Vitamin D is a really important vitamin. Our clever bodies make it in the skin when it is exposed to sunlight, in particular UVB.
Vitamin D is used by the body control calcium levels in the blood and is therefore important to grow and maintain strong muscles and bones. Children who don’t get enough vitamin D can get soft bones that might grow bent and break easily. Adults with low vitamin D are more likely to have weak bones that break more easily with a condition called osteoporosis.
Pre-covid studies found that about 30% of Australians are vitamin D deficient. Vitamin D levels change depending on the season and our sunlight exposure. And darker skin needs more sunlight exposure to make vitamin D than lighter skin. Other risk factors for adult vitamin D deficiency include:
- Being older, disabled or living in care
- Dark skinned people especially if migrants or people who wear modest dress
- People with a disability or chronic illness
- Fair skinned people and those at risk of skin cancer who avoid sun exposure
- Obese people
- People working in an enclosed environment such as office workers, factory or warehouse workers, taxi drivers, nightshift workers.
And considering how we have all been pretty housebound over the past 18 months, many of us will be at considerable risk of vitamin D deficiency.
Clinically, Brian has noticed an increase in avulsion fractures recently. Avulsion fractures occur when a ligament or tendon is pulled off the bone taking a bit of bone with it.
Adults and children both get avulsion fractures but they happen a bit differently. In adults the tendon or ligament tends to fail first and then the bone fractures. In children the bone breaks before the tendon or ligament. Children’s bones grow from the growth plates, and if the ligament or tendon attaches near the growth plate, the bone may fracture through the growth plate affecting the future growth of that bone.
Acute trauma is the most common cause of an avulsion fracture. However, a predisposing factor might be vitamin D deficiency.
There are some dietary sources of Vitamin D – fatty wild caught fish such as North Sea Salmon, herring and mackerel, liver, eggs and fortified foods such as margarine and some low fat milk. However, for most people, dietary intake will not be enough. Interestingly, counties like Canada & the USA mandate minimum levels of fortification and consequently average dietary intake is about double the estimated average Australian intake.
However, you can overdo vitamin D and excessive levels of vitamin D can lead to hypercalciuria and hypercalcaemia – too much calcium in your urine and blood, and your body has leached it from your bones! So mega supplement doses don’t help, but instead a little every day.
In Australia we are generally very good at being sun smart to avoid skin cancer, but this also means we have some of the highest rates of vitamin D deficiency. The melanin in darker skin needs more sun exposure to make vitamin D.
Check out the table from Betterhealth.vic.gov.au to see how much sun you need to maintain your vitamin D levels.
If you think you or your family might be at risk of Vitamin D deficiency – talk to your GP. They may recommend taking a supplement, especially over winter and lockdown. Prevention is better than cure!