Our bodies need iron to make hemoglobin, the protein found in red blood cells that transports oxygen throughout the body, says Suzie Finkel, RD, founder of Well Digested Nutrition.
"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, poor strength and pale skin," she says.
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. Try to avoid these foods two hours before or after your main iron-rich meal.
1. Eggs
Do eggs block iron absorption? The answer is yes 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, according to 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.
An 8-ounce glass of skim milk contains about 300 milligrams (mg) of calcium, according to the U.S. Department of Agriculture (USDA).
Calcium has little or no effect on iron absorption when you get less than 50 mg, but it can inhibit heme iron and non-heme iron absorption when you take in 300 to 600 mg daily.
So does cheese block iron absorption? It can, depending on how much you eat. More than a 1-ounce serving is likely to inhibit iron absorption. Other foods high in calcium, including yogurt, sardines, canned salmon, tofu, broccoli, figs, turnip greens, and rhubarb may also block iron absorption.
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, according to 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 — also known as antioxidants that help remove damaging free-floating cells from the body.
That also means your morning cup of coffee inhibits iron absorption.
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, according to the Iron Disorders Institute.
Other polyphenol-rich foods include apples, peppermint, and some herbal teas, spices, walnuts, blackberries, raspberries, and blueberries.
5. Walnuts
Is there a link between walnuts and iron absorption? Yes. 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, according to the Iron Disorders Institute.
Other sources of phytates include almonds, sesame, dried beans, lentils, peas, cereals, and whole grains.
6. Medications
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, according to the Iron Disorders Institute.
