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How to react to the latest stories on vitamin D

You’ve been diligently taking vitamin D for your bones and recently you’ve seen more headlines saying that supplements don’t improve bone health. What should you do?

In January I wrote a post about calcium and vitamin D supplements after reviews of the research concluded that they didn’t reduce the risk of fractures.

What I said then was that calcium and vitamin D are just parts of the big picture of bone health, everyone’s circumstances are a bit different, and you need to weigh things up.

A colleague of mine jokes about getting a t-shirt made up that says: “It depends”. He’s not specifically referring to bone health; “It depends” applies to most areas of health.

With vitamin D, whether you take supplements depends on factors such as how much sun you get, and what your current level is. 

As you probably know, the reason for taking it in relation to bone health is that it helps calcium absorption.

But low levels of vitamin D are also linked with a range of other conditions, including heart disease and depression.

An Australian study done from Melbourne Uni queried whether it might also be important for brain ageing in women.

That study looked at vitamin D levels in women aged 55-67 in 2002, and again 10 years later in 2012. Those with the healthy vitamin D levels did better on cognitive tests at both the start and finish of the study. 

As much as recent media reports about vitamin D not improving bones might sound conclusive, rest assured that the people who do these studies are still arguing about dosages, how long supplements need to be taken, what constitutes a deficiency and whether the way we measure vitamin D gives us the most useful information. 

Yes, there’s still a lot we don’t know. 

As an illustration of that, a recent Danish study on post-menopausal women with low vitamin D gave half of them a supplement over the winter. 

After three months those taking the supplement had higher vitamin D levels but their bone density hadn’t changed. That might seem like evidence that the supplements didn’t make any difference.

Yet the women’s bone strength had improved along with the thickness of some of the bone in their legs and hips, perhaps suggesting that as a measurement bone density doesn’t tell the whole story. 

So what’s the upshot of all this? I think there are four things to consider.

First, vitamin D does seem to be important, and not just for bones.

Second, we probably only need to do something about it if we’re deficient — and the review that attracted all the recent headlines didn’t focus on studies of people who were deficient. If your levels aren’t low in the first place, it’s unlikely that a supplement will make much difference. 

Osteoporosis Australia says a deficiency is a test result of less than 25 nmol/L, and that a reading of less than a 50 nmol/L at the end of winter is insufficient. Our levels will probably be a bit higher in summer. So that’s a guide.

Third, remember that nutrients don’t work in isolation, and vitamin D also needs calcium, phosphorus and K2.

Finally, some people acknowledge these first three points but argue that supplements aren’t the answer. Supplements are probably never the ideal, if there’s a more natural option available. 

In the case of vitamin D, the obvious natural source is the sun. Yes, get your vitamin D from the sun. Sometimes though, that’s not easy. 

It’s also not easy to get your vitamin D from food, although those foods that contain some — e.g. eggs, oily fish, good quality dairy, and mushrooms — deserve a place in our diets if we tolerate them well.

To sum up, the latest headlines aren’t a good reason to throw out your supplements.

Take them if your levels are too low, though with summer upon us, you mightn’t need them for a few months. And if you’re taking them for your bones, make sure you’re getting the spectrum of bone health nutrients.

Photo Source: Bigstock


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Wednesday, November 28, 2018 | Rhonda Anderson