How is calcium primarily absorbed in the body?

• A. In the stomach
• B. In the large intestine
• C. In the small intestines
• D. Through the skin

Answer: (C)

Calcium is primarily absorbed in the body through the small intestines. This critical absorption process occurs primarily in the duodenum and jejunum parts of the small intestine, where specialized transport mechanisms and dietary factors enhance calcium uptake.

When calcium is ingested, it's often bound to food or other substances. Active transport mechanisms, such as the calcium-binding protein and various channels, facilitate the movement of calcium ions across the intestinal epithelium into the bloodstream. The efficiency of calcium absorption can also be influenced by various factors, including the presence of vitamin D, which enhances calcium uptake, and the composition of the diet, as certain foods may promote or hinder absorption.

Understanding this process is crucial in the context of bone health, as adequate calcium intake is necessary for maintaining bone density and preventing conditions such as osteoporosis. Therefore, focusing on maximizing calcium absorption in the small intestines is key to ensuring sufficient calcium levels in the body.