‘Relevant research requires a wide perspective and confidence in one’s own expertise’

Dick Heederik will retire in December 2025. He was appointed Professor of Health Risk Analysis at the Institute for Risk Assessment Sciences (IRAS) at Utrecht University in 2002 and has since held numerous other roles, including chairman of the board of the National Expertise Centre for Substance-Related Occupational Diseases (Lexces) and chair of the advisory committee on Occupational Diseases of the Ministry of Social Affairs and Employment. On 9 December 2025, he will deliver his farewell lecture, “The nitrogen crisis: lessons from the antibiotics dossier”, together with Hans Kromhout, who will also be stepping down.

How do you look back on your professorship?

“First of all, it was a great honour, an appointment that came with considerable responsibility. In my work, I placed strong emphasis on the interconnectedness of humans, animals and the environment. This led to education and research on antimicrobial resistance in animals, transmission to humans and associated health risks. But it also extended to livestock farming and the health of nearby residents, for example in relation to Q fever and chronic respiratory diseases such as asthma and COPD.

Later, research on nitrogen emissions in livestock farming was added. This is a fascinating issue that has affected the entire country (the Netherlands). Through the Foodvalley Regional Deal, we are trying to help move processes forward with solid scientific input. These projects have all fostered collaborations within and beyond the Faculty of Veterinary Medicine, with researchers such as Jaap Wagenaar, Dik Mevius, Mirjam Nielen, Arjan Stegeman and Marc Bonten.”

Which research project has had the greatest impact?

“Several projects have had substantial impact, each in its own way. Our work on antimicrobial resistance contributed to the establishment of the Netherlands Veterinary Medicines Institute. I was invited to join the expert panel and later succeeded Dik Mevius as chair: a challenging but meaningful role. Together with all stakeholders, we achieved more than a 70 per cent reduction in antibiotic use. The livestock sector now also uses far fewer substances deemed critical for human health.

What makes these results particularly notable is that they were achieved without extensive new government regulation. The government set broad objectives, an expert panel translated these into concrete targets for sectors and individual farms, and antibiotic use was transparently monitored and reviewed. But the true breakthrough came when veterinarians and livestock farmers themselves implemented the measures that ultimately led to this sharp reduction.

Our research on livestock farming and the health of local residents led to a Health Council recommendation, published just this week. And our work on nitrogen emissions is still ongoing. I am pleased that we secured another major grant that will allow a strong team to continue this line of research. I have full confidence in the future.”

I recognise the same outward-looking mindset in the current generation of IRAS professors

What are the biggest challenges ahead?

“Throughout my career, I have tried to build bridges between the health of people, animals and the environment. I trust that my successors will continue this approach. IRAS is uniquely positioned: its research sits at the crossroads of multiple faculties and universities, and the challenges of the future demand this interdisciplinary collaboration. I recognise the same outward-looking mindset in the current generation of IRAS professors.

As Vice-Dean of Research, I have also tried to stimulate collaboration. The Faculty of Veterinary Medicine, being one of a kind, can sometimes appear closed, while openness is essential, also for veterinary research in the broadest sense. I have seen how this mindset has led to new projects and partnerships across research groups. Relevant research requires a wide perspective and confidence in one’s own expertise.”

With the knowledge you have now, what would you have done differently?

“That is a difficult question. I am immensely proud of my students and PhD candidates, who have found their path both in the Netherlands and abroad and who have translated the IRAS approach into new (international) collaborations. I look back on a very meaningful and fulfilling career, and I am grateful to the university for the trust it has placed in me over the past decades.”