Propionate, A Poison Right Under our Noses

October 06, 2024

Propionic Acid – a Poison Under Our Noses

Ever heard of propionic acid? It fits right before beta=hydroxybutyrate, a 4-carbon organic acid that is the principal ketone made with digesting fat and fermenting green vegetables in our colons. The biome of our colons thrive on beta-hydroxybutyrate, and indeed, it is the main food for the cells lining our colon.

Propionate is one carbon shorter. It is a three-carbon organic acid, also made in the colon at a much lower content. Acetate, another organic acid in the colon is a two-carbon fragment. There you have it. The family of 2,3 and 4-carbon acids, all made in the colon from fermenting complex carbohydrates by the biome of our gut.

Propionate has not been researched as much as the others as it is a “lesser” player. However, it has been shown to lower fatty acids in the liver, increase immune function, decrease appetite, and improve insulin sensitivity. These are all good, yes? There are review articles in the literature that suggest propionic acid plays a key role as a major mediator between nutrition, gut microbiota, and physiology. It sounds like nature has used a natural, 3-carbon acid in a sensible, balanced way. So far, so good.

What happens if we get too much? Propionic acid is a pretty good food preservative, so adding a bit of it to bread products gives you a longer shelf life. It is also naturally present in “Swiss Cheese” as the propionibacteria that help make the carbon dioxide bubbles in Swiss Cheese also make a lot of propionic acid. It is Generally Recognized as Safe (GRAS) in food products. But is it? It is naturally there, after all.

The problem is too much. When added to food products, the amount of propionic acid appears to exceed a threshold in human brains, particularly young ones. Autism has been rising precipitously and many, many mothers will tell you their affected children do much better when taken off bread products.

When human neural stem cells are exposed to propionic acid at levels found in bread and dairy products, the normal differentiation of the stem cells is drastically changed from making neurons to making glial cells. The neurons also didn’t migrate, like they were meant to. This leads to altered brain structure. Oh dear, this is a big problem. Plus, the gut biome was altered. Which comes first? Is it the changing gut biome altering the immune system or the brain that then talks back to the gut?

The Europeans require a ceiling of 3000 mg per kg of propionate. Swiss cheese routinely measures between 3-5000 mg. Bread products also come close to pushing that ceiling. In America, the GRAS certification, (Generally recognized as safe) means bread and wheat product makers can use all the propionate they need to get long shelf lives of their pretzels, hot dog buns, bread, donuts, and pie crusts.

Our modern food supply is heavily dosed with preservatives like propionic acid. Of course, we don’t want moldy, spoiled bread. Maybe we should be doing what the Europeans do, go down to the bread store every day and get fresh bread.

Many of those preservatives, notably propionic acid are labelled as GRAS. They might “appear” to be GRAS is perfectly healthy, adults who have reserve metabolic resources, but they dangerously tip the scale. If they are dangerous for small children, they aren’t much better for older folks. We just haven’t yet learned how to quantify the danger. It’s not a poison per se, but it is a stark example of the dysfunction that occurs when subtle metabolic ratios and balances are altered.

www.What will Work for me? ADHD is autism “light”. Both are on a skyrocketing trajectory. The teeny bit of estrogen in girls over boys is enough to tilt the odds of autism to 3:1 over girls, so this is by and large a boys’ problem. This creates another reason to avoid wheat products. We haven’t had the research yet on adults who can’t lose weight, but it is not surprising to me anymore when I see a weight loss book that includes staying away from wheat. If you have any children or grandchildren who demonstrate the least bit of ADHD, get them off wheat. Maybe if you make it yourself from pure, organic wheat flour, you may be ok. And if it’s bad for kids, it can’t be oh-so-good for you.

References: Progress in NeuroPsychoPharmacology, Foods, Biochem Biophys Acta, Nature Briefing, Foods Sci Biotech, 

Pop Quiz

1. What is propionic acid?                   Answer. A three-carbon acid naturally found in gut digestion as part of the digestion of various food products.

2. Why is it a problem, or a poison?                   Answer: It’s all in the balance and total amount. When added to commonly consumed food products, it increases the total amount, raising the concentration.

3. What do we see in autism in regard to propionate?                   Answer: We find much higher levels in the stool of autistic kids and many improve when taken off of it.

4. Lab research on neuronal stem cells and propionate shows what?                 Answer: dramatic alterations of what cells develop into neurons (like an 80% decrease in quantity) and altered migration, leaving a brain that has structural damage.

5. Besides wheat, what other foods have propionate in them?                        Answer: Cheeses, particularly Swiss or Emmental cheeses.