Why we need iron in our diet
Tired all the time? Feeling low on energy? Can’t concentrate? There are many factors that can contribute (#life!), but one reason could be your iron level. Before you start self-diagnosing with ‘Dr Google’ or dosing up on iron tablets, it’s important to get your facts straight about this mineral. “Iron is a vital dietary mineral as it gives us the energy we need for everyday life,” says Program & Nutrition Manager, Nour Nazha. We need it for a healthy immune system, and it’s involved in a lot of basic bodily functions, such as transporting oxygen around the body and producing red blood cells.
12% of pregnant women and 15% of non-pregnant women of reproductive age have anaemia, with iron deficiency a major cause, according to the Medical Journal of Australia.
The benefits of iron
“While our bodies are good at storing iron – mostly in haemoglobin (a blood protein), or as protein reserves called ferritin in the liver, we can’t make iron, so we have to get all of our daily requirements through the foods we eat,” says Nazha.
Iron-rich food includes meat, fish, poultry and wholegrain or fortified cereals (see boxes for top sources), so a healthy diet that includes animal products should usually give you what you need. However, it’s important to note that you’ll only absorb some of the iron you eat. “There are two types of iron – haem iron from animal sources and non-haem iron from plant sources,” says Nazha. “We absorb just under 25 per cent of the iron we digest from animal sources, where as we end up absorbing between two and eight per cent of the iron we eat from plant sources,” she says. So you can see how vegetarians and vegans need to plan their food choices more carefully to fulfill their RDI requirements, which is 18mg a day for women aged 19 to 50 with an additional 9mg a day required during pregnancy. “Post menopause, women have the same RDI as men, which is 8mg a day, because they’re no longer losing blood (and therefore iron) through menstruation,” explains Nazha.
“What else you’re eating can also affect how much iron you absorb,” says Nazha. “Certain substances in food and drink, like caffeine, tannins (in wine and tea), fibre and dietary calcium can decrease iron absorption, so go easy on drinking coffee, tea or wine with meals, particularly if you have low iron status.” The rate we absorb nutrients in food can vary, but on average, leave around 30-60 minutes before you indulge in a coffee or wine if you’re trying to boost your iron intake. “If you’re taking any medication or herbal supplements it’s worth checking with your doctor to see if they might interfere with iron absorption too,” says Nazha.
Boost your iron intake
Vitamin C is the magic partner to pump up your iron absorption. It boosts your body’s ability to absorb non-haem iron, so loading your plate with foods such as capsicum, berries and brussels sprouts is a good idea. Animal haem iron also boosts iron absorption from plant sources.
“To help you get enough of this vital mineral, choose a cereal that’s fortified with iron; eat lean red meat such as beef or kangaroo three to four times a week, and combine your meals with a vitamin-C burst like stir-fry beef strips with capsicum,” suggests Nazha.
A lot of women are iron-deficient, most commonly in their late 40s, says general practitioner Dr Ginni Mansberg. “During peri-menopause, which lasts seven years on average, you can have extremely heavy periods, so iron deficiency is most common at that time,” she says. “Then in the early years of menopause you may be playing catch-up.”
However, iron deficiency is usually caused by not consuming enough iron. “It can sometimes be due to fad diets or an inadequate vegetarian or vegan diet,” says Nazha. Some health conditions, such as hypothyroidism or coeliac disease, can also result in a deficiency, as your body is less able to absorb iron.
Not surprisingly, when less oxygen reaches your tissues, your body struggles to find the energy it needs so the most common symptom of iron deficiency is tiredness. And that’s why it can be hard to know if you’re affected – after all, who doesn’t feel tired from time to time? But if your fatigue is coupled with headaches, feeling weak, irritable, unable to focus, or getting out of breath when you’re doing things that don’t usually bother you (like walking upstairs), it might be a good idea to visit your GP.
Do you need iron supplements?
If you think you might be low in iron, don’t head for the supplement aisle just yet – see your doctor first to have your ferritin (iron levels) checked. “Iron doesn’t naturally wear out – you can’t lose it from your body unless you bleed it out, so it’s possible to overdose on it,” says Dr Mansberg. The upper limit for iron intake is 45mg a day for women and men. Above this, you risk toxicity. In extreme cases iron overload can damage internal organs and increase the risk of heart attacks, diabetes and even some cancers, according to research. So resist the temptation to self-diagnose. “I wouldn’t be taking an over-the-counter supplement without a blood test or regular monitoring by your doctor,” says Dr Mansberg. Another reason not to take supplements lightly: “Iron tablets are non-haem iron, which means they’re poorly absorbed by the gastrointestinal tract and tend to stay put, causing bloating and constipation,” she adds. “I’ve never met a woman who enjoys that.” Fair point.
RDI of iron for women aged 19-50: 18mg, Pregnant women: 27mg and men and post-menapausal women: 8mg
Sources of iron
The best way to ensure you've got enough iron is to eat iron-rich foods. Here are some of the best iron sources.
|Top plant based sources||Amount||Top animal based sources||Amount/100g|
|30g Weet-Bix||4.2mg||Chicken liver||11mg|
|1 cup kidney beans||3.1mg||Kangaroo||3.2mg|
|1 cup green lentils||3mg||Lamb||2.5mg|
|1 cup chickpeas||2.7mg||Salmon||1.28mg|
|1 cup wholemeal pasta (cooked)||2.3mg||Tinned tuna||1.07mg|
|30g (about 20) cashew nuts||1.5mg||Pork||0.8mg|
|1 cup spinach (raw)||1.2mg||Chicken||0.4mg|
|30g rolled oats||1.1mg||Snapper||0.3mg|
|30g (about 5) dried apricots||0.93mg|
|1 cup broccoli||0.86mg|
|1 cup brown rice||0.7mg|
|1 slice wholegrain bread||0.4mg|