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Is folic acid a miracle cure?

Boz magazine, 64: 6, September.

Brian J Ford

That's the wonderful thing about medicine. People find new things, and miracles happen. You discover insulin, and diabetes is immediately treatable. You stumble across vitamin C, and scurvy becomes a memory. You realise that taking folic acid during pregnancy can prevent the scourge of spina bifida, and find a bacterium, Haemophilus influenzae, that causes 'flu.

And they are all true. Well, not the last one; Haemophilus influenzae was once believed to cause influenza, and was even given its name to commemorate the idea; but was later found to be an organism that likes to live in 'flu victims, and was not the cause at all.

Actually, the penultimate example is probably untrue, too, even though everyone thinks it's a fact. Why, I even heard Siobhán (the new doctor's wife in The Archers in Radio 4) telling to her husband that she had been sure to take folic acid during her pregnancy, to make quite sure the foetus didn't suffer from spinal defects. Shame they didn't do a post-mortem after her miscarriage and have a look.

Spina bifida is a dreadful disease. There's a lot of it in Wales. The spine begins as a groove down the back of the embryo, and as the groove closes the spinal cord becomes enclosed by the spine. In victims of spina bifida the slit doesn't close, and the spine remains partly open to the air. During the 1980s, evidence began to accrue that folic acid, taken during pregnancy, could prevent the condition. Of course! It's like vitamins and deficiency diseases—take the right tablet, and your problems are over.

The medical Expert Advisory Group in the United Kingdom recommended in 1992 that women who were trying to conceive should take 0.4 mg folic acid each day. The facts were soon headline news in all the magazines. It featured on TV, and splashed across the newspapers. All the chemists' shops stocked up with folic acid in plastic jars, ready for the stampede.

At first, the statistics were very impressive. In the early 1970s there were more than 200 cases of spina bifida out of every 100,000; it fell to less than 40, a drop of eighty percent. What's interesting is that the fall took place by 1990, before folic acid was popular. A team in London, headed by Dr Rezan A Kadir at the Royal Free and University College Medical School in London, has inspected the figures and show that—ever since folic acid has been widely available—the rate of decrease has actually slowed down, and not (as you might expect) increased.

Over-the-counter sales of folic acid in chemists' shops went up dramatically between 1990 and 1994, but they declined in 1995-6. Here Dr Kadir and his colleagues relied on the data from the shops, apart from Boots, that is. As the researchers say, in the British Medical Journal, 'data for over the counter sales do not include information from Boots pharmaceutical stores because they do not provide this information'. Thanks, Boots, for being so open and helpful. This will be a great encouragement for people to patronise your stores.

What's the reason for these astonishing findings? It may be that the supplements are not taken at the right time, or perhaps they are not be taken by those women who are at the highest risk; possibly the recommended dose may be too low. Whatever the answer, the facts remain: for all the hype about folic acid in pregnancy, there has been no effect whatever on the incidence of spinal defects in new-born babies. Whatever has caused a reduction was happening before folic acid was ever promoted as a miracle cure.

This has happened before. Campaigns of immunisation or the use of antibiotics have been claimed to have slashed diseases which were actually on the way down before the new treatment was ever introduced. Medicine is sometimes too quick to find cause-and-effect. Sales of folic acid have been a huge bonanza for the drug companies, who have said little about these new conclusions.

The giant multi-nationals may not want to release their sales figures, but—as long as we go on buying—why should they stoop to assist us? We are helping them pay their share-holders, and in the real world of medicine that's all that counts. Explaining reality isn't the aim; it's selling pills that matters.

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