Final answer:
Vitamin D plays a crucial role in the absorption of calcium through the intestines. A deficiency of vitamin D can lead to a decrease in absorbed calcium, which can have negative effects on bone health.
Step-by-step explanation:
Calcium is absorbed through the intestines under the influence of activated vitamin D. A deficiency of vitamin D leads to a decrease in absorbed calcium and, eventually, a depletion of calcium stores from the skeletal system, potentially leading to rickets in children and osteomalacia in adults, contributing to osteoporosis.