What factors can negatively influence calcium absorption?

High sodium intake and low Vitamin D levels are significant factors that can negatively influence calcium absorption in the body.

Sodium has the potential to promote calcium excretion through urine. This can lead to an increased loss of calcium, which consequently lowers the amount of calcium available for absorption in the intestines. Therefore, a high-sodium diet may adversely affect the body's calcium balance.

Vitamin D, on the other hand, plays a crucial role in facilitating calcium absorption in the gut. It helps to regulate calcium levels in the blood and promotes the absorption of calcium from dietary sources. When vitamin D levels are low, the efficiency of calcium absorption decreases, resulting in insufficient calcium being incorporated into bones and other bodily functions.

Together, high sodium intake and low vitamin D levels create a challenging environment for optimal calcium absorption, making this option correct.