How Much Vitamin D Should You Be Supplementing With? RDs Weigh In

As awareness around the importance of vitamin D for a bunch of different aspects of our health grows, more and more people might consider adding a supplement to their daily routine. Seems like an easy enough investment in your health, right?

While the right vitamin D supplement can totally help you get your levels to an optimal place (and keep them there!), you won't reap much benefit from popping the wrong form of the important nutrient—or too little of it. And, sad but true: Research actually suggests that many of us might be making one or both of these supplement mistakes—and that they're keeping us from achieving the vitamin D status we need to feel our best.*

Why does it seem like everyone's deficient in vitamin D?

Here's the deal, folks: Nationally representative data and robustly designed research1 on more than 26,000 adults in the U.S. (called the National Health and Nutrition Examination Survey, or NHANES) show that 41% of Americans are vitamin D "insufficient" [meaning they have serum 25(OH)D levels less than 30 ng/ml], while 29% are flat-out "deficient" (their levels are less than 20 ng/ml).

The numbers are pretty alarming—and what's even more alarming is that they take into account all of the different ways we can get vitamin D, including foods and drinks (including fortified products like milk and OJ), the sun, and supplements.

What to look for in a vitamin D supplement

"This raises the question: How insufficient are most people's vitamin D supplements? Very," says nutrition scientist Ashley Jordan Ferira, Ph.D., RDN. "This national statistic suggests that many people aren't supplementing and are instead relying on vitamin-D-scant diets and unreliable sun exposure and that those who are taking supplements are consuming sub-efficacious supplement doses."

Basically, the current state of vitamin D supplementation in the U.S. clearly isn't doing enough to prevent these staggering rates of insufficiency and deficiency (which are most likely to affect minorities, people who have overweight or obesity, and the physically inactive, by the way).

Bottom line: These statistics suggest that we can't expect willy-nilly vitamin D supplementation to guarantee healthy levels and that many of us need to take a much more diligent, specific approach to boosting our intake of the sunshine vitamin.

How much should you supplement with?

Of course, there is a place for some of the lower-dose vitamin D supplements you see out there (think anything less than 3,000 IU)—specifically when someone is taking multiple supplements that contain vitamin D3, like a multivitamin and a bone or immune health supplement, highlights dietitian Jess Cording, M.S., R.D., CDN.* A lower-dose product can also be an easy way to augment your current D routine in the winter months, she suggests.

In these cases of multiple D inputs, Ferira explains that you'll want to "think of your daily D3 supplement as your critical foundation to achieve and maintain healthy vitamin D levels and approach the lesser but useful bits of vitamin D from a multivitamin, immune complex, diet, and sunshine as a complementary, extra bonus if you will."*

The takeaway

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.