Over-the-Counter Drugs, Herbal Supplements, Vitamins, and Minerals Practice Test

Oral iron commonly causes gastrointestinal side effects, especially stomach upset and constipation. To improve absorption, pairing iron with vitamin C is effective because vitamin C helps convert iron to a form that the body can absorb more readily and keeps it soluble in the gut. This is why consuming a vitamin C source (like orange juice or a citrus fruit) around the time you take iron increases uptake. At the same time, calcium can interfere with iron absorption, so it’s best to avoid taking calcium-containing foods or supplements at the same time as iron or to space them several hours apart. This combination of addressing the common GI side effects while optimizing absorption explains why the given option is the best choice.