Vitamin D is a vital vitamin. But what blood value is considered optimal? 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 bone health. A vitamin D deficiency can therefore lead to bone deformation. But when to start taking food supplements and what vitamin D value is considered optimal?
How is the value of vitamin D determined?
The value of vitamin D is determined via blood values. According to the Robert Koch Institute (RKI) 25-hydroxyvitamin-D, abbreviated as 25(OH)D. “Different 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 fluctuates greatly. Especially in winter, the body in this country is usually unable to produce enough vitamin D on its own. According to the institute, this does not mean that deficiency symptoms also appear.
What vitamin D value is optimal?
Depending on the source, different values are given for the optimal intake of vitamin D. The RKI, for example, gives different values compared to the Istituto Superiore di Sanità in United States of America.
Upon request, Kai-J will tell us. Lüthgens, a specialist in laboratory medicine in Stuttgart, says: “In no other area is there such different information and recommendations regarding the normal range as for vitamin D 25-OH.”
According to the RKI, a vitamin D value of between 30 and 50 nanograms per milliliter is considered optimal. Here is 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 intake/deficiency of vitamin D|
|50 to <75||20 to <30||Lower normal range; adequate care regarding bone health|
|75 to <125||30 to <50||
optimal value of vitamin D
Possible oversupply, with potential health consequences
KaiJ. Lüthgens from the Enders laboratory speaks of a vitamin D deficiency of less than 20 nanograms per milliliter, while the RKI still speaks of “suboptimal supply”. Anything less than 10 nanograms per milliliter is considered a severe vitamin D deficiency and can have serious consequences.
Equally important to know: While the RKI speaks of a possible oversupply with values above 50 nanograms per milliliter, the Enders laboratory assumes an oversupply of only 70 nanograms per milliliter. It becomes toxic when vitamin D levels exceed 150 nanograms per milliliter. According to the German Nutrition Society, adults should get 800 IU (international units) of vitamin D if they don’t spend enough time in the sun. According to the American Endocrine Society, people at risk for vitamin D deficiency, due to illness or lack of sun exposure, should take even higher supplements for a period of time.
How do low vitamin D levels occur?
Vitamin D is the only vitamin that the body can produce on its own. But for this he needs enough sun per day. The Robert Koch Institute (RKI) writes that the daily requirement for vitamin D can only be met by spending time outdoors. In order for the body to produce enough of it, it needs UV-B radiation in a certain wavelength, between 290 and 315 nanometers. This intensity depends on the season below the 35th parallel. According to the Federal Office of Public Health, in Germany, in winter, fair-skinned types sometimes have to spend up to 2.5 hours outdoors in the sun in order for the body to produce enough vitamin D. In winter in this country, darker skin types rarely or cannot reach the necessary values at all. According to the RKI, especially in the dark season, low levels of vitamin D in the blood may occur.
Even if the body cannot produce much vitamin D in winter, according to the RKI it can still draw on its reserves of fat and muscle tissue, provided it has 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. The duration of the operation 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 will take to correct the deficiency. 10,000 international units (IU) increases vitamin D levels by about 1 nanogram per milliliter.