Elena M. Comelli

Lawson Family Chair in Microbiome Nutrition Research

Did you know that we have 10 times more microorganisms living in and on our bodies than the number of our own cells? The largest and most diverse community of microorganisms resides in our intestines and is called the gut microbiome. Because of the microbiome’s importance to almost every aspect of human health, some scientists even consider it an additional organ. Elena M. Comelli, the Lawson Family Chair in Microbiome Nutrition Research (2014 - 2019), explores the complex nature of this community of microorganisms and tries to understand how it can be used to prevent and treat disease.

Our microorganisms serve us in many ways. One of their main functions is to help us digest food. There are some carbohydrates that we simply can’t process on our own — this is where the gut microbiome steps in. The bacteria in our gut break these “tough nutrients” down for us into substances that we can then absorb. The 'army of microbes' in our gut also helps to produce some vitamins, contributes to mineral absorption, and strengthens our immune system. Unfortunately, not all microbes are helpful; however, in healthy bodies, there is a healthful microbiome composition, where the helpful microbes outnumber and reduce the adverse effects of the harmful ones.

Children’s microbiome is particularly important. “When we are born, we do not have this complex community yet,” says Comelli. “As newborns, our guts are practically sterile. But we acquire it very rapidly, in the first two to three years of life. At this age, the structure and the composition of the gut microbiome is almost identical to that of an adult. It will remain very similar for the rest of one’s life. So it is critical that we have the ‘right’ microbiome composition from early age because if things go wrong, we may be stuck with the ‘wrong’ one.”

Comelli is leading a number of studies in the area of microbiome research. She is looking into what is called 'nutritional programming,' or how the mother’s diet during pregnancy and breastfeeding periods impacts the offspring’s microbiome and long-term health. Comelli is also studying probiotics – the bacteria that are considered to be good for us – how they work on the molecular level, and how probiotic supplements to our diet can improve our digestion system and overall health.

Comelli also works with another group of researchers to explore the relationship between guts and bones. Bones in obese people are more fragile, not only because of the excess weight, but also because of the different molecular mechanisms happening during bone formation at a young age. She and her co-investigator try to understand how the gut microbiome affects bone health.

“The microbiome is critical to almost every aspect of human functioning and health,” says Comelli. “Microorganisms in the gut are qualitatively and quantitatively different in healthy and obese children. Our research will help to find out how and when is the right time to modify diets in order to reduce risk and prevent chronic disease.”

Beyond her research, Comelli teaches an undergraduate nutrition microbiology course at the Faculty of Arts & Science and supervises students working in her lab. “I love working with my students,” she says, “the Lawson Centre also provides them with a great opportunity to be exposed to cutting-edge multidisciplinary research in child health and nutrition. This helps to transfer knowledge to the new generation of scientists who will be able to answer the questions we can’t answer now.”

Overall, Comelli says she is fortunate to be part of the Lawson Centre. “I am lucky because my personal mission is aligned with the mission of the Lawson Family Chair in Microbiome Nutrition Research. Our research at the Lawson Centre has strong public health implications. It will help to inform nutritional guidelines. We come up with solutions that are important in clinical practice that will help treat patients and prevent disease. Because of the Lawson Centre’s partnerships with government agencies, industry partners and clinicians, my research can have a much greater impact on improving public health.”

At a glance:

Elena M. Comelli, PhD

Research Interests

  • Relationship between diet, gut microbiota, and health
  • Linking gut microbiota, intestinal barrier, and the metabolic syndrome
  • How the establishment of the gut microbiota in early life may be linked to developing this condition in later life


In the Media


  • Lawson Family Chair in Microbiome Nutrition Research, The Joannah & Brian Lawson Centre for Child Nutrition (2014 - 2019)
  • Associate Professor, Department of Nutritional Sciences, University of Toronto


See Elena’s profile on the Department of Nutritional Sciences website for more information