Effects of the Ketogenic Diet on Inflammatory Markers and the Gut Microbiome in Children with Autism Spectrum Disorder

by | Jun 26, 2024 | 2024, Autism, Brain Health, Digestive Health, Infant and Children's Health, Recent Articles

Written by Harold Oster, MD. Results suggest that the ketogenic diet decreases inflammatory markers and has beneficial effects on the gut microbiome in children with autism spectrum disorder.

young smiling boyAutism spectrum disorder is a developmental disorder characterized by repetitive behaviors and deficits in social communication. The etiology of autism is poorly understood but may involve abnormal neuronal growth, neuroinflammation, and environmental factors1. Alterations in the normal gut microbiome have been associated with autism and other neurologic disorders, possibly due to increased inflammation and direct effects on neurotransmitter levels2. MicroRNAs (miRNAs) are small non-coding RNA sequences involved in silencing and activating target genes. Numerous human miRNAs have been linked to disease processes, including cancer and inflammation3. The ketogenic diet, a diet very low in carbohydrates and high in fat and protein, improves the gut microbiome and may have beneficial effects in neurologic disorders, including autism4.

Nina P. Allan et al. studied the effects of the ketogenic diet on the gut microbiome, inflammatory markers, and miRNAs in children with autism. Forty-seven children with autism spectrum disorder were recruited as part of an earlier study that suggested that the ketogenic diet improved behavioral symptoms in children with the condition5. The participants were placed on a ketogenic diet for four months. Adherence to the diet was confirmed by testing urine for ketones twice daily for the first month and once daily for three months. Blood was tested at the beginning and end of the study for interleukins involved in inflammation6, brain-derived neurotrophic factor (BDNF), which is elevated in the serum of children with autism7, and several miRNAs involved in BDNF regulation8,9. Stool samples were tested at the beginning and end of the study for diversity of bacteria and butyrate kinase expression. Butyrate kinase is the enzyme bacteria use to produce butyrate, a marker of a healthy microbiome10.

The authors noted the following:

  • Out of the forty-seven participants, eleven completed both rounds of blood testing, and seven provided both requested stool samples.
  • There was a significant improvement in stool bacterial diversity at the end of the study.
  • Butyrate kinase expression increased after the ketogenic diet.
  • The inflammatory markers, interleukin-1b and interleukin-12p70, decreased after the ketogenic diet.
  • BDNF levels decreased at the end of the study.
  • Levels of three miRNAs associated with BDNF changed after the ketogenic diet: Mi-134 and mi-132 levels decreased, and mi-375 increased.

Results suggest that in children with autism spectrum disorder, the ketogenic diet decreases levels of BDNF and some inflammatory markers and has beneficial effects on the gut microbiome. The ketogenic diet may affect levels of miRNAs involved in BDNF regulation. A limitation of the study is its small sample size.

Source: Allan, Nina P., Brennan Y. Yamamoto, Braden P. Kunihiro, Chandler KL Nunokawa, Noelle C. Rubas, Riley K. Wells, Lesley Umeda et al. “Ketogenic Diet Induced Shifts in the Gut Microbiome Associate with Changes to Inflammatory Cytokines and Brain-Related miRNAs in Children with Autism Spectrum Disorder.” Nutrients 16, no. 10 (2024): 1401.

© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/
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Posted June 26, 2024.

Harold Oster, MD graduated from medical school in Miami, Florida in 1992 and moved to Minnesota in 2004. After more than 25 years of practicing Internal Medicine, he recently retired. Dr. Oster is especially interested in nutrition, weight management, and disease prevention. Visit his website at haroldoster.com.

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