Your Body: Iron, Haemoglobin and Anaemia, Oh My!

Hello Team Science! Before today’s post, just a tiny little note to say that on 30th June I will be running the Race for Life with a team of amazing women, led by the brilliant Aisling of Any Other Woman. Our sponsorship page is here, so if you do have any spare pennies lying around, and would like to use it to help fight cancer, chuck them our way. We will be hugely and endlessly grateful. I’ve lost people I loved to cancer, and I’ve seen how vicious it can be, how heartbreakingly cruel and unfair. Anything we can do to fund research into fighting it is one step closer.
Also, I will be on holiday next week, living it up in Italy, by which I mean I will be lying around reading and eating gelato, so no posts next week Im afraid. But I’ll be back in July, full of science and gelato, a winning combination…
Today’s post is about anaemia, and what it actually means. I’ve been diagnosed as anaemic in the past, and although I always knew it meant I was iron-deficient, and needed to start eating spinach like Popeye in an emergency, I never really connected that to why it made me so tired all the time. As always, I think it’s kind of awesome to understand how your body works, and how things can shift and go wrong, and the effects that can have. Your body is so interconnected, everything works together in such a smoothly organised way, that when something is off balance, it can have some major effects.
To understand anaemia, we really need to get to grips with the role of iron in the body. Clearly it’s important, or the lack of it wouldn’t make me so droopy and inclined to curl up in a ball under our duvet and try to refuse to come out for anything less than nuclear war, or the promise of ice-cream (garnished with spinach, naturally). Iron is involved in the transport of oxygen in the blood. It’s the sidekick of a protein that lives in red blood cells, called haemoglobin.
Haemoglobin is actually one of  my favourite proteins (and that’s a tough top ten to call, trust me). Basically, it transports oxygen around the body. It’s the circulatory system’s taxi service for all O2 molecules with someplace important to go. Haemoglobin is made up of four subunits, which stick together to form a perfect oxygen carriage. Each of the four units is made up of two parts, a heme group and a globular protein chain. The protein chain forms the structure of the carriage, and the heme group is the oxygen’s comfy little seat.

This is haemoglobin, with it’s four carriages. The heme ‘seats’ are in green.
Image source.

The seat for oxygen is not just any seat, it’s pretty special, what with oxygen being a VIP in the body, it deserves first class transport around the place, and anyway, it’s far too much of a diva to get around on its own. The heme group consists of a chemical ring known as a porphyrin, with a charged iron molecule held in the centre. Oxygen climbs into its ‘seat’ by binding to the iron molecule.
This is the bit that makes me love haemoglobin, because each carriage has four seats, four spaces for oxygen molecules to bind. However, each seat doesn’t gain an oxygen haphazardly, the process of binding is cooperative. So, when the first oxygen straps into its seat, the iron ion shifts back slightly. Because the entire protein carriage is built and fitted together so neatly, this shift, and it really is only a very very tiny movement, causes the other three units to also shuffle around slightly. This very minor shuffle results in a slightly changed position for the three remaining seats; making it easier for oxygen to hop on board. When I first learnt about this, I had one of those mind-blowing “the body is INCREDIBLE” moments… it’s developed a system where the binding of one oxygen makes it easier for successive oxygen molecules to bind. This makes the whole thing take less energy, which is ace because everyone knows saving energy is important. How amazing is your body?!
Anyway, it’s pretty clear from the way that oxygen binds to iron in order to be transported speedily around that body that iron is an Important Thing. Without sufficient iron, the body cannot produce enough haemoglobin, and without enough haemoglobin, there’s a limit to how much and how quickly oxygen can be ferried around the body. This is what happens when you get iron-deficiency anaemia. There’s just not enough oxygen getting around your body, so you feel tired and lethargic. You might also, in more serious cases, experience shortness of breath and a pale complexion. Luckily, it’s fairly simple to fix this, you just need to Get More Iron. Although this isn’t entirely straightforward, because your body needs to absorb the iron before it can do anything vaguely useful, but the way the body takes up iron is a subject for another post, I think!
So that’s anaemia in a nutshell, you need hulking strong iron molecules to transport diva-ish oxygen around the place and give you sufficient energy to run around and do stuff. It’s a simple thing, with a big effect. Biochemistry rocks.
*As always, I want to make it clear that Im a science nerd with a bizarre habit of anthromorphising molecules in my spare time, Im not a doctor or qualified in any health profession at all. If you think youre suffering from anaemia, see your doctor. Thats an Actual Order. Thanks.*

3 thoughts on “Your Body: Iron, Haemoglobin and Anaemia, Oh My!

  1. Having just given birth & needed a blood transfusion for blood loss & low iron this couldn’t be more apt. I’ve learnt, that you already know but it fits into amazing body thoughts, that iron is key to producing breast milk & low iron means low breast milk production plus all the tears. The difference I felt even at 3am half way through the transfusion was miraculous.

  2. With all the pregnant girlies and new mummies around this is an incredibly well timed post. I recently finished a course of iron tabs, thought nothing of it until I spent this entire weekend sleeping on the couch (with a baby on my chest of course, obligatory!)… Off to the docs this afternoon for more. Breastfeeding just suuuuuuucks all the iron from you, even 4 months down the line!! Thanks for writing this, amazing as always. Xx

  3. I think it was discovered that spinach does not actually contain much of iron, contrary to the popular belief. There is more iron in beans than in this famous vegetable. It is one of the most famous number mistakes of all the times. It’s a funny story – I reccommend you read it.

    Very nice website! I love reading it!

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