Published on 4th December 2020

As part of our ongoing work to support human milk banks this December, we’re thrilled to be interviewing Dr Natalie Shenker of the Hearts Milk Bank and the Human Milk Foundation. Join us on a deep dive into her origins as a human milk scientist, the ongoing benefits of human milk donation, and her exciting plans for 2021.

The interview

Q: Well, thank you so much for taking the time to speak with me. We're thrilled to be partnering with the Human Milk Foundation and learning more about the incredible work you do. So, pretty basic question, but can you please introduce yourself and talk about how you became involved with milk banking? 

 Natalie: It was nothing I planned! I was doing my PhD at Imperial College, working on finding markers of breast cancer risk. And, as with any PhD, there were lots of things in the research that was frustrating. To add to this, I had my first baby during that time! I had a really difficult birth, followed by difficulty breastfeeding straight afterward. I came into it thinking that I would know everything because of my background in medicine, but it turned out that I knew almost nothing.

 I was lucky and got some great support from a community midwife and local breastfeeding group just as I was on the point of stopping, I ended up with an oversupply and a baby who refused milk from anywhere else except me. A friend told me I could donate the spare milk to the local hospital and I remember saying to her, “Good grief, whatever for?” To cut a very long story short, that led to a great research project with the milk bank at Queen Charlotte’s, which means that I could take cells from human milk and look at their epigenetic markers to see whether we can pick up screening tools for women at risk of having breast cancer. 

 Q: Wow. And this continued to be an ongoing project for you? 

 Well, that’s the next part of the story. We had created a huge project, and if we can recruit enough mothers into it, then we could potentially develop the necessary screening tools. Unfortunately, we couldn’t get funding for it. While we were getting rejected for grants because human milk science wasn't seen as a research priority, I was also watching the milk bank infrastructure in London diminish. We couldn't do the research without a functioning milk bank network. By then, I knew exactly what milk banks were for and why they were so important for preterm babies and their families. At that point, I just needed to do something about it. That’s what led me to co-found the Hearts Milk Bank with Gillian Weaver – the idea was that if we could create a large enough milk bank, then we could provide milk into many research studies and learn whether milk was just useful for the care of preterm babies, or whether there were uses beyond that. 

Q: You touched on funding issues, but were there other hurdles in getting your milk bank off the ground? 

Natalie: There were so many hurdles. A wonderful academic named Stephanie Tempest from Brunel looked at how many people in the UK knew about human milk banks and found it was only 1%. At the time, that included me, and I’d worked at neonatal units for several years by that point. Because it was so niche and tucked away, whenever milk banks tried to raise awareness about their work, they were overwhelmed by the response from mothers who wanted to donate. But unfortunately, they don’t have the infrastructure, staffing, or money to be able to recruit them all. 

 In a way, we’re still facing the same problems. It’s all about raising awareness and understanding of the differences between human milk and formula. For instance, a lot of people don’t know that infant formulas are mostly made from cow’s milk, or that human milk has unique properties for a baby’s development. Ultimately, human milk is very different from the milk of other mammal species, and many doctors and policymakers are not aware of that either. 

 The other major hurdle was the “why?” As in, why are we bothering to do this when we have access to infant formula, which is both readily available and relatively cheap? What is it about having access to human milk that makes a difference? When speaking to mothers and fathers, it was clear that they wanted access, they wanted support, they wanted to breastfeed their own babies, and they just needed a safe alternative to formula to bridge that gap. 

Q: I’ve broached this topic with others in milk banking, but why do you think there is such a knowledge gap? 

 Natalie: When speaking with families, we found time and time again that the same question arose: why doesn’t this exist already? I did many talks to raise funds in local community groups when we were first starting, and many of the audience were in the older population. Afterward, there would always be one or two women who would stay behind to share how they shared their milk in the hospital or had gone to the local milk bank, or a grandfather remembering how he drove his wife’s milk across London to donate it. When I looked into this, milk banking used to be ubiquitous. But we’ve forgotten that because several things happened in the 1980s, starting with the HIV epidemic. This became a problem, not only because HIV can be transmitted through the milk and you need the team to on-hand to be trained in screening, but also if mothers who wanted to donate and had an HIV test, they couldn’t necessarily get the life insurance they needed due to the stigma. 

 At the time as well, formula companies were responding to what had happened in developing countries, when a report in the 1970s revealed that tens of thousands of babies were dying as a result of unsafe formula practices. These companies initially had been financially impacted by boycotts and public shock at their practices, so in response, they diversified their product market away from just one kind of formula to more diverse products, including specialised medically-focussed formulas – one of the most successful being their preterm formula ranges. These were marketed heavily to the medical community. 

And so the question in the minds of the healthcare sector was that if you have access to the preterm formula for a few pennies for every feed, why would you keep a relatively costly milk bank going, with all of the efforts of donor recruitment and pasteurization of the milk? As a result, most milk banks had closed by the early 1990s, with only six remaining in the UK. Although there have been some improvements in the last few years, donor milk is still largely restricted to babies born less than 2-3 months prematurely. This is the ongoing work we have today. 

Q: It appears that the formula companies have a stronghold on the industry, and it’s a bit of an uphill battle when speaking with parents? 

