Many have attributed increased weight and diabetes incorrectly to gluten, as I illustrated with the science in my book on the topic. Research is now confirming that propionate, a common preservative added to commercial breads and other wheat-based foods, alters hormones linked to weight gain and insulin resistance.
Propionates such as calcium propionate are common additives in many commercial breads, pastas, crackers, cookies and other wheat-based foods. These are used to prevent mold and other microbial forms of spoilage. This is a good thing, right?
Not so fast. In my book, The Gluten Cure,
Researchers from Harvard University released 2019 research1 that first tested mice, and then humans with propionate.
The medical scientists fed populations of mice with diets that contained amounts of propionate equivalent to what humans would eat in their breads. The researchers found the mice with the propionate in their diets became obese and suffered from insulin resistance.
Seeing this clear trend among the mice, even with such small amounts of propionate, the researchers set out to see if humans would have the same metabolic responses.
The Harvard researchers tested 14 people. They were split into two groups. One group ate a meal that contained one gram (very small) of propionate. The other group ate a similar meal but without the added propionate. They preceded and followed the meal with metabolic and blood testing in both groups.
Those who ate the meal with the propionate had significant increases in a hormone called norepinephrine just after eating the meal compared to the other group. At the same time, they also experienced increased levels of glucagons and a hormone called fatty acid-binding protein 4 (FABP4).
FABP4 is a hormone involved in the production of glucose from fats and proteins.
These metabolic changes indicated to the researchers that propionate is a “metabolic disruptor,” which can boost the risk of obesity and diabetes.
Dr. Amir Tirosh, a professor of medicine at Tel-Aviv University medical school is also a research fellow at Harvard Chan School. According to Dr. Tