Vitamin D is a vital vitamin. But what value in blood is considered ideal? Read the answer here.
Vitamin D has many functions in the body. However, its role in bone metabolism is particularly important. Vitamin D promotes the absorption of calcium and phosphate and is therefore essential for healthy bones. Vitamin D deficiency can therefore lead to bone deformation. But when should you start taking nutritional supplements and what amount of vitamin D is considered ideal?
How is the value of vitamin D determined?
The value of vitamin D is determined through blood values. According to the Robert Koch Institute (RKI) 25-Hydroxyvitamin-D, abbreviated as 25(OH)D. “Several reference values can be used to evaluate serum 25(OH)D values,” writes the RKI. A commonly used classification is that of the US Institute of Medicine (IOM). There are classifications that indicate the serum value in nanomoles per liter (nmol/l), nanograms per milliliter (ng/ml) or micrograms per liter.
According to the RKI, the serum value varies greatly. Especially in winter, the body in this country often cannot produce enough vitamin D. According to the institute, this does not mean that deficiency symptoms also occur.
What vitamin D value is ideal?
Depending on the source, different values are given for optimal vitamin D supply. The RKI, for example, gives different values from the National Institute of Health in USA.
Upon request, Kai-J will tell us. Lüthgens, a specialist in laboratory medicine in Stuttgart, said: “In almost no other area is there as much different information and recommendations regarding the normal range as for 25-OH vitamin D.”
According to the RKI, a vitamin D value between 30 and 50 nanograms per milliliter is considered ideal. Here’s the overview:
|25(OH)D in nmol/l||25 (OH)D in ng/ml||possible effects|
Vitamin D deficiency
|30 to <50||12 to <20||Suboptimal supply/vitamin D deficiency|
|50 to <75||20 to <30||Lower normal range; proper care when it comes to bone health|
|75 to <125||30 to <50||
ideal vitamin D value
Possible oversupply, with potential health consequences
Kai J. Lüthgens from the Enders laboratory speaks of a vitamin D deficiency at levels below 20 nanograms per milliliter, while the RKI still speaks of “suboptimal supply”. Anything less than 10 nanograms per milliliter is considered a serious vitamin D deficiency and can have serious consequences.
It is also important to know: while the RKI speaks of a possible oversupply of values above 50 nanograms per milliliter, the Enders laboratory only assumes an oversupply of 70 nanograms per milliliter. It becomes toxic when vitamin D levels exceed 150 nanograms per milliliter. According to the German Nutrition Society, adults should take 800 IU (international units) of vitamin D if they do not spend enough time in the sun. According to the American Endocrine Society, people at risk of vitamin D deficiency – due to illness or lack of sun exposure – should even take higher supplements over a certain period of time.
How do low vitamin D levels occur?
Vitamin D is the only vitamin that the body can produce itself. But for this he needs enough sun per day. The Robert Koch Institute (RKI) writes that the daily need for vitamin D can only be met by spending time outdoors. For the body to be able to produce enough, it needs UV-B radiation at a certain wavelength – between 290 and 315 nanometers. This intensity depends on the season below the 35th parallel. According to the Swiss Federal Office of Public Health, in Germany, fair skin types sometimes need to spend up to 2.5 hours outdoors in the sun in winter so that the body can produce enough vitamin D. Darker skin types can hardly or not reach the necessary values in this country in winter. According to the RKI, low levels of vitamin D in the blood can occur, especially in the dark season.
Although the body in this country cannot produce much vitamin D in winter, according to the RKI, it can draw on fat and muscle tissue reserves – provided you have spent enough time in the sun beforehand.
How long does it take to correct a vitamin D deficiency?
If low levels of vitamin D are detected in the blood, the deficiency must be corrected. How long this takes depends on two factors: body weight and blood serum levels. The lower the vitamin D value and the greater the body weight, the longer it takes to correct the deficiency. 10,000 international units (IU) increases vitamin D levels by about 1 nanogram per milliliter.