UV exposure may lower folate levels

April 9, 2014

A new Australian study reports that pregnant women who take a supplement with folic acid may be at risk of reducing the folate effect through sun exposure.

The observational study measured changes of blood folate concentrations in 45 young healthy women (aged 18 to 47) who had taken 500 mcg of folic acid daily for two weeks followed by one week of different degrees of sun exposure (1). The study results showed that participants with high rates of sun exposure (between 10am and 3pm, with little sun protection) accounted up to a 20% reduction in folate levels.

The researchers concluded that increasing solar UV radiation exposures reduces the effectiveness of folic acid supplementation, especially in women prior to and during pregnancy. Folate has been found to reduce miscarriage and neural tube defects such as spina bifida in unborn babies (2). Previous in vitro research has shown that folic acid is degraded by both UVA and UVB radiation (3).


  1. Borradalea D. et al. Exposure to solar ultraviolet radiation is associated with a decreased folate status in women of childbearing age. Journal of Photochemistry and Photobiology B: Biology. 2014; 131:90–95.
  2. Kondo A. et al. Neural tube defects: prevalence, etiology and prevention. Int. J. Urol. 2009; 16:49–57.
  3. Juzeniene A. et al. The action spectrum for folic acid photodegradation in aqueous solutions. J. Photochem. Photobiol. B: Biol. 2013; 126:11–16