Gut dysbiosis in autism spectrum disorders

Gut dysbiosis is more common in people with autism spectrum disorders (ASD) and leads to increased production of toxic compounds that alter behavior (Kushak et al., 2017). The term dysbiosis refers to an imbalance in the gut flora with a proliferation of potentially pathogenic microorganisms. How some foods can promote dysbiosis and intestinal inflammation. Some foods can promote dysbiosis and may therefore need to be excluded. Studies show that avoiding gluten and dairy products improves intestinal permeability, reduces inflammation and contributes to a better sense of well-being (Elder et al., 2006; Lau et al., 2013). As a result, the effect of other therapies is better.

Although it may sound strange to many, fecal transplantation is one of the possible procedures to manage gut dysbiosis in autism. Fecal transplantation (FT) has been carried out by man for thousands of years. The first record of its therapeutic use was in one of the oldest medical texts, excavated in an ancient tomb in China, called “Fifty-two treatment formulas”. It is estimated that the document was written in 770 BC and in the book the so-called “yellow soup” was recommended for detoxification.⠀

Since then, research on transferring feces from a healthy donor to a sick person has evolved significantly. The first transplant in Brazil was announced in 2014. Diluted feces can be administered, with medical indication and supervision, using a nasogastric tube (less common) or by colonoscopy (more common). ⠀

The objective is to transfer microorganisms that will restore the balance of the intestinal microbiota. But why not drink kefir, yogurt, kombucha, eat sauerkraut or supplement with a probiotic? What happens is that many people have serious illnesses and cannot wait. As positive results obtained through diet and/or use of probiotic supplements are slow, transplantation is a quick and effective way to modify the unbalanced microbiota.⠀

Transplantation is currently authorized in Brazil only for the treatment of serious intestinal infections caused by Clostridium difficile. Other countries are studying fecal transplantation for several other conditions such as autism.

A systematic review was conducted in 2023 to evaluate the effect of FT in children with ASD. The search identified a total of five studies: two prospective open-label studies, two retrospective observational studies and one case report; however, no randomized controlled trial was identified.

All five studies reported a significant improvement in neuropsychological assessment of ASD after FT treatment. The two prospective open-label studies indicated that Autism Behavior Checklist (ABC) and Social Responsiveness Scale (SRS) scores decreased from baseline at post-treatment assessment.

The two retrospective observational studies suggest that FMT contributes to the improvement of ASD symptoms. One observational study reported that the Childhood Autism Rating Scale (CARS) score and ABC score of the constipation group decreased from baseline after the second course assessment (Zhang et al., 2023).

Safety of the fecal transplant technique

For it to be safe, the donor needs to be healthy. Therefore, it is important to rule out diseases and have good lifestyle habits. A medical and psychologist interview are important. Biochemical tests (blood count, blood glucose, bilirubin, creatinine, liver enzymes) and serology for infectious diseases (HIV, syphilis, hepatitis, COVID) are indicated.

During the physical examination, the doctor will assess weight, BMI, heart and respiratory rate, and blood pressure. If approved in all phases, the donor will deliver 3 stool samples, with a minimum interval of 2 days between them. A genetic sequence of the intestinal microbiome will be carried out to understand the donor’s microbial profile. These precautions aim to guarantee the biological safety of the procedure.

Furthermore, the procedure must be carried out by a qualified professional to avoid intestinal perforation during colonoscopy. Even so, no procedure is completely safe. Therefore, you have to weigh the pros and cons. Do you think in the future the pharma industry will provide fecal capsules for certain conditions? Would you take it or provide for your children?