Extensive research has demonstrated that exercise is good for the body and also for the brain. In particular, and in healthy and neurodegenerative rodent models, endurance exercise (i.e. activities that increase the heart rate and breathing) stimulates the production of biomolecules that play a critical role in the growth and survival of neurons, reduces the imbalance of antioxidants in the body and improves the function of the cell organelles in charge of producing energy. Ketone bodies, which are produced by the liver, represent a source of energy when glucose is not available. They can cross the blood-brain barrier and have similar neuroprotective effects (i.e. support cognitive memory, contribute to learning and the overall brain health) similar to those of exercise. However, it is still unclear what happens when the liver cannot produce them and whether or not exercise can compensate this impairment in ketone production.
In a recent study published in The Journal of Physiology, a team of researchers led by Dr Taylor J. Kelty and Dr R. Scott Rector from the University of Missouri-Columbia (Missouri, USA) investigated the role of hepatic ketone production on brain health in healthy 344 six-month-old female rats. Researchers knocked down the expression of a molecule in charge of the production of ketone bodies. Then, they subjected the rats to either a bout of acute exercise or four weeks of chronic treadmill running (five days/week) followed by cognitive behavioural testing. When ketone production (i.e. ketogenesis) is limited in the liver, there is a noticeable decline in memory and brain function. However, endurance exercise can reverse some of this cognitive decline even when the production of ketone bodies is impaired. These findings emphasise that exercise protects against cognitive decline when hepatic ketogenesis is compromised, establishing a link between liver and brain function. Although more studies are needed in this emerging field of liver-brain research, these findings help raise awareness of the importance of ketone production for brain health and exercise in mitigating liver impairments.