twoweek
IF you are an average responder , then you can expect your blood level to rise by 25 (nmol/L) for every 1000 IU ( 25microgram ) of Vitamin D 3 that you take , as a daily supplement , taken over the long term. Your blood level will stabilise after about 90 days on that particular dose. ( an average 75 kg adult... actual Vit D requirements depend upon total weight ). IF you stop taking that dose , then your blood level will start to drop, over a few months, to your starting point.
The normal .. ie common level in UK is generally 30 - 70 , sometimes a bit higher in summer when sunlight is strong enough to make Vitamin D in your skin. Over winter , that is November to March , you cannot make vitamin D from sunlight , the UVB radiation is absorbed by the atmosphere at our latitude 50 + degrees North.
Many people have symptoms of low vitamin D , especially in the winter, particularly those with levels below 30.
Many medical bodies worldwide , recommend a level 75 and above. As humans that evolved in sunny Africa., we evolved with levels of about 120 -140 . That is our natural level, our physiology expects it. You will be healthiest with that level.
That level is seen as within the healthy acceptable band by the NHS. Although , it is quite uncommon here in the UK. As soon as we humans live an outdoor life , in plenty of sunshine , at a lower latitude , where we can make Vit D all year round , THEN our levels rise to 120 - 140 , some people even more .
The fact that we have only been in our northern latitudes for about 500 generations , only after the last ice age means our physiology has not changed that much to cope with the reduced levels of Vitamin D that it now encounters , here in the UK. Evolution does not work that fast. There are many consequences of a low Vitamin D , because every cell in your body has receptors for it , 2000 genes in those cells have vitamin D response elements VDREs.
Vitamin D becomes a hormone , in our bodies , it enables those genes to be read , and for those cells to produce proteins, modify behaviour, signal other cells , fight off invaders, bacterial and viral etc .
From this explanation , you might see that it is very worthwhile getting your blood level up , many Vitamin D researchers recommend at least 100 , and up to 150. A daily , long term, supplementation of 2000 IU to 5000 IU should achieve that for most of us. Some people are lower responders , and might need more. ( If you are higher BMI ) IF you have been given a large loading dose , don't just stop taking at least some Vit D , when that has finished. Your levels will just drop again , unless you change your lifestyle , and go outside a lot, in sunshine in summer , without suncream , for at least 20 mins . It is difficult to keep a higher blood level in Britain. Food contains very little Vit D , cows milk contains none, eggs only 40 IU each. ( a tiny tiny amount) . None in fruit and veg. Wild caught oily fish such as salmon has a few hundred units per portion , however farmed salmon only 1/4 of that , as their feed is deficient.
In summary , it makes sense to take a supplement , to raise your level , 2000 IU will raise it by about 50 , and take you up around the 100 nmol/L mark. Another thousand should will take you up around the 120 level., a better place to be.
Hope that is useful.
best of luck with your levels.
If you want to check blood levels , you can get a blood spot test sent from this NHS laboratory. <a class="break-all" href="http://www.vitamindtest.org.uk/" rel="nofollow" target="_blank">www.vitamindtest.org.uk/</a>
If the test is not doctor ordered , they do charge £28 , but it is a good investment in your own health.
BTBH
PS. If anyone wants any more info, just get back to me..!.