West Michigan Doctor Warns Against Vitamin D Overdose This Winter

Holland Hospital physician says vitamin D toxicity is on the rise and cautions Michiganders to watch their supplement dosage.

Mar. 10, 2026 at 6:19pm

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A family physician at Holland Hospital Primary Care in Hudsonville, Michigan is warning residents about the dangers of over-supplementing with vitamin D during the winter months. Dr. Ada Pariser says she has been diagnosing an increasing number of people with vitamin D toxicity, which can lead to higher-than-normal calcium levels in the blood and potentially serious health issues like kidney failure and heart problems.

Why it matters

Vitamin D is an essential nutrient, especially for those living in northern climates with less sunlight exposure during the winter. However, Dr. Pariser cautions that many vitamin D supplements are not well-regulated, and it's easy for people to inadvertently take too much, leading to toxic levels in the body.

The details

According to Dr. Pariser, the recommended safe daily dose of vitamin D is generally between 2,000 to 4,000 IUs. However, many over-the-counter multivitamins already contain 2,000 IUs, so it's important not to combine those with additional standalone vitamin D supplements. Vitamin D toxicity can cause higher calcium levels in the blood, which in turn can lead to kidney failure, heart arrhythmia, unsteady gait, and confusion.

  • In recent months, Dr. Pariser has been diagnosing a number of patients with vitamin D toxicity.

The players

Dr. Ada Pariser

A family physician at Holland Hospital Primary Care in Hudsonville, Michigan who is warning about the dangers of over-supplementing with vitamin D.

Holland Hospital

A hospital located in Holland, Michigan where Dr. Pariser practices.

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What they’re saying

“There are plenty of people who have low vitamin D levels living in Michigan in the winter. But we have to remember that supplements are generally not regulated by the FDA. The dosing recommendations are not as readily available, and you can buy all kinds of different doses over the counter.”

— Dr. Ada Pariser, Family Physician

“Vitamin D, along with a few other vitamins, are what are considered fat-soluble. They can stay in the body for longer and accumulate. So, if you're taking high doses of vitamin D over a long period of time, those stores are building up in your body, and that will affect the way that your body manages calcium.”

— Dr. Ada Pariser, Family Physician

What’s next

Pariser recommends that anyone concerned about their vitamin D levels or potential toxicity should consult with a healthcare provider, who can test their blood levels and provide guidance on safe supplementation.

The takeaway

This story highlights the importance of being cautious when taking vitamin D supplements, especially during the winter months when many people are deficient. While vitamin D is essential, it's easy to inadvertently take too much, leading to potentially serious health issues. Consulting with a doctor is the best way to ensure you're getting the right amount of this important nutrient.