Which of the following is a common nutritional deficiency in older adults?

Calcium is indeed a common nutritional deficiency among older adults due to several factors. As individuals age, their bodies may absorb calcium less efficiently, and dietary intake often decreases due to factors like reduced appetite, dietary restrictions, or health issues that limit food choices. Additionally, older adults may require higher amounts of calcium to maintain bone density and prevent osteoporosis, making it essential to ensure adequate intake. Insufficient calcium can lead to weakened bones, putting older adults at increased risk for fractures. Consequently, promoting calcium-rich food sources or supplements is a vital aspect of nutritional care for this age group. The other options, while important, do not predominantly reflect the common deficiencies that are particularly prevalent in older adults.