Our bodies need iron to make hemoglobin, the protein found in red blood cells that transports oxygen throughout the body, says Suzie Finkel, RD and founder of Well Digested.
"Iron has a role in a wide range of vital processes, including energy metabolism, respiratory processes, and growth and development. Insufficient iron in the body can lead to iron deficiency anemia, which often causes shortness of breath, fatigue, fast heart rate, cold hands and feet, poor hair/nail growth or strength and pale skin," she says.
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There are two types of dietary iron: heme iron and non-heme iron, according to the National Institutes of Health.
Heme iron is found only in meat, fish and poultry, while non-heme iron is found in fruits, vegetables, dried beans, nuts and grain products. (You can also get the nutrient in the form of iron pills.) Iron deficiency anemia occurs when red blood cells do not contain enough iron due to pregnancy, blood loss, a diet low in iron or poor absorption of iron in the body. Taking iron supplements can help restore your iron levels, if recommended by a doctor.
Knowing which foods inhibit iron can help keep your iron levels where they need to be — and therefore help you avoid low levels of iron. Try to avoid these foods 2 hours prior to or following your main iron-rich meal.
Eggs block iron absorption because they contain phosvitin, a protein compound that binds iron molecules together and prevents the body from absorbing iron from foods.
One boiled egg can reduce iron absorption by as much as 28 percent, per the Iron Disorders Institute.
2. Calcium-Rich Foods
Milk can also work as an inhibitor of iron absorption, potentially affecting your iron levels. The reason is calcium, an essential mineral and the only known substance to inhibit the absorption of both non-heme and heme iron.
One cup of milk contains about 300 milligrams of calcium, per the USDA.
Calcium has little or no effect on iron absorption when you get less than 50 milligrams, but it can inhibit heme iron and non-heme iron absorption when you take in 300 to 600 milligrams on a daily basis.
Foods high in calcium include dairy such as yogurt and cheese as well as sardines, canned salmon, tofu, broccoli, figs, turnip greens and rhubarb.
3. Foods High in Oxalates
If you drink a lot of tea with your meals, you may not be getting enough iron from those foods.
Tea contains oxalates — oxalic acid compounds that impair the absorption of non-heme iron, per the Iron Disorders Institute. Other oxalate-rich foods include spinach, kale, beets, nuts, chocolate, wheat bran, rhubarb, strawberries and herbs such as oregano, basil and parsley.
4. Polyphenol-Rich Foods
Cocoa and coffee can both inhibit iron absorption in the body because they contain polyphenols, or phenolic compounds — aka antioxidants that help remove damaging free-floating cells from the body.
That also means your morning cup of coffee inhibits iron.
Cocoa can inhibit 90 percent of iron absorption in the body, while 1 cup of coffee can prevent iron absorption by as much as 60 percent, per the Iron Disorders Institute.
Other polyphenol-rich foods include apples, peppermint and some herbal teas, spices, walnuts, blackberries, raspberries and blueberries.
These heart-healthy nuts can reduce the amount of iron your body absorbs from iron-rich foods. Walnuts contain phytates — compounds found in soy protein and fiber. Even low levels of phytates have a strong inhibitory effect on your body's ability to absorb iron from food.
Phytates can reduce iron absorption from food by about 50 to 65 percent, per the Iron Disorders Institute.
Other sources of phytates include almonds, sesame, dried beans, lentils, peas, cereals and whole grains.
Not exactly a food, but it's important to know that certain medications can inhibit your body's ability to absorb iron.
In particular, medications that cut back the amount of acid in the stomach, including antacids and proton pump inhibitors (PPIs), can affect absorption, per the Iron Disorders Institute.