Some of you might not know that I worked for over 10 years in a pathology laboratory as a Technical Manager, where I'd spend my days pouring over the medical literature. I recall many years ago at the beginning of my time there, having understood the importance of Vitamin D, I dived deep into the research around Vitamin D supporting so many bodily systems (such as thyroid health, immune health, mood and bone health to name a few). It took some time for the pathologists and scientists to also see the benefits that the research was touting, and now fast forward 20+ years and we all agree on the importance of ensuring adequate levels of Vitamin D are met. Here's everything you need to know about Vitamin D.
What is vitamin D?
Vitamin D is both a vitamin and a hormone . Often nicknamed "the sunshine vitamin," vitamin D3 is synthesised in our skin via UVB sunlight exposure.
Some foods contain Vitamin D, but we can't get enough from food to really impact our Vitamin D levels in a meaningful way.
Vitamin D supplements are a necessity for people who aren't able to get their fix from sunshine or food (which, it turns out, is pretty much all of us) or for those who are simply interested in achieving and maintaining a consistent state of vitamin D sufficiency throughout life.
The benefits of Vitamin D
All nutrients are crucial for maintaining health, but Vitamin D is especially important as it is essential for nearly every single bodily system and function. Vitamin D plays a role in thyroid health, supporting immunity, promoting gut health, improving mood and alongside calcium helps to support healthy bones.
How to find out if you're vitamin D deficient
To monitor your baseline vitamin D status (and even track the success if you're supplementing), you can monitor your blood levels. Your health care practitioner can order a 25-hydroxyvitamin D test, which is also known as the 25(OH)D test. This is the biomarker for vitamin D status in your whole body.
The optimal (not just "normal") amount you want to see, is +50 ng/ml. In some cases, even higher levels may be appropriate. You are considered Vitamin D deficient if you are lower than 30 ng/ml.
I recommend having your 25(OH)D levels tested twice a year—and perhaps even more often if your health care practitioner thinks it useful to determine your required dosage.
How to get more vitamin D.
The amount of vitamin D you'll need to overcome deficiency or insufficiency and achieve true sufficiency depends upon your individual makeup, body composition, baseline lab test results, and other vitamin D inputs, so check with your health care practitioner for personalised recommendations on how to keep your levels in check. (You can learn more about signs of Vitamin D deficiency here)
As a quick rule-of-thumb, to achieve a 50 ng/ml or higher 25(OH)D lab test result, this will require 5,000 IU of vitamin D3 for most normal-weight adults. Individuals with more weight will need proportionately more vitamin D. Supplementation with a good quality D3 is a great way to ensure levels are maintained.
One quick way to up your vitamin D is to get moderate sunlight exposure each day. That means never letting your skin burn, and I like to personally follow the Cancer Councils recommendations on safe sun exposure;
"The best source of vitamin D is UVB radiation from the sun. UV radiation levels vary depending on location, time of year, time of day, cloud coverage and the environment.
For most people, adequate vitamin D levels are reached through regular incidental exposure to the sun. When the UV Index is 3 or above (such as during summer), most people maintain adequate vitamin D levels just by spending a few minutes outdoors on most days of the week.
In late autumn and winter in some southern parts of Australia, when the UV Index falls below 3, spend time outdoors in the middle of the day with some skin uncovered. Being physically active (e.g. gardening or going for a brisk walk) also helps boost vitamin D levels."
From there, be sure to protect yourself with your preferred SPF. However, since many people can't safely get enough exposure to move the needle (whether because of an indoor job or where in the world they live), the sun isn't the only answer. And others seek to avoid cumulative sun exposure for other obvious skincare and health risk reasons.
Foods and Vitamin D.
References
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618598/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3604145/