Outdoor workers and others who spend a lot of time in the sun are at risk of depleting their folic acid, say Australian researchers.

Women who spend a lot of time in the sun are at risk of losing folic acid, according to a new study.

This means outdoor workers and others should speak to their GP if they are pregnant or likely to become pregnant, says researcher Professor Michael Kimlin from the Queensland University of Technology.

He and Dr David Borradale found a 20 per cent reduction in folate levels in a study of Brisbane women aged 18 to 47 who had high rates of sun exposure.

“This is concerning as the benefits of folic acid are well known,” Professor Kimlin said.

Folate has been found to reduce miscarriage and neural tube defects in unborn babies.

Pregnant women or those planning a pregnancy are encouraged to take 500 micrograms a day.

High exposure to sun left women with folate below the recommended range for those considering pregnancy, according to the study published in the Journal of Photochemistry and Photobiology.

Women who spend time outside from 10am to 3pm with inadequate sun protection are most at risk.

Folic acid is a B vitamin found in green leafy vegetables, citrus fruits, legumes, whole grains and vegemite.

In Australia it is also added to foods such as bread.