Autism- A Closer Look

Among the many reasons that some parents refuse to vaccinate their children, the most prevalent is the mistaken connection with autism. 

The subject of Autism Spectrum Disorder (ASD) is a complex one. Many questions have arisen in recent years:

- is autism truly on the rise, or is there simply a growing awareness of the condition?

- if it is actually on the rise, is that due to the definition of autism being expanded?

and obviously, what is causing it?

An Overview

WebMD recently published a comprehensive report written by KathleenDoheny and reviewed by Louise Chang,MD, which attempted to answer these questions.

“The number of children diagnosed with autism or related disorders has grown at what many call an alarming rate. In the 1970s and 1980s, about one out of every 2,000 children had autism. Today, the CDC estimates that one in 150 8-year-olds in the U.S. has an autism spectrum disorder, or ASD. This expanded definition refers not only to autism but also to a collection of brain development disorders such as Asperger's syndrome and a condition known as pervasive developmental disorder -- not otherwise specified (PDD-NOS). Though all the disorders share some symptoms, they are different in other ways, including the timeline of symptoms and the severity, according to the CDC.

“‘The debate about whether the reported increase in autism is affected by factors such as more awareness misses the point’, says Isaac Pessah, PhD, a professor of toxicology, director of the Center for Children's Environmental Health Sciences, and a member of the MIND Institute at the University of California Davis. Rather than argue about whether the increase is because of some children being reclassified or other factors, he says, ‘We need to understand why it's one in 150.’”

“'There won't be one single explanation,’' says Marvin Natowicz, MD, PhD, a medical geneticist and vice chairman of the Genomic Medicine Institute at the Cleveland Clinic. ‘There's been a lot of progress in the last few years in terms of understanding the causes of autism, We know a lot more than we did.’ Still, he says, research has a long way to go. ‘One number you see often is that about 10% of those with autism have a definitive diagnosis, a causative condition.’ The other 90% of cases are still a puzzle to the experts.

“Often, a child with autism will have a co-existing problem, such as a seizure disorder, depression, anxiety, or gastrointestinal or other health problems. At least 60 different disorders -- genetic, metabolic, and neurologic -- have been associated with autism, according to a report published in The New England Journal of Medicine. On one point most agree: A combination of genetics and environmental factors may play a role. Scientists are looking at both areas.

“A variety of environmental triggers is under investigation as a cause or contributing factor to the development of ASD, especially in a genetically vulnerable child. Exposure to pesticides during pregnancy may boost risk. In a study published in Environmental Health Perspectives,researchers compared 465 children diagnosed with ASD with nearly 7,000 children without the diagnosis, noting whether the mothers lived near agricultural areas using pesticides. The risk of having ASD increased with the poundage of pesticides applied and with the proximity of the women's homes to the fields.

“Another toxin to the brain is mercury in its organic form. But according to a report published in Pediatrics, there is no evidence that children with autism in the U.S. have increased mercury concentrations or environmental exposures. Though many parents of children with ASD believe their child's condition was caused by vaccines that used to contain thimerosal (a mercury-containing preservative), the Institute of Medicine concludes there is no causal association.

“Pessah and other researchers are focusing on how the interaction of genes and the environment play a role in autism. Among the findings so far, he says, is that the immune system functioning of the mother may play a role in the child's later development of autism.

“In another study, the UC Davis team found that levels of leptin, a hormone that plays a role in metabolism and weight, was much higher in children with autism than in normally developing children, especially if their autism was early in onset.

“Even if some environmental exposures or other findings do stand out, he says, we are going to have to resist the temptation to say, 'This is it’, Newschaffer says. Natowitz of Cleveland Clinic agrees. ‘There won't be one single explanation.’"

The Importance of “Good” Gut Bacteria

The gastrointestinal connection to autism appears over and over in the literature. The importance of a proper balance and quantity of “good” gut bacteria in the intestines of children is thought to be an important factor. 

In an article in Autism Speaks in July of 2013, an important study was discussed:

“The study appears today in the journal PLOS ONE. Rosa Krajmalnik-Brown and Jin Gyoon Park, of Arizona State University’s Biodesign Institute, led the investigation.

Researchers using high-tech DNA analysis found that children with autism have fewer kinds of intestinal bacteria than do children without autism. However, this reduced “biodiversity” did not relate to the severity of gastrointestinal problems.

