Your Vitamin D Supplement Might Not Be As Effective As You Think

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?

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).

Note: Optimal vitamin D status is 50 ng/ml plus (for more info, check out this article).

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.

"This raises the question: How insufficient are most people's vitamin D supplements? Very," says mbg's VP of scientific affairs 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).

"For people with known low vitamin D levels, I typically recommend choosing a vitamin D3 supplement of 5,000 IU and taking it daily for eight to 12 weeks before retesting blood levels," suggests Crouch. "That said, seasons of the year, typical sun exposure, skin tone, and body fat should all be considered, as these traits could increase a person's supplement needs."*

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."*