Dr Libby Weaver on New Zealand's iron deficiency, how to fix it and what's driven her 14th book

NZ Herald

17-05-2025

But not Weaver. Behind closed doors, the 50-year-old has been on a quest to resolve iron deficiency and its debilitating consequences once and for all.
'I can't bear unnecessary suffering,' the author tells the New Zealand Herald, revealing she gets 'choked up' when even using that phrase.
'There are so many people who have a really hard time in life that don't need to – and nutrition is a huge factor.'
Weaver has always wanted to help, crediting her upbringing and a professor for fostering her desire to learn and pass on that knowledge.
'I grew up very, very simply – no one in my family had gone to university and I just loved learning,' she says. 'I just felt so privileged to be getting this education, but it's all wasted if I don't share the information that I have.'
The realisation came when Weaver was presenting her PhD and a professor challenged her to 'do it as if you are on the 6pm news', explaining her research so the public could understand.
Despite being put on the spot and not being prepared for the challenge, the biochemist says it was 'one of the best gifts ever'.
' It helped me see that it all gets wasted if I can't translate complicated things into ways people can understand and action. That little moment in time changed everything because it made me realise that was what I wanted to do – take things that would otherwise stay in laboratories or stay really complicated, that people couldn't necessarily access.'
And that's what she's done with her latest book, the 14th in her collection – Fix Iron First: The One Thing That Changes Everything.
The book started life as something different, but when Weaver , got 65,000 words in to the writing process, she realised that 11,000 of those words were about iron.
'It dawned on me that I really only wanted to talk about iron,' Weaver says, with a laugh.
'I'd seen how when we correct [iron], so many other things fall into place. So I changed course and went back and took those original 11,000 words and turned them into a book of their own.'
So why iron? It's hardly the most hyped element and doesn't pack anywhere near the social media fanfare that protein and collagen do.
' Iron deficiency is the most common nutritional deficiency globally,' says Weaver, revealing it's most prevalent in menstruating women, pregnant women, athletes, toddlers and children.
'That really feels unacceptable to me – it's something that we can test for and can be easily recognised and yet we just don't seem to be doing a good job as a society at large. We're just not doing a good job at addressing it.'
The author wanted to bring it to 'the top of the pile of conversation' so that people would address the deficiency and no longer accept living with the symptoms.
'We've sort of made health really complicated, and sometimes it's really simple things that make the difference,' she says.
And Weaver gets it – making sure we hit all those magic nutritional numbers can feel impossible. What we need also changes with every age and stage of our life, she says.
When it comes to symptoms of iron deficiency, Weaver says there are many, but the face is usually the first giveaway.
'Our faces become a little pale – that's your first telltale sign because we need iron to deliver oxygen to all of our cells.'
For adults, fatigue and mood are also heavily influenced by a lack of iron, she says, citing a 2023 study titled Psychiatric Manifestations of Iron Deficiency Anaemia, which revealed anxiety was also a symptom of iron deficiency.
'They found that low iron levels were linked to anxiety, low mood, restlessness, heart palpitations and even symptoms that are often mistaken for depression. And they noted that essentially correcting the iron levels improved mood, reduced anxiety, and even alleviated symptoms.'
But Weaver notes that iron deficiency looks different in everyone, with young children's symptoms, in particular, being hard to spot.
'They'll often have a pale appearance, they have a poor appetite, or they can be a picky eater,' Weaver says.
'In their little temperaments, there's a tendency to irritability and agitation. They find it difficult to concentrate. You might notice they have a rapid heart rate if you were to feel their pulse. They'd often develop and grow slower than is ideal. They have pale gums or a pale lining inside their eyelid.'
Another surprising thing for parents to look out for is an aversion to meat.
'I've had lots of parents say to me, 'My child's a vegetarian, even though the family is not vegetarian'.'
So what can we do to fix it? According to Weaver, much like anything, our focus needs to shift to recognising what's happening and then making small changes to our diets first.
'So the richest food source of iron is offal – not that that appeals to everybody – liver and those sorts of things.'
For the organ-adverse, Weaver recommends the next best source – red meat.
' Red meat and lamb. If people don't eat those foods, then there's some iron in eggs and then our plant sources like lentils, legumes, peas, seaweed and parsley.
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'It is widely spread throughout foods, but our absorption of it from our plant foods is typically poorer than it is from the animal sources.'
For those looking to improve their general health, Weaver says there's one free thing we can all do right now to drastically alter it.
'Slow your breathing right down – the way we breathe has such a profound impact on the information that all of the cells in our body receive.'
She says you can instantly spot when people aren't breathing correctly – the upper part of their chest is moving in sharp, shallow breaths. This is driven by adrenaline and can lead to health consequences, especially around sleep and clarity of mind.
'That type of breathing communicates to all the cells in our body that we're not safe,' says Weaver, suggesting that if you watch a healthy baby breathe, it's done so in the tummy.
'When we're small, we breathe diaphragmatically. Sadly, over time we move away from that – breathing in a way that is very disruptive to our body receiving the truth, which is that we are thankfully very safe.
'It sounds too simple to make a difference, but it is profound when we become more breath aware and slow our breathing down.'
Helping people better understand what their body is trying to tell them is what keeps driving Weaver, and what will likely drive her 15th, 16th and 17th books to come.
'Part of what I try to do is evoke for people just how extraordinary their body is. Because I think if we lived a little bit more in touch with just how extraordinary it is, then we would live a bit more.'
Jenni Mortimer is the New Zealand Herald's chief lifestyle and entertainment reporter. Jenni started at the Herald in 2017 and has previously worked as lifestyle, entertainment and travel editor.