What factors can Block or Inhibit NON-HEME Iron Absorption?
Medications: Non-heme iron requires an acidic environment for optimal absorption. Medications that reduce the amount of acid in the stomach such as antacids or proton pump inhibitors can lead to low non-heme iron absorption.
Examples: Tums, Prevacid, Nexium, Omeprazole.
Phytates and Fiber: Phytate compounds have a significant effect on the amount of non-heme iron that is absorbed from a meal, and can reduce non-heme absorption by 50-65%.
Examples: Almonds, walnuts, peas, soy, rice, cereal, whole grains, beans, lentils, wheat bran.
Oxalates: Naturally-occurring food chemicals found in numerous food sources, and may inhibit the body’s iron absorption by combining with non-heme iron to form a compound called iron oxide.
Examples: Spinach, kale, potatoes, yams, dark chocolate, raspberries, beets, nuts & seeds, oregano, basil, parsley.
Calcium: (like iron) is an essential mineral, which means the body must get this nutrient from diet. As a mineral, calcium competes for the same absorption sites as iron.
Examples: Milk, cheese, yogurt, broccoli, kale, almonds, collard greens, rhubarb, tofu.
Tannins and polyphenols: Biological compounds that can bind with iron, therefore making non-heme iron insoluble. Of the polyphenols, cocoa (chocolate) and tea demonstrates the most powerful iron absorption inhibiting capabilities, in some cases up to 90%. Coffee is high in tannin and chlorogenic acid; one cup of coffee can inhibit non-heme iron absorption by as much as 60%.
Examples: Coffee, tea, chocolate, blackberries, blueberries, tomatoes, herbs, spinach, broccoli, blackberries.
Low stomach acid: Non-heme iron requires an acidic environment for optimal absorption, so low stomach acidity can greatly decrease the amount of iron absorbed in your stomach. Elderly individuals or bariatric patients often have less acidic stomachs. Frequent use of antacids or PPIs (proton pump inhibitors) can affect your stomach’s iron absorption.
Eggs: Contain phosphoprotein, a compound with iron-binding capacity that can impair non-heme iron absorption. Studies have shown that one hardboiled egg can reduce the absorption of iron in a meal by as much as 28%.