We’re sorry if you’re all ironed out, but we can’t stand to see a stone left unturned! As a human biologist, nutrition just gets my blood pumping both literally and figuratively. This will be the last time you see any of us nerd out over it for at least a little while though, we promise… You’ve come this far, so you might as well read on to separate the fact from the fiction and learn exactly why asking where you get your iron from features on the “oh you’re vegan?” bingo card. We’ll try not to repeat ourselves too much after our anaemia post, but it’s all good revision!
What is iron (apart from something that my mum wishes I would use on my wardrobe)?
I’ve always found the fact that we need to eat iron a bit weird – since when was I some sort of cyborg with metal inside my body?! Explains a lot about why it tastes so weird when you bite your tongue, though: iron is essential for blood production and proper functioning.
Around 70% of the iron in your body can be found in the -globins: haemoglobin and myoglobin. Haemoglobin is the anaemia component: it’s a protein in red blood cells that carries oxygen, and to function properly it needs an iron to make up the heme groups (we’ll come back to heme, but it’s basically a little blob that grabs hold of the oxygen molecules and holds on tight!). Myoglobin is similar to haemoglobin and still has those pesky heme groups, but instead of helping to transport oxygen it stores it in your muscles and waits patiently until the oxygen is needed for the muscles to move. Fun* fact: the two -globins are responsible for making blood and red meat red!
Another 25% is being stored in ferritin or transported by transferrin: these lil guys are responsible for keeping the balance right, and vitamin C gives them a helping hand! Weirdly, the average adult male has about 1,000 mg of stored iron (enough for about three years), whereas women on average have only about 300 mg (enough for about six months). How unfair is that?!
The rest is found in molecules called enzymes. These act as catalysts to help speed up chemical reactions, like the conversion or breakdown of one thing into another.
These tiny molecules all come into a league of their own when you realise how rubbish we’d feel without them! Read on to find out more…
Iron types and absorption
In food, iron can come in two forms: haem (told you it’d come back to haunt us) iron is found in meat or fish, and as it’s from an animal source it’s no surprise that as animals our bodies find it the easiest to deal with. Non-haem iron comes from vegetable sources and isn’t so easily used by the body, but it’s still the most common form. Maybe a little surprisingly, the general population of the UK (i.e. including meat-eaters) get around 75% of their iron stores from non-haem sources – so they can stick that in their pipes and smoke it!
On a chemical level, i.e. in supplements, there are a few common forms of iron:
- Ferrous (a fancy word for ‘with iron’) sulphate
- Ferrous fumarate
- Ferrous gluconate
- Ferrous phosphate
These have unique sets of pros and cons such as strength, cost and stability, but their absorption doesn’t vary too much. You’ll likely see different names on packets depending on whether you’re looking at tablets, capsules, drops or gummies.
Iron absorption is affected by a few different factors at the gut level, so it’s especially important to take these into account if you’re anaemic and supplementing. The NHS recommends that you take your supplements alongside a vitamin C supplement (or at least with a glass of orange juice) to increase absorption from the gut and help that ferritin get to grips with it in storage. They also tell you not to take it with tea, coffee, eggs, dairy products and soybean products, and not to let a full stomach get in the way. Oh, and if you’re a heartburn sufferer then don’t take it at the same time as your antacid! Complicated, isn’t it?
So not only are veggies already at risk without any haem iron in their diet, they’re also more likely to be replacing those haem sources with soya-based substitutes – nightmare! Soy has been found to have an inhibiting effect on the absorption of non-haem iron, so an already weaker form faces another hurdle. Keep scrolling to find out what problems that might pose, eek!
IRON. HUH. WHAT IS IT GOOD FOR? Quite a lot, actually…
Obviously anaemia is a buzzword that goes hand-in-hand with iron in the diet, but we’ll restrain ourselves from letting that take over. Instead, you can head here to read our dedicated article about it – aren’t you a lucky lot! Apart from fending off anaemia (and in turn helping to alleviate tiredness and fatigue), there are a few other places iron comes in super handy.
Remember we talked about enzymes earlier? Well, without iron’s involvement in the body’s metabolism then we wouldn’t be able to convert food to energy so easily. This means that not only might muscles not be getting enough oxygen – they might not be getting enough energy either! And I thought I was tired… It also helps make up catalysts involved in nerve function and digestion of the food in the first place.
Iron plays an important role in the immune system – vital as we approach cold & flu season! Having too little iron degrades non-specific immunity, which is your body’s first line of defence against pathogens. A healthy iron intake helps your immune system to work properly.
Iron has also been found to contribute to brain function, so it’s especially important in a child’s diet because it’s associated with developmental delays and can affect attention, learning and motor skills. An improvement in focus, attention, concentration and overall intelligence wouldn’t be frowned upon by anyone of any age, though!
Last but not least, a healthy iron intake might help you get a better night’s sleep. Iron upregulates the dopamine pathway, and increased dopamine levels mean increased wakefulness, but go too far the other way and a lack of dopamine can lead to restless sleep.
Quick then, how can we avoid all the nastiness above?!
Iron can be found in a lot of plant-based sources naturally, or because deficiencies are so common a lot of foods like bread and cereals are fortified too.
Make sure you eat plenty of:
- Beans, peas and lentils
- Tofu and tempeh
- Pumpkin, sesame, hemp and flax seeds
- Almonds, cashews, pine nuts and macadamia nuts (and their butters)
- Leafy greens (kale and spinach)
- Broccoli, cabbage and Brussels sprouts
Sometimes though, no matter how many leafy greens you eat, it’s still not enough. Everyone’s metabolism is different, so if you’re concerned make sure you get a blood test (free on the NHS if you tell your GP you don’t eat meat)!
The recommended daily intake is in the table below – if you’re worried you’re not hitting it, then maybe supplements are the answer?
|Birth to 6 months
|Infants 7–12 months
|Children 1–3 years
|Children 4–8 years
|Children 9–13 years
|Teens boys 14–18 years
|Teens girls 14–18 years
|Adult men 19–50 years
|Adult women 19–50 years
|Adults 51 years and older
Who needs it, and when?
So there’s no denying that vegans and vegetarians are more likely to need to supplement their iron intake, but that’s not the only factor!
People who have periods are more susceptible to anaemia because they experience monthly blood loss, so the physical number of red blood cells they have moving round the body is depleted. This is the same for anyone who has experienced physical trauma, or had an invasive operation.
Pregnancy, as if it wasn’t enough to ask of a person already, also draws on the body’s iron resources as it has to provide enough for the growing foetus at the same time. Iron supplements are therefore often prescribed during pregnancy.
Stores are seriously depleted during puberty – adjusting to the increased muscle mass from growth spurts and the blood loss from periods at the same time is a killer combo! As we mentioned iron is also used up during early childhood for growth and brain development, so keep your eyes peeled for the signs in your kids too.
Older people can also really feel the adverse effects of iron deficiency, because physical weakness might reduce already impaired motor skills and confusion can be even more noticeable (and scarier!) when the brain has already slowed down.
There can be other things that mean you’re predisposed to deficiency though, from something as simple as having a poorer absorption rate compared to the next person, to having unseen blood loss from something like a stomach ulcer. That’s why if you’re seeing the signs, get yourself checked out before you start chowing down on the supplements!
*Arguably not fun, but we’ve got to take what we can get with science…