Popular sports supplement protects the brain from inflammation

The popular sports supplement creatine prevented brain inflammation, nerve cell damage, and disruption of electrical activity in the hippocampus of rats with chronic colitis. The results of the study were published in the scientific journal Brain, Behavior, and Immunity.

Spanish scientists from the University of Seville studied the "gut-brain" axis — a bidirectional communication network between the digestive tract and the central nervous system. In inflammatory bowel diseases, inflammatory signals from the gut can reach the brain and trigger secondary inflammation there, which is associated with mood disorders and cognitive problems in patients.

The researchers used young rats of both sexes, dividing them into four groups: healthy, healthy with creatine, with colitis, and with colitis on creatine. Colitis was induced by dextran sodium sulfate in drinking water over three weekly cycles with breaks — this mimicked the flare-ups and remissions of ulcerative colitis in humans. Creatine was added to the water at a dose of 1 g per kg of body weight, starting 10 days before colitis induction.

After one month, the scientists examined the rats' hippocampus: they measured levels of inflammatory molecules, assessed the physical condition of neurons, and tested the electrical properties of the cells.

Chronic colitis reduced creatine levels in the hippocampus of rats of both sexes. Intestinal inflammation also triggered a strong immune response in the brain: microglia — the brain's first line of immune defense — became activated, and levels of inflammatory molecules increased.

The consequences differed by sex. Males developed physical damage to hippocampal neurons: loss of structural proteins and a reduction in the number of neurons in the CA1 region. In females, neuronal structure was preserved despite the inflammation. Electrical tests showed a similar divide: in males with colitis, neuronal membranes became "leaky," and the minimum current required to trigger a signal increased by approximately 60%. In females, no significant electrical changes were observed.

Creatine largely prevented these changes. In rats with colitis that received the supplement, creatine levels in the hippocampus were 20–30% higher than in those that did not receive it, and corresponded to the levels of healthy animals. The supplement prevented microglial activation and the rise of inflammatory molecules in both sexes. In males, creatine protected the structural health of neurons and maintained normal electrical resistance and excitation thresholds.

"The changes were not limited to a single marker. We found converging evidence of neuroinflammation, neuronal damage, and altered electrical properties of hippocampal neurons, particularly in males," says study co-author María D. Vázquez-Carretero.

The authors caution that the results cannot be directly extrapolated to humans.