Vitamin D - information on requirements, intake, raw materials

Information on vitamin D

80 - 95% of the vitamin D requirement is formed in the skin, but only under the influence of the sun.

In summer, 10 minutes of midday sun is sufficient for people with a light skin colour. People with a darker skin colour are less sensitive and therefore need 20 to 60 minutes*. 1/3 of the skin surface should be exposed to the sun.

If we assume that healthy and sporty people who regularly spend a lot of time outdoors produce enough vitamin D, then there should not actually be any people with vitamin D deficiency. This is apparently the ideal conception of many media, where non-experts (which unfortunately also include many so-called medical journalists) spread the idea that vitamin D, like all other vitamins, is completely superfluous or harmful.

The catch is that not everyone is young, sporty, has a healthy diet, is free from chronic illnesses and is constantly out and about in the fresh air.

Factors or situations that make vitamin D production in the skin difficult or impossible:

• Old people who don't get out much
• People who work indoors all day until they can only go out in the evening - when the sun is too weak or, depending on the time of year, has disappeared completely
• People who go outside wearing a veil
• People with special illnesses, some of whom have a greatly increased need for vitamin D or lose it
• Children and young people who spend more time in front of the PC and TV and almost never go outside
• People, mostly parents with children, who immediately reach for sun cream outdoors, preferably factor 50. A tip: Leave the children and yourself in the sun for 15 minutes in swimwear before applying sun cream!

Here are just a few examples. You can work out for yourself whether the opinion of the vitamin-bashing faction that Germany is so wealthy that nobody has a vitamin deficiency is correct or the opinion of the supporters, who also see a widespread vitamin D deficiency as proven by studies.

Vitamin D deficiency - frequent and widespread

More than half of all people in Germany have a vitamin D deficiency. The German Nutrition Society (DGE) considers a serum concentration of 20 ng/ml to be sufficient. According to the Robert Koch Institute, 58% of women and 57% of men have a vitamin D deficiency. This figure is even higher in the winter months.

Today, however, experts often assume a normal value of 40 - 80 ng/ml. A mild deficiency is considered to be 20 - 30 ng/ml, a severe deficiency less than 20 ng/ml.

Vitamin D intake through food

Only a few foods contain significant amounts of vitamin D. The DGE recommends a daily intake of 20 micrograms of vitamin D per day for children, adolescents and adults. This would roughly correspond to the daily consumption of 16 hen's eggs, 5kg of cheese, 80g of herring or 2 tins of sardines.

In this respect, daily supplementation to cover the vitamin D requirement with a food supplement makes sense and ensures an adequate supply - especially in winter.

Vitamin D level in the blood

An optimal vitamin D level (the 25 OH vitamin D3 level in serum is measured) is between 30 - 70 ng/ml. According to the recommendation of the German Nutrition Society (DGE), the vitamin D concentration in serum should be at least 20 ng/ml (= 50 nmol/l). However, most experts consider this value to be too low and recommend a minimum value of 30 ng/ml. It is not the actual vitamin D3 that is measured, but its storage form calcidilol (25-hydroxy-vitamin D). The reason is quite simple: if vitamin D3 were measured, you would only have a snapshot of the current status. The storage form, on the other hand, provides information about the long-term vitamin D supply.

The following guide values provide a good orientation:
below 10 ng/ml - severe vitamin D deficiency
10 - 20 ng/m - vitamin D deficiency
20 - 30 ng/ml - mild vitamin D deficiency
30 - 70 ng/ml - normal range
over 70 ng/ml - vitamin D level too high
Levels that are more or less above the 70 ng/ml mark (100 ng/ml at the latest) are potentially toxic and can lead to health problems. A value above 150 ng/ml is definitely considered toxic. There is as yet no information on the long-term consequences of such extremely high levels (which can only be achieved by excessive intake of extremely high doses of over 20,000 IU per day). Exceptions to this are certain diseases (e.g. multiple sclerosis). However, even in cases of illness, high-dose therapy should be carried out under the supervision of a doctor.

Laboratory values

Possible units of measurement in the laboratory are: ng/ml (nanogram per millilitre), or nmol/l (nano-mole per litre). Sometimes values are also given in yg/l (micrograms per litre). These values correspond to the values in ng/ml (i.e.: 36 yg/l = 36ng/ml).

