City Assays Vitamin D Blood Spot Test £25
£20 if you buy 10 and share with friends/family)
5000iu vitamin D is available online for less that £5 years supply. Most people require around 1000iu per 25lbs to get to above 125nmol/l 50ng/ml the level at which vitamin D is most effective as an anti inflammatory agent.
We do have to understand that in order for the circulating form of vit d to switch to the active hormonal form the presence of MAGNESIUM is required. Most of us do not consume the RDA for magnesium. There are online calculators that enable you to check the magnesium content of the foods you consume. There are several different ways of improving magnesium status. Magnesium citrate/malate or a chelate are all reliable (avoid magnesium oxide as only 4% bioavailable) You can also consider epsom salts (magnesium sulphate or magnesium chloride (dead sea salts) both of rthese are cheap by the 20kg sack and can be chucked in a hot bath and a 20minute soak will relax muscles help sleep quality and improve magnesium status.
The conversion of calcidiol to calcitriol is also improved when the omega 3 DHA level is high. We tend to have higher omega 6 levels now than when human DNA evolved (grain fed meats + omega 6 corn/soy/sunflower/rapeseed,canola oil,cottonseed oil,safflower oil) and these all negate/neutralize the action of omega 3. Avoiding omega 6 completely while increasing fish oil consumption and consuming oily fish regularly will enable the ratio of omega 3 to omega 6 to rebalance and this will improve the ability of vitamin D to function properly. (DHA also acts directly as a vitamin d ligand so works in more than one way to improve the ability to activate the hormone as required)