June 26, 2020, by Lexi Earl
Understanding micronutrient deficiencies for better health: an interview with Dr Molly Muleya
Molly Muleya is a postdoctoral researcher on the Future Protein’s Platform. Molly’s research examines the protein and mineral digestibility from foods of dietary and planetary importance. Her research is at the interface of agriculture, food science, nutrition and health and seeks to understand factors across the food chain, that modify protein and mineral bioavailability of foods. Before joining the Future Food Beacon, she was an IMMANA fellow at the University of Nottingham and she completed her PhD in Food Science and Nutrition at the University of Ghent in Belgium.
Tell me about your research?
I work at the interface of agriculture, food science, nutrition and health. I’m interested in food security issues, mainly pertaining to mineral micronutrient deficiencies. About 1/3 of the global population suffer from one form of mineral deficiencies, of which iron and zinc are the most prevalent. One of the reasons for this is because many people, particularly from low-income countries, subsist on monotonous cereal staple foods. These staple foods have low concentrations of bioaccessible iron and zinc. That means that the proportion of minerals that can be potentially absorbed from the cereals is pretty low and this is mainly due to the presence of mineral binding compounds which restrict their digestibility. A lot of my work focused on the digestibility and/or bioaccessibility of iron and zinc in these staple crops. I am particularly interested in how certain processes employed along the food production chain can modify the mineral bioaccessibility of crops.
What kind of crops make up staple crops?
My focus has been on maize because maize is consumed by millions of people in sub-Saharan Africa, including Zimbabwe where I come from, and by people on other continents. I have extended this work to sorghum and millets too. In Zimbabwe, sorghum and millets used to be the staple foods before maize came into the picture in the 1920’s. There is now more maize consumption than sorghum and millets. However, a lot of evidence now suggests millets are probably nutritionally superior to maize, so they are rapidly re-emerging into food supply chains and more and more people are adopting them in their diets.
How did you become interested in this area of research?
I’ve always been interested in food and nutrition security. I grew up in a high density suburb in Zimbabwe where food security issues were real. I noticed there was always lots of food during the harvest season, followed by massive scarcity in the dry season. This was because of post-harvest losses due to lack of processing or preservation know-how. In addition, under-nutrition in children was prevalent and I became really interested in understanding some of the reasons for this. That is how I became interested in food science and nutrition. I went to do a Masters in Food Technology in Belgium, as I wanted to learn about the processing aspect of food in particular; how to add value to underutilised food ingredients in Zimbabwe. After my masters, the Zimbabwean government had just finished a micronutrient survey, and that survey revealed that about 30% of children under the age of 5 years were stunted. Stunting is a good indicator of zinc deficiency. And more than 50% of children were iron deficient. That spoke a lot to me, so I decided to pursue a PhD examining the iron and zinc bioaccessibility of cereal crops – these are the major suppliers of dietary iron and zinc for vulnerable populations. My PhD research focused on food based strategies to improve bioaccessibility of iron and zinc in maize, sorghum and millet porridges typically consumed by children in Zimbabwe. Most people affected by mineral deficiencies are small-holder farmers who grow food on their own farms and do their own processing. The entire food chain, from farm to fork, is experienced on the farms, so I was keen to find household based processing solutions that are affordable, feasible and acceptable. I explored the potential of household cooking methods such as fermentation and food-to food fortification to modify the iron and zinc bioaccessibility of cereal porridges. The microorganisms produced during fermentation can produce important enzymes that can allow more iron and zinc to be released from the food matrix. Food-to-food fortification entails the fortification of foods with other food ingredients that have been identified to have high mineral concentrations or to have properties that can improve bioaccessibility. I looked at the potential of indigenous forest foods, like baobab fruit pulp which contains a high concentration of vitamin C and also edible insects like mopane worms.
How did you become interested in science and scientific processes?
There are things that we have always known, through traditional knowledge in Zimbabwe, but people didn’t really know how to explain them. That is how I became interested in science, I wanted to scientifically validate some of the traditional knowledge about our indigenous foods, and be able to explain to people what we are doing, why we are doing it, how that might improve nutrition, and ultimately achieve food security for all.
After your PhD, what did you do?
