Vitamin D deficiency linked to diabetes and cancer risk, experts advise testing and supplementation

Family physician Dr. Li Si‑xian warned that many people in Taiwan have insufficient vitamin D, a condition associated with higher rates of type 2 diabetes, autoimmune thyroid disease, and several cancers such as colorectal, breast and prostate. He recommends blood testing for 25‑(OH)‑D levels and maintaining concentrations of 40–60 ng/mL under medical guidance.

Gastroenterologist Dr. Will Bulsiewicz highlighted the broader role of vitamin D in gut health, urging individuals to base supplement use—including vitamin D, probiotics, pre‑biotics, omega‑3, magnesium, zinc and melatonin—on laboratory results and personalized plans. He stressed that targeted supplementation can improve insulin sensitivity, immune regulation, and intestinal barrier function when taken appropriately.