Why Vitamin D Is a Gut Health Power Player (Not Just for Bones)
Vitamin D3 supports gut health, immunity, and microbiome balance.
Vitamin D isn’t just for strong bones, it's essential for a healthy gut too. Up to 42% of Americans and nearly 100% of people with Crohn’s or ulcerative colitis are deficient. Low vitamin D can disrupt your microbiome, weaken the intestinal barrier, and increase chronic inflammation. And that’s why vitamin D is added to every NeuroFiber bar.
Why This Matters for NeuroFiber
Vitamin D supports the same gut foundations NeuroFiber is designed to nourish: a strong gut barrier, a balanced microbiome, and lower inflammation. Combined with prebiotic fiber, essential vitamins, and omega‑3s, the vitamin D in NeuroFiber helps create a gut-brain environment that supports digestion, immunity, and mental well-being.
Vitamin D and Gut Barrier Strength
According to Dr. David A. Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School, vitamin D binds to receptors in the gut and immune cells, helping regulate inflammation, cell growth, and immune behavior. Low levels have been linked to a weakened intestinal barrier and gut dysbiosis, both important factors in IBD and inflammatory digestive conditions. (Medscape, 2025)
Vitamin D Supports a Balanced Microbiome
The article highlights studies showing that vitamin D supplementation can improve microbial diversity and stability in the fecal microbiome - meaning healthier, more resilient gut communities.
IBD and Vitamin D: A Meaningful Connection
People with inflammatory bowel disease frequently have low vitamin D levels, roughly 45% in ulcerative colitis and up to 100% in Crohn’s. Johnson notes that deficiency may both result from and contribute to disease activity. Clinical data demonstrate that daily vitamin D supplements can lower relapse risk in Crohn’s by around 36%, though evidence on symptom improvement is mixed.
Vitamin D and Other GI Conditions
The Medscape article also links vitamin D deficiency to higher risk of diverticulitis, colorectal cancer, and liver disease, especially in metabolic dysfunction-associated steatotic liver disease (MASLD). Sunlight exposure, vitamin D status, and location seem to interact: individuals in low UV regions show higher rates of diverticulitis complications.
Does Vitamin D Supplementation Help?
Dr. Johnson confirms that daily supplementation with up to 2000 IU of vitamin D3 presents minimal safety risks and is supported by large clinical trials. The preferred form is D3, which raises blood levels more reliably than D2.
The Endocrine Society recommends screening only in specific cases: osteoporosis, malabsorption disorders, older age, or high-risk conditions. Routine universal screening remains controversial. Dr. Johnson indicates that physicians should consider testing vitamin D levels as part of GI disease management.
Based on findings summarized in David A. Johnson, MD. “The Overlooked Link Between Vitamin D and GI Health.” Medscape. May 20, 2025.
Gut-Friendly Vitamin D Strategy
Test your 25‑hydroxy vitamin D level if you’re at risk for deficiency
If results are below ~50 nmol/L, consider supplementing with 1000–2000 IU of vitamin D3 daily
Pair with a fiber-rich diet, proper hydration, and prebiotic support for optimal gut synergy
Retest after 3–6 months to track changes and adjust dosage
Your doctor may order a vitamin D test or you can obtain one directly from Ulta Lab Tests or Walk-In-Lab from $60 and up.
Vitamin D and Parkinson’s
Research shows that people with Parkinson’s disease often have lower levels of vitamin D, which is associated with poorer motor control, faster symptom progression, and increased inflammation. Since vitamin D also supports gut health and microbial balance, it may be especially important for those living with PD.