The conversion factor from ng/ml to nmol/l = 2.5.
(Examples: 20 ng/ml = 50 nmol/l or 30 nmol/l = 12 ng/l)

Best dosage forms: Soft capsules with oil or oil as drops
Vitamin D is a fat-soluble vitamin. Fat-soluble means that it needs fat/oil as a transport medium. Only then can the body utilise it at all.
Natural, oil-based liquid D3 has a very high bioavailability - meaning it can also be absorbed by the body.
Important to know: Vitamin D3 in the form of tablets or coated tablets does not contain any natural oils. They also often contain unnecessary additives.

Always take vitamin D3 together with vitamin K2

Why should high doses of vitamin D always be taken together with vitamin K2?
Vitamin D3 controls the absorption of calcium from the food we eat into the blood. If it remains there, it is deposited in the body as useless and harmful slag. In the long term, such deposits lead to dangerous calcification of blood vessels and organs. The body must therefore be able to utilise the calcium in the blood properly.

And this is where vitamin K2 comes into play. Vitamin K2 activates the proteins osteocalcin and MGP (Matrix Gla Protein), which are responsible for the utilisation of calcium in the blood. These proteins ensure the transport and storage of calcium from the blood into the hard substance of bones and teeth. Only in this way, with the help of vitamin K2, does the calcium get to where it belongs and where it is needed.

Vitamin K2 therefore prevents the calcium in the blood from settling as plaque (deposits) in the artery walls and thus keeps our blood vessels clean.

Vitamin D therefore always needs vitamin K2 to utilise the calcium. As a dietary supplement, vitamin D should therefore always be taken together with vitamin K2, as the two vitamins complement each other in their functions for the organism.

The big misconception

It is often said that vitamin D stores calcium in the bones. This is not correct. Together with the parathyroid hormone, vitamin D ensures the absorption of calcium from the intestine into the blood, i.e. higher calcium levels in the blood. The proteins osteocalcin and MGP then "transport" the calcium to the bones and teeth, i.e. to where it is needed - provided they are activated by vitamin K2. The "reason" for this "error": Vitamin K2 in the form MK-7 is very expensive. It is therefore omitted from almost all vitamin D products. The lack of effect is then pragmatically attributed to vitamin D.....

Vitamin K2 as 100% natural all-trans MK-7
But there are also big differences in vitamin K2.

The form MK-7 (all-trans) used in proSan Vitamin D3+K2 (MK-7) comes 100% from natural plant sources and has a so-called trans content of over 98%.

You should avoid these forms of vitamin K2: MK4 (very poor bioavailability, must therefore be given in extremely high doses), MK7-cis (practically ineffective), MK9 (little researched, mostly synthetic, not authorised in Germany). but also mostly very cheap MK7 products (often from abroad), where the trans content is only very low.

Beware of cheap vitamin K2 products - often from abroad

A carefully produced MK7 all-trans active ingredient is currently still very expensive. In many supposedly cheap products that are offered on the Internet, especially from abroad, cheap imported active ingredients with a low all-trans content are used (i.e. they have a high cis content!!!) and are therefore largely ineffective. Our advice: Trust reputable manufacturers (with whom you can easily communicate and make sure of the quality) and not the supposedly cheap internet bargains. Quality has its price.

In combination with vitamin D3, the long-acting form vitamin K2 (MK-7 all-trans) is the best way to ensure an adequate supply of all organs and tissues.

Vitamin D - overdose

The Federal Institute for Risk Assessment (BfR) speaks of a "vitamin D overdose" if the serum value is greater than 160 ng/ml or 400 nmol/litre. The BfR describes the main risk of such an overdose as hypercalcaemia, i.e. too much calcium in the blood. Typical symptoms of such hypercalcaemia are kidney stones and calcification of blood vessels, heart and lungs.

How can a vitamin overdose occur?

An overdose through UV radiation and food is not possible. The most common cause is the intake of excessive amounts of vitamin D. Especially on the Internet, products from abroad are offered with 50,000 i.U. or even 100,000 i.U. Sect-like groups, especially in the social media, ensure that they are sold. These products always come from abroad. As a rule, nothing is known about quality standards during production. The ingredients are often insufficiently declared or not declared at all - so you often don't know what's really in them. It is not for nothing that such dietary supplements are banned in Germany - but they can still be easily obtained via the Internet.

The safe dose

The Federal Institute for Risk Assessment (BfR) describes a vitamin D intake of 100yg = 4,000 i.U. daily as the so-called Upper Intake Level - i.e. the maximum safe dose that should be taken daily.