Nine out of 10 Aussies have low vitamin D intakes, but why do we need vitamin D and why aren’t we getting enough of it?
Nine out of 10 Aussies have low vitamin D intakes, but why do we need vitamin D and why aren’t we getting enough of it?
In this episode, Sarah is joined by Dr Eleanor Dunlop to talk about the role vitamin D plays in our bodies and why some of us are vitamin D deficient. Dr Dunlop also discusses how her research could help inform nutrition policy in Australia and increase our intake of the ‘sunshine vitamin’.
Nine out 10 Aussies have low vitamin D intakes, Curtin study shows
2021 Premier Science Awards
Bush tucker and vitamin D
Dr Eleanor Dunlop, Research Associate, Curtin School of Population Health.
Dr Eleanor Dunlop is an accredited practising dietitian and postdoctoral researcher focusing on vitamin D, food composition and the role of diet in the onset and progression of multiple sclerosis.
Her PhD project, Investigating dietary vitamin D in Australia, was completed in 2022 and received the Curtin Chancellor’s commendation. Eleanor is an active research communicator and was a finalist in the 2021 Premier’s Science Awards.
Connect with Eleanor:
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Read the transcript here.
Host: Sarah Taillier
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Speaker 1: 00:00
This is The Future Of, where experts share their vision of the future and how their work is helping shape it for the better.
Sarah Taillier: 00:09
I'm Sarah Taillier. Vitamin D is a nutrient we eat and something our bodies make. We need vitamin D to maintain strong bones, muscles, and overall health. Vitamin D deficiency may lead to a range of health issues, including rickets, and may contribute to an increased risk of heart disease, multiple sclerosis, and cancer. One in four Australian adults are vitamin D deficient and new research has shown that 95% of Australians have low intakes of vitamin D. In this episode, I was joined with Dr. Ellie Dunlop, a researcher at Curtin's School of Population Health. Ellie and I talked about the role vitamin D plays in our bodies, where we can get vitamin D from, and why we're not getting enough of it. We also explored how her research is working to improve our vitamin D intake. If you'd like to find out more about this research, you can visit the links provided in the show notes. Hello, Ellie.
Eleanor Dunlop: 01:07
Sarah Taillier: 01:08
Just firstly, what is vitamin D, why do we actually need it?
Eleanor Dunlop: 01:12
So we know that vitamin D is really crucial for good bone health. What isn't quite as clear is the other health conditions that it might play a role in. So it might protect against things like cardiovascular disorders, some cancers, type two diabetes, autoimmune conditions, and even respiratory infections, which has peaked a bit of interest around COVID. But the evidence is still inconclusive around those things, but we do know that it's important that we get enough to keep our bones healthy.
Sarah Taillier: 01:40
And when you say enough, how much do we actually need?
Eleanor Dunlop: 01:43
So the Australian recommendations say that from food, we should be aiming to consume about 5 micrograms per day. And that's if we're aged up to 50 years. It increases a little up to 10 and 15 micrograms per day as we get older. But those recommendations are in need of update. Elsewhere, like in the US and Canada and Europe, they recommend more around 10 to 15 micrograms for people of all ages. And that's based on much more evidence and much more recent evidence than the Australian ones.
Sarah Taillier: 02:14
So obviously, that gap there, which we'll come to a little later on, but where can we actually get vitamin D from?
Eleanor Dunlop: 02:21
Yeah. So our bodies can make vitamin D if we spend enough time out in the sun, but it's really important to be aware of the risk of skin cancer, skin damage. So it's important to be SunSmart as per the Cancer Council's guidelines on that. We can get it from food, of course, it's only a few foods though, quite a short list. Oily fish is the richest source. So fish like salmon, mackerel, sardines, trout. Eggs are also a nice source, and it's in some meats. But because it's not in that many foods and in quite low concentrations, it can be quite difficult for us to get enough vitamin D from food. And we know that a lot of Australians aren't getting enough.
Eleanor Dunlop: 03:01
There are, of course, vitamin D supplements, but doctors might recommend those to people who are at higher risk of vitamin D deficiency, but they're not really appropriate for us to recommend at the population level because they don't necessarily reach the people that need them. You have to buy them, you have to be able to afford them, then you've got to remember to take them. And a lot of people might not need the dose levels that a supplement provides as well.
Sarah Taillier: 03:27
So just taking a look at your research, you found that one in four Australians are deficient in vitamin D despite living in such a sunny climate, the irony there I'm still getting my head around, why is this number so high and how do we compare to other countries?
