in unborn babies. Neural tube defects are caused by disruptions in the development of the brain and spinal cord. The most well known neural tube defect is spina bifida.
Fortification of Bread with Folate
Mandatory folic acid fortification of wheat flour used in bread commenced in Australia in September 2009 to reduce the incidence of neural tube defects. Voluntary fortification of certain foods with folic acid has been permitted in Australia since 1996. Based on current evidence, the benefits of folic acid fortification for reducing the incidence of neural tube defectss outweigh any potential increased risk of cancer.
Folate and Cancer Risk
There is probable evidence that foods containing folate reduce the risk of pancreatic cancer and limited but suggestive evidence that they reduce the risk of oesophageal and bowel cancer. Cohort studies suggest that a high dietary folate intake may reduce the risk of post-menopausal breast cancer, particularly for women with a family history of breast cancer.
However, while inconclusive, some studies show that high intakes of folate appear to promote existing bowel adenoma (tumour of the glandular tissue in the bowel). While dietary folate (even from foods fortified with folic acid) may have no adverse effects, some studies suggest that the combined impact of folic acid from supplements and fortification could promote pre-existing adenomas.
Cancer Council NSW supports the Australian Dietary Guidelines and recommends that people obtain their nutritional requirements from whole foods, such as fruits, vegetables, breads and cereals rather than individual nutrients in a supplement form. However women who are pregnant or planning on starting a family may need to take a folic acid supplement to ensure they are meeting the requirements to prevent neural tube defects.
People with existing bowel adenomas and those with an increased risk of developing bowel adenomas should avoid taking high-dose folate supplements.