The wisdom of Donguibogam stating that brain function declines when the liver tires can be explained even more clearly through the modern scientific concept of the gut-liver-brain axis. The liver is the body's most crucial detoxification organ and metabolic center. Everything we eat and drink passes through the liver to be detoxified and metabolized, and if problems arise during this process, it directly affects the brain.
A prime example is ammonia. The liver converts ammonia, a toxic substance generated during protein metabolism, into urea to excrete it from the body. However, when liver function declines, its capacity to detoxify ammonia drops, causing ammonia levels in the blood to rise and enter the brain. Ammonia entering the brain induces neurotransmitter imbalances and interferes with the energy metabolism of brain cells, resulting in cognitive dysfunction such as impaired concentration, memory impairment, and even confusion. This can appear as early symptoms similar to hepatic encephalopathy.
In addition, the liver plays a central role in blood glucose regulation. The brain uses glucose as its primary energy source; if the liver fails to properly regulate blood glucose, the brain either falls into an energy deficit or, conversely, is exposed to excessive glucose and suffers oxidative stress. This blood glucose imbalance can directly impact brain function, becoming a major cause of cognitive decline.
Moreover, the liver is deeply involved in maintaining overall homeostasis, synthesizing precursors of neurotransmitters, regulating hormone metabolism, and coordinating inflammatory responses. When liver function declines, systemic inflammation increases, and this inflammation can cross the blood-brain barrier to trigger neuroinflammation in the brain. Growing research shows that chronic neuroinflammation leads to brain cell damage and dysfunction of neural circuits, serving as a driver of brain fog, chronic fatigue, mood changes, and long-term cognitive decline. As such, the liver and brain are an exquisitely connected system, and liver health is directly linked to brain health.