I was fortunate to be awarded a fellowship from IMMANA, (Innovative Methods and Metrics for Agriculture and Nutrition Actions) funded by the UK’s Department for International Research. The aim of the fellowship is to train and empower emerging leaders in agriculture and nutrition linkages. At the end of my PhD, I realised that the food processing step was a good way to add value to our staple foods, but the level of minerals in our staple crops were inherently low, and that is probably because of the agricultural aspect. So I wanted to focus on this aspect because agriculture is the key entry point for minerals into the food system. I joined Liz Bailey and Martin Broadley who were already working in that area. I investigated the effect of agronomic biofortification on mineral bioaccessibility of cereals and legumes. For example, I looked at how selenium fertilization could enhance selenium concentrations and bioaccessibility in major cereals and legumes in Malawi. I also examined how nitrogen based fertilizers amended with iron and zinc could modify iron and zinc bioaccessibility of major cereals and legumes grown in Zimbabwe. After the IMMANA fellowship, I got the opportunity to join the Future Proteins project.
Tell me about working on Future Proteins?
I am working on the digestibility of future proteins, particularly those underutilised proteins from plants, insect protein and new proteins that might be produced from bacteria, algae and fungi. Developed countries rely a lot on animal-based proteins, and it is predicted that as income rises in low-income countries, more people will also shift to animal-based proteins. However, the environmental degradation associated with animal production along with some negative health effects means that there is an urgent need to find other sources of protein. The digestibility of these alternative proteins underpins their success. They must be digestible – after consuming them, we must be able to absorb key amino acids that are required for optimal health. Replacing animal protein with alternative sources of protein, could cause unintended effects of more mineral deficiencies because animal protein is a very good source of bioavailable iron and zinc. So alternative sources of protein must also be good sources of bioavailable iron and zinc. The work that I did during my PhD and IMMANA fellowship really fits in together with the work we want to do now in the Future Proteins Platform.
It seems a bit different to jump from minerals to proteins but proteins and minerals are connected. The type of compounds that restrict protein digestibility also do the same for minerals. It is a good opportunity for me to look at the two aspects at the same time. Most people who are vulnerable to mineral deficiencies rely on plant and/or under-utilized protein, so having the opportunity to study both the protein and mineral digestibility of future protein is like killing two birds with one stone.
I am working within a multidisciplinary team including soil scientists, plant nutritionists, and human nutritionists, so it has been highly stimulating and I am looking forward to some fantastic research in the future.
Do you have a greatest career moment?
That is quite difficult! I’m not sure if I have reached the greatest career moment yet. I think I’ve had great career moments, I’m looking forward to more great moments. When I finished my PhD, I felt that level of accomplishment – I did this and I’ve contributed to science! Then when I got the IMMANA fellowship, that was a proud moment for me because that fellowship is only awarded to five people globally for each cohort. It affirmed that the work I am doing is important, and is making an impact in the world. I look forward to achieving more great things, especially now with the Future Food Beacon. The availability of cutting-edge equipment and high level of cooperation with other researchers means that the sky is the limit!
Is research impact important to you?
Of course! All the work that I am doing is really work I can share with an ordinary person, and they understand. If I tell someone that I work in the field of food science and nutrition, they always ask, ‘what kind of diet should I be on?’, ‘is this type of food healthy for me or not?’ And so on….It is something we talk about almost every day. It is real and tangible to many people. It is something that people are asking more and more every day. It has an immediate impact to the ordinary person.
How do you translate your lab work into real world applicability?
With the work that I did in Zimbabwe, it was easy to translate it to the public domain because I was working with rural communities and I established learning centres where I could go and share evidence from the samples they had provided for research. Those learning meetings became routine. Publishing papers is important, that is part of sharing what I am doing with the rest of the scientific community and also engaging with the general public, industry people and policy makers.
Do you have any advice for any potential new scientists?
I think it is about pursuing what you really love. I’ve always wanted to do a PhD, but I focused on doing something that spoke to my heart. I identified the people who were pushing boundaries in that kind of research and could help me to advance my career. My advice for someone who wants to pursue a PhD would be to really know what they love, and aggressively seek opportunities to pursue that with leaders within that field. Don’t be afraid to knock on important doors.