The so-called “sunshine vitamin” has its downsides. Just like not getting enough vitamin D can have serious health consequences, it turns out that getting too much can be harmful too.
Scientists have been cautioning for some time that not everyone benefits from vitamin D supplements. In fact, taking high doses can sometimes be toxic, particularly for young children and older adults.
As this supplement becomes more popular, it’s crucial for both patients and healthcare providers to be aware of the recommended dosages and the potential risks. These complications aren’t common, but they seem to be on the rise, and in the worst cases, they can be life-threatening.
Excess vitamin D increases calcium absorption, which can lead to hypercalcemia. This condition can cause dangerous calcium deposits in arteries or soft tissues, heightening the risk of kidney stones and upsetting bone metabolism. Symptoms can be quite unpleasant, including nausea, fatigue, constipation, muscle weakness, and bone pain.
The majority of people tend to recover from vitamin D toxicity once they stop the supplements and get IV fluids or medication to reduce calcium levels. However, there are rare instances where untreated toxicity can lead to kidney failure needing hemodialysis or even fatal intestinal bleeding.
Interestingly, some studies indicate that seniors with high blood levels of vitamin D may be more prone to falls.
A review in 2018 highlighted a “considerable complacency” when it comes to the toxic effects of vitamin D. There is still some disagreement among scientists about what constitutes too much vitamin D.
“With the increased interest in vitamin D, partly fueled by popular books singing the praises of high doses, it’s no wonder there’s been a rise in reported vitamin D toxicity cases,” concluded the authors of this review.
Vitamin D earns its nickname as the sunshine vitamin since the body produces it when exposed to sunlight. Usually, about 90 percent of our vitamin D comes from sun exposure, with the rest gathered from foods like fatty fish or fortified dairy.
This vitamin plays a crucial role in helping the body absorb calcium, maintaining immune functions, supporting cell growth, and regulating metabolism and neuromuscular actions. Prolonged vitamin D deficiency heightens the risks for various serious conditions, including neurological issues, autoimmune disorders, bone diseases, and heart disease.
However, there’s still debate around the effectiveness of vitamin D supplements. While some studies suggest they can slow aging, enhance cognition, or even alleviate depressive symptoms, others question their real benefits.
Plus, these supplements aren’t without risks. Often, cases of vitamin D toxicity arise from mismanagement while trying to treat deficiency.
For example, there was a case of an 80-year-old man who accidentally took a high-dose vitamin D tablet daily—meant to be taken weekly—after being prescribed it by his naturopathic doctor. Thankfully, everything returned to normal once the error was identified and the supplement was stopped.
This issue isn’t exclusive to older individuals, either. Back in 2016, Denmark’s health authority had to recall a supplement that contained 75 times the recommended amount of vitamin D. Consequently, around 20 children developed toxic symptoms after consuming the capsules.
Between 2000 and 2014, more than 25,000 cases of vitamin D toxicity were recorded. From 2005 to 2011, reported cases surged by 1600 percent, with many involving children or teenagers.
Luckily, there were no fatalities during that period, but five cases did result in significant medical issues.
Harvard Medical School recently cautioned, “Keep an eye on your numbers.” If you’re on vitamin D supplements, it’s generally advised that you shouldn’t exceed 15 to 20 mcg (600 to 800 IU) daily. Unless a healthcare provider suggests otherwise, avoid surpassing 100 mcg (4,000 IU) each day, as this is considered a safe upper limit.
Doctors from Harvard recommend starting with fortified foods if someone is vitamin D deficient, as these are much less likely to lead to toxicity.
As always, it’s wise to consult with a healthcare professional when beginning or stopping any medication or supplement.
