Occurrence, dietary sources, quantification and bioactivities of natural antioxidant ergothioneine – A longavity vitamin?

Summary This review addresses the knowledge gap surrounding ergothioneine which is a naturally occurring antioxidant, by examining both its beneficial properties and the challenges associated with its study. Ergothioneine, often termed a ‘longevity vitamin’, is present in various foods such as mushrooms, grains and certain animal tissues and is synthesised by specific microorganisms. Despite its recognised potential in promoting healthier and extended lifespans, the mechanisms and full spectrum of its effects remain inadequately understood. This article provides a balanced overview of ergothioneine, covering its prevalence, methods for quantification and a wide range of bioactivities, while its antioxidant capabilities, including the neutralisation of free radicals and reactive oxygen species, highlight its promise for enhancing cellular health and preventing age‐related diseases. In addition to that, this review also discusses the limitations and gaps in current research. Notably, ergothioneine's bioaccumulation in tissues vulnerable to oxidative stress suggests its significant role in longevity. Preliminary studies suggest benefits such as reduced inflammation, protection of mitochondrial function and support for brain health, yet comprehensive studies are required to fully understand its mechanisms. This review aims to present an unbiased and thorough understanding of ergothioneine, emphasising the need for further research to unlock its full potential in human health and ageing.