Iron is absorbed the best when taken on an empty stomach. However, some people have stomach cramps, nausea and diarrhea when taking iron and may need to take their iron with a small amount of food.
Milk, calcium and antacids should NOT be taken at the same time as iron supplements. You should wait at least two hours after ingesting these before taking your iron supplements.
Foods that you should NOT eat at the same time as you take your iron include:
■ High-fiber foods, such as whole grains, raw vegetables and bran
■ Foods or drinks containing caffeine
If you have questions about how to take iron supplements, talk with your doctor or pharmacist. Always consult your doctor before taking any dietary supplement, as some may interfere with prescription medications you are taking and some may not be appropriate for people with certain medical conditions.
— Source: National Institutes of Health