Vitamin D may be best known for its role in supporting a balanced mood and healthy immune system, but it also aids the trendiest of all body systems—the gut.* Emerging research suggests your vitamin D status plays a key role in the health of your gut and its all-important good bacteria.* Vitamin D plus gut health is exactly the wellness collab we didn't know we needed—there's no better mashup than the hottest topic in health and everyone's fave vitamin.
The link between vitamin D and the gut microbiome.
Research suggests that vitamin D contributes to a diverse gut microbiome and even restores good bacteria along the digestive tract.* In a 2020 cross-sectional analysis published in Nature Communications, men with higher levels of the active hormone form of vitamin D showed greater diversity in their gut microbes1, even when taking into consideration other determinants of microbial diversity like age and antibiotic use.* To fully support our gut health, it seems wise to address vitamin D status—after all, a staggering 29% and 41% of American adults2 are deficient or insufficient, respectively, in vitamin D.*
"The vitamin D pathway is important in the regulation of immune responses and gut health. There are different genes regulated by the vitamin D receptor that can affect the integrity of the gut barrier and the immune defenses in the gut. With deficiency of vitamin D, one could hypothesize that changes in these aspects of the gut could lead to changes in the composition of the microbiota,"* says Adrian F. Gombart, Ph.D., a professor of biochemistry at Oregon State University's Linus Pauling Institute.
A healthy gut deserves the hype, too. A diverse gut microbiome, which is a key indicator of a healthy gastrointestinal tract, protects against unwelcome invaders, helps to optimize the extraction of nutrients and energy, and contributes to healthy immune function3. Yes, it means better digestion but also better mood and cognition and much more.
And it's a two-way street. Not only does vitamin D influence the gut, but the gut also influences vitamin D—particularly, how well it's absorbed.* Previously thought to be a passive process, research suggests the absorption of vitamin D4 is affected by the upper digestive tract and proteins in the intestinal membrane. In other words, a healthier gut is able to absorb vitamin D more effectively. (That, and throwing some healthy fats in the mix.)
But there is much more room for understanding. According to Gombart, this is an emerging area of research, and further studies will allow for a better and deeper knowledge of this important interaction.
How to get adequate vitamin D.
A vast number of American adults (93%, to be specific5) aren't consuming enough vitamin D daily. Because numerous factors affect the body's ability to synthesize vitamin D in the skin during exposure to sunlight, diet and high-quality supplementation are key to achieving optimal vitamin D status (and even diet isn't the most efficient way to get enough D—more on that later).*
These sun-confounding factors include time of day, time of year, location, skin tone, wearing SPF, air pollution, and even age. Combined with the reality of our lives—which are mostly spent indoors, these factors make getting enough D from the sun unrealistic.
When it comes to dietary sources of vitamin D, it's not as simple as eating your vegetables. The only "veggie" (it's really a fungus) that contains the essential nutrient is irradiated mushrooms, which are exposed to UV light to get their vitamin D2 (a significantly less potent form of vitamin D).
Other modest sources of D include a list of animal products (like cod liver oil and eggs) and fortified foods like milk, O.J., and cereal. These are all fine, but the problem comes when you consider how much of those food items you actually need to consume for an optimal dose of 5,000 IU or more a day. According to mbg's director of scientific affairs, Ashley Jordan Ferira, Ph.D., RDN, that shakes out to 294 cubes of Cheddar cheese or 7 cups of irradiated mushrooms every single day. (Yikes!)
Unless you want to live on cubed cheese for the rest of your life, you might want to opt for an efficacious supplement that can do the trick—like mbg's vitamin D3 potency+, which provides 5,000 IU of sustainable D3 derived from organic algae and organic olive, avocado, and flaxseed oils for optimal absorption, all in just one gelcap a day.*
What we're saying is, when it comes to gastrointestinal health, be gastro-intentional and consider what adding a vitamin D supplement to your routine could do for your gut.* While you're waiting for that vitamin D status to reach serum 25(OH)D levels above 50 ng/ml consistently, be on the lookout for new research on the intriguing connection between vitamin D and the gut.
Josey Murray is a freelance writer focused on inclusive wellness, joyful movement, mental health, and the like. A graduate of Wellesley College, where she studied English and Creative Writing, her work appears in Women’s Health, Cook & Culture, and more. By expressing her own vulnerability, she writes with warmth and empathy to help readers find self-compassion and true wellness that’s sustainable for body, mind, and planet.