Most iron is found in red blood cells where it is part of hemoglobin, the molecule needed to ferry oxygen around the body. Without iron, the body has trouble delivering oxygen to cells where it’s needed for energy production. Signs of iron deficiency include fatigue, rapid heartbeat and shortness of breath.
Vegans may have an advantage over other vegetarians regarding iron nutrition since dairy foods provide very little iron. Consuming too much milk and cheese displaces iron-rich foods from the diet, and dairy products may also interfere with iron absorption. In young children, an over-reliance on cow’s milk might be one reason for their high incidence of iron-deficiency anemia.
But iron-deficiency is a public health problem in all types of populations. It’s especially common in younger women since women lose significant amounts of iron through menstruation. And, vegetarians may have higher iron requirements than people who eat meat. This is because whole grains and legumes contain compounds called phytates which bind to iron and inhibit its absorption.
There are a number of factors that counteract the effects of phytates, though. For example, the type of fermentation that takes place when bread is leavened can break the bond between phytate and iron, freeing the iron for absorption. But by far, the best way to boost iron absorption is to eat more vitamin C rich foods. Just 50 milligrams of vitamin C—the amount in about ½ cup of cooked broccoli—can counteract the effects of phytate in a meal. In fact, some researchers have suggested that adding more vitamin C to vegetarian diets is better than taking iron supplements for improving iron status.
Because of this relationship between plant iron and vitamin C, the iron requirement of vegetarians remains an area of some debate. The Institute of Medicine, which establishes the RDAs for Americans, says that vegetarians could need nearly twice as much iron as meat-eaters. But, the actual requirement really depends on vitamin C intake. Vegetarians probably need to exceed the RDA for vitamin C in order to have good iron status. And, it’s not enough to pop a vitamin C supplement once a day. Vitamin C needs to be consumed at the same time as iron-rich foods in order to maximize absorption.
So meeting iron needs depends on how much iron and vitamin C are in your diet, and we don’t have the perfect formula for that. The best advice is to get plenty of both by doing the following.
- Eat a variety of grains, legumes and vegetables since they all contribute iron to the diet. In fact, so many plant foods provide good amounts of iron, that vegans often have higher intakes than omnivores. The best sources are spinach, Swiss chard, pumpkin, sea vegetables, all legumes, tofu, pumpkin seeds, tahini, blackstrap molasses, dark chocolate, some veggie meats, and fortified cereals. Whole and enriched grains provide more moderate amounts of iron, but they still make important contributions to intake.
- Include a good source of vitamin C at all of your meals. The best sources are cantaloupe, grapefruit and grapefruit juice, guava, kiwi, mango, oranges, papaya, pineapple, strawberries, broccoli, Brussels sprouts, kohlrabi, peppers, and tomato juice.
- Eat plenty of fruits and vegetables in general. Organic acids in these foods—in addition to vitamin C—can also help increase iron absorption.
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