Le Formulaire Nutrition || The Sunshine Vitamin
As the days get darker and summer starts to feel like a distant memory, we at Le Formulaire think it’s a perfect time to turn our attention to vitamin D, the sunshine vitamin!
Vitamin D is actually a pro-hormone that is synthesised by the skin when exposed to ultraviolet V (UVB) sunlight. During the summer months, most of us will get enough through sunshine-skin contact, provided we spend about 15 minutes outdoors getting sun over our face, arms & legs. Sunscreen as we all know is one of the most effective ways of fighting signs of ageing and reducing risk of skin cancer by blocking harmful UVB rays, and it is important to note that our skin can still make enough vitamin D when wearing sunscreen (1).
Why is Vitamin D important?
We all know that vitamin D is important for supporting bone health and a healthy immune system. It is also required for cardiovascular health, brain function and muscle health. When it comes to the skin, vitamin D helps cells to divide and renew. It has additional roles in fight infections as well as promoting wound healing and tissue repair after injury. If we are lacking adequate amounts of this vitamin, many common skin and hair conditions, such as psoriasis, eczema, acne, hair loss and auto-immune dysfunction could be aggravated (2).
Are you getting enough?
Our northern hemisphere's latitude makes it difficult to get sufficient UVB rich sunshine in order to produce vitamin D, especially throughout the months of October and March. This means that even on those precious sunny winter days, we need to seek Vitamin D elsewhere.
Vitamin D can be found in our diets, but it could be hard work trying to get enough solely by the food on our plate alone. The best sources are oily fish (salmon, sardines, tuna, mackerel). Small amounts are found in meat, dairy food and eggs (particularly yolks), and some foods have been fortified with vitamin D such as breads, breakfast cereals and margarine. As we don’t consume large enough quantities of these foods, they can’t be our sole source of vitamin D.
Older adults, people with darker skin tones, those that prefer to keep their skin covered and that are not often outdoors should consider taking a daily vitamin D supplement all year-round to avoid deficiency. For the rest of us a supplement should be considered during the winter months.
How much do we need?
It is recommended that we take a vitamin D supplement between October and (at least) March and for most Irish adults, 2,000iu (or 20-25 mg) per day is the recommended level. Some people may need more or less than the recommended dose due to several factors, so it is always important to consult your GP if you are unsure.
Supplements come in many forms and some examples include capsules or sprays; but look at the label to make sure you are buying vitamin D3. It is important you are consuming D3 as it is the active form, rather than vitamin D2. Most of the supplements are in the D3 forms these days, but it is always best to check
How to take it?
It’s advised to take vitamin D alongside meals, especially one that contains a portion of healthy fats like olive oil or avocados, as this fat soluble vitamin is likely to be better absorbed in this environment.
It is also important to make sure we have enough magnesium. A review found that vitamin D cannot be metabolised without sufficient magnesium within the body (3). Rich sources of magnesium include nuts, beans, legumes and leafy greens. In general, foods containing a high amount of dietary fibre are also good sources of magnesium.
What if we get too much?
As vitamin D is fat soluble vitamin that is subsequently stored in fat, excess amounts over a long period can build up in the body. This may subsequently cause excess build up of calcium in the body, known as hypercalcaemia. Hypercalcaemia is a medical condition that can lead to organ dysfunction as well as nausea, constipation and excessive thirst. This is extremely rare, but adults should not take more than 100µg (4000IU) a day, unless recommended and monitored by a doctor. You cannot overdose on vitamin D from exposure to sunlight, however it is important to wear sunscreen and to cover your skin if you’re in the sun for long periods as we have mentioned sunscreen does not appear to be a barrier to making vitamin D.
At Le Formulaire we usually take our vitamin D supplements in the morning with our green smoothies (which are packed with leafy greens and fats). This ensures optimum availability (as absoprption is maximised in the presence of magnesium and fats) of the vitamin D we are consuming to ensure we are topped up over winter.
References
Neale, R. E., Khan, S. R., Lucas, R. M., Waterhouse, M., Whiteman, D. C., & Olsen, C. M. (2019). The effect of sunscreen on vitamin D: a review. The British journal of dermatology, 181(5), 907–915. https://doi.org/10.1111/bjd.17980
Mostafa, W. Z., & Hegazy, R. A. (2015). Vitamin D and the skin: Focus on a complex relationship: A review. Journal of advanced research, 6(6), 793–804. https://doi.org/10.1016/j.jare.2014.01.011
Anne Marie Uwitonze, Mohammed S. Razzaque. Role of Magnesium in Vitamin D Activation and Function. The Journal of the American Osteopathic Association, 2018; 118 (3): 181 DOI: 10.7556/jaoa.2018.037