Folate, a natural B vitamin, is essential for good health. It can also be taken as a synthetic form known as folic acid. Many countries, including the New Zealand Ministry of Health, recommend that women take the recommended dose of folic acid supplements before and during early pregnancy. This considerably reduces the risk of their baby developing neural tube defects, a type of birth defect. However, for various reasons many women are not able to follow this practice. To increase folate intake among women, many countries have made it mandatory to fortify some staple foods with folic acid. This has been shown to reduce the rates of neural tube defects, in some cases to a substantial degree. However, due to commercial and consumer concerns over the safety of folic acid fortification, New Zealand currently relies on industry-led voluntary fortification of bread.
This report reviews the scientific literature on the health benefits and risks of folic acid, particularly in relation to food fortification and consumption of higher-dose supplements. It concludes that mandatory fortification is unequivocally associated with lower rates of neural tube defects, and that taking folic acid supplements at the recommended doses in pregnancy has no adverse effects on pregnancy outcome or the child’s health. There is no evidence that folic acid supplements increase the risk of neurological/cognitive decline, diabetes, or cardiovascular disease, or that unmetabolised folic acid that remains within the body’s circulation is harmful. There is no strong evidence of adverse effects on risks of some common cancers, or total cancers. There is limited evidence from genetic studies involving people born with lower blood folate levels, that relatively higher blood folate may be associated with lower risks of breast and total cancers, but higher risks of prostate and colorectal cancer. This is an ongoing area of research which should be monitored.
Based on an overall assessment of the evidence, and also considering the need to ensure that disadvantaged people including Māori receive benefit, the Expert Panel concludes that the benefits of mandatory fortification of packaged bread with folic acid outweigh any potential adverse effects.
In addition, the Panel strongly encourages the continued use of folic acid supplements by pregnant women as recommended by their healthcare professionals, and encourages all women of childbearing age to ensure that their folate intakes are adequate.