When taken regularly, a vitamin D supplement can help ensure you’re getting enough of the key vitamin so your body can function at its best.* Here’s a breakdown of what to know about vitamin D supplements, the effects of vitamin D in the body, and how to make sure your routine is working for you. And while you can certainly try to add more fatty fish to your diet (which provides some vitamin D) and spend more uninterrupted time in the sun, taking a vitamin D supplement is almost always necessary to get optimal amounts D (i.e., achieve vitamin D sufficiency and stay there).* In fact, according to Sina Gallo, Ph.D., RDN, a nutritional sciences professor at the University of Georgia, the reality is that it’s actually quite difficult to get all of the vitamin D you need just from diet and sun alone.* Luckily, there are plenty of vitamin D supplement options out there that can support your body.* Integrative dietitian Whitney Crouch, RDN, CLT, recommends taking a vitamin D supplement that provides up to 5,000 IU of vitamin D3 (since that’s the body’s preferred form at a dose known to achieve sufficiency)—and ideally one that also contains healthy fats to support absorption.* (Vitamin D supplements that also provide high-quality healthy fats are harder to find, so mbg formulated vitamin D3 potency+ to fill the gap.) For more specific recommendations, check out our vitamin D supplement roundup. However, this isn’t how it works when you get your vitamin D from food or supplements—in which case, it is technically possible (albeit much more challenging than you might think) to get too much, she says. Typically, the first sign that you’re in vitamin D overdrive is hypercalciuria, or too much calcium in your urine. This is usually accompanied by hypercalcemia, or too much calcium in your blood, Gallo explains. Over time, this can contribute to kidney and blood vessel issues. But unless you’re taking mega (like mega) amounts of the vitamin, vitamin D toxicity isn’t really a concern, and the totality of science to back this fact2 is compelling. Case in point: One study in Canadians3 found that while taking 20,000 IU of vitamin D3 daily (more than 100 times4 the amount most people consume daily) did successfully increase whole-body vitamin D levels, participants didn’t even come close to levels associated with toxicity. As mbg’s vice president of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN, explains further, “Just because vitamin D is fat-soluble by design doesn’t mean it’s toxic at clinically useful doses, like 5,000 IU. That’s a complete misnomer. In reality, true reports of vitamin D toxicity with clinical evidence2 have occurred at 200,000 to 300,000 IU per day—yes, you read that correctly—in vulnerable populations like infants of folks with medical issues.” So, rest assured. According to the National Institutes of Health11, some of the first signs of hypercalcemia include:
