We’ve all seen the adverts, usually accompanied by a photograph of a glowing pregnant woman or an adorable baby, selling vitamins and minerals ‘specially designed’ for pregnancy. They’re often expensive, but for many woman, the reassurance of taking a supplement that seems to promise a healthy pregnancy and a bouncing baby is well worth the expense.
But is it? I investigated the evidence behind supplements in pregnancy for the evidence-based medicine journal Drug and Therapeutics Bulletin, published by BMJ. And guess what? Aside from folic acid and (probably) vitamin D, there’s precious little evidence to show that other vitamins or nutrients are worth the money.
Folic acid is vital, greatly reducing the chances of having a child with a neural tube defect. There’s less direct evidence for vitamin D, but we know that many women in the UK are deficient in vitamin D for at least part of the year, and deficiency can lead to problems with bone formation. The other nutrient some women may need is iron, but only if they are actually low in iron or anaemic (something that can be picked up by blood tests). If you don’t need extra iron, it’s not a great idea to take it because it can cause constipation.
Unbranded versions of folic acid, vitamin D and iron can be bought for pennies a day. The expensive, heavily-marketed multi-nutrient complexes seem to be an unnecessary expense at a time when most couples could well use the extra cash. Better to spend the money on good food – a balanced, healthy diet with plenty of vegetables and fruit should supply all the other nutrients you need.
Working for DTB is a whole different ball game from writing for most media outlets Firstly there’s the evidence pack – a hefty pile of scientific studies that arrives on your doorstep, delivered by a groaning postman. Then there’s the detailed brief, and the requirement to read, extract and summarise all relevant information. It’s detailed, analytic and thorough work.
Then there are the two rounds of peer review, and the fact check, all of which will challenge any vagueness, any statement left unreferenced, any assumption. Only after it’s been through this process, and a careful technical edit, and made the editor and the editorial board happy, does the article see the light of day. Because of this team editorial process, the pieces don’t carry individual bylines. But they are some of the most satisfying work I do.
This morning, seeing the DTB study I worked on widely reported across the media, was especially satisfying. I hope some pregnant women will be reassured to know that you don’t have to spend a fortune to have a healthy pregnancy.
Vitamin supplementation in pregnancy. DTB doi:10.1136/dtb.2016.7.0414