Tegan Taylor: So Norman, while you were on vacation a few weeks ago, we covered the story of a man who was hospitalized with vomiting, abdominal pain, leg cramps, increased thirst, and he also had lost nearly 13 kilograms and he didn’t need to lose that much weight. Do you know what was wrong with him?
Norman Swan: I looked back and it was a vitamin D overdose, right?
Tegan Taylor: Yeah, vitamin D supplements, he was taking way too much. And I don’t know if it’s just me but I feel like everywhere I look I see other people overdosing on vitamins. There was a different man who made headlines for overdosing on vitamin D, there were women who had accidentally taken so much vitamin B6 that a woman’s doctor thought she had multiple sclerosis and that the other had apparently lost sight in one eye, according to a story from our ABC Melbourne colleagues.
Norman Swan: Yes, while a little is good for you, more is not necessarily better.
Tegan Taylor: Exactly. So let’s take a closer look at what’s going on here with the help of Dr Ian Musgrave who studies natural pharmacology at the University of Adelaide. Hi Ian.
Ian Musgrave: Hello how are you?
Tegan Taylor: Good. So, are vitamin overdoses on the rise, or are we hearing a lot about it these days?
Ian Musgrave: It’s a little hard to say. Vitamin overdose is definitely a thing, but it seems to come in waves. For example, a lot of vitamin D overdose happens because people thought it might be a good way to prevent Covid. Unfortunately, tragically, it is practically useless as a preventive measure for Covid. One of the problems with B6 is that, as your colleague said, we all know vitamins are important to us, we all know we need vitamins for health, but we think that because a little is good for us, maybe a lot is better. And unfortunately, tragically with vitamins, that’s not true. And also what people don’t realize is that B vitamins can be found in different types of supplements. So what happened with one person, for example, was they were taking a number of different supplements and foods that had B6 in them, and it all added up so they ended up with B6 toxicity.
Tegan Taylor: It adds up from different sources without them perhaps realizing it.
Ian Musgrave: Yes indeed. Unless you are very careful about what you take, you may not realize that there is enough B vitamin in everything you take to constitute a harmful dose. And again, most people don’t think of vitamins as having toxic effects, especially water-soluble vitamins like B vitamins, we don’t think of them as having potentially toxic effects. But, for example, B6 is where it’s relatively easy to hit a dose that can cause nerve damage. So we don’t necessarily consider it to be toxic on its own, but if you take more than 300-500 milligrams of B6 over time, it can cause nerve damage. This is something that is not really known because until the advent of high potency vitamin supplements, the chances of getting a B6 overdose were marginal.
Tegan Taylor: Yes, you are not going to see it just from your diet. So what’s going on here? Should we better regulate them? If it’s possible to get those kinds of effects, do people need to be better informed by… presumably most of the time you buy them from a pharmacist or someone who’s in the business of health recommended you get them, maybe a naturopath or something. Do they need to be regulated a bit more like drugs rather than foods?
Ian Musgrave: Well, they are regulated like drugs in Australia, but having said that, I would like to point out that in Australia drugs are regulated by the Therapeutic Goods Administration and they are regulated at two levels. You have low risk medicines like vitamins which are regulated by the Australian Therapeutic Goods Register where you don’t need prescriptions or a lot of information about it because they assume you will read the instructions on the box and take them accordingly. And registered drugs, which are things like, for example, paracetamol where we not only have strong evidence of their effectiveness, but also strong evidence of their safety.
Tegan Taylor: The result is to read these labels.
Ian Musgrave: Yes, and if there is no AUSTL or AUSSTAR number on it, do not buy it.
Tegan Taylor: Thank you very much Dr Ian Musgrave for joining us.
Ian Musgrave: Thanks.
Tegan Taylor: Dr Ian Musgrave is a molecular pharmacologist and toxicologist at the University of Adelaide.