May 9, 2024 – Autism Spectrum Disorder (ASD), characterized by social and communication difficulties alongside repetitive behaviors, affects a significant proportion of children globally, with particularly high rates in the United States. Recent research has unveiled a potential link between ASD, immune dysfunction, and heightened inflammation levels, with greater severity of symptoms correlating with increased pro-inflammatory cytokines.
Moreover, children with ASD commonly exhibit distinctive T-cell activation patterns and prevalent gastrointestinal issues, suggesting a disrupted gut microbiome. In light of these observations, dietary interventions like the Ketogenic Diet (KD), known to elevate blood ketone levels, have garnered attention for their potential to alleviate symptoms by exerting neuroprotective effects through the gut-brain axis. However, further exploration of the intricate interactions between gut microbiota, ketone bodies, and butyrate is imperative for the development of effective therapeutic strategies.
The Study: Unveiling the Potential of Ketogenic Diet
Conducted at Shriner’s Hospital for Children in Honolulu, the study enlisted participants with ASD. A tailored KD was devised for the participants’ metabolic requirements, incorporating medium-chain triglyceride (MCT) oil and maintaining gluten restrictions. The dietary regimen restricted daily carbohydrate intake to 20-25 grams, with protein adjusted based on weight and age, while additional calories were sourced from fats. Notably, MCT oil constituted 20% of the participants’ energy needs, with caregivers monitoring ketosis levels through urine tests.
Blood samples were meticulously processed to isolate plasma and cells, with plasma stored at -80°C for subsequent analysis. Stool samples were collected using a prescribed protocol, stored in a stabilization solution, and subjected to DNA and RNA extraction. Analytical techniques included polymerase chain reaction (PCR) amplification, sequencing for microbial diversity assessment, and quantitative PCR (qPCR) for gene expression profiling.
Plasma cytokines and brain-derived neurotrophic factor (BDNF) levels were quantified using multiplex immunoassays, while miRNA extraction from plasma samples was facilitated by advanced techniques. The study encompassed an array of miRNAs, including miR-125b-5p, miR-132-3p, miR-134-5p, miR-375, and miR-134-3p, analyzed through qPCR assays.
Key Findings: Unveiling the Impact of Ketogenic Diet
Over the four-month study duration, pre- and post-diet stool and blood samples were analyzed to discern the diet’s effects. Notably, plasma ketone body levels surged significantly, affirming the successful alteration of metabolism induced by the KD.
Sequencing data from stool samples unveiled alterations at the phylum level, accompanied by a notable increase in microbial diversity. Beneficial bacteria, including Lactobacillales, experienced significant upsurges, contrasting with declines observed in taxa like Bacteroidaceae and Ruminococcus.
Moreover, individuals adhering to the KD showcased reduced pro-inflammatory cytokine levels, with interleukin 1β (IL-1β) and IL-12p70 levels exhibiting significant decreases. Although the anti-inflammatory cytokine IL-10 demonstrated an uptick, statistical significance eluded due to the study’s limited sample size. Additionally, a substantial reduction in plasma BDNF levels, a protein implicated in neuroinflammation and ASD, was evident.
Noteworthy alterations were observed in miRNA levels, particularly reductions in miR-134 and miR-132, both associated with BDNF activity in the brain. Conversely, miR-375 levels exhibited a significant increase, while miR-125b levels remained unchanged.
Conclusions: Pioneering Insights into Ketogenic Diet’s Therapeutic Potential
The study’s findings underscore the evolving understanding of the Ketogenic Diet’s therapeutic potential for ASD. Beyond prior associations with improved social interactions attributed to elevated ketone body levels, the study elucidates broader impacts of the KD. Noteworthy alterations in gut microbiome composition, inflammation levels, and circulating miRNAs linked to BDNF suggest a multifaceted mechanism underlying the diet’s efficacy.
These findings align with existing research, suggesting that the Ketogenic Diet may ameliorate social behavior in ASD by mitigating brain inflammation, enhancing metabolic pathways, and fostering gut health. As investigations into the KD’s therapeutic landscape progress, these insights offer promise for refining therapeutic approaches and enhancing outcomes for individuals with ASD.