Jan-Åke Gustafsson, professor of medical nutrition and former member of the Nobel Assembly, passed away on 4 September 2026, at 83 years of age.
Jan-Åke Gustafsson received his PhD in 1968, his medical degree in 1971, and was appointed Professor of Medical Nutrition at Karolinska Institutet (KI) in 1979. For nearly three decades, he served as head of the Department of Medical Nutrition, later the Department of Biosciences and Nutrition, and remained fully active at KI until 2008. Thereafter, he divided his time between KI and the University of Houston, where he had been recruited to establish a new research center and where, until this year, he held the Robert A. Welch Professorship in Biology and Biochemistry.
For his outstanding contributions to KI, Jan-Åke Gustafsson was awarded the Grand Silver Medal in 2011.
The professorship in medical nutrition provided the platform for building a large and vibrant research constellation. PhD students, postdoctoral researchers, and senior scientists were recruited from around the world to what developed into an internationally competitive research environment. Jan-Åke Gustafsson himself regarded the world as his workplace.
Embraced new methods and techniques
His long research career came to span broad areas, but with a focus on molecular endocrinology. The opportunities offered by molecular biology were embraced early on, with new methods and technologies playing an important role in driving the research forward. Technologies for generating monoclonal antibodies and transgenic animals came to play a central role in his major research breakthroughs. The emergence of omics technologies and systems biology in the 2000s led to further discoveries. Projects were often pursued with great persistence and frequently through national and international collaborations.
Through systematic and persistent work during the 1970s and 1980s, Jan-Åke Gustafsson's research group succeeded in purifying the receptor for glucocorticoid hormones, enabling detailed studies of the hormone's mechanism of action. The development of antibodies against the receptor enabled the cloning of the receptor in an international collaboration, with the key results published in Nature 1984 and Cell 1986.
The glucocorticoid receptor emerged as a founding member of a newly discovered class of proteins, the nuclear receptors, which function as central regulators of gene expression. Over the following decade, these nuclear receptors became a major field of research, with Jan-Åke Gustafsson as one of its pioneers and leading scientists.
Major discovery concerning oestrogen
In the mid-1990s, curiosity-driven experimental research and the search for entirely new nuclear receptors led to a completely unexpected and groundbreaking finding: the discovery of the second receptor for the sex hormone oestrogen. This was a major discovery of significance for our understanding of the actions of oestrogen, with potential diagnostic and therapeutic opportunities across a range of disease areas.
Over the following decades, Jan-Åke Gustafsson continued to advance the molecular understanding of numerous nuclear receptors and their roles in physiology and disease.
For his scientific achievements, Jan-Åke Gustafsson received prestigious national and international awards, including the Nordic Fernström Prize, as well as honorary doctorates. He was an elected member of the Royal Swedish Academy of Sciences and the Royal Swedish Academy of Engineering Sciences, an International Honorary Member of the American Academy of Arts and Sciences, and a Foreign Associate of the U.S. National Academy of Sciences.
When Jan-Åke Gustafsson moved his KI activities to Huddinge Hospital and Flemingsberg in 1981, he saw great opportunities to create a dynamic environment where research, innovation, entrepreneurship, and industry could interact and contribute to the development of the surrounding community - what today is often referred to as a cluster.
Visionary, entrepreneur, mentor
Many have contributed to the development of Flemingsberg into what it is today, with several universities and higher education institutions, a diverse business sector, and well-developed transport links. Jan-Åke Gustafsson initiated several milestones in its early development, including the creation of Novum Research Park and the establishment of Södertörn University. The Jan-Åke Gustafsson Lecture Hall in the Neo building is a testament to his importance for the development of Campus Flemingsberg.
The business sector is a cornerstone of a dynamic innovation cluster. The nuclear receptors, among which Jan-Åke Gustafsson's research identified new receptors and increased our understanding of them, have properties that make them suitable as drug targets, as they can be activated by small molecules. Against this background, and with a number of patents as a starting point, Jan-Åke Gustafsson became one of the founders of KaroBio AB in 1987.
We remember a forceful scientist and mentor who leaves behind groundbreaking scientific discoveries and generations of doctoral and postdoctoral researchers trained in the research environment he created. We remember a driving visionary and entrepreneur whose ambitions extended far beyond scientific discovery.
He is survived by his wife, Professor Margaret Warner, his son Jan, and grandchildren.
For colleagues and friends at KI: Karin Dahlman-Wright, Eckardt Treuter and Cecilia Williams.