 Natalie: For many, many parents in the UK, feeding babies with formula is seen as the norm. I mean, that’s what we all grew up seeing and it’s how most of us were fed. I was fed with formula after the first 3 months, I fed my baby with formula when I couldn’t supply enough milk… No one in milk banking would say that formula was a terrible thing – there is always going to be a need for it, and it needs to be as safe as possible. But, when you know that there are babies and mothers out there where having access would make a difference to their health and there are so many wonderful women out there who want to donate – it’s frustrating not to have the logistics and infrastructure in place already. It’s a fillable gap that can solve a lot of problems and heartache.  

 The stories of mothers whose babies are in hospital, and where donor milk hasn’t been given and babies have developed NEC and died, are an incredible reminder of why we work so hard in this. We’ve also been running a programme at Hearts over the past couple of years to support mothers at home who are desperately trying to establish breastfeeding. We work with their healthcare team, and give them support in their feeding journeys with access to donor milk if needed - around 70% of these mothers have gone on to establish their own feeding. More than that, this support can have a profound impact on how a mother feels about the situation she is in – one described it as a virtual hug, and that’s just how it needs to be. My research group is trying to work out which women will have the most benefit, but it’s the sort of programme the charity aims to extend across the country.

Interviewer: This is off-piste, but as someone who was born in the US, this idea of looking after mothers hits home. I spoke with my mother recently about this, and she told me about how she gave birth to me on a Saturday and was back at work on Monday. It was normal and expected. 

 Natalie: Honestly, women are just amazing. After having a baby, you know, it's like a part of your brain kicks in that makes you want to help other mothers because you know just how difficult it can be. Lots of mums are lucky to have good support networks around them, but we do suffer from so many societal pressures and the idea that we must be seen to be a certain way. All I wanted to do was sit around in my dressing gown for six months, if not longer. 

 Interviewer: Ain’t nothing wrong with that. Haha, that’s my life right now in the pandemic, and I don’t even have a legitimate reason for it to be. There’s this pervasive notion of what a woman is expected to be… 

 Natalie: Exactly that, and you know, I guess I was also working a couple of hours after my daughter on my laptop with her sleeping next to me, which I guess isn’t great... So, you know, I kind of want it every way! 

Q: Speaking of work, it bears asking how the pandemic has affected your plans at the Human Milk Foundation? 

 Natalie: We were so hopeful at the start of 2020 – as a new charity it had been a rollercoaster but by the start of the year we had everything planned out, month by month – a roadmap of the entire year. We pretty much had to rip that up about four weeks into the year. But I think we’ve learned and grown so much as both an organisation and as a team. And now, we’re just hoping that with our campaign with you (Elvie), and the support of so many people out there, we’ll be ready to launch into 2021 with a huge amount of energy. 

 What we’re trying to do as an organisation is to reach a stage where only the smallest amount of donor milk is actually used, and make sure that mothers have all the lactation support that they need – babies developed to expect their own mother’s milk, and each of the nutrients is tailor-made for them. Donor milk can’t replicate that, but at least contains the very unique elements that help support the baby’s development and immune system. We’re hopeful that the plans we have for 2021 will help roll this out, especially with an expansion in the works and two new members of the team starting – every time a new member of the team starts, the actual amount of families we can support increases by 150%. And one thing that’s been really amazing out of the pandemic is the collaborations we’ve started with other milk banks and scientists across the world. The Human Milk Foundation helped to establish a global alliance of milk bank leaders in 40 different countries and that means we’re learning quickly how other countries do things so we can implement the most useful practices for women in the UK. 

 Q: That’s really exciting, and I wish you the best in your endeavours. Do you have any final thoughts you would like to share? 

Natalie: I can’t finish an interview without mentioning the subject that still fascinates me the most – how milk evolved and what it is about human milk that sets it apart from other mammals. It’s one of the aspects that makes us so unique as a species. Our brains, the speed of messages in our brains, are supported by factors in milk that help in brain development. Milk itself changes over the course of a single feed, the time of day, the season of the year. It changes in response to infections and produces antibodies that act to neutralise the virus that causes COVID-19. It changes depending on where in the world a woman lives, how hot it is outside. It can’t simply be replicated by creating artificial milk or by adapting the milk of another species. 

 The adult sugars in human milk, which are really evolutionarily ancient, produce over 200 different types of other sugars that work together to protect the baby against bacteria, supports immune system development, and brain development. And the most magical thing? They’re completely unique for each mother. They’re governed by everything from genetics, environment, the season of the year… and some of the moms who are donating, have had unique properties that helped to protect babies against disease. The work starts next year to see if we can start matching milk with particular properties to sick babies with particular needs. We really want to start to look at milk from different directions using lots of different experiments to see whether we can actually start personalising the use of donor milk to different babies in clinical conditions. Maybe a future milk bank service will match milk to babies like the blood transfusion service matches blood donations. We’re really excited! 


Want to find out more? 

Read Natalie’s article about breast milk in The Biologist

Read Natalie’s article about breastfeeding during lockdown in The Conversation 

The Hearts Milk Bank

Human Milk Foundation