Using an innovative approach, an international team of scientists including ethologists, chemists, neuroscientists, anthropologists, and developmental, cognitive, and health psychologists will study the importance of the newborn's sense of smell for the successful initiation and maintenance of breastfeeding. We asked three leading scientists on this new project, Prof. Craig Roberts from the University of Stirling, Prof. Jan Havlíček from the Faculty of Science, Charles University, and Prof. Benoist Schaal from the Centre for Smell, Taste and Food Science in Dijon, about the aims of the new project and its practical applications.
You have known each other for quite some time. When did you start discussing your research topics together?
BS: It is a long story about friendship and sympathies. Our research has a common theme – communication, especially olfactory communication. We each have our specific topics of interest, but we discussed our research with each other.
JH: We met regularly at conferences, some of which we organised together. I think it started at a symposium Chemical Signals in Vertebrates in Cardiff in 2017. Then we organised a Royal Society Meeting in Chicheley in 2019, which was Craig’s idea, and we met on many occasions.
How did you come up with the idea of applying for a grant for this research topic together?
CR: It was at that meeting in Chicheley that we had the first discussion about this project. There was a talk by Jonathan Williams, who is a chemist at the Max Planck Institute in Mainz, Germany. His contribution regarding the online measurement of odour chemistry and how it can change from second to second provided a new solution to the problem of linking real-time changes in behaviour with real-time changes in chemistry. One of the conversations that was going on during that conference was, whether humans have pheromones, which is still a controversial concept.
JH: We must point out that it is Benoist, who has been working on this topic all his academic career since the late 70s. If you come across any major discovery regarding olfaction from this era, Benoist was involved. So, Craig and I became part of the ongoing journey of his research.
CR: Pretty much everybody agrees that the work Benoist is doing is the best prospect for discovering a human pheromone. If there is a human pheromone, it is most likely to be the breast pheromone signalling to babies, because it is a long-standing evolutionary issue. Breastfeeding is common to all mammals and it’s really a matter of life and death, so the selection pressure for such a signal is extremely high. So, this is our story – the confluence of us being together, discussing the idea of human pheromones, realizing that we should probably be focusing on infants, and then the new methodology that was suddenly available to us. This all began to set the scene for this project.
Which game-changing advantages does the new methodology bring?
CR: One of the main aims of this project is to detect the changing breast odour chemistry. In the Dijon maternity hospital, Benoist and his team will measure changes in the odour from one breast as the baby is feeding from the other breast. In collaboration with Jonathan Williams, the main chemist of the project, they will try to identify the chemical compounds responsible for the attraction to the nipple.
BS: This is one of the new exciting aspects of this project. We will have a real-time recording of the changes in the odour from the breast. We should, therefore, see if there is a signal for the baby to locate the nipple. With this new method, which is used by atmospheric chemists, we can follow up to several hundreds of compounds at the same time and track their changes over the breastfeeding period.
Can you please specify the role of the individual teams – Czech, French, and Scottish – within this project?
BS: We have previously had several grants which focused mainly on mammalian models (rabbits, mice, sheep) and their odour communication. We were trying to find the chemical compounds of interest, which could be defined under the concept of pheromones. In 2003, we found it in the rabbit, but this is the only case so far, even though we have some hints in mice. But the focus species for the new project are humans – mothers and their newborn babies.
JH: In the Czech Republic, we will investigate factors that influence the production of chemical signals of the breast and their changes during pregnancy and after birth. We will repeatedly collect samples from the breasts of the mothers.
CR: The Scottish team will be looking at more general aspects of odour management in the relationship between the mother and the baby. We will be looking for barriers and facilitators of odour communication between mothers and babies in different societies around the world. We will describe them and correlate them with differences in what we could call national differences in breastfeeding success, meaning rates of early initiation of breastfeeding.
photo: Magda Křelinová
I know that you also do some behavioural experiments with newborn babies in Dijon. What does that mean? Can you give me an example of such an experiment?
BS: Babies are very sensitive to any stimuli so you can study their orientation toward a familiar and an unfamiliar face, towards sound, and also to different odours. When you present the odour of the mother’s breast and another odour, the babies turn toward the odour of the breast and even try to approach the sample and suck it. So, you can behaviourally test how newborn babies perceive odours. We also study sleeping babies. We present them with odours and record the expressions they make and whether they try to suck at the presented sample or not.
Can you please explain the possible applications of the results you will get throughout this project?
CR: We will be looking for ways to introduce interventions or recommendations to change practice in maternity hospitals. The contextual framework for this project is following the World Health Organization’s recommendations and targets regarding breastfeeding. The three main ones are 1) Latching to the breast should be initiated within one hour after birth, 2) There should be exclusive breastfeeding for the first six months of life, and 3) Breastfeeding should continue up to 2 years of age. We are focusing mainly on the first recommendation because our focus is early initiation of breastfeeding – within the first hours, maybe up to three days. This should have a knock-on effect on the other recommendations as well.
BS: As Craig mentioned, the aspect of early initiation of breastfeeding is a matter of life and death of the baby. When there is a delay to the first breastfeed, it is a huge problem, especially in societies, which are not medically advanced. The mortality of newborns increases steeply with the prolonged initiation of breastfeeding. There is an even bigger problem with premature babies because they have lower motor abilities for sucking. The coordination of sucking, swallowing, and respiration is not optimal in these babies, so it is difficult for them to suck at a breast successfully. If we get access to the compounds emitted from the breast, we would be able to promote a repeated experience with the odour and stimulate the orientation towards the nipple. So, we may be able to reduce the time when the baby is fed exclusively with artificial milk and speed up the initiation of breastfeeding through chemical signalling.
CR: Once we identify the chemical compounds of breast odour, we need to test that these are species-specific odours for all humans. So, we will be extending the work that we do in Dijon to other countries, and we will test the compounds in two representative populations – Japan and Bolivia – that are genetically and culturally different from France.