The Role of Macronutrients and Gut Microbiota in Neuroinflammation Post-Traumatic Brain Injury: A Narrative Review

Abstract

Traumatic brain injury (TBI) represents a multifaceted pathological condition resulting from external forces that disrupt neuronal integrity and function. This narrative review explores the intricate relationship between dietary macronutrients, gut microbiota (GM), and neuroinflammation in the TBI. We delineate the dual aspects of TBI: the immediate mechanical damage (primary injury) and the subsequent biological processes (secondary injury) that exacerbate neuronal damage. Dysregulation of the gut-brain axis emerges as a critical factor in the neuroinflammatory response, emphasizing the role of the GM in mediating immune responses. Recent evidence indicates that specific macronutrients, including lipids, proteins, and probiotics, can influence microbiota composition and in turn modulate neuroinflammation. Moreover, specialized dietary interventions may promote resilience against secondary insults and support neurological recovery post-TBI. This review aims to synthesize the current preclinical and clinical evidence on the potential of dietary strategies in mitigating neuroinflammatory pathways, suggesting that targeted nutrition and gut health optimization could serve as promising therapeutic modalities in TBI management.

Keywords: gut microbiota; neuroinflammation; polyunsaturated fatty acids; probiotics; traumatic brain injury.

Figure 1

The gut microbiota undergoes significant changes following traumatic brain injury (TBI), characterized by the depletion of beneficial species such as Lactobacillus gasseri and Eubacterium ventriosum and an increase in potentially harmful species like Marvinbryantia formatexigens and Eubacterium sulci. This dysbiosis may exacerbate systemic inflammation and negatively impact neurological recovery through the gut–brain axis.

Figure 2

The main biochemical actions by the GM-friendly bacteria on the CNS.

Figure 3

The figure demonstrates the influence of the CNS on the gut microbiota and vice versa. It also illustrates the hypothesis of the interconnection between the gut–brain axis and other axes of the microbiota and their influence on homeostasis for the health of the host.

Figure 4

Some probiotic bacteria that influence the function and structure of neurons.