Vegan Nutrition with Dina Aronson, M.S. R.D.

Dina Aronson, MS, RD is a vegan dietitian whose specialties include chronic disease prevention, vegetarian/vegan nutrition, and lifestyle management. She is the founder and director of VeganRD.com, a nutrition consulting company. Active in many vegetarian nutrition organizations, Dina was the recipient of the American Dietetic Association's Recognized Young Dietitian of the Year Award in 2002.

Iron Deficient Anemia: Is it true that a high intake of calcium prevents the absorption of iron? I've always had a low iron level since I'm vegan and I drink a lot of calcium-added soy milk. Can this be the reason?

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It is very likely not the main reason for your low iron. When it comes to mineral balance (particularly iron and calcium), there are many players involved, not just one. Furthermore, the interactions are complex, difficult to measure, and subject to variation from person to person. Bioavailability (or, absorption rate) of iron is regulated by many factors. High calcium intake (particularly from supplements) can interfere with iron absorption in the short term, but no long-term study has found that high calcium intake negatively impacts iron status over time. This is not to say that it's impossible; rather, it's important to assess your overall diet and tweak it to maximize mineral absorption. Therefore, it's important to understand what factors limit and what factors maximize iron absorption, so that you can compensate the "inhibitors" with the "enhancers."

The factors that most strongly enhance iron absorption in the vegan diet include vitamin C (foods high in vitamin C help the body absorb iron from the same meal), other organic acids (such as citric, lactic, and malic acids, found in fruits—especially citrus, veggies, and condiments with added organic acids as a preservative), low iron intake, and low iron status (the lower our intake or status, the higher the absorption—the body is so intelligent!).

The factors that most strongly inhibit iron absorption include phytic acid (found in legumes and whole grains), tannins (in tea and coffee), flavonoids (in red wine), concentrated proteins such as whole soybeans, high fiber intakes, antacids, zinc supplements, and finally very high calcium intakes.

Wait a minute, you might be thinking—the very foods recommended for optimal health are bad for iron absorption? Well, sort of, and no. You should not avoid foods like whole wheat and beans. A reasonable approach, if your iron status is less than optimal, is to eat plenty of iron-rich foods throughout the day (paired with vitamin-C-rich foods when possible) and avoid things like large intakes of isolated wheat bran, which bind iron pretty tightly.

The amount of iron that people (vegans and otherwise) need is a controversial subject. The daily requirement for non-vegetarians varies wildly throughout the life cycle, and in reality varies from person to person. Some women, for example, lose so much iron due to menses that it's particularly challenging to replace it with food. Others suffer from iron overload, which can make a person very ill. Regardless, the best research we have has yielded the following recommendations for NON-vegetarians:

(values are milligrams per day)

Infants 0-6 months 0.27
Infants 7-12 months 11
Children 1-3 years 7
Children 4-8 years 10
Children 9-13 years 8
Boys 14-18 years 11
Girls 14-18 years 15
Men 19+ years 8
Women 19-50 18
Women 51+ years 8
Pregnancy (all ages) 27
Lactation under 18 years 10
Lactation 19+ 9

The Food and Nutrition Board (the division of the Institute of Medicine that recommend these values) also state that vegetarians need to multiply each of these values by 1.8. (The reason is because iron from vegetarian foods is not as easily absorbed as iron from animal foods—not that this makes iron from vegetables any less valuable or that from animals more valuable!) This is highly controversial in the vegetarian nutrition community. The numbers can get too high; a pregnant vegetarian, by these standards, would need 48.6 milligrams of iron a day, which is actually HIGHER than the upper limit for safety established by the same organization. The problem is, everyone is different. The numbers provide a good starting point, but iron needs really should be established on an individual basis. Not only diet but genetics, gut health, and many other factors determine the amount of iron each of us needs. So my recommendation is to get annual blood tests to assess iron status. Should values be normal, keep doing what you're doing. Should values be low, maximize healthful, iron-rich foods, while being mindful of absorption enhancers and inhibitors. If your values are dangerously low, talk to your healthcare provider about iron supplements.

Here's a short list of vegan foods that are good sources of iron (over 2 milligrams per serving):

firm tofu
leafy greens, especially spinach (no, the calcium in the spinach won't keep the iron from being absorbed)
baked potato
dried beans, especially white beans and chick peas
sesame seeds and tahini
pumpkin seeds
quinoa
blackstrap molasses
enriched grains and breads
fortified breakfast cereals

Here are some vegan foods that contain a moderate amount of iron (1/2 to 2 milligrams per serving):

carrots
green beans
avocadoes
dried fruits, especially apricots, raisins, prunes
most nuts, especially cashews
soy milk (brands differ)
mushrooms
watermelon
dried beans not in the list above

Disclaimer: The advice given here is for eductional purposes only. You should not use this information to diagnose or treat a health problem or disease without consulting with a qualified health care provider.

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