The rise of understanding around Vitamin D, and how it is an essential element to our Immune system is continuing all the time. As we live in Central Queensland primarily, the role of the mild winter can't be overlooked. The role of Vit D on our B-cells, T-cells and antigen presenting cells (these make up our immune cells), means it has the ability to act in a local immune response manner. (Aranow, 2011).
What this means is it can modulate the innate and adaptive immune responses. Therefore a deficiency in the Vit D can be associated with an increased autoimmunity and an increased susceptibility to infection. (Aranow 2011). According to Iruretagoyena et al (2015), Vitamin D comes from 3 potential sources:
1. It can be made in the skin from exposure to sunlight
2. Nutritional sources
This article also states that in humans, it is mainly synthesised in the skin after exposure to UVB, with only a minor part, less than 10%, being derived from diet. The two different forms of Vit D can both be obtained through the skin, with the D3(cholecalciferol) from both exposure to sunlight and present in oil-rich fish.
So what does all of this mean?
Well basically, its best to get your exposure to sunlight, and keep it up during the winter months. We often get asked, how much is the right amount, and there isn't a really true answer.
I had heard that once your skin gets a pinkish hue, that's a good sign. Definitely in summer months, keeping an eye on the UV ratings at certain times of the day is essential, because we don't want to contribute to skin cancer rates.
According the the NHS in the UK, exposure of forearms, lower legs and hands, uncovered and without sunscreen prior to 11am and after 4/5pm is the best plan in the summer months.
In Australia, we all know how much our summer sun can burn. In fact, I gardened in the middle of the day the other weekend, and got a touch of pink on the back of my neck. Ensuring you aren't trying to get that Vitamin D exposure during these times is really important for all of us.
So I guess, be sensible with it. 10 minutes on the forearms and lower legs both morning and afternoon, before there is any sting to the suns' rays, thats going to be a great time to get that Vitamin D up.
Then ensuring that you have some adequate fish intake is also essential. I remember reading somewhere that the oily fish, particularly mackerel and sardines are fabulous. I know that when I make sardine or salmon patties, I always ensure I use the bones too, as this is an extra great source of natural minerals. Lucky for us, we live in an area that has access to some great fish, and the ability to source these oily fishes in our supermarkets as well. The other foods that contain Vitamin D are red meat and eggs. Ensuring you have some serves of this in your weekly diet can also be really beneficial.
But like the research says, making sure that you get out in some sunshine every day, is going to be one of the best ways you can boost your Vitamin D, help your immune system, and keep your Winter Sun and Winter Fun quotient nice and high.
Happy sunshine chasing!
1. Cynthia Aranow, 2011. "Vitamin D and the Immune System", J Investig Med. Aug; 59(6): 881-886 <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/>
2. Mirentxu Iruretagoyena et al, 2015 "Immune response modulation by vitamin D: role in systemic lupus eruthematosos", Front. Immunol., 12 October 2015. <https://doi.org/10.3389/fimmu.2015.00513>
3. NHS "How to get Vitamin D from sunlight", <https://www.nhs.uk/live-well/healthy-body/how-to-get-vitamin-d-from-sunlight/>