To B3 or not to B3, that is the question

3 minute read

Australian research has generated up a lot of coverage about niacin intake before and during pregnancy. But it's just a mouse study!

One of the best things about general practice is the variety it offers.

Everyone sees their GP – the young, the old and everyone in between. And, as we know, people go to their GP for a wide range of issues, not just acute problems but also health advice. They often want clarifications of health news heard elsewhere. Is barbequed food really as bad as smoking? I ate frozen berries, could I have hepatitis A? Is leaky gut the cause for my child’s autism?

These questions are asked in earnest and provide a wonderful opportunity to build rapport and engage patients in conversations about evidence-based medicine. It also allows us to be honest about the limitations of this principle. Sometimes the answer is a very dark shade of grey.

I wasn’t surprised then to have a few of my patients who are pregnant come to me asking me if they need to start vitamin B3 supplements based on the recent, highly publicised study that it could reduce miscarriages and birth defects. The intervention appears harmless – everyone has supplements! Pregnant women are already taking folic acid, calcium, iodine and often iron, so how is this different? Then the anxiety sets in. Is it too late for this pregnancy? How much B3 is the right amount? How many vegemite sandwiches a day would cover it?

Even more anxiety-provoking is the potential if pregnant women don’t take it – cardiac birth defects and miscarriages.

It is important to acknowledge the patient’s concerns, but also to discuss the study itself.

The study was based on mice models. The results have not been proven in humans and extrapolations are premature. All that can be said is that high levels of niacin in pregnancy may negate the effect of two very specific genes involved with miscarriages and congenital abnormalities.

There is also no way of knowing what the right amount in humans is, because the study was not conducted on humans. In addition, the Australian diet, with its niacin-fortified cereals and flour, means that niacin deficiency would be unlikely among pregnant women here, so the effect of supplementation is also unknown in this country.

The study is an important one and further research may change the way we advise women who wish to fall pregnant or are in the early stage of pregnancy. But, as the RANZOG says, currently there just isn’t enough evidence to advocate for additional oral supplementation of vitamin B3.

Nonetheless, given the publicity, I’m guessing vegemite sales might be set for an upswing in the coming months.

Dr Aajuli Shukla is GP Editor of The Medical Republic. Email:  

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