“Among children with autism, GI problems such as constipation and gut pain are common. Some have suspected that imbalances in intestinal bacterial are to blame. Other research has suggested that problematic gut bacteria might contribute to autism symptoms by triggering inflammation that reaches the brain. Considerable research has shown that intestinal bacteria play important roles in both digestion and regulation of the immune system in all persons.

“The researchers found significantly decreased microbial diversity (fewer types of bacteria) in the children with autism. However, they were  surprised to find no link between this lowered diversity and the severity of GI symptoms. Nor did they find links to differences in the children’s diets. Among the types of bacteria reduced in those with autism, Prevotella was the most conspicuous. It occurred only in very low levels in the children with autism. By contrast, it was common in those not affected by autism – who altogether had more diverse and robust communities of intestinal bacteria.”

Then, on Oct 22, 2014, Autism Speaks announced that they had “selected two major research projects – one focused on intestinal bacteria, the other on chronic constipation – to advance understanding of autism’s gut-brain connection. Funding for the studies, each spanning three years, will total more than $2.3 million.

“‘Listening to our parents, we hear how often autism and GI problems can go hand in hand,’  says Autism Speaks Chief Science Officer Rob Ring. ‘While we now know that autism and gastrointestinal problems frequently co-occur, improving our understanding of the underlying biology becomes essential for developing needed treatments.’”

Are Antibiotics Altering Gut Bacteria?

Might the indiscriminate use of antibiotics be a reason for the lack of quantity and diversity of the gut bacteria? James B. Adams of Arizona State University was part of a team of researchers that addressed this and other issues. The study was published in BioMed Central in March of 2011. Excerpts from the report:

“… a study by our group of 51 children with ASD compared to 40 typical controls ages 3-15 found that 63% of children with autism were reported to have moderate or severe chronic diarrhea and/or constipation, vs. 2% of the control children. In summary, these studies demonstrate that GI symptoms are common in autism.

“The cause of these GI problems is unclear, but it appears to partly relate to abnormal gut flora and possibly to the excessive use of oral antibiotics which can alter gut flora. Several studies by our group and others have reported significantly higher oral antibiotic use in children with autism vs. typical children. 

“Oral antibiotics were primarily used for treating otitis media (ear infections), which may suggest an impaired immune system. Commonly used oral antibiotics eliminate almost all of the normal gut microbiota, which play an important role in the breakdown of plant polysaccharides, promoting gastrointestinal motility, maintaining water balance, producing some vitamins, and competing against pathogenic bacteria. Loss of normal gut flora can result in the overgrowth of pathogenic flora, which can in turn cause constipation and other problems.” 

The Role of Glyphosate (Roundup) in Altering Gut Bacteria

If the gut bacteria/autism link can be accepted as at least likely, then any agent, including antibiotics, that alters gut bacteria should be examined more closely. 

The subject of genetically modified organisms (GMO) warrants an extensive commentary of its own. But due to their potential for adversely affecting the balance of gut bacteria, I believe that an overview is in order. 

The active ingredient in Roundup, a Monsanto herbicide, is glyphosate. In brief, glyphosate kills plants by interfering with the shikimate pathway in plants, by inhibiting the enzyme EPSP. Genetically modified crops are designed to overcome that inhibition. 

The shikimate pathway is a seven step metabolic route used by bacteria, fungi, algae, parasites, and plants for the biosynthesis of aromatic amino acids (phenylalanine, tyrosine, and tryptophan). This pathway is not found in animals; therefore, phenylalanine and tryptophan represent essential amino acids that must be obtained from the animal's diet.

Monsanto’s basis for its safety claims for Roundup is that the shikimate pathway does not exist in animals and humans. But since it does exist in bacteria, it matters if their various forms are affected differently. Unfortunately the beneficial ones such as the forms of enterococcus, bifidobacterium and lactobacillus are susceptible to glyphosate. Pathogenic bacteria such as the various forms of salmonella and clostridium are highly resistant. This leads to an inevitable imbalance of gut bacteria, thereby contributing to the GI problems suspected of being a cause of autism.

Experts in the field of ASD research are clear that there are many possible causes for autism, but one of them is not vaccinations. Vaccines have not contained mercury since 1999, and many such as MMR, Polio, and HPV (Gardasil) never contained it. They also realize that there is probably not one clear answer, and much more research needs to be done.

Concerned parents, whether or not they have children with autism, need to beware of the effects of antibiotics. They would do well to research the subject of gut bacteria. Probiotics show promise, and may eventually prove to be a viable option for treatment.

D. Norman