Eleanor Dunlop: 03:44
Yeah. So it actually started from the Australian health survey that found that one in four Australian adults are vitamin D deficient. Our studies on other population groups within that found that it's actually even more common in some groups. So nearly a third of young adults, almost 40% of Aboriginal and Torres Strait Islander people living in remote areas, and more than a third of, for example, people who've immigrated from Africa and Middle Eastern countries as well. So it is very high given that we have year-round potential for sun exposure in most areas of the country.
Eleanor Dunlop: 04:17
So why that is? I guess people are really aware of the risk of skin cancer and that is important. It's thanks to a long-running and very successful campaign by Cancer Council with the SunSmart campaign. We also live increasingly indoor lifestyles. We know that it's difficult to get vitamin D from food and we haven't known a lot about dietary vitamin D in Australia until our recent studies. So we haven't been able to look at strategies around that as well. So I guess other countries you mentioned, it is a global issue, vitamin D deficiency. It varies around the world depending on climate, latitude, the amount of vitamin D in the food supply, and just cultural lifestyle factors as well.
Sarah Taillier: 05:03
And you touched on that need for strategies in this space when it comes to sun exposure, how do you find that balance? Is there any kind of early indications for how you strike that balance between getting a vitamin D intake from the sun and not being overly exposed to sun?
Eleanor Dunlop: 05:21
Yeah, that is a very difficult one. We don't yet have the detailed guidelines in Australia that tell us how much sun exposure is good for optimal vitamin D production or how much safe sun exposure is good. There is a study underway, the Sun Exposure and Vitamin D Supplementation Study, that'll hopefully improve the evidence around that question, but it only includes participants with three of six different skin types. So we're still going to need some more evidence for people with sort of paler skin and also more deeply pigmented skin. So in the meantime, we would say to try and spend a little bit of time outside in the sun each day, ideally being physically active, if you can, and follow the Cancer Council guidelines, be SunSmart. There are websites and apps you can check the UV index and if it's more than 3 or above, then be SunSmart and protect your skin.
Sarah Taillier: 06:14
More than 3 and above, that's a good guide to have. So the amount of melanin in our skin can affect our uptake of vitamin D as you touched on from the sun. Why is that?
Eleanor Dunlop: 06:24
Yeah. So the melanin in our skin actually protects us from the UVA and UVB radiation from the sun, but it's the UVB radiation that kickstarts the production of vitamin D in our skin. So early people would've involved to have more or less melanin that is either more lightly or darkly pigmented skin depending on the geographical region and the climate. But now, people can move around the world so fast that the amount of melanin in our skin doesn't necessarily match the climate conditions that we live in. So people with more darkly pigmented skin can be at higher risk of vitamin D deficiency because they need to spend more time in the sun to make the same amount of vitamin D as someone with more lightly pigmented skin. But also, people with paler skin can be in sunnier climates as well because they tend to avoid the sun just for fear of being sunburnt.
Sarah Taillier: 07:14
So are there other factors that can affect our uptake of vitamin D?
Eleanor Dunlop: 07:18
There are, yes. There are factors that affect our production of vitamin D and also absorption of the vitamin D that we eat. So if you are indoors a lot, work indoors a lot, or if you cover your skin regularly when you go outdoors, that affects how much of the UV exposure that you get and how much vitamin D you produce. Being less physically active or overweight or obese, and those two things might be linked because being less physically active might mean you're outdoors less, it also might mean you're more likely to be overweight or obese. And because vitamin D is fat-soluble, it can get taken up and kind of locked away, if you like, in the fat cells so it's not available for use. And that's probably more likely to happen in people that are overweight or obese.
Eleanor Dunlop: 08:08
And then people who are older, the effects of ageing, that can affect the efficiency of how we produce vitamin D, how we absorb it, and convert it into its usable form. Also, older people tend to have lower appetites, so they just simply consume less. And maybe issues with mobility might be being outdoors a bit less. But our research actually showed that older people weren't overall more likely to be vitamin D efficient. And it might be because they're more likely to take supplements to maintain their bone health as they get older.
Sarah Taillier: 08:40
Sure. So together with your colleague, Associate Professor Lucinda Black, you've put together Australia's first comprehensive database of vitamin D in foods. How could or is this database being used to help us increase our vitamin D intake?
Eleanor Dunlop: 08:58
Yeah. So the problem that we had before we had this new database was that we didn't know exactly how much vitamin D was in foods in Australia. And that's fundamental to working out how much people are consuming. Do they need more and what do they eat to get more? And that's not just a problem in Australia, it's a global problem because vitamin D is quite difficult and quite expensive to measure in food and there's only a few labs worldwide that can do it well. But we're lucky now to have one in Australia, because the National Measurement Institute developed a method over in Melbourne and also Associate Professor Lucinda Black won NHMRC funding or National Health and Medical Research Council funding to create the database. And that was a huge project involving the purchase of more than 900 food samples from across the country. So now that we have that, how it can be used, at the population level, we've already used the database to make the first accurate estimates of usual vitamin D intakes in the Australian population.
