What is the upper limit and NOAEL and are they justified?
February 26, 2013 -- John Cannell, MD
The upper limit (UL) for vitamin D, set by the 2011 Food and Nutrition Board, is 4,000 IU per day. This is defined as the highest level of daily consumption that causes no side effects in humans when used indefinitely without medical supervision.
The same board set the No Observed Adverse Effects Level (NOAEL) at 10,000 IU/day. The NOAEL is the dose at which there are no published studies showing any adverse effects of that dosage. As an aside, if there are any studies showing 20,000 IU/day is unsafe, I would like to see them.
Anyway, the Upper Limit is simply calculated from the NOAEL by dividing by a safety factor. In vitamin D’s case, they divided the NOAEL of 10,000 IU/day by 2.5 to get the Upper Limit of 4,000 IU/day.
At the Vitamin D Council, we recommend that patients exceed the Upper Limit, but not exceed the NOAEL of 10,000 IU/day, unless they are under medical supervision or know what they are doing. But why do we recommend more than the Food and Nutrition Board’s Upper Limit?
Because the question is, will 4,000 IU/day get 97.5% of the population above a certain 25(OH)D threshold, such as 30 ng/ml? Or are doses higher than 4,000 IU/day needed to achieve blood levels above 30 ng/ml, 30 ng/ml still being much lower than average 25(OH)D levels found in hunter gatherers living around the equator, which are about 46 ng/ml.
Vitamin D status in indigenous populations: Part 1 Posted on August 27, 2012 by John Cannell, MD
Doctor Etienne Cavalier and colleagues of the University of Liège in Belgium recently tried to find out if 4,000 IU/day is enough by giving large or stoss doses to a total of 140 subjects. Continue reading → (no membership required) Vitamin D and autoimmune disorders: The latest research
March 2, 2013 -- John Cannell, MD
Researchers at the Chaim Sheba Medical Center in Israel recently reviewed the evidence that vitamin D is involved in autoimmune disorders. Continue reading → (membership required) Can vitamin D help with chronic pain?
March 1, 2013 -- John Cannell, MD
Researchers in Iran wanted to know if treating patients with vitamin D and calcium would improve their chronic pain. Continue reading → (no membership required)
Children in Mexico: Good sun exposure habits?
February 27, 2013 -- Kate Saley
Researchers in Mexico report that vitamin D levels among young children are surprisingly sufficient compared to their United States neighbors. Continue reading → (no membership required) Calcium absorption: How does vitamin D and dieting factor in?
February 21, 2013 -- John Cannell, MD
By taking 5,000 IU vitamin D every day, do you absorb enough calcium from your diet without having to rely on supplements? Continue reading → (membership required)
Vitamin D deficiency in polycystic ovary syndrome
March 4, 2013 -- John Cannell, MD
Doctors of the Medical College of Virginia recently tested vitamin D levels on eight women with polycystic ovary syndrome (PCOS), before and after treating them with diazoxide, a common treatment for PCOS. Continue reading → (membership required)
Does vitamin D help with fracture healing?
March 3, 2013 -- John Cannell, MD
Researchers in Germany recently studied vitamin D levels in people with fractures. Continue reading → (no membership required)
Dear Dr Cannell: Shaken baby syndrome
February 27, 2013 -- John Cannell, MD
A mother accused of child abuse writes to Dr Cannell for advice and information about shaken baby syndrome. Continue reading → (membership required)
Vitamin D deficiency linked to active Crohn's disease
March 4, 2013 -- Vitamin D Council News
Researchers in Denmark report that people with active Crohn’s disease are more likely to have low vitamin D levels when compared with patients in remission. Continue reading → Vitamin D, Calcium recommendations
March 5, 2013 -- Vitamin D Event
Today's Grassroots health webinar features Dr Robert Heaney, MD, who will be discussing the topic: "Vitamin D & Calcium: Fractures, and kidney stones - What do we do?"
Dr Heaney will respond to the controversial USPSTF report recommending against daily vitamin D (400 IU) and calcium (1,000 mg) supplementation.
Register here for today's webinar, which starts at 10am PST! Have a vitamin D question? You can submit your questions for Dr Heaney when you register. --
RSS Feed