By Anil Minocha MD, author: Guide to Alternative Medicine and the Digestive System
Short chain fatty acids (SCFA)
- Propionic acid or propionate, acetate and butyrate are predominant short chain fatty acids in the body. produced as a result of fermentation of undigested carbohydrates by intestinal bacteria.
- SCFAs are involved in satiety and obesity
- High levels of bacteria like clostridia produce high levels of propionate which has been implicated in neurodevelopmental disorders like autism.
Background facts about gut and autism
- Patients with autism have impaired carbohydrate digestion and absorption.
- Some studies suggest that GI symptoms correlate with severity of autistic symptoms in patients and this is associated with alterations in intestinal bacteria
How may short chain fatty acids (SCFAs) play role in Autism
Short chain fatty acids perform numerous diverse functions in the body that have potential to play role in pathogesesis of autism (ASD)
- Alter several neutransmitters including glutamate, dopamine, norepinephrine
- Affect brain signaling and transmission in nerves affecting behavior
- Affect mitochondria (cellular respiration)
- Modulate expression of genes in the body
- Suppress appetite and feel filled up early
- Aversion internal cues making kids picky eaters
Major sources of short chain fatty acids
- Carbohydrates in diet
- Food preservatives
Short chain fatty acids from and bacterial fermentation of undigested carbohydrates
- Undigested carbohydrates are acted upon by bacteria. Bacterial fermentation reseults in formation of short chain acids that are then absorbed into the body.
- The type of SCFA (acetate, butyrate or propionate) depends in part on the type of bacteria in the gut.
Propionic acid or propionate in food
- Propionic acid is contained in many food preservatives. Calcium propionate is FDA approved food preservative widely used in wheat, bread, cheese, juices, as well as dried fruit.
- Propionic acid in food represents only a small fraction of what is encountered in gut as a result of bacterial metabolism.
- Absorbed prioinic acid once absorbed into the blood circulation crosses the blood brain barrier and enters the brain where it can exert its affects.
Propionic acid or propionate in healthy kids
- Consumption of large amounts of propionate makes kids irritable, inattentive, and restless associated with sleep problems [Dengate 2002]
Propionic acid in autistic kids
- Anecdotal reports suggest that some kids with autism may suffer worsening of symptoms on consuming processed foods like wheat or diary containing propionate as food preservative.
Propionic acid in animals
- Propoinate injection in rats into brain directly or into abdomen leads to developmental and cognitive and social impairments. The brain in such rats shows inflammation also.
- Propionic acid suppresses appetite in animals as well as probably humans [ Liljeberg 1995].
- Sodium propionate induces aversion internal cues as well as early satiety in sheep.
- Sodium propionate is widely used in farm feeds.
Dr. Minocha’s comments
- Data on role of propionate in human autism is indirect and preliminary.
- A low FODMAP diet may lower the amount of short chain fatty acids in the gut and may help some patients. Of note, low FODMAP diet has been shown to be helpful in irritable bowel syndrome.
- A drawback of low FODMAP diet is that it lowers the prebiotic component of the diet.
- Always be sure to talk to your doctor before making any significant changes in diet or medications.