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Vitamin D Side Effects: What To Know About Taking Vitamin D Supplements

Josey Murray
mbg Contributing Writer By Josey Murray
mbg Contributing Writer
Josey Murray is a freelance writer focused on inclusive wellness, joyful movement, mental health, and the like.
4 Perks You Might Notice When You Supplement With Vitamin D*

So you've either finally decided to add a daily vitamin D supplement to your routine, or you're at least thinking about it. At this point, you're probably wondering what to expect from consistently boosting your intake of the all-important sunshine vitamin—and how you can ensure you don't overdo it. After all, any time you adjust your supplement routine, it's important to understand the potential effects you might experience, so good on you for doing your homework!

As long as you remember to take it regularly (why is that so hard sometimes?), a vitamin D supplement can help you rest assured that your body is getting enough of the all-important sunshine vitamin to function at its best.* Plus, you may even notice a few positive effects of vitamin D that'll make you extra happy you decided to commit to striving for optimal levels. Here's a breakdown of what to know about supplementing, the effects of vitamin D in the body, and how to make sure your routine is working for you. 

What to know about vitamin D.

Newsflash: Most of us don't get enough vitamin D—like, not even close to enough.* (Research shows that almost 30% of us are flat-out deficient by clinical standards, and that statistic considers all inputs like the diet, sun, etc.)

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 supplement is almost always necessary to get the optimal amount (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.*

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vitamin D3 potency+

Your daily D essential: bones, muscles, immunity, whole-body*

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Fortified milk, UV-exposed mushrooms, and walks outside only get most people so far—and people with darker skin tones, who experience long winters, or who have liver or kidney issues or trouble absorbing fat, face an even higher risk of D deficiency.

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.)

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Can you take too much vitamin D?

When your body produces vitamin D in response to sun exposure, it basically naturally shuts down production (and increases its metabolism) after getting its fill, according to Gallo. That's why lifeguards, for example, don't experience vitamin D toxicity, she says.

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.

Unless you're taking mega (like mega) amounts of vitamin D, though, vitamin D toxicity isn't really a concern, and the totality of science to back this fact is compelling. Case in point: One study in Canadians found that while taking 20,000 IU of vitamin D3 daily did successfully increase whole-body vitamin D levels, participants didn't even come close to levels associated with toxicity.

As mbg's director 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 evidence 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.

The positive side effects of vitamin D.

Adding a vitamin D supplement to your routine can help you support healthy levels in the body to promote bone, teeth, muscle, immune, and whole-body health.* Here are just a few of the positive side effects you may experience as you strive for optimal vitamin D intake:*

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1. Solid bone health.*

Because vitamin D facilitates (actually, it's critical for) the body's absorption and balance of calcium and phosphorus, supplementing your vitamin D intake can support these essential minerals in the various roles they play in the body, including bone health (which includes your teeth, too!), according to Gallo.*

2. Healthy muscle function.*

Since calcium also plays a role in muscle function, checking that vitamin D box helps there, too. In fact, a comprehensive review of clinical trials revealed a link between supplementing with vitamin D3, specifically, and muscle strength.* Good news for anyone looking to support their movement routine!

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"This vitamin D is sustainably sourced, organic and a highly-absorbable form."*

Whitney Crouch, R.D.N., C.L.T. Integrative Registered Dietitian

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3. Healthy blood sugar regulation (aka metabolic health).*

An exciting area of research, clinical trial research clearly demonstrates that vitamin D sufficiency and supplementation (to achieve sufficiency) have a positive impact on long-term glycemic control, insulin sensitivity, and even one's metabolic health trajectory.*

4. Balanced mood.*

Science has established a pretty strong connection between vitamin D and mental well-being.* In fact, according to a 2020 review, multiple clinical studies have identified the link, even highlighting that those with mood health needs have been seen to have lower vitamin D levels. Other evidence suggests that vitamin D supplementation may help reduce negative emotions.*

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Signs you're taking too much vitamin D.

Though too much vitamin D is far from a concern for the average person (but of course, partner with your health care provider to be sure), your tipoff that you might be too high in the D department, according to Gallo, is hypercalcemia (remember, that's too much calcium in your blood, determined by a blood test at the doctor's office).

According to the National Institutes of Health, some of the first signs of hypercalcemia include:

  • Nausea
  • Vomiting
  • Muscle weakness
  • Loss of appetite
  • Dehydration
  • Excessive urination and thirst

If you experience any of these, check in with your health care provider, stat.

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The bottom line on vitamin D and its effects.

Because so many people don't come close to getting enough vitamin D through food and sunshine alone, supplements can be incredibly helpful (if not essential) in achieving healthy levels and experiencing immune, bone, muscle, and whole-body benefits.*

vitamin D3 potency+
★ ★ ★ ★ ★
★ ★ ★ ★ ★
(16)
vitamin D3 potency+

vitamin D3 potency+

Your daily D essential: bones, muscles, immunity, whole-body*

vitamin D3 potency+

vitamin D3 potency+

Your daily D essential: bones, muscles, immunity, whole-body*

★ ★ ★ ★ ★
★ ★ ★ ★ ★
(16)
vitamin D3 potency+

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