Gonadal Hormone Status Dictates Neurobehavioral, Metabolic and Immunological Benefits of Ketogenic Diet in Female Mice through Gut-Metabolic-Brain Axis

The ketogenic diet (KD) is recognized for its broad therapeutic potential across metabolic, neurological, immunological, and aging-related domains; however, its efficacy and durability in females remain underexplored. This study investigated the effects of a short-term, intermittent KD on neurobehavioral function, lipid metabolism, immune response, and gut microbiota composition in sham-operated (intact) and ovariectomized (OVX, estrogen-deficient) female mice, aiming to delineate the interactions between diet and gonadal hormones. In sham females, KD reduced circulating estradiol levels and induced low-grade systemic inflammation, without producing measurable behavioral benefits. Conversely, KD exhibited reduced compulsivity, anxiety, and depression-like behaviors with improved well-being in OVX females, suggesting enhanced neurobehavioral resilience under estrogen-deficient conditions. Biochemical analyses revealed KD-induced hyperlipidemia in both groups, although the lipid load was attenuated in OVX mice. KD further decreased low-density lipoprotein cholesterol but led to uremia and histopathological evidence of hepatic steatosis and fibrosis in OVX females, despite unaltered liver function markers. 16S rRNA sequencing revealed hormone-dependent remodelling of the gut microbiota, characterised by distinct compositional shifts between the sham and OVX cohorts. Correlation analyses linked microbial alterations to improved lipid profiles and reduced anxiodepressive behaviors, implicating the gut-metabolic-brain axis in mediating the effects of KD. Collectively, these findings suggest that KD confers neurobehavioral and metabolic benefits in the absence of ovarian hormones but may also pose risks to the liver and kidneys. These results highlight ketogenic nutrition as a potential non-pharmacological strategy to mitigate menopause- and aging-associated neurobehavioral, metabolic, and immune dysfunctions through modulation of the gut microbiota.