Ferrous Sulfate Administration: With or Without Meals
Take ferrous sulfate on an empty stomach (1 hour before or 2 hours after meals) for optimal absorption, but if gastrointestinal side effects are intolerable, taking it with small amounts of food is acceptable to ensure compliance. 1
Optimal Timing for Maximum Absorption
The American Gastroenterological Association recommends taking iron once daily in the morning on an empty stomach to maximize absorption when hepcidin levels are lowest. 1
Food consumed within 2 hours before or 1 hour after oral iron can reduce absorption by as much as 50%, making empty stomach administration significantly more effective. 1
Taking iron in the morning is superior to afternoon or evening dosing because serum hepcidin increases during the day and reduces absorption. 1
When Taking With Food Is Acceptable
If significant gastrointestinal side effects occur (heartburn, abdominal pain, nausea), taking ferrous sulfate with small amounts of food may improve tolerability, though this reduces absorption. 1
The guideline explicitly states that closer proximity to meals is acceptable if it ensures compliance—adherence to therapy is more important than perfect absorption if the patient otherwise won't take the medication. 1
An alternative strategy for managing side effects is taking the supplement at bedtime rather than with meals. 1
Enhancing Absorption Strategies
Take ferrous sulfate with 500 mg of vitamin C to enhance absorption, especially if you need to take it with meals due to side effects. 1
Consuming iron with meat protein can improve absorption. 1
Avoid taking iron within 1-2 hours of coffee, tea, or calcium-containing foods, as these are powerful inhibitors of iron absorption. 1
Optimal Dosing Frequency
Once-daily dosing is superior to multiple daily doses because iron doses ≥60 mg stimulate hepcidin elevation that persists for 24 hours and blocks absorption of subsequent doses. 1
If side effects are problematic, consider alternate-day dosing (every other day), which significantly increases fractional iron absorption while reducing gastrointestinal symptoms. 1
Common Pitfalls to Avoid
Never use enteric-coated ferrous sulfate formulations—these show significantly lower iron absorption (3.5% vs 12% for uncoated tablets) and should be avoided despite marketing claims of better tolerability. 2
Don't take iron more than once daily, as this increases side effects without improving absorption due to hepcidin elevation. 1
Don't take iron with aluminum-based antacids or phosphate binders, as these reduce iron absorption. 1