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Wall Street Journal Best Seller Dr. M's Seven-X Plan for Digestive Health
Differences in gastrointestinal flora between autistic children especially those with severe manifestations and controls has been documented in several studies. Literature also documents lower biodiversity of bacteria in autism and many other chronic disorders depriving the human body of full complement of types of bacteria needed for optimal gut health and immune system.
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Bacterial patterns in autism
- Severely autistic kids tend to have higher numbers of Bacteroidetes bacteria which are Gram negative spore forming organisms. This is associated with a decrease in Firmicutes. Bacteroidetes help in breakdown of large proteins and carbohydrates in the gut lumen. Of these, bacteriodes are opportunistic pathogens.
- Most but not all the data suggest that Clostridia species may be the culprit and as such may not be the sole gastrointestinal factor contributing to pathology.
- Presence of Clostridia spores in the gut can be a constant threat since their overgrowth during vulnerable times can overwhelm the body defenses leading toxic intermediates as well gastrointestinal inflammation harmful to the body.
Desulfovibrio overgrowth in autism and role of antibiotics
- Recent studies suggest that Desulfovibrio species, an anaerobic Gram-negative bacillus, is more prevalent among autistic subjects as compared to healthy controls.
- Patients with regressive type of autism are more likely to have received antibiotic treatment prior to onset of autism behavior. Desulfovibrio is resistant to most commonly used antibiotics and that use could allow these bacteria to flourish freely at the expense of other species which would be diminishing under the killer effect of medications.
- Dr. Peterfreund’s laboratory at the Perelman School of Medicine at the University of Pennsylvania have documented different patterns of ecological succession following antibiotic treatment especially in context of Clostridia.
- Functioning of genes (active or turned off) of gut bacteria change as a reaction to antibiotics or any other potentially toxic substances in gut lumen. This is consistent with argument by Maurice and colleagues who state we need to investigate effects of inter-individual variations in bacterial mixture to better understand bacterial metabolic activity and the unintended consequences of xenobiotics.
Wall Street Journal Best Seller Dr. M's Seven-X Plan for Digestive Health
Is the problem Desulfovibrio or Clostridia?
The data on Desulfovibrio does not negate a potential effect of Clostridia, and they could have a additive or synergistic disease-promoting effects in the bowel.
How could Desulfovibrio contribute to autism?
- Autistic subjects have higher level of bacterial LPS endotoxin that correlates with severity of the autistic signs and symptoms. LPS endotoxin is known to occur in Desulfovibrio species.
- Desulfovibrio competes with the other healthy butyrate-producing bacteria for the lactate leading to production of greater amounts of propionic acid from lactate. Studies in animal models of autism have demonstrated that propionic acid injection in animals can produce autism like manifestations.
- Low grade inflammation caused by the bad bacteria produces proinflammatory chemicals in the body as well as leaky gut. The absorption of potentially harmful substances though the leaky gut as well as proinflammatory chemicals reach the brain causing inflammation in brain and changes in neurochemical signals which lead to abnormal behaviors. There is a direct correlation between levels of bacterial endotoxin in the body and anxiety, depression, as well as diminished cognition and memory.
- Bacteria help detoxify harmful things in gut lumen. Changes in bacteria and damage to gut wall may result in decreased metabolism and increased absorption of potentially bioactive compounds like tyramine, and serotonin that may be present in many foods and can act as neurotransmitters.
- There is a wide range in metabolizing and detoxification capacity for different metabolic pathways across the human based in part based on genetic makeup. Studies have documented an already reduced sulfation capacity in autism. There is thus a decrease in detoxification capacity of the liver to eliminate toxic compounds absorbed through the gut, which normally would have been detoxified in the gut by the bacteria. This is consistent with a decreased sulfation capacity to metabolize acetaminophen (Tylenol )seen in low functioning autism. Same sufation pathways are used for removing excess neurotransmitters from the brain.
- Desulfovibrio in gut may result in increased production of sulfide from sulfate contained in diet which then could bring about structural and functional changes in the gut barrier as well as the gut associated immune system. Hydrogen sulfide is toxic to the gut as well as the genes. Damage to the gut wall by hydrogen sulfide resulting in inflammation can further adversely impact the body’s detoxification mechanisms.
Wall Street Journal Best Seller Dr. M's Seven-X Plan for Digestive Health
Dr. Minocha's comments
- Increased sulfur compounds like hydrogen sulfide due to increased Desulfovibrio in gut coupled with decreased detoxification capacity in liver may be a double whammy causing havoc in a genetically predisposed individual. Targeting this imbalance in gut bacteria offers a potential target for amelioration of clinical manifestations.
- Studies on intestinal bacteria is a moving target and one should not jump to conclusions too quickly. It may not be individual species of bacteria but the bacterial communities that may be more critical in causation of disease. This is underscored by Kang and colleagues who have speculated that Desulfovibrio may actually play a beneficial role in conjunction with Prevotella cluster of bacteria decreased in autism.
Wall Street Journal Best Seller Dr. M's Seven-X Plan for Digestive Health
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