The sun vitamin for strong bones and positive moods

Vitamin D

The year is drawing slowly to a close and, when you go out for a walk, the scent of mulled wine lingers in the fresh air. All the houses are decorated with Christmas lights and the mood is set to festive.
But maybe this joyful ambience does not match your state of mind. It is not unusual to feel exhausted and listless at the darkest time of year. In the Swiss population, this fatigue may be the result of a widespread lack of vitamin D.

Vitamin D

Vitamin D is a hormone that the human body can produce itself. The production of vitamin D is activated by sunlight on the skin and this constitutes the majority of our vitamin D supply (up to approx. 85%). The remaining approximately 25% is taken in through food. The levels of vitamin D in the blood change with the annual fluctuation in exposure to sunlight. As the half-life of vitamin D is only three to six weeks, it is not possible to top up during the summer for the winter months. We feel the lack particularly in the months with less sun (November until the end of April). In Switzerland, approximately half the population is affected by vitamin D deficiency, regardless of age, and this is particularly pronounced in the winter. Counteracting this deficiency is recommended, because vitamin D is extremely important for both our bones and our mood.

Vitamin D for bones

Calcium is the body’s most important building block for bones, because it makes them hard and rigid. Almost 100% of the calcium in the body is bound to bones. If a little calcium is present in blood, it has been released from the bones. In the long term, bone strength will suffer from this, and may, in combination with other deficiencies, result in osteoporosis/bone density loss. Vitamin D aids the uptake of calcium and phosphate in the gut. This is why increased bone resorption is often observed with persistent vitamin D deficiency. This results in muscle weakness and a higher risk of falling, particularly in old age. The vitamin D expert Heike Bischoff-Ferrari of Zurich University Hospital has published several studies on the sun vitamin. The researcher has demonstrated that the right vitamin D supplement in older ages (from approximately 60) can minimise the risk of hip fractures and the number of falls. But vitamin D is not just of great importance in older people. In children, too, an adequate vitamin D intake is essential, because a high deficiency may lead to rickets (skeletal deformation).

Vitamin D for the mood

Enjoying the sun is well known to have a positive effect on our moods. In places like the Mediterranean, where the sun shines a lot, seasonal affective disorder (SAD) is rarely encountered. By contrast, it is very common in regions with relatively little sun, such as Scandinavia. There are numerous research studies that hypothesise a link between vitamin D deficiency and depression. People who suffer from depression often have lower vitamin D levels in the blood than people without depression. However, this link is established in the long term only in older people (>60 years old). In addition, the relationship between cause and effect remains to be clarified. However, it is certain that the symptoms of seasonal affective disorder can be alleviated with light therapy. The effect of light rays is comparable with that of anti-depressants and thus constitutes a cost-effective alternative therapy with practically no side effects. You can find more information about light therapy here.

Vitamin D deficiency – now what?

If the vitamin D level is too low, this mostly becomes evident due to the following symptoms:

  • Fatigue
  • Loss of appetite
  • Weak muscles and/or bone pain
  • Sleep disorders

Infants, children, pregnant and breastfeeding women and older people are at increased risk of vitamin D deficiency. Chronically ill, overweight, and dark-skinned people are also more likely to be affected. Without a blood test, a doctor cannot definitively diagnose a deficiency.

The Federal Food Safety and Veterinary Office (BLV) is raising awareness of the fact that the body does not produce sufficient vitamin D in winter. Therefore, experts advise eating a lot of food rich in vitamin D or taking vitamin D supplements during the darker time of year. You can find the recommended supplement dose on this link. A vitamin D overdose can only be caused by an excessive consumption of supplements. When this happens, the blood calcium concentration becomes too high. This can lead to feeling weak, headaches and heart arrhythmias. That is why it is worth informing yourself about the optimum dose in advance.

Although diet plays only a minor role in the vitamin D balance, up to 20% of the vitamin is taken in through food. The following foods are rich in vitamin D:

  • Fish (eel, herring, trout, salmon, tuna)
  • Ceps and field mushrooms
  • Eggs
  • Avocados

However, you would need to eat an unrealistically large amount of these foods to cover your daily vitamin D requirements.

In addition, you can boost your personal vitamin D production in the winter months by spending 5-30 minutes outside every day (preferably in the morning) and exposing yourself to light. All the better if the sun is shining, but a few (weak) rays will reach your skin even if it is foggy.

 

References:
Anglin, R., Samaan, Z., Walter, S. & Mcdonald, S. (2013). Vitamin D deficiency and depression in adults: Systematic review and meta-analysis. The British Journal of Psychiatry : The Journal of Mental Science, 202(2), 100-107.
Bischoff-Ferrari, HA, Dawson-Hughes, B, Willett, WC, et al. (2004). Effect of Vitamin D on Falls: A Meta-analysis. JAMA. 291(16):1999–2006. doi:10.1001/jama.291.16.1999
Bischoff-Ferrari, HA, Willett, WC, Wong JB, Giovannucci, E, Dietrich, T & Dawson-Hughes, B.  (2005). Fracture Prevention With Vitamin D Supplementation: A Meta-analysis of Randomized Controlled Trials. JAMA. 293(18):2257–2264. doi:10.1001/jama.293.18.2257
Golden, R., Gaynes, B., Ekstrom, R., Hamer, R., Jacobsen, F., Suppes, T., . . . Nemeroff, C. (2005). The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence. The American Journal of Psychiatry, 162(4), 656-662.
Milaneschi, Y., Hoogendijk, W., Heijboer, A.C., Schoevers, R., van Hemert, A.M., Beekman, T.T.F., Smit, J.H., Penninx, B.W.J.H. (2013). The association between low vitamin D and depressive disorders. Molecular Psychiatry, 19(4), 444-451.
Parker, G., Brotchie, H. & Graham, R. (2017). Vitamin D and depression. Journal of Affective Disorders, 208, 56-61.

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