Vitamin D stimulates the absorption of __ from food in the intestine.
A vitamins
B calcium
C sodium
The correct answer and explanation is:
Correct Answer: B) Calcium
Vitamin D plays a crucial role in maintaining proper bone health and calcium balance in the body. It stimulates the absorption of calcium from the food in the intestine. Calcium is a vital mineral necessary for the development and maintenance of strong bones and teeth, and it also supports proper muscle function, nerve signaling, and blood clotting.
The process begins when the body is exposed to sunlight or consumes foods rich in vitamin D. The skin produces vitamin D3, or cholecalciferol, which is then converted in the liver and kidneys into its active form called calcitriol. Calcitriol acts like a hormone and binds to vitamin D receptors in various cells throughout the body, including the cells lining the small intestine.
When calcitriol reaches the cells of the small intestine, it increases the production of calcium-binding proteins such as calbindin. These proteins help transport calcium from the intestinal lumen across the intestinal wall and into the bloodstream. Without sufficient vitamin D, the efficiency of this calcium absorption process decreases significantly, even if dietary calcium intake is adequate.
This is why a deficiency in vitamin D can lead to weakened bones, a condition known as rickets in children and osteomalacia in adults. Over time, lack of proper calcium absorption can also contribute to osteoporosis, a disease where bones become fragile and more likely to break.
While sodium and vitamins are also essential nutrients, vitamin D does not primarily enhance their absorption. Sodium is absorbed through other mechanisms largely controlled by the kidneys and specific cellular transporters. Other vitamins are absorbed in the intestine but do not rely on vitamin D for their absorption. Therefore, the most accurate and biologically correct answer is calcium.