Eleanor Dunlop: 09:59
And until then, we didn't have the evidence that people might need to increase their intake. And it turns out that probably at least 95% of Australians do. So that's crucial baseline evidence for us to have. We can then use those intakes estimates and the database to simulate the effect of adding different concentrations of vitamin D to different foods to find the best model that would safely and effectively improve vitamin D intakes in the population. And we also publish new dose-response data that we can use to take that modelling one step further to see how that might translate to a change in vitamin D status as well.
Eleanor Dunlop: 10:38
So that's at the population level, but at the individual level, the data will be freely available. So individuals and their health professionals like dieticians, they'll be able to work out their individual intakes and then look to see which foods they need to, or they could eat to improve their intakes. And producers and manufacturers will be able to work out how much vitamin D is in their products and then they can market good sources so that consumers know which foods to choose for vitamin D.
Sarah Taillier: 11:06
And when do you hope that will be available?
Eleanor Dunlop: 11:08
It is actually already available on the Food Standards Australia New Zealand website or the analytical databases. We've done a lot more work from that and I'd say mapped it to thousands of foods that are in the Australian Food Composition Databases and that the survey database. That will be made available with future releases of the Australian Food Composition Database.
Sarah Taillier: 11:36
Amazing. What a use for a resource. So you touched on this a moment ago that some countries already do this, for example, with milk, it's routinely fortified with vitamin D in some countries. How soon can we expect to see fortified foods on supermarket shelves?
Eleanor Dunlop: 11:59
Yeah. And you're right, there are other countries where foods like milk are routinely fortified. Finland's a great example of success there. They reduced the prevalence of vitamin D from around half the population down to just 9% by doing just that. And they also allow fortification of other foods as well. In Australia, I guess the answer to the question in terms of how soon will we see things on supermarket shelves, it's in two parts, there's what can be done now and what might be able to be done in the future. So right now in Australia, margarine must be fortified with vitamin D. So that is already available. Some other foods like dairy foods, their alternatives, and some breakfast cereals are allowed to be fortified, but actually, many are not. So Australian manufacturers could right away start adding vitamin D to things like fluid milks and their alternatives.
Eleanor Dunlop: 12:52
And we hope that our research will encourage that. The Food Standards Code does allow for this. So we did a study recently and we recently published that showing that if fluid milks and their alternatives were fortified with the maximum level allowed, then that would increase population intakes by around about two micrograms per day. So it would be a safe but modest, but also useful increase that would have good reach across the population. The second part of the answer as to what could be done, that study also showed that we would need to add more vitamin D to more foods in order to allow Australians to achieve intakes of, say, 10 micrograms, which is the recommendations elsewhere. And it would be more foods and at greater concentrations that are currently allowed by the Food Standards Code. So it will take quite some time to work out whether or not that can happen.
Eleanor Dunlop: 13:54
So anyone can make an application to have the Food Standards Code changed, but it needs to be supported by a lot of evidence that shows that there's a need, that it would be safe, and that the foods that are going to be fortified have good nutritional value. So Australian consumers are really well, and rightly so, protected in that regard by the Food Standards Code. We've already produced a lot of the data that would underpin the future research around that, but there's still lots more to do. We need to do more modelling fortification scenarios. And we have a PhD student, Belinda Neo, who will work more on that. We also need updated data on vitamin D status across the population. There is a gap there in nationally representative data in children. We know that they have the lowest intakes, but we don't know yet whether that translate to poorer vitamin D status. And we also need updated recommendations on how much Australians should be aiming to consume whether it's that five micrograms or whether it is more like 10 or 15 micrograms per day.
Sarah Taillier: 14:55
A lot of room for more research.
Eleanor Dunlop: 14:56
Yeah. Lots to do.
Sarah Taillier: 14:58
Given your recent research that you've worked on with your colleagues, do you hope that might lead to greater education that could spur on food companies to go down their own pathway and actually start pursuing increasing vitamin D or adding vitamin D?
Eleanor Dunlop: 15:15
Yeah, I do hope so. And as I said, there are foods that manufacturers could start adding vitamin D to. And I guess it's been maybe a lack of awareness and a lack of demand as well, but hopefully, by doing things like this and getting the research out there, we do hope that it will drive that. Yeah.
