For better health
For better health
27 FEBRUARY 2025
Yanyang completed her master’s degree in China focusing on chemosensory science. Recognizing the limited global research on this topic, she moved to the Netherlands to pursue a doctorate and contribute to this important field of study. Her research investigates the complexities of smell loss, a condition that has gained increasing attention due to the COVID-19 pandemic. “Smell loss can have a much greater impact than people think. It not only affects the ability to experience odours but also influences the brain’s structure and function,” Yanyang explains.
Unravelling the mechanisms of smell loss
The primary goal of her research is to better understand the causes and duration of smell loss, and how it corelates with changes in brain. “We aim to examine how the brain responds to smell loss, both in terms of brain functional and structural changes. Many studies focus on either the brain's structure or its neural activity, but we aim to link these two aspects to gain a more comprehensive understanding,” Yanyang says.
Many existing studies fail to differentiate between individuals born with smell loss and those who experience it due to conditions like the flu or COVID-19. This can lead to results that are not applicable to all populations. To address this, the smell and taste centre is focusing on understanding the differences between these groups. A key part of our research is distinguishing between different types of smell loss, such as that caused by colds or COVID-19, head injury and rhinosinusitis. By studying these specific populations, we can gain a clearer understanding of the effects of smell loss caused by different factors.
Over the past 10 years, data have been collected from approximately 1,000 patients in the smell and taste centre, ZGV. This unique dataset allows us to divide the participants based on the different causes of their smell loss, enabling us to examine how each type affects the brain and compare each cause.
Innovative research methods
To conduct this research, Yanyang uses advanced technologies such as structural MRI (Magnetic Resonance Imaging), functional MRI (fMRI) and EEG (Electro Encephalography), combined with a computer-controlled olfactometer to deliver odours to a patient’s nose. “Structural MRI can show changes in the anatomy of the brain, while fMRI measures how the brain responds when someone smells different odours. EEG measures real-time electrical brain activity, offering precise timing information along with advantages such as portability, low cost, non-invasiveness, and therefore better applications in clinical settings,” Yanyang explains. These technologies are crucial not only for mapping brain structure, but also for understanding how the brain processes smells.
Smell loss and eating behaviour
One consequence of smell loss is its impact on eating behaviour and in particular smell loss. “When you lose your sense of smell, you are left with only basic tastes, such as sweet-sour bitter and salty, which makes food less flavourful and enjoyable. This lack of enjoyment can reduce appetite. Moreover, it is possible to lose ones sense of smell, as well as to experience distorted or altered smell perception, in most cases negative, such as smelling garbage instead of coffee. This may have even greater impact on food choices and eating habits and can result in weight loss for some individuals, and weight gain for others. There is no conclusive explanation for this, but we’re aiming to dig deeper into it,” Yanyang mentioned.
Contributions to smell loss treatments
Current treatments for smell loss primarily focuses on smell training. However, Yanyang hopes that her research will lead to more precise diagnostic and therapeutic approaches for treating smell loss. “EEG is a promising tool for measuring brain activity related to smell function. In the future, we may develop a reliable biomarker to help doctors better diagnose and treat smell loss,” she says.
Collaboration and impact
The Nutrition and Healthcare Alliance plays a crucial role in connecting research with practical application by translating research findings into patient care and public health strategies. This connection with clinical practice ensures implementation of research to improve rehabilitation, recovery, and health outcomes. The Alliance’s network brings together experts from various fields, creating opportunities for interdisciplinary research. It also provides researchers the chance to share findings with academic peers as well as with policymakers, guideline developers, and the general public, helping to extend the impact of the research beyond the academic world.
Yanyang’s supervisors are Dr. Sanne Boesveldt en Dr.Paul Smeets, both from the Sensory Science and Eating behaviour group at the Division of Human Nutrition and Health of Wageningen University; as well as ENT doctor Wilbert Boek, Hospital Gelderse Vallei, Wieteke Verhoef-Lubbers and clinical assistants are further supporting this research.
Collaboration with healthcare institutions like the Hospital Gelderse Vallei is crucial to the success of this research. "ZGV provides valuable patient data that helps us understand the impact of smell loss on the brain," emphasizes Yanyang. Additionally, doctors assist by explaining medical terms in patient files.
The future of smell loss research
Yanyang hopes her research will not only contribute to better treatments but also increase awareness about the broader impact of smell loss. “Many people underestimate how smell loss affects their daily lives, but it has a significant impact on the brain and overall well-being also beyond nutrition. I hope my research helps brings attention to this issue and leads to more adapted targeted group treatment options,” she says.
The findings from her study are expected to contribute to the development of new guidelines for diagnosing and treating smell loss and may ultimately pave the way for more personalized patient care.
Upcoming Developments
Although there are no publications yet, Yanyang is working on a systematic review about the relationship between brain function and smell loss. This review, expected to be published in the coming months, aims to advance understanding and guide future research and treatment innovations.
Further reading
