Down's syndrome is something that every expectant mother worries about, especially if she is over 30 years old.
But researchers from Tel Aviv University have discovered that the link is much more to do with the woman's inability to metabolise folate and methyl. This is a characteristic of neural-tube defects (NTD), which includes spina bifida. It is this lack, rather than age, that is the more significant marker.
Although a dose of just 0.4 mg of folic acid every day was believed to be enough to protect against NTD, the researchers say a dose of around 5 mg is needed. The effect is amplified if the woman also takes cobalamin.
Other researchers have suggested that women need only eat food that is fortified with folic acid, but the Tel Aviv research team argues that supplementation works far better as a preventative. This last recommendation is significant, and goes against the general view that fortified food, and especially flour, is sufficient to raise the nutritional status of most women.
Interestingly, the Birth Defects Foundation in the UK supports supplementation, and urged women to continue taking folic acid in the wake of the recent Food Standards Agency report that seemed to suggest all vitamins and supplements were, at best, lethal.
(Source: The Lancet, 2003; 361: 1331-5).