Sarah Taillier: 15:33
So you are also involved in a project with Associate Professor Black that's supported by the Telethon Kids Institute where you're working closely with Aboriginal communities here in Perth and up in the Kimberley to find ways to increase vitamin D intake among Aboriginal populations. Can you tell us a bit more about that project?
Eleanor Dunlop: 15:50
Yeah. It's a great project. It's a big collaboration between Aboriginal communities and several organisations. So here in Perth, on our Perth team, we have Auntie Dale Tilbrook and Uncle Noel Nannup. And then we have a few people from Curtin, of course, Telethon Kids Institute, Cancer Council WA, the National Measurement Institute, and Telethon Kids Kimberley. And then we also have elders and community members up in Ardyaloon and Lombadina and Djarindjin communities up in the Kimberley and also community dieticians that work in those areas as well. So Aboriginal people have always known that bush tucker is good tucker. It's healthy, it's nutritious, and there's the physical activity that goes along with hunting and gathering that as well. But elders have told us that they're really excited to have scientific data to compliment those existing stories and the knowledge that they already have, especially when they're looking to promote bush tucker to the younger generations.
Eleanor Dunlop: 16:54
So the project involves measuring vitamin D in bush tucker. Aboriginal people will be selecting the foods that they want to have vitamin D measured in. They'll be collecting samples in Perth, surrounding regions, and up in the Kimberley. And then there'll be yarning groups to yarn about and find out about attitudes to sun exposure as well so that we can look at both dietary and sun exposure strategies so that people can have good vitamin D status.
Sarah Taillier: 17:22
Is there a layman's term way of describing actually measuring vitamin D in things like bush tucker and various foods?
Eleanor Dunlop: 17:30
Yeah. So this is the method that the National Measurement Institute over in Melbourne have developed. Sorry. Do you mean actually what the method's called or the-
Sarah Taillier: 17:39
I was interested in actually the process. How do you actually measure vitamin D within bush tucker?
Eleanor Dunlop: 17:46
Oh, well, first we have to buy a lot of sample, well, in this case, actually with the bush tucker, we'll be collecting a lot of samples. With the previous database, it was actually purchasing all the samples. Then they literally get couriered over to the National Measurement Institute. It's quite a complex process. It takes two days, hence why it's quite expensive to do. It needs quite a lot of specialist skill and a lot of preparation, obviously, as well. It's quite a lengthy process. They have to extract the vitamin D from the food. We usually also prepare the foods as they would be eaten so that we get a better, I guess, representation of what the vitamin D content is when someone actually eats it, rather than having to use factors to convert things. Yeah, so they extract the vitamin D out and then they measure it, in simple terms, but it's obviously a lot more complicated than that. Yeah.
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Sarah Taillier: 19:14
You're an accredited practising dietician. What actually inspired you to become a researcher in dietetics and vitamin D in particular?
Eleanor Dunlop: 19:23
So, actually, it was when I was doing my Master of Dietetics. It was a very small part of the course, but I did a little research project. It was supervised by Associate Professor Black who's been working on all the other vitamin D work and also Associate Professor Jill Sherriff. They were both really inspiring people to me. I really enjoyed the research project and, actually, the data from that became pilot data for the study, the bigger project that became my PhD project. And that's been, again, supervised by Associate Professor Black, Dr. Tony James, and Dr. Cunningham here at Curtin and also Associate Professor Anna Rangan over in Sydney. So yeah, I've been supervised and supported by many inspirational people here at Curtin and elsewhere. And there's a wonderful support network in the nutrition and dietetics department at Curtin as well, that I'm really grateful for.
Sarah Taillier: 20:19
With vitamin D, what are your hopes for the way we understand vitamin D, the way the community relates to it? What are your hopes in that space?
Eleanor Dunlop: 20:28
I think, hopefully, if we can get the findings of our research, that will bring a lot more awareness to the community and food producers, food manufacturers. I think maybe that needs to drive the demand for... Or not drive the demand, but highlight the need to do more research into these areas, especially things like the fortification scenarios, that we can do more to explore those. It's a very fine balance, I guess. We have to be careful because we can have too much vitamin D. So there can be some concerns there. And that's where all that modelling, the studies will come into that so that we can make sure that if we were to propose something, that it would be safe and that it would work.
Sarah Taillier: 21:17
Thank you so much, Ellie, for coming in today and walking us through the key role vitamin D plays, your research in this space, and the impact vitamin D can have on improving our health.
Eleanor Dunlop: 21:29
Oh, thank you, really. I appreciate the chance to come in and talk about the research. Thank you.
Sarah Taillier: 21:33
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