Get the facts on iron

The widely-held stereotype of vegans as pale and anaemic doesn’t fit with the research, which clearly shows that Australians on plant-based diets are no more likely to be anaemic (which means having low haemoglobin levels in their blood) or to have depleted iron stores than omnivores.

Vegans tend to have lower iron stores (ferritin levels) than omnivores, but this may be a health advantage: high iron stores are associated with chronic liver disease, liver cancer, cardiac arrhythmias, metabolic syndrome and diabetes.

Nonetheless, when you first switch to a plant-based diet it can take some time for your body to adapt to only having non-haem iron (the kind we get from plants) and no haem iron (the kind that’s in red meat), so it’s important to eat plenty of plant foods that are high in iron.

Men and postmenopausal women only need 8 mg of iron per day, according to the National Health and Medical Research Council, while women in their fertile years need 18 mg per day, and pregnant women 27 mg per day.

Here’s a selection of high-iron plant foods:

As you can see, it’s not that difficult to get enough iron if you make wise food choices throughout the day.

It’s often argued that haem iron, the kind of iron we get from red meat, is ‘better absorbed’ than the non-haem iron we get from plant foods. The reality is that iron absorption is very tightly controlled by the cells that line our small intestine, so that we can absorb more iron if our stores are running low (for example, after an accident in which we lose a lot of blood, or in women during their menstrual period), and absorb less when we don’t need it (when our iron stores are sufficient). Haem iron bypasses these controls, forcing our bodies to absorb iron whether they need it or not, and pushing up iron stores to the point where they actually increase our risk of some rather nasty diseases, like type 2 diabetes.

In a study which followed 536 969 Americans aged 50-71 at baseline for 16 years, those with the highest intake of haem iron had the highest risk of dying from cancer, heart disease, respiratory diseases, stroke, diabetes, infections, kidney or liver disease, as well as all-cause mortality (dying from any cause).

And while depleted iron stores are a problem, high iron stores are too:

“Iron deficiency may exist when ferritin levels decline to less than about 12 ng/mL, whereas ferrotoxic disease may occur with levels greater than about 50 ng/mL.”

How well does the absorption regulation process work? Pretty darn well. We typically only absorb about 5-10% of the iron we consume in food, but during their menstrual period, women can absorb up to 8 times as much iron as usual! The same process happens in pregnancy, during which absorption of non-haem iron increases from less than 1% in early pregnancy to 7% at 12 week’s gestation, 36% at 24 weeks and 66% at 36 weeks. Smart body, eh?

A note of caution: Even if you consume plenty of iron-rich foods, you may still run into problems with iron if your intake of substances that block its absorption is too high. The most common villains are:

1. Polyphenols (including tannins found in black tea and some herbal teas), coffee, some wines, chocolate and cocoa. Coffee reduces non-haem iron absorption by 24%-73% depending on the type of food consumed, while tea reduces it by 70%. Among herbal teas, rooibos is extremely low in tannins and has minimal effects on iron absorption, fennel and chamomile contain moderate amounts, and peppermint and hibiscus tea are extremely high in tannins. Avoid drinking coffee or high-tannin teas within 2 hours of eating iron-rich foods.
   
2. Phosvitin, a protein found in eggs. 1 egg can reduce iron absorption by 28%.
3. Milk proteins.
4. Prescription and over-the-counter drugs for suppressing stomach acid, including proton pump inhibitors and H2 antagonists. Fortunately, adopting a plant-based diet clears up indigestion and reflux pretty quickly for most people!

So that’s the deal with iron: make like Popeye and eat your dark green leafy vegetables – along with legumes (dried beans, peas and lentils), whole grains and seeds, preferably with some lemon juice, sauerkraut or other food rich in vitamin C, citric acid or lactic acid to boost absorption – keep your absorption-blockers to a minimum, and let your body take care of the rest.

Want more info on iron? You can watch the webinar ‘All About Iron’ and download the fully-referenced slides by joining EmpowerEd, my online health and nutrition education program. Register for your 1 month free trial of EmpowerEd for instant access to this and dozens of other content-packed webinars.

For personalised help with addressing iron-related disorders, apply for a Roadmap to Optimal Health Consultation.