Low folate levels could lower baby's birth weight
if they want their child to reach optimal weight, finds new
research that links the vitamin for the first time to birth weight.
The researchers from the University of Newcastle upon Tyne in the UK, who examined nearly 1,000 women and their newborn babies, found that women in early pregancy with lower levels of folate were more likely to have a lighter, and therefore less healthy, baby.
Folic acid is already known to prevent birth defects but the new study is thought to be the first to link folate levels commonly seen in UK mothers in early pregnancy with birth weight.
The findings also have implications for public health policy on food fortification - scientists have long called on the British government to add folic acid to everyday foods to make sure that all mothers have sufficient levels of the nutrient.
There has been some resistance to the plan, despite evidence from the US and Canada that it works, as it might mask deficiency of other nutrients in the elderly, according to government experts.
The new study looks set to boost the cause for fortification however. Seven per cent of all babies born are low birth weight (less than 2.4kg or 5.5lbs) and they have a 50 per cent chance of having a severely disabling condition as a result of being too light. Healthy birth weights are also generally a marker for good health in infancy and later life.
"Folic acid is highly important in preventing birth defects which affect a small number of pregnancies. This study suggests that it is also important in every pregnancy to help the developing baby reach a healthy birth weight," said Dr Caroline Relton, lead author.
She added that many women are missing the critical first few weeks of gestation during which their baby really needs folic acid to grow and develop because advice on the nutrient is not handed out until women go for their first pregnancy check-up. This could be too late.
The study was based on blood samples taken from 998 expectant mothers attending a hospital in North West England for antenatal visits. Researchers recorded the amount of folate in their red blood cells - these cells show activity over the previous three months - and gathered lifestyle information, such as smoking habits, from a questionnaire, as well as the weight of each baby when born.
Folate status was found to be "a significant predictor of birth weight".
Further, expectant mothers who smoked were more likely to have lower levels of folate in their blood, which might explain why women who smoke often have lighter babies, said the researchers in today's issue of the British Journal of Nutrition (vol 93, pp593-599).
Folic acid is thought to influence birth weight because it is an essential nutrient for growth and gene expression in the foetus. Smoking is likely to reduce a women's folate levels because it is a significant source of oxidative stress and may alter the ability of the cell to metabolise and ultimately store the vitamin.
"Fortifying a range of foods promises to be a more effective solution than a campaign to encourage women to take folic acid supplements," added Dr Relton.
"Our previous research shows younger women and those from deprived backgrounds are less likely to take these supplements, and although some cereals are currently fortified in the UK, they tend to be the more expensive, brand-name products."
