Kirk: Unless you have the 25 hydroxy blood test, you have NO idea whether you are deficient or not, so I'd suggest you request the test for your next physical. I personally target 80 ng/dl using this test which is high but still below the currently suggested upper limit (100 ng/dl). For me this requires around 10k IU daily during light months (e.g. June-September at 35N latitude when I normally wear T-shirts and shorts) and 15k daily during dark months (October-May). These dosages are NOT dangerous for me but each individual must optimize the dosage based on their actual levels as measured by testing (I'm also an ex-HP engineer so I'm sure you recognize the need for measurements). This is absolutely necessary since Vitamin D absorption ca depend on age, weight, skin color, amount of sun exposure (a function of clothing, outdoor activity and latitude) among other things. One dosage recommendation does not fit all.
"In the United States and Canada as of 2016, the amount of vitamin D recommended is 400 IU per day for children, 600 IU per day for adults, and 800 IU per day for people over age 70"
Given that I'm 75, am taking 10 to 20 times their suggestion resulting in only 80% of the currently suggested upper limit of 100 ng/dl, I call BS on the above. Brought to you by the same folks that suggested the low-fat, low-cholesterol diet which has resulted in ~40% of our population being obese!
Suggested limits for Vitamin D have gradually increased as more is learned about its benefits. About 15 years ago the upper limit was 60, then 80 and now 100 ng/dl (per LabCorp). Toxicity does not occur until >150. Regarding excess calcium, Vitamin D can result in more calcium being deposited into tissues. This is why it is very important to also take Vitamin K (I use LifeExtensions Super-K which has K1 and two versions of K2). This facilitates calcium being deposited into hard tissues (bones and teeth) instead of soft tissues (like arteries and calcifications). My wife has been on Vitamins D and K for several years. Within about 5 years her DexaScan results have reversed her osteoporosis to osteopenia.
|
