Vitamin D is commonly associated with bone strength, but its role in digestive health is equally important. Beyond its role in calcium absorption and maintaining strong bones and teeth, vitamin D plays a key role in gut health by influencing the gut bacteria, enhancing the intestinal barrier, and regulating inflammation—all of which are vital for a healthy digestive system.
One of the most crucial roles of vitamin D in digestion is its ability to help the body absorb calcium through the intestinal lining. Dr Sarada Pasangulapati, Consultant Medical Gastroenterologist and Hepatologist at Yashoda Hospital explains that without adequate vitamin D, calcium cannot be effectively absorbed, potentially leading to weakened bones. But more than that, vitamin D helps keep the intestinal lining intact, supporting the “tight junctions” between gut cells and reducing the risk of leaky gut syndrome, where harmful substances escape from the gut into the bloodstream.
"Maintaining healthy vitamin D levels is particularly important for individuals with inflammatory bowel diseases like Crohn’s disease and ulcerative colitis, as the vitamin helps control inflammation and supports immune regulation in the gut," says Dr Pasangulapati. Deficiency in vitamin D not only affects calcium absorption but is also linked to imbalances in the gut bacteria, which may contribute to conditions such as irritable bowel syndrome (IBS), obesity, type 2 diabetes, and other autoimmune diseases.
Recommended Dose For Vitamin D
Every day, the digestive tract is exposed to a wide variety of microbes daily. A healthy gut bacterium supports nutrient absorption, immune function, and even brain health. "Vitamin D supports this gut bacteria by helping the body maintain a balanced environment in the gut," says Dr Pasangulapati.
She further adds that there's no gut-specific recommended dose of vitamin D, however, general guidelines suggest an intake of 600 IU (15 micrograms) per day for people aged 14 to 70. "Sunlight remains the best source of vitamin D, but in today’s indoor lifestyle, especially during winters, it can be hard to get enough. Mushrooms, bananas, spinach, fortified milk, yoghurt, orange juice, tofu and cereals are also good dietary sources," suggests Dr Pasangulapati.
Who Are at The Risk of Vitamin D Deficiency
Certain groups are at higher risk of Vitamin D deficiency: older adults, people with darker skin, those who spend little time outdoors, and individuals with digestive conditions like Crohn’s or celiac disease that impair fat absorption. "People who have undergone gastric bypass surgery may also require higher amounts. If you belong to any of these groups, it’s wise to talk to your doctor about vitamin D testing and possible supplementation," recommends Dr Pasangulapati.
While vitamin D supplements are generally safe, they should be taken under medical advice—especially when combined with other medications. Taking them with a fat-containing meal helps improve absorption. "Keeping your vitamin D levels within range isn’t just about bone health—it could be the key to a healthier gut and stronger immunity," says Dr Pasangulapati.
Dietary Habits and Vitamin D Deficientcy
India’s diverse dietary habits also play a role. Traditional vegetarian diets, while rich in other nutrients, often lack sufficient sources of vitamin D, which is primarily found in fatty fish, egg yolks, and fortified foods. “Most Indians rely on vegetarian diets that don’t provide enough vitamin D,” says Dr. Anumiita Pathakk, a Nutritionist. “Even non-vegetarians don’t consume adequate amounts of fish or fortified products. "Foods, such as fatty fish, fortified dairy products, and mushrooms are high in Vitamin D. If one doesn't consume them, and have excess body fat can reduce the availability of Vitamin D in the body," adds the nutritionist. ”
Additionally, cultural practices such as wearing full-body clothing for modesty further limit sun exposure. “These cultural factors, combined with a lack of education about the importance of sunlight and supplementation, exacerbate the problem,” Dr. Pathakk adds. Pregnancy and breastfeeding can also lead to a decrease in Vitamins if not adequately addressed.
