"My toxic trait is throwing myself into risky situations"

"My toxic trait is throwing myself into risky situations"

Born and trained in Malawi, Bernadette Chimera qualified as a medical doctor at 21 and was heading towards a career in surgery when she kept meeting patients who were too malnourished to operate on. She left the hospital to help build Malawi's first clinical dietetics programme, then took an MSc at University College London and a PhD at the International Agency for Research on Cancer in Lyon, studying how the diversity of species in people's diets shapes cancer risk, the metabolome and the gut microbiome. She has joined CBMR's Loos Group, led by Ruth Loos, as a BRIDGE Fellow.

In this interview she explains why national dietary guidelines may be too blunt an instrument, how a glucose challenge can sort people into metabolic subtypes, and why she keeps emailing scientists who have never heard of her.

You were on your way to becoming a surgeon. What changed?

In Malawi it is almost certain that when you finish medical school you become a paediatrician, internist or a surgeon, and I had begun to believe surgery may be my calling. But then I started seeing patients who came in for an operation and were too malnourished to have it, so we would have to wait and feed them up. With oesophageal cancer, they come in and they cannot eat, and by the time they are ready for surgery the tumour has grown too much. It was a vicious cycle, and I thought there is something that needs to be done.

You don't study medicine and then go into nutrition, that was not a thing. It was actually looked down on. I was frustrated and a little burnt out, so I took three months at my mom's house and started writing to professors. One didn't reply about four times, but I kept at it, and then he told me there was an opening to help set up a dietetics programme. I thought, dietetics? I don't know what I'll do there, but it's worth a shot. I became the clinical coordinator, the only MD on the team. No doctor writes "see dietitian", because that didn't exist, so I went into every ward to explain what we wanted to do, and it became advocacy as much as teaching. We also had to lobby government to create dietitian posts. Four years later Malawi had clinical dietitians, and I led the team that built the first undergraduate programme.

Is it right that you have twice landed a position by writing to a stranger?

It's the thing I always do. I like to joke that my toxic trait is throwing myself into risky situations. At UCL I came across a paper on the European Prospective Investigation into Cancer cohort and thought, who is this person? I wrote them a very long email and they wrote back. That is how I got my PhD. Then I wrote to Ruth, who did not know me at all. She replied. My first idea didn't fly, and then we came up with the one I'm doing now. Before I joined her, I was doing metabolomics and microbiome, and now I'm doing genomics, which I had never done before. She asked if I could do it and I said yes.

What is the project?

Well, we are trying to get a lot more precise with how we look at diet and health. We keep developing drugs for obesity, but we still don't understand why we keep seeing the rise. We have dietary guidelines that are an umbrella for everybody, and yet in trials comparing low fat and low carbohydrate diets, the average weight loss often comes out the same. Why is that? Because people respond differently to the same food, based on their genes, their metabolism and their lifestyle. There was an Israeli study where they gave people ice cream and sushi. One person's glucose spiked on the sushi and stayed flat on the ice cream. So maybe it is not only about the type of food, but also the type of person.

So, we are asking whether tailoring diets to someone's metabolic profile actually improves their health. Using large population studies, I sort people into metabolic subtypes, partly from genetics and partly from how they respond to a glucose challenge. For some people glucose goes really high after 30 minutes, for others it's a flat line. Then I am testing whether matching a person's diet to their subtype leads to better weight management and lower risk of diabetes and heart disease.

Couldn't we solve most of this by telling people to eat better?

But what is eating better for you and for me? My PhD speaks to that. I looked at food biodiversity, the number of species you eat. Instead of prescribing "please eat a carrot", we tested whether eating more than 80 species a year changes cancer outcomes. When you diversify the species you diversify the gut microbiome, and the metabolism became more anti-obesogenic and anti-inflammatory. That message works across nations. In Malawi we cannot eat the Mediterranean diet, olive oil costs an arm and a leg. But if you tell us species, we cut whatever we have nearby.

What has it been like joining the Loos Group?

I wanted to be mentored, not only to do research but research that gains momentum and makes an impact. One thing that shook me when I got here was the Wednesday meeting. Someone was on their first slide and got so many questions that I thought, I am not going to survive. I'm naturally an introvert, so it takes me time to say what I want to say in a room. I like to digest an idea and bring it out when it's smelling like lilac. Ruth creates an environment where you can just put it out there.

What do you want to do with all of this?

I want to grow into an independent international scientist someday, and push the envelope in precision nutrition.  That is why I am a BRIDGE fellow right now. However, it's still an ambition to contribute to cardiometabolic research in Malawi, and Ruth has been supportive. But I also want to pass it forward. I call myself a clinician scientist, which is not a path you get taught in medical school in Malawi. I graduated at 21, and by 24 I was helping build a programme, so people had faith in me when I didn't know the direction of my career. I hope I can do that for upcoming African scientists rising behind me. But I don't have to be limited to Malawi. I'd like to be an international scientist who came from Malawi and did good things in Malawi, but not only for Malawi.