According to the German Nutrition Society, our body requires 20 micrograms of vitamin D every day. Supplying the body with sufficient vitamin D is pivotal. Even if the body can produce the vitamin itself, the vitamin D stores are usually empty during the dark season and deficiency symptoms can occur. Read on to discover why our body needs vitamin D and how to detect respective deficiencies.
Vitamin D: surely you have heard the term in the past. Why is it so important for our body? Strangely enough, vitamin D is not a vitamin but a hormone, and plays a vital role in the absorption of calcium from the small intestine and in the incorporation of the mineral into the bones. Therefore, a sufficient supply of vitamin D and calcium is the prerequisite for a stable bone structure. In addition, we know that the muscles have vitamin D receptors and that the vitamin plays a significant role in the body’s regeneration, growth and athletic performance.
Covering the daily requirement of 20 micrograms through diet is only possible to a limited extent. Few foods contain the hormone, and if they do, they only show minimal amounts. Mostly, our body generates vitamin D by itself. With the help of UV light (sunlight), the body produces 80 - 90% of the vitamin D it needs through the skin. However, the prerequisite for this is that you spend time outdoors on a regular basis and that enough sunlight hits your skin. According to recent studies, 91% of women and 82% of men do not meet the recommended vitamin D levels. Nevertheless, severe vitamin D deficiency is extremely rare in Germany. The store is empty in the examples of many young adults and seniors, so that sufficient vitamin D production cannot be guaranteed, especially during winter months when sunlight is rather scarce. Other factors that influence the production of vitamin D are the place of residence, the position of the sun, age, lifestyle habits and, last but not least, skin type. In the case of infants and small children, the body's own production of vitamin D is not yet fully developed, and in older people the body's own production of vitamin D declines rapidly as well.
What happens when there is a vitamin D deficiency?
A vitamin D deficiency leads to insufficient calcium absorption in the intestine and a decline in the calcium blood level. The body tries to compensate for this lack and increasingly produces parathormone in the parathyroid glands, leading to the release of more calcium by the bones in order to restore the required calcium level. The regeneration of the bone is disturbed, resulting in premature ageing. The bones become brittle and more susceptible to fractures. Osteoporosis may develop, resulting in a risk in bone fractures as a consequence of falling.
As described above, vitamin D levels are insufficient during infancy and childhood. Resultingly, the risk occurs that the bones will not be mineralised extensively, thus remaining soft and deformed (rickets). In adults and older people, there is an increased risk of bone fractures and bone softening with muscle weakness and bone pain. However, vitamin D does not only influence bone formation, it also supports many functions of the organism, such as the immune system, nerves, muscles and the cardiovascular system.
The following symptoms can indicate a vitamin D deficiency:
- Tiredness and problems concentrating
- Sleep disturbances
- Growth disorders
- Depressive moods ("winter blues")
- Respiratory infections, higher susceptibility to infections
- cardiac arrhythmias
- Increased risk of diabetes, high blood pressure and multiple sclerosis
How to prevent vitamin D deficiency
Go outside - preferably every day. During summer, five to ten minutes of midday sun are enough to replenish your vitamin D stores for the autumn and winter months. In the winter months, spend at least 10-20 minutes outside every day. It also makes sense to rely on vitamin D supplements during the cold and dark season. Supplements with a weekly dose of at least 2000 international units are optimal for adults.
Vitamin D supplements are particularly important for:
- babies and young children
- people who spend little or no time in the sun
- People who cover most of their body with clothing for religious or cultural reasons
- People with darker skin, as they are less able to produce vitamin D
- Elderly people
- Osteoporosis patients
- Competitive athletes
You may also improve your vitamin D supply in moderation through an specific diet. Fatty fish, e.g. salmon, herring, mackerel or liver are particularly suitable for this purpose. Egg yolk and some edible mushrooms also contain vitamin D.
The proper dosage
An overdose, due to excessive exposure to sunlight or increased consumption of natural vitamin D sources is unlikely; an overdose is conceivable if vitamin D supplements are taken excessively. The consequences could be the formation of kidney stones or kidney calcification. People with kidney metabolism problems should therefore consult their doctor when taking vitamin D supplements. An overdose or the wrong combination of preparations can possibly do more harm than good; pregnant women should get the approval of their gynaecologist.