Iron is an essential nutrient that is available in both PLANTS and ANIMALS. While they are both “iron”, they are two different chemical forms of iron. Animal products (eggs, meats, dairy) have mostly heme iron and plant products have nonheme iron. So…why should anyone other than chemistry geeks care about this? Because they are not equally absorbed due to this chemical difference!
Good plant sources of iron include legumes, tofu, some dark leafy vegetables, seeds, dried apricots, prunes, raisins, blackstrap molasses, and then iron-fortified bars, cereals, breads, and whole grains. Vegan and plant based diets typically provide plenty of nonheme iron.
It’s important for vegans and even those on plant based diets to be aware of how to get the most out of their iron sources. Our bodies are very efficient at storing iron, with about 90% being recovered and reused daily, so dietary iron requirements are not as high as you might think, and it takes a serious depletion of our stores to result in iron deficiency anemia. The Dietary Reference Intakes for iron are listed below, so NOTE the difference in requirements based on age and sex, because over-supplementation of this mineral is actually dangerous (especially when people eat a lot of fortified products without thinking about the high vitamin and mineral content).
So back to how heme and nonheme iron are absorbed. Here’s what you need to know: heme iron is easily absorbed through the intestinal cells and nonheme iron requires a few extra chemical reaction steps to get into our blood. Vitamin C (aka ascorbic acid) ingested with food facilitates a reaction that enhances absorption of nonheme iron, by helping get more of it across our intestinal cells into our blood.
Try to include citrus fruits, juices, or other high vitamin C fruits and vegetables such as papaya, red peppers, green peppers, broccoli, cabbage, or collard greens with your meal as a great way to get the most out of your nonheme iron! When considering your daily Dietary Reference Intake for iron, remember that simply eating the recommended amount of iron from plant sources doesn’t mean that’s what you are actually getting. You will need to eat a bit more of the iron rich foods and think about adding the vitamin C to help enhance absorption.
Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Iron
Food and Nutrition Board, Institute of Medicine, National Academies
(taken from the DRI reports, see www.nap.edu)
1-3 yrs 7 mg/day
4-8 yrs 10 mg/day
9-13 yrs 8 mg/day
14-18 yrs 11 mg/day
19 and older 8 mg/day
9-13 yrs 8 mg/day
14-18 yrs 15 mg/day
19-50 yrs 18 mg/day
51 and older 8 mg/day
Here is a link to a USDA list of iron content in mg of foods: http://www.nal.usda.gov/fnic/foodcomp/Data/SR17/wtrank/sr17a303.pdf
By Alison Weppler, MS, RD
Krause’s Food, Nutrition, & Diet Therapy, 11th Edition. 2004.
American Dietetic Association Complete Food and Nutrition Guide, 3rd Edition. 2006.
USDA website: http://fnic.nal.usda.gov/