A new paper, Trends in Use of High-Dose Vitamin D Supplements Exceeding 1000 or 4000 International Units Daily, 1999-2014, published by JAMA, has been making its way through all media platforms, casting a shadow over vitamin D supplementation. The Vitamin D Council exists to provide clarity on research regarding vitamin D. So, when findings become misinterpreted by the media and begin causing mass confusion, it is our duty to intervene.
First, let’s try and understand just what this paper is about, and what the results might mean for vitamin D. The media portrays this paper as evidence proving that doses of vitamin D higher than the Food and Nutrition Board’s recommended dietary allowance (RDA) and upper limit (UL) are dangerous. However, the research conducted in this paper provided no such evidence that vitamin D doses higher than the RDA is dangerous, only that the trends in supplementation are changing.
Researchers from this study used data from the National Health and Nutrition Examination Survey (NHANES) to determine the trends in vitamin D supplementation from 1999-2014. To be more specific, they were trying to determine the prevalence of individuals supplementing with either 1,000 IU of vitamin D or more, or with 4,000 IU D3 or more. The researchers excluded individuals who were pregnant, under the age of 20 or who did not provide adequate information on their supplementation routine. Participants were required to report their daily supplemental vitamin D intake over the last 30 days. The researchers collected the data on the 39,243 individuals who reported their vitamin D intake.
Here is what the researchers found:
- Prevalence of daily supplementation of 1,000 IU or more in 2013-2014 was 18.2%, compared to 0.3% in 1999-2000 (P <0.001).
- Prevalence of daily supplementation of 4,000 IU or more was 3.2% in 2013-2014. Prior to 2005-2006, the prevalence of individuals supplementing with 4,000 IU or more was less than 0.1% (P <0.001).
According to our standards, this research suggests a positive shift for public health. So why has this paper been picked up by so many media outlets? While discussing the results, the researchers warn of the dangers of vitamin D toxicity.
The researchers stated,
“The IOM report noted possible harm (eg, hypercalcemia, soft tissue or vascular calcification) for intakes above the tolerable upper limit, which is the highest level of intake likely to pose no risk of adverse effects for most adults.”
This statement is true. Vitamin D toxicity can cause adverse effects that stem from high blood calcium, also known as hypercalcemia. However, the researchers do not state the serum 25(OH)D level that may place individuals at risk of vitamin D toxicity, only that doses above the UL (4,000 IU) can cause possible harm. Research suggests that vitamin D toxicity can occur at doses much higher than just 4,000 IU, let alone 10,000 IU, which is the Vitamin D Council’s recommended UL.
The researchers based their concerns for vitamin D toxicity of the paper published in 2011 titled, Dietary Reference Intakes for Calcium and Vitamin D. In this review, the researchers stated:
“Hector DeLuca (2009) concluded that, overall, the toxicity of hypercalcemia becomes evident at vitamin D intakes above 25,000 IU/day, corresponding to a serum 25OHD level of about 500 nmol/L (200 ng/ml).”
And there was more:
“Hathcock et al. (2007), following an analysis of more than 20 publications, concluded that there was no association between harm and intakes of 10,000 IU/day. Although toxic effects associated with 400 IU/day seem implausible, the diverse range of intakes and serum 25OHD levels is notable. Most reports suggest that the toxicity threshold is between 10,000 and 40,000 IU of vitamin D per day. Also, most do not identify toxicity until serum 25OHD levels of 500 to 600 nmol/L (200-240 ng/ml).”
The conclusions on the UL of vitamin D and toxicity in this paper were misleading, to say in the least. Remember, vitamin D toxicity is very rare. Dr. John Cannell addressed this issue back in 2015 with his blog, How common is vitamin D toxicity? According to his article, from 2000-2014 there were 25,397 calls to poison control about overdoses of vitamin D. Only three serious cases of toxicity arose from those reports, and there were no deaths. In comparison, there were approximately 3,000 deaths due to Tylenol overdose during that same period. Review this page on our website that addresses vitamin D toxicity and the recommendations we have made based on the available research.
In addition to the misleading claims on supplementation and vitamin D toxicity, this paper asserted that vitamin D could have adverse effects for patients with cancer, specifically prostate and pancreatic cancer, as well as all-cause mortality, kidney stones and risk of falls and fractures in the elderly. This claim is another key point of the JAMA paper that the media has utilized as evidence suggesting that vitamin D supplementation above the UL is dangerous. However, after looking into the sources for such claims, I was again brought back to the 2011 review, Dietary Reference Intakes for Calcium and Vitamin D.
It is important to understand the problem with using this paper to back the few, short sentences that made such big headlines. First, this paper was published in 2011. Did you know, the Vitamin D Council sorts through approximately 30-50 new studies on vitamin D per day? That means tens of thousands of new studies and new conclusions on vitamin D have been published since this paper was released. This includes research that has revealed data that contradicts the evidence presented by this paper.
While research on some topics, such as the relationship between vitamin D and fractures and falls in the elderly, still provide conflicting evidence, other conclusions are much clearer. For example, the research on vitamin D and mortality seems to conclude that higher vitamin D levels are significantly associated with a decreased risk of mortality. In addition, there have been hundreds of studies with positive findings on the relationship between vitamin D and cancer risk, multiple sclerosis, chronic pain, asthma and autism, to name just a few. The claims made in this paper on the negative effects of higher vitamin D doses must be put into perspective. Not only do the researchers use an outdated source, but they neglect to include information on the available data that supports the benefit of higher vitamin D levels.
Regardless, the aim of the JAMA paper was not to assess the effect of higher doses of vitamin D, only to study the trends of supplementation over time. If anything, we need more research like this. Awareness on the importance of vitamin D has increased, as shown by an increase in supplementation over time. Hopefully, this will encourage more research to be conducted on the effects of vitamin D supplementation, providing further clarity on any unanswered. In the meantime, it is important to remember that even scientific research can be skewed by media interpretation.
Hundreds of new studies on vitamin D are released every week. The Vitamin D Council is here to help you sort through and understand the research so that you may make your own conclusions on vitamin D. As always, if you have questions, we are here for you. Comment below, email [email protected], post on our Q&A board or message us on Facebook.
Peterson, R. & Cannell, JJ. Vitamin D Council addresses media claims of the dangers regarding increased vitamin D supplementation in recent years, 2017.