If you’ve ever been wary of popping too many supplements, this story may confirm your concerns: A new report published in the BMJ documents the case of a four-year-old boy who became severely ill after taking a slew of alternative medicines prescribed by a naturopath. 

His parents brought him to London's Newham Hospital because he was suffering from a variety of symptoms, including vomiting, constipation, extreme thirst, and weight loss (6.5 pounds in two weeks). When the doctors ran tests, they discovered the boy had severe hypercalcemia, or too much calcium in his blood.

Hypercalcemia can be caused by anything from dehydration to cancer to excess vitamin D (which stimulates the digestive tract to absorb more calcium). A vitamin D test revealed the boy's level to be toxic.

But it wasn't until a few days into his hospital stay that the boy's mother told his doctors he had been taking 12 supplements for months. To help with his autism, a naturopath had recommended a long list of alternative medicines including vitamin D (2,000 IU), cod liver oil (containing 1,000 IU vitamin D), calcium magnesium citrate (80 mg calcium), camel milk (600 mg calcium), silver, zinc, Epsom salts, sodium chloride, and more. "It was felt that the supplements he was taking were the most likely explanation for his hypercalcaemia," the doctors wrote. The Recommended Dietary Allowance for vitamin D is 600 IU for children and adults ages 1 to 70.

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The doctors gave him fluids and medication to regulate his calcium levels, and the boy was released from the hospital two weeks later. But the experience took a toll on the entire family: "His parents were devastated that something they had given to their son with good intent had made him so unwell," according to the case study.

The authors point out that many families view alternative medicines as safer options for their children—but that's not always the case. "There is significant potential for adverse effects," they warn.

Supplements are popular among grown-ups too: A new study published in JAMA found that 52% of American adults reported taking them in 2011 and 2012, and that supplement use has remained stable since 1999. The researchers also reported that from 1999 to 2012, the amount of people taking vitamin D (from sources other than multivitamins) has increased from 5.1% to 19%; and the percentage of people taking fish oil has risen from 1.3% to 12%.

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This little boy's case report is a powerful reminder of the need to discuss any supplements with an MD. The information may turn out to be key. As the authors of a JAMA editorial wrote, “It is now known that many supplements contain pharmaceutically active botanicals, which can have important clinical effects.”