Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.

嗅觉，即嗅觉，具有明显的年龄依赖性，因此老年人的嗅觉能力更有可能较差。这些损害被认为大多是不可逆转的，对生活质量和饮食行为具有潜在的深远影响，并构成死亡、认知功能障碍和痴呆的警告信号。在这里，我们回顾了衰老和嗅觉研究的现状，重点关注我们认为与该领域特别相关的五个主题：营养和健康、认知和痴呆、死亡率、环境和遗传学以及基于培训的增强。在每个标题下，我们提供了最先进的概述，并讨论了我们知识中的空白，这些空白可能通过进一步的研究来填补。了解嗅觉能力在衰老过程中如何减弱，以及如何缓解或恢复嗅觉能力，涉及到研究人员在未来几年面临的一系列具有挑战性的任务。