Feast or Fake: Dietary Fats and Artificial Sweeteners as Modulators of Immunity

Julianna Blagih, PhD
Assistant Professor
Centre de Recherche de l'Hôpital Maisonneuve-Rosemont
Department of Obstetrics-Gynecology
Department of Pathology and Cellular Biology
Université de Montréal

This conference is hosted by Javier Di Noia, PhD. This conference is part of the 2025-2026 IRCM conference calendar.

About this conference
Dietary patterns have shifted dramatically over the past century, characterized by increased consumption of ultra-processed foods and diverse nutritional regimens. While it is well recognized that diet influences human health, its precise effects on immune function remain incompletely defined. Among major dietary components, fat represents a particularly controversial nutrient. Although traditionally viewed as detrimental, fats vary structurally and functionally, with medium- and long-chain saturated fatty acids exerting distinct biological effects. Our studies reveal that modulating the type of dietary fat can alter B cell responses and the progression of B cell lymphoma. Conversely, in the pursuit of weight management, the widespread use of artificial sweeteners has introduced novel metabolic cues that may also impact immunity. We found that sucralose modifies CD8⁺ T cell differentiation and impairs their anti-tumour activity, while promoting regulatory T cell expansion and graft tolerance. Together, these findings underscore that dietary components—whether fats or non-nutritive sweeteners—can serve as powerful modulators of immune responses. Depending on the context, such dietary interventions may be therapeutically exploited or detrimental to host immunity.

About Julianna Blagih
Julianna Blagih is an immunologist who completed her PhD with Dr Russell Jones at McGill University, focusing on how nutrient sensors – namely the LKB1-AMPK pathway - and the nutrient microenvironment affect T cell metabolism and function. Julianna then pursued her postdoctoral training in the United Kingdom with Prof Karen Vousden at the Francis Crick Institute in London. During her postdoc, Dr Blagih expanded her expertise in immunometabolism and cancer immunology, notably how common tumour-specific mutations influence the tumour microenvironment and tumour-immune response. Her work later expanded to nutrition and how it can regulate immunity. Specifically, how sweeteners, such as fructose and non-nutritive artificial sweeteners, can act as immunomodulators in innate and adaptive immunity. In 2023 Dr. Blagih joined the Faculty of Medicine at the University of Montreal and the Hôpital Maisonneuve Rosemont Research Centre as an assistant professor. The Blagih lab focuses on how nutrient microenvironments, cellular metabolism, and dietary exposures can impact immune cell function in cancer and inflammatory responses. 

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