Why is iron so crucial to health?
“We need adequate iron to produce hemoglobin and myoglobin, an essential part of red blood cells that carries oxygen throughout the body,” says Julie Stefanski, a registered dietitian nutritionist and spokesperson for the Academy of Nutrition & Dietetics.
Stefanski says low levels of the mineral can leave you feeling tired and weak, impair brain function and weaken the immune system. Optimal levels of hemoglobin are important for endurance.
But research suggests iron deficiency is on the upswing. A study last year in The Journal of Nutrition found that the rate of iron deficiency among Americans has been rising since 1999, as have the rates of severe anemia and fatalities attributed to iron deficiency anemia.
The researchers attribute this largely to a drop in iron intake: a 9.5% decrease in females and a 6.6% decrease in males between 1999 and 2018. Using federal nutrition numbers from dozens of foods, the reserchers determined there was a drop in iron levels in 62% of both animal and plant-based foods analyzed, which might be the result of changes in agricultural practices.
As more people switch to plant-based eating, Stefanski says the risk for poor iron status might rise.
“The form of iron in plants is not as bioavailable to us as is the iron in animal-based foods, and certain natural parts of plants known as phytates and tannins can bind with iron and limit how much is absorbed by the body,” she says.
According to the National Institutes of Health, vegetarians and vegans need to consume about twice the amount of iron as others.
One other reason you might be low on iron is your body’s demand for it might have increased. This often occurs in pregnant women and people who lose blood through blood donation, intestinal conditions or menstruation.
“If a person has a digestive disease such as celiac disease or bacterial overgrowth, poor iron absorption and anemia can result,” Stefanski says.
The Institute of Medicine of the National Academy of Sciences recommends men 19 to 50 yeas old consume eight milligrams of iron a day, and premenopausal women consume 18 mg of iron a day. After menopause, women’s iron needs drop to the same level as men’s.
The body doesn’t make iron. You need to get it through diet or supplementation. Since red blood cells have a short lifespan, the body needs a constant supply.
Dietary iron can be heme (from animal foods including meat, poultry, fish and eggs) or nonheme (from plant foods like legumes, whole grains, spinach, dark chocolate and fortified foods). Though nonheme iron is the more abundant form, the body more readily absorbs heme iron. So you can more easily increase iron levels by consuming foods such as steak, shellfish, lamb and pork.
Also, Stefanski says: “People can improve their absorption of iron from plant foods by pairing them with foods high in vitamin C ,such as strawberries, citrus fruits,and dark green leafy vegetables like collard greens and broccoli.”
Research shows fermentation can improve the bioavailability of plant foods by reducing levels of compounds like phytates that can hinder iron absorption. So tempeh, which is fermented soy, could be a better source of iron than non-fermented tofu.
Cereal grains in the millet family including sorghum and teff have been shown to help raise hemoglobin and serum ferritin levels. And molasses is fairly high in non-heme iron.
If a blood test reveals you have an inadequate ferritin count (ferritin is a blood cell protein that binds with iron), you’ll most likely be instructed to take a supplement.
Environmental Nutrition is a newsletter written by experts on health and nutrition.
