Definition: Protamins, also known as vitamin D and vitamin D-like substances, are a group of substances that play a crucial role in maintaining bone health. They are essential for the development and maintenance of healthy bones, muscles, and skin. The main types of protamins include: 1. Vitamin D: This is primarily produced by the body through exposure to sunlight or from diet rich in fatty fish like salmon, eggs, and fortified foods such as milk products. It helps regulate calcium levels in the blood.