This Unsuspecting Factor Can Change How Much Vitamin D You Really Need

As we’ve discussed before: How much vitamin D you actually need relies on a variety of individual factors. Essentially? It’s personal. The most personal element of them all, perhaps, is your DNA—everyone has a unique genetic code, after all. 

But as integrative gastroenterologist Marvin Singh, M.D., tells us on the mindbodygreen podcast, you can actually test your genes to see whether they have a stake in your vitamin D status: It’s a clever concept called nutritional genomics. “Nutritional genomics is one of my favorite tests,” he says, and below, he explains just how it works. 

We repeat: Everyone has unique DNA, which can affect your response to vitamin D and other essential micronutrients—which, in turn, means you might need extra help to make sure you achieve (and maintain) proper nutrition levels. So if you know that you have a genetic risk for vitamin D insufficiency, you can take targeted measures to close the gap proactively. (We argue supplements are the most efficient way to do so.*)

Regardless of your genes, the vitamin D gap is very real. Over 93% of the U.S. population is failing to consume just 400 I.U. of vitamin D from our daily diet, and meanwhile, over 40% of American adults meet the clinical criteria for vitamin D insufficiency.

As for the specific single nucleotide polymorphisms (SNPs) that affect vitamin D status, researchers have identified a few key players. Ready for some science speak? First, vitamin D blood levels [serum 25(OH)D] can be influenced by gene rs2282679, which affects the vitamin D binding protein (VDBP). If your VDBP levels are higher, more 25(OH)D will be bound to it and less available to do its job. And so, you may need to up your vitamin D intake to compensate for this anomaly. 

“Two other SNPs related to 25-hydroxylase (rs10751657, CYP2R1) and 1α-hydroxylase (rs10877012, CYP27B1) have also been identified,” says mbg director of scientific affairs Ashley Jordan Ferira, Ph.D., RDN, regarding genetic variability. “These are the enzymes that convert vitamin D into its circulating form and active hormone form, respectively. And then FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232), and TaqI (rs731236) are genetic polymorphisms linked to the vitamin D receptor (VDR) and thus the ability of vitamin D to bind and do its many critical jobs in the body.”* 

First, we should note that nutritional genomics is a rapidly growing field, and we’re continuing to learn more about it every single day. Plus, everyone is a unique individual, so it’s difficult to offer an exact action plan based on these genetic differences—and different testing companies might tell you different things. As Singh notes: “The [genetic testing] methodology is pretty straightforward; however, how you interpret those genes and use the information to tell somebody what the result is—that is where the difference [lies].”

If you’re interested in getting a nutritional genomics test, Singh is partial to a company called Nutrigenomix. “They are associated with the University of Toronto, so it comes from an academic place, and the folks who run the company are leaders in the field of nutritional genomics.” Then you might consider finding an integrative-minded health care practitioner that is comfortable using that data for a personalized nutrition assessment and action plan.

If you don’t have access to a genetic testing company (or simply don’t want to test your DNA, which is fine!), a slew of other factors that can also affect your response to vitamin D, anyway—just take a look at this list.