My homework report for vit D supplementation
I don't know who did the comprehensive report that Tanya linked on hte vit D thread.
http://www.mothering.com/discussions...hypercalciuria But the agenda seems pro-supplementation from the language, persuasive agenda, inclusion of studies considered disreputable by the Cochrane Review standards of double blind, non-interest funded research. It references specific studies of which I have also read quite a few today.
http://www.ajcn.org/cgi/content/full/79/5/717#R2
Here is the net version:
"A normal serum circulating 25(OH)D concentration in the United States is considered to be > 15 ng/mL (20). Using information from the National Health and Nutrition Examination Survey a group of researchers concluded that having low levels of vitamin D (<17.8 ng/mL) was independently associated with an increase in all-cause mortality in the general population.[71] One study found an elevated risk of ischaemic heart disease in Southern India in individuals whose vitamin D levels were above 89 ng/mL.[70]
Vitamin D stored in the human body as calcidiol (25-hydroxy-vitamin D) has a large volume of distribution and a half-life of about 20 to 29 days.[16] In healthy individuals, calcidiol levels are
normally between 32 to 70 ng/mL (80 to 175 nmol/L). The U.S. Dietary Reference Intake Tolerable Upper Intake Level (UL) of vitamin D for children and adults is 50 micrograms/day (2,000 IU). Some symptoms of vitamin D toxicity are a result of hypercalcemia (an elevated level of calcium in the blood) caused by increased intestinal calcium absorption. Vitamin D toxicity is known to be a cause of high blood pressure."
http://en.wikipedia.org/wiki/Vitamin_D#cite_note-PDR-15
I've also read that during stress, we use up about 3000 IU per day.
"The data show that for every 1 µg (40 IU) of vitamin D intake, circulating 25(OH)D increases by 0.28 ng/mL over 5 mo on a given supplemental regimen. Note that a steady state appears to be achieved after {approx}90 d of each dose tested (2, 3).
Thus, doses of 400 IU (10 µg), 1000 IU (25 µg), 4000 IU (100 µg), and 10 000 IU (250 µg) vitamin D/d for 5 mo will result in theoretical increases in circulating concentrations of 2.8, 7.0, 28, and 70 ng 25(OH)D/mL, respectively, all of which values are in the normal range of circulating concentrations according to reference data (20). In the study by Heaney et al (3), not one case of hypercalcemia or hypercalciuria was observed. " (
***sample size less than 70).
Mind you, the sample size of most every study I examined was fewer than 200 "healthy people", usually fewer than 70 people in the study, some quit before the end of the study.
Based on this, my recommendation is a MAXIMUM of 2000 IU of vit D3 (cholecalciferol) total intake (check and include multi-vitamin vit D) per day for 90 days and then retest, as "A 0.5-h exposure to the summer sun between 1000 and 1400 in a bathing suit ({approx}3 times the minimal erythemal dose) will initiate the release of {approx}50 000 IU (1.25 mg) of biological vitamin D into the circulation within 24 h of exposure in white persons (25)." (
Btw, this naturally acquired vit D is stored for future use.) Varies by race and latitude and cover.
I would not recommend dosing that high on days that one spends a lot of time outside. There are concerns of hypercalcemia and urine calcium excretion, with supplementation; which theoretically could precipitate kidney stones. Personally, I would only recommend supplementing during the October to March time frame, max.
"Food and Nutrition Board guidelines specify 50 µg/d (2000 IU) as the highest vitamin D intake that healthy adults can consume without risking hypercalcemia [it is the upper limit, or the no adverse effect level (NOAEL)].
A prolonged intake of 95 µg (~4000 IU) vitamin D/d is said to be the lowest observed adverse effect level (LOAEL),
a dosage that causes hypercalcemia in healthy adults (1). These intake limits have changed little from previous guidelines (2). However, the current guidelines (1) are based on the data of Narang et al (3), who reported that mean serum calcium concentrations were abnormally high in 6 healthy subjects who consumed 95 µg vitamin D/d for 3 mo. More recently, Adams and Lee (4) reported a high urinary calcium-creatinine ratio in 4 patients taking nutritional supplements containing vitamin D2 (ergocalciferol).
Substantial concern has been expressed about the safety of consuming vitamin D at dosages greater than the highest dosage available without prescription (25 µg/d) (1000 IU) (1, 5)."
http://www.ajcn.org/cgi/content/full...2b0d9c10eb4a4c
I've also read Dr. Mercola's recommendations:
http://articles.mercola.com/sites/ar...u-thought.aspx
And Sally Fallon's perspective:
http://www.westonaprice.org/basicnut...fications.html
regarding vit A ratios and supplementation of vit A.
Pat
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