Nutrient needs may be altered because of long-term medication use and lack of ambulation. Use of drugs such as anticonvulsants and/or Phenobarbital for epilepsy, antacids, anti-inflammatory drugs, and laxatives can interfere with calcium and vitamin D absorption, which negatively affects bone metabolism. Likewise, those with spinal cord injury or who cannot ambulate are less likely to place weight-bearing stress on the bone, or absorb calcium and vitamin D properly, which can affect the onset of osteoporosis.

Read the entire article and others in the nutrition series at http://www.ncpad.org/296/1838/Factors~Affecting~Nutrient~Absorption.