Vitamin D Blood levels are seldom ordered by doctors, or demanded by patients, in spite of the fact that it is the “vitamin of the decade”.
Vitamin D is the sunshine vitamin, since the UVB light normally converts skin cholesterol into vitamin D. The white skin of peoples who migrated into temperate zones such as Europe was very likely a survival factor due to the low amount of sunlight in northern climates compared to the African tropics, and white skin permits increased vitamin D production.
Vitamin D is most famous as the factor that prevents the childhood bone disease “rickets”. The industrial revolution resulted in kids being in factories, getting insufficient sun exposure, and having an epidemic of rickets.
The Covid pandemic resulted in orders of magnitude more deaths among the elderly, especially those in sunless retirement homes. Eventually, vitamin D became implicated in immune deficiency, and the ability to survive Covid.
Vitamin D Is suspected as a factor in multiple sclerosis, tuberculosis, and even seasonal affective disorder, where there is a great increase in depression during the dark months of winter in extreme northern climates.
The NFL, ever striving to keep their players in top physical condition and accelerate recovery from injury, now supplements their players, and, I hear, requires blood levels of 60 ng./ml and above, more when they are injured. Vitamin D thought to improve muscle strength, and the rate of repair in muscle injury.
A lot of studies have failed to show the benefits claimed for vitamin D, but a recent large study from Harvard showed that the beneficial effects of vitamin D occur only among thinner individuals with a BMI of less than 25, which is a shrinking percentage of our population. It seems that already healthy people who are not overweight are the only recipients that can benefit from vitamin D, a fat soluble vitamin, which may be tightly held by the excess fat of overweight people.
Although I am waiting for more and better studies, I obtain yearly vitamin D blood levels. in fact, I was rather worried recently that my 5000 i.u./day supplementation might be excessive. Not so; it came back as 51 ng/mL The normal level is now considered to be above 30 ng/mL. This was determined in part by finding that the parathyroid hormone blood level was elevated with lower levels of vitamin D, and reached normal only at 30 ng.
How much is too much? It has been documented that most lifeguards in the summer have levels above 100.ng/ mL and there has never been Vitamin D toxicity based on with sun exposure as the sole source of elevation in vitamin D level. “
Getting your vitamin D by sun exposure can lead to skin cancers in later life, however, and my opinion is that VITAMIN D BY ORAL SUPPLEMENTATION IS SAFER.
Checking your blood vitamin D level should be done at least twice. Once to check the baseline, and, since most people in our mostly inside, sunscreen-using population will not have an adequate level, a second test to be sure that you are adequately and not excessively, supplemented.
My recent results:
Result Value: 51 ng/mL (Vitamin D, 25 Hydroxy)
Reference Range: 30-100 ng/mL (1 ng/mL = 0.83 IU/mL)
Deficiency is < 20 ng/mL.
Insufficiency 20-29 ng/mL
Sufficiency 30-100 ng/mL