Metabolism-Boosting Agents

Antiobesity Agents/Nutrient Depletion:

  • Beta-caroteneBeta-carotene: Based on human evidence, orlistat (Xenical?) may decrease absorption of beta-carotene and other fat-soluble vitamins (8852391). The manufacturer of orlistat recommends that patients take a multivitamin supplement and separate the dosing time by at least two hours from orlistat.
  • CalciumCalcium: Based on human evidence, orlistat (Xenical?), a pancreatic lipase inhibitor, has been shown to induce a relative increase in bone turnover (increased resorption or bone loss), which may be due to the malabsorption of vitamin D and/or calcium (11486790).
  • Vitamin A/retinolVitamin A/retinol: Based on human evidence, orlistat (Xenical?) may decrease the absorption of fat-soluble vitamins, although studies suggest that vitamin A is not affected as much by orlistat as other fat-soluble vitamins (8844448). Nonetheless, the manufacturer of orlistat recommends that all patients take a multivitamin supplement containing all the fat-soluble vitamins (including vitamins A, D, E, and K unless otherwise contraindicated), separating the dosing time by at least two hours from orlistat.
  • Vitamin D/calciferolVitamin D/calciferol: Based on human evidence, orlistat (Xenical?) may reduce vitamin D levels (9225173). The manufacturer of orlistat recommends that patients may consider taking a multivitamin with fat-soluble vitamins at least two hours before or after orlistat, or at bedtime.
  • Vitamin EVitamin E: Based on human evidence, orlistat (Xenical?) may reduce dietary vitamin E absorption (8844448).
  • Vitamin KVitamin K: Based on human study, orlistat treatment for three to six months may cause a decrease in vitamin K due to reduced absorption in the gastrointestinal (GI) tract (12126214).