According to the National Diet and Nutrition Survey (NDNS), this figure placed the women at an elevated risk of their babies being born with a neural tube defect (NTD) such as spina bifida and anencephaly.
“The new results from this survey provide confirmation that folate levels are dropping across the population,” said Food Standards Scotland (FSS) in response to the findings.
“Food Standards Scotland maintains its call for mandatory fortification of flour with folic acid on a UK-wide basis to help address this concerning drop in folate levels.”
The survey, also found 16% of women of childbearing age (16 to 49 years) had a blood folate below the threshold of 305 nanomols per litre (nmol/L), placing them at an increased risk of anaemia.
Current fortification approaches in the UK have seen mandatory fortification of flour with other nutrients such as iron and calcium and the B vitamins thiamin and niacin.
Efforts to include folic acid in the mix received a much-needed push last year, when the Scientific Advisory Committee on Nutrition (SACN) published a review on Folic Acid.
Like the FSS, the SACN continued to recommend mandatory fortification of flour with folic acid, along with the controls on voluntary fortification.
The Food Standards Agency (FSA) also recommend the mandatory fortification of bread or flour with folic acid in order to reduce the risk of neural tube defects in foetuses.
Rationale for folic acid fortification
Much research points to higher folic acid intakes before pregnancy and during pregnancy reduces the risk of NTDS.
While women are advised to take folic acid supplements, the compliance rate is low or they begin supplementing too late into the pregnancy term.
The FSA believes that if bread or flour were fortified with folic acid this would increase folic acid intake of women with otherwise low intake who may become pregnant.
This approach could also be most effective way of reaching sections of the population with the lowest folate intakes i.e. younger women from the most socioeconomically deprived areas.
It has been estimated that there are between 700 and 900 pregnancies affected by neural tube defects each year in the UK.
In Europe, approximately 5000 pregnancies are affected by a neural tube defect annually.
Fortification efforts in the region used to include Ireland, which had an extensive voluntary fortification program.
In Switzerland, about 250 food products are voluntarily fortified with folic acid. A trio of European countries - Finland, France and Sweden - consider supplementation unnecessary if a healthy diet is adhered to.
The NDNS survey, designed to collect data on the food consumption, nutrient intake and nutritional status of the general population, also released results of nutrient intakes in those 65 to 74 years and 75 years and over.
It found that in general mean daily intakes of most vitamins from food sources were close to or above the Reference Nutrient Intake (RNI) for all the older age/sex groups.
However, 10% of women aged 75 years and over had intakes below the LRNI for vitamin A and 13% for riboflavin.
Mean intakes of vitamin D (excluding supplements) were below the RNI in all older age/sex groups: 35% of the RNI for adults aged 65 to 74 years and 28% of the RNI for adults aged 75 years and over.
Mean intakes of minerals were close to or above the RNI for all older age/sex groups with the exception of magnesium (range 76% to 95% of RNI), potassium (64% to 91% of RNI) and selenium (58% to 72% of RNI).
The survey acknowledged that misreporting of food consumption (generally under-reporting) occurred in the NDNS as in all dietary surveys, pointing to evidence that it is an occurrence in all age groups, including those aged 65 years and over.