The majority of our vitamin D comes from the sun and a small amount comes from our diet. Surprisingly, even though Australia is known for its sunny weather, approximately one-third of Australians are deficient in vitamin D.
With the knowledge that vitamin D increases the effect of calcium, it is common sense to assume that it would be good for bone health. To make the assumption even stronger, supplementation also leads to an increase in bone mineral density.
In theory vitamin D supplements should reduce fractures risk. After going through every study in the past 20 years on the subject, the conclusion seemed to be that vitamin D supplements do not reduce the risk of fractures in the general elderly population.
One study showed a significant increase in fractures risk, but the overall trend was that there was no effect.
When people are severely deficient in vitamin D prior to supplementation, there appears to be a reduction in the risk of fractures. This is likely related to the increase in bone mineral density. There is also increases in muscle strength associated with reversing vitamin D deficiency which should contribute to reducing falls risk too.
While the general population probably should not worry about supplementing vitamin D to reduce the risk of fractures. But the evidence is clear that people who are deficient will benefit from increasing their levels of vitamin D. This could be through supplements, diet or sunlight.
What Does This Mean?
If you think you are at risk of vitamin D deficiency, it is worth checking with your GP. All it takes is a quick blood test.
If you are deficient, vitamin D supplements could be a wise choice. For anybody else, or anybody who does not want to supplement, the best thing to do is to increase sun exposure. Another addition is a healthy diet containing plenty of vitamin D.
In Australia, 10 minutes of sun in the summer is usually enough to maintain optimal vitamin D levels. This increases to 30 minutes in winter.
People with darker skin can require up to 3-6x the amount, which can be difficult to reach. It is even more difficult to reach if you have something preventing you from being outside easily. It can be hard to get sufficient sunlight if you have a 9-5 job for example.
Getting any more sunlight than this will not increase your vitamin D levels further in a beneficial way. But it can increase your risk of skin cancer, so it is a bit of a balancing act. While sunscreen protects you from UV radiation, it also blocks vitamin D absorption as well.
To get this balance right, one option is to avoid sunlight in the middle of the day in summer. It also makes sense to put on sunscreen after having the right amount of sunlight.
Vitamin D does not appear in many foods naturally, but there are plenty of foods which are commonly fortified with it. Foods sources of vitamin D include salmon, egg yolks, milk, cheese, bread and fortified cereals.
While calcium is vital for reducing the risk of fractures, it is also clear that avoiding a vitamin D deficiency is important.
By keeping vitamin D levels high, consuming sufficient calcium and staying active, it is possible to drastically reduce the risk of falls and fractures. Avoiding falls and fractures can help maintain a high level of physical function for an extended period of time. This is something I’m sure the majority of us would like to achieve.