Iron. Does it conjure images of Popeye eating spinach from a can? Or maybe you envision scenes of Arnold doing bicep curls at Gold’s Gym in the 70’s? Iron is a mineral, a metal and stands in line as the fourth most common element found in the Earth’s crust. It’s crucial in the development of steel as well as in its role in the human body, by helping carry oxygen from your lungs to the tissues of your body. Although not as common as other nutrient deficiencies, iron deficiencies do affect the population with a whopping 34% of people not meeting the Recommended Dietary Allowance (RDA) (Berardi, 2016).
Iron rich foods come in two forms – heme and nonheme sources. Heme iron is predominantly found in red meat, poultry and seafood (50% heme and 50% nonheme) in the hemoglobin and myoglobin found in the flesh of the animal. This type of iron is the most readily absorbed by the human body. Nonheme iron is found in nuts, beans, vegetables and fortified grain products and is less bioavailable than heme iron. Although the bioavailability of both types of iron can be affected by other dietary components, which I’ll explain later, it’s nonheme sources that are more greatly affected.
Fatigue and general exhaustion are a telltale sign that you may be experiencing a nutrient deficiency. Knowing which specific nutrients you’re lacking may require blood and/or urine analysis, but you can also do a little speculation for yourself too. Iron deficiency anemia is the most common deficiency in the world and can present with common symptoms like fatigue and in sever cases, impaired cognitive function. Certain groups of people are at a higher risk for developing an iron deficiency. Pregnant women, women who experience heavy periods, infants and children, and people with compromised gastrointestinal tracts may be more at risk of an iron deficiency. Vegetarians are also at higher risk as are people (predominantly females) who engage in regular, intense physical activity (Otten et al., 2006). Without reaching for iron supplements (unless advised by your health practitioner), which can be hard on your stomach, you can take a look at how you’re consuming iron rich foods and identify certain dietary interactions that may be inhibiting (or enhancing in some cases) its absorption.
Eating This with That…
Vitamin C (ascorbic acid) & IRON
- Vitamin C strongly enhances the absorption of nonheme iron
- Up to at least 100 mg of vitamin C per meal
- It improves iron absorption through the release of nonheme iron bound to inhibitors
Animal Meat Proteins & IRON
- Meat, fish and poultry enhance nonheme iron absorption
- Involves low molecular weight peptides that are released during digestion
Phytates & IRON
- Phytates inhibit nonheme iron absorption
- Absorption of iron from food with high amounts of phytates such as soybeans, black beans, lentils, mung beans and split peas is very low.
Polyphenols & IRON
- Polyphenols inhibit nonheme iron absorption
- Polyphenols, such as those found in tea, grain products, red wine and some herbs, inhibit iron absorption through the binding of iron to tannic acids in the intestine
Vegetable Proteins & IRON
- Vegetable proteins inhibit nonheme iron absorption
- Due to the phytate content of the food
Calcium & IRON
- Calcium inhibits the absorption of both heme and nonheme iron
- Calcium inhibits iron absorption during transfer through the mucosal cell
Zinc & IRON
- High iron intakes may reduce zinc absorption
- May occur with supplemental iron if both are taken without food, but does not inhibit zinc absorption if it is consumed with food