Vitamin D is Safe
As a guinea pig, the owner and operator of this site has kept his vitamin D in the upper levels for over 3 years in order to demonstrate the safety of this vitamin. There was nothing foolhardy about this, since all the researched about "D" documents that 10,000 IU a day is its safe upper limit.
While conventional medicine absolutely refuses to recognize the importance of vitamin D, as a case study of one, I can happily report that so far nothing bad has happened.
I took my first blood test on July 29, 2011 (103 ng/mL) which indicates that I first started seriously supplementing with "D" during April 2011. My second blood test was taken on January 9, 2012 (90.8 ng/mL). Finally, the third test was taken a few days ago on August 22, 2013.
I was surprised by the test results since I was expecting higher blood levels of "D" (73.4 ng/mL). In addition, this time, the lab checked for blood levels of calcium (9.0 mg/dL). For what it is worth, after two years of serious supplementation with vitamin D, my blood levels of calcium were in the dead center of normal.
Since I had wanted it, at least in the 80 ng/mL (200 nmol/L) range my summer time supplementation routine was slightly off. Thus, while I felt like I was still in the 100 ng/mL range, I clearly was not. The only way to accurately obtain your vitamin D status is by taking a 25-Hydroxy blood test.
Further, we can see that your body actually uses vitamin D for something since your blood levels of vitamin D will steadily drop once you stop supplementing with it.
25-Hydroxy Vitamin D Blood Test
A vitamin D revolution is taking place, in some circles at least. Nutritional supplement sellers have flooded the market with different supplement options. In addition, the 25-Hydroxy blood test is now being offered just about everywhere.
Since I have been taking my oil-soluble vitamins on an empty stomach, one at a time, in the morning, I would conclude that I should be taking 5,000 IU of vitamin D-3, 8 or 9 times a week during summertime.
I would, also, comfortably conclude that for an adult weighing around 150 pounds, 68 kilograms, or 11 stone; 5,000 IU a day of vitamin D-3 taken with a meal would probably result in blood levels of 50 - 60 ng/mL (125 - 150 nmol/L), all other things being equal.
Of course, all other things are never equal. That is why discussing your health situation with a health care professional of your choice is always advisable. Hence, once again, the only way anybody can accurately find out what his or her vitamin D status is by taking a 25-Hydroxy blood test.
How you choose to supplement probably affects your vitamin D requirements as much as your body weight or genetics does. First, you have to pick a brand of vitamin D that you are comfortable with. You can take "D" first thing in the morning on an empty stomach, during the day between meals, or with a meal. Further, you can take vitamin D alone or with other supplements. Whatever you decide to do will affect your blood level results.
There is a wide variation in how people respond to vitamin D supplementation.
Drug interactions can, also, be a factor. We know, for example, that taking vitamin A along with "D" has an adverse effect. Following our recommendations to take the animal form of vitamin A
(i.e., retinol) just once a week, rather than daily, will help to minimize this problem.
While daily supplementation is probably the best advice, taking a week's worth of vitamin D all in one shot on just one day of the week, is another possibility. However, be warned, trying to take an insane dosage of 600,000 IU of "D" in just one shot twice a year yields some very negative results.
Above all else, yo-yo supplementation with vitamin D is no more advisable than yo-yo dieting. What you need to do is develop a supplementation routine that you can comfortably live with, for the rest of your life.
Nobody really knows for sure how much vitamin D a specific person should be taking.
Obviously, we are talking about totally unknown territory. While science is immortal, people are not. We are talking about something here that is very inexpensive and has a strong potential of being a wellspring of longevity.
While everything has a safe upper limit, we are hardly advocating insanely high levels of vitamin D in the 250+ ng/mL range.
To prevent cancer with vitamin D, what everyone should to do is pick a blood level of vitamin D that he or she are comfortable living with. Then monitor your blood levels until whatever you are supplementing with, achieves consistently the same levels. As you can see, I have taken three different tests, all with different results.
The younger that you are, maintaining a mid range of vitamin D will probably do an adequate job, while the older that you are the higher the levels you would want to achieve, in order to make up for lost time. You should always keep in mind the enormous task of "D".
The human body is estimated to contain at least 100 trillion cells, each one of which should have one molecule of vitamin D attached to it. In addition, vitamin D helps to boost your natural immunity. It kills cancer cells out right with a process called apoptosis, which results in the gradually shrinking of abnormal and precancerous growths throughout your body. As well, as prevents abnormal cell growth from taking place in the first place.
Older adults with a few years of sufficient vitamin D supplementation behind them could conceivably cut back a tad bit, to a perhaps more comfortable maintenance level of vitamin D at around 60 to 70 ng/mL (150 - 175 nmol/L).
Here again nobody can say with any large degree of certainty precisely how much vitamin D a given individual should be taking, let alone the optimum dosage. Remember that vitamin D-3 is very inexpensive. So feel free to waste much of what you take, since your good health and long life is worth it.