Vitamin D supports strong bones, immunity, and overall health, but too much can be harmful. Because it is fat-soluble, excessive supplementation can cause vitamin D toxicity and dangerously high calcium levels, leading to nausea, constipation, dehydration, frequent urination, bone pain, kidney stones, headaches, or confusion. Most adults need about-
600–800 IU daily, with 4,000 IU generally considered the upper daily limit unless higher doses are medically prescribed. To avoid overuse, rely on safe sunlight exposure and vitamin D-rich foods such as fatty fish and fortified dairy, and consult a healthcare professional before taking high-dose supplements.
