How much vitamin D a day do you really need?

Without vitamin D , our body cannot function. But how much vitamin D a day do we really need?

The vitamin is primarily needed to regulate our calcium metabolism as well as to build our bones. More precisely, the hormone calcitriol and not vitamin D is responsible for this. Vitamin D is only the precursor of this vital hormone and must first be activated by the body.

Although we can also absorb the vitamin through the diet through certain foods, such as fatty fish, most of the vitamin D requirement is usually met by sunlight.

If this intake via the sun is limited due to your living conditions, a deficiency of vitamin D can occur over time. If you suffer from such a deficiency, you are far from alone. The large-scale study on the health of adults (DEGS) by the Robert Koch Institute, the results of which were published in 2012 and 2013, showed, for example, that about 30% of adults in Germany are poorly supplied with vitamin D.

Of course, this raises the question of how much vitamin D per day we really need. The answer to this question is far from clear.

So how much vitamin D a day should it be? Good question!

The question is not so easy to answer. Science does not always agree on the actual recommendations of how much vitamin D a day we need.

On the one hand, this is of course due to the fact that the intake of vitamin D looks slightly different for each person, as it depends on individual factors such as skin type, eating habit or time in the sun. On the other hand , the study situation in connection with vitamin D is not always clear.

So far, only a statistical relationship between low vitamin D levels and an earlier death is more or less clear. However, the extent to which vitamin D is associated with increased mortality has not yet been clarified. Of course, the question of whether the low vitamin D level was the cause of a disease or merely its symptom would be particularly interesting.

However, researchers are optimistic that this question will be clarified in the coming years.

The current reference values for the vitamin D daily requirement

The German Nutrition Society (DGE) is relatively uncomplicated with its recommendation for an appropriate vitamin D intake: A vitamin D intake of about 800 IU per day is recommended here, regardless of age and gender. Only for infants, the value is set lower at 400 IU.

This rough recommendation is mainly due to the relatively ambiguous research situation. It is simply not yet known exactly whether the body mass, or the body fat percentage and thus the gender have effects on the vitamin D requirement.

It should also be noted that the recommendations of the DGE were made in the case of lack of endogenous vitamin D synthesis. This means that you do not produce vitamin D yourself, for example, because you spend the whole day indoors or for other reasons do not get sun. In addition, vitamin D, which is absorbed from the diet, has already been taken into account.

For infants, the recommendation applies regardless of whether they spend time in the sun or not. In their case, an additional administration of vitamin D is generally recommended for the prevention of the bone disease rickets.

800 IU? How many mg per day is that?

One microgram (μg) corresponds to 40 International Units (IU). Converted into micrograms, the DGE’s recommendation on the daily intake of vitamin D is as follows:

Other recommendations for vitamin D

In addition to the values of the DGE, there are a number of other recommendations on how much vitamin D per day you can or should take.

For example, the US Institute of Medicine (IOM) bases its recommendation at 15 μg per day , but also speaks of a tolerable upper intake of up to 100 μg per day in adults. As far as this still harmless maximum limit is concerned, the European Food Safety Authority also joins in.

The many different recommendations once again illustrate the still uncertain research situation around vitamin D.

At the other end of the spectrum is the Endocrine Society – an international medical society that focuses on endocrinology, a branch of internal medicine. Researchers at the organization suggest that as much as 50 μg, or about 2000 IU of vitamin D per day, may be appropriate for adults.

Furthermore, Canadian researchers from the University of Alberta drew attention in a published letter in 2014 to an alleged calculation error in the calculation of the general recommendation of vitamin D. According to them, a much higher dose of more than 8000 IU could be needed to optimally supply the body with vitamin D. However, this has not yet been confirmed.

So should you play it safe and focus on more vitamin D right away? As with most nutrients, caution should be exercised with vitamin D in this regard.

Is too much vitamin D harmful?

If you take in too much vitamin D, this can have serious consequences. Since we need vitamin D to regulate our calcium levels, an overdose leads to harmful calcium deposits in the body in the long term.

Especially your kidneys can be affected. Possible symptoms include:

• strong thirst despite sufficient hydration
• increased urination
• Nausea and vomiting
• physical weakness
• Headache
• Kidney stones up to serious kidney damage

In case of doubt, see a doctor

As always, if you think your vitamin D levels are too low or too high, ask your doctor for advice. With a relatively uncomplicated blood test, it can be determined whether you really suffer from an undersupply of the vitamin.

If you then have certainty, dietary supplements can help you to meet your needs in the long term. This is how you make sure your body gets everything it needs.