Can Too Much Vitamin D Harm Your Health?


Here at The Wellman Clinic, we have written before about the not inconsiderable health benefits of Vitamin D, as well as the specific issue of Vitamin D deficiency currently facing the UK. As a nation, we’re not exactly renowned for blazing, glorious sunshine, and as such many of us struggle to get the recommended daily intake from natural light alone. A 2010 study found that over 50% of the adult population of the UK suffer from Vitamin D deficiency,[1] which can contribute to a range of medical conditions including cognitive impairment, diabetes, rickets, cardiovascular disease and even cancer.

As a result of this, the general consensus has existed for a while now that we need to be taking more Vitamin D, especially through supplementary sources to natural daylight. In fact, during the last few years the recommended daily allowance (RDA) of Vitamin D has risen steadily, with some calling for it to rise higher still.

However, recent research has suggested that, while it carries unquestionable health benefits, there is such a thing as too much Vitamin D – and it can be harmful to our health. A study by the University of Minnesota examined survey data to compare people’s Vitamin D intake during the period from 1999 to 2014.[2] The study found that the amount of people taking in excess of the recommended daily limit of 4,000 IU (international units) had risen noticeably between during this time. The study’s authors drew attention to some of the potential harmful effects of too much Vitamin D – in particular the overabsorption of calcium, which can lead to calcium deposits building up in soft tissues such as the heart and kidneys. It would seem that in an attempt to top up on supplementary Vitamin D, more and more people are overcompensating for deficiency and taking excessive amounts.

This is not the first study to have questioned excessive Vitamin D consumption. A 2013 study published in The Endocrine Society’s Journal of Clinical Endocrinology and Metabolism suggested that both extremely low and extremely high levels of Vitamin D supplementation showed no positive impacts, and that genuine health benefits were most clearly evidenced in those taking medium doses of Vitamin D. [3]

Of course, none of this should be seen as evidence that taking supplementary Vitamin D is, in itself, harmful. Perhaps more significant are the findings by the University of Surrey throwing doubt on the current guidelines that claim the body cannot distinguish between the plant-based D2 and animal-based D3 varieties of Vitamin D.[4] Instead, the study suggested that D3 is twice as effective as D2 at raising the levels of the vitamin in the body.

Although the evidence suggests that excessive amounts of Vitamin D are to be avoided, there remains plenty of evidence for the health benefits of reasonable doses. With its links to multiple health issues, Vitamin D deficiency should not be underestimated as a cause for concern, and sensible amounts of supplementary Vitamin D, taken in moderation, are not only safe, but strongly advisable – especially in sun-starved Britain.

The Wellman Clinic is the UK’s first dedicated private men’s health clinic in London, with over 25 years of experience. From health screening to testosterone replacement therapy, we offer tailored, professional medical advice to men in a friendly and confidential environment. Please get in touch to arrange a consultation.

[1] http://www.bmj.com/content/340/bmj.b5664

[2] https://www.sciencedaily.com/releases/2017/06/170620114156.htm

[3] https://www.ncbi.nlm.nih.gov/pubmed/23533239

[4] http://ajcn.nutrition.org/content/early/2016/09/20/ajcn.116.138065.full.pdf+html

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