23 Apr Vitamin D: If this is the sunshine vitamin are Irish people not fecked?
We have an intimate relationship with rain on this emerald isle. We have a million and one ways to describe the type of rain and discussing this persistent precipitation is very much part of the Irish vernacular. Be it misty or drizzly, rain means clouds which means lack of sunshine for us.
This coupled with spending the majority of our modern lives indoors, high spectrum sunblocks and an almost irrational fear of the sun between 11-3pm means that we are not producing the vitamin through our skin like our ancestors did and are relying on our diet to keep our levels adequate, but is it enough?
Firstly let’s discuss what Vitamin D is:
Vitamin D is a fat soluble vitamin essential for many functions in the body.
It helps with:
- calcium absorption for healthy, strong bones,
- gene expression, how information from the gene is used to make a gene product like a protein and
- immune regulation.
Deficiency symptoms can be severe including rickets in children and osteomalacia in adults. Low levels of vitamin D are also linked with fractures and falls as well as higher incidences of cancer, autoimmunity, hypertension and cardiovascular disease (1). One Australian study even concluded that low blood levels of vitamin D were associated with an increased risk of death overall. (2).
So how do we get more of this vital nutrient?
According to the Food Safety Authority Ireland, the recommended amount of vitamin D is being reassessed but dietary guidelines in America suggest 5µg for infants and young children up to 3 years of age (2), with no daily recommendations for adults (3).
To ensure you’re getting good dietary sources, the following foods are excellent sources of vitamin D:
- Duck eggs
- Trout Eel
- Chicken eggs
- Beef liver
As the fat soluble vitamins work together, consider adding more vitamin K and A to the diet to ensure a balance of each. Good sources of vitamin K include:
- Natto (fermented soya beans)
- Hard and soft cheeses
- Egg yolks
- Other fermented foods
Liver and cod liver oil are good sources of vitamin A but speak to your GP about vitamin A if you are pregnant.
To really ensure you’re getting enough, you might consider getting a serum test at your Doctors before thinking about supplementation. More is not better here as vitamin D has an upper limit and can lead to toxicity. Though a high level from sunlight exposure is closely regulated in the body it does not produce toxicity (4).
Recommended sun exposure to make Vitamin D
Understandably, Irish and UK advisory groups don’t want to give a one size fits all approach to the amount of time we spend in the sun. It depends on a combination of factors including skin tone, location in the world and the time of year.
However, cancer research UK recognises the need for a certain amount of sun exposure recommending that: “Most white people should be able to make enough vitamin D from short, casual exposure without sun protection like you might get just by going about your daily life…Enjoying the sun safely, while taking care not to burn, should help most people get a good balance. ” They all agree that sunburn should be avoided at all costs but that a certain amount of sun exposure is useful in helping us to create this essential vitamin, what our bodies have evolved to do.
When we can make Vitamin D?
In Ireland, we cannot make vitamin D in the winter months (October to March) because of the type of UV rays available (6). This makes sense that we make it in the summer when there is plenty of sunshine and store it to get us through the winter.
Finding the balance
We are all too aware that too much sun exposure can lead to cancer but now emerging research is saying too little vitamin D can lead to cancer so there needs to be a balance. We have evolved with this biological mechanism to make this essential vitamin and this, in my opinion, is not to be ignored.
But we can be smart about it; always avoid burning and take the necessary precautions to prevent skin damage from the sun. A certain amount of sun exposure and good dietary sources, can go a long way towards no only helping to avoid deficiency of this vitamin but also to promote health with all the benefits this vitamin can have.
- Holick, M. (2007). Vitamin D Deficiency. New England Journal of Medicine, 357(3), pp.266-281.
- Dobnig, H. (2008). Independent Association of Low Serum 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Levels With All-Cause and Cardiovascular Mortality. Archives of Internal Medicine, 168(12), p.1340.
- Fsai.ie. (2019). Vitamin D | FAQs | Food Safety Authority of Ireland. [online] Available at: https://www.fsai.ie/faq/vitamin_d.html.
- HSE.ie. (2019). Vitamin D – HSE.ie. [online] Available at: https://www.hse.ie/eng/health/az/v/vitamins,-minerals-and-supplements/vitamind.html.
- Webb, A. and Holick, M. (1988). The Role of Sunlight in the Cutaneous Production of Vitamin D3. Annual Review of Nutrition, 8(1), pp.375-399.
- Boran, G. and Seheult, J. (2018). Laboratory Testing for Vitamin D Deficiency [online]. Available at: https://www.hse.ie/eng/about/who/cspd/ncps/pathology/resources/lab-testing-for-vit-d-deficiency11.pdf
*The information given is considered general advice and should not be used in place of professional medical expertise or treatment.