A summer break for Vitamin D?

04. August 2016, Redaktion, Micronutrients

It’s summer finally! While those of us who love the sun cannot wait to go outside and enjoy the rays, some are not as pleased with the heat and prefer being inside and hiding from the sun. People in employment do not have a choice anyway, they are, very often, stuck inside. And in case there is time for going outside and enjoying the sun, many only do it after applying sun screen. This is not a bad thing, however, we are dependent on ‘unprotected’ insolation for a certain amount of time in order for our bodies to produce a sufficient amount of Vitamin D. A vitamin that is not only necessary for strong bones. 

What makes Vitamin D special?

Vitamin D is, as the name suggests, a vitamin-however it is not a vitamin in the proper sense: while essential vitamins and other vital micronutrients are directly acquired from food, our bodies can produce vitamin D through sunlight, which is important, since food contains only small amounts of vitamin D.  
Vitamin D’s function inside the body is unique. Many associate vitamin D with healthy bones-which seems to be common knowledge. However, vitamin D is more than just a ‘bone-vitamin’- many recent studies show that vitamin D is highly important for our general well-being. This is also evident when looking at the general structure of the human body. More than 35 tissues of our body-practically from head to toe- are considered to be docking sites for the ‘sun-vitamin’. Ultimately, vitamin D is not only vital for the bones, but also for immune function as well as for maintaining normal muscle function. 

The ‘D’-lemma behind the vitamin D-production

In our part of the world, young people can meet their vitamin D needs by exposing themselves to the sun every once in a while (for people with fair skin, 5-10 mins, 2-3x a week, uncovering arms and legs, is enough). However, the body’s’ ability to produce vitamin D is influenced by many different factors, such as: cold weather, advanced age, darker skin type as well as the application of sunscreen.  The body cannot produce enough or any vitamin D if people use creams, make-up or sunscreen above 8 SPF.  
In addition, the body’s ability to produce vitamin D is dependent on the sun’s position: in the winter months as well as in the morning and evening hours we, in central Europe, cannot produce enough vitamin D. A rule of thumb to judge whether the sunlight is intense enough for the body to produce vitamin D is to compare one’s own shadow with the body length: if the shadow is longer than your actual body height, the radiation intensity is too low. Thus, in central Europe, our bodies cannot produce vitamin D during the winter months; but also in summer, after 16.00, the radiation intensity is not strong enough anymore. To produce vitamin D, the body has to be exposed to the midday sun.

It is always vitamin D season; all year around

Vitamin D supply is not a topic of interest dependent on the season, for some people it is highly relevant, even in summer. People who do not expose themselves to the sun and/or are influenced by factors mentioned earlier, can find out about their vitamin D-level in their bodies through a blood test. Ideally, the results would lie between 40-60 ng/ml or 100-150 nmol/l. Your doctor will gladly provide you with further details. 

Event tip: On September 27th, Dr. med. Univ. Andreas Faux, will talk about the ‘Tausendsassa unter den Vitaminen’-please sign up in a time. This event is free.


Gröber U, Holick MF: Vitamin D. Die Heilkraft des Sonnenvitamins. Wissenschaftliche Verlagsgesellschaft Stuttgart; Auflage: 2., durchgesehene und akt. Auflage 2013. 
Holick MF. Sunlight, ultraviolet radiation, vitamin D and skin cancer; how much sunlight do we need? Adv Exp Med Biol. 2014;810: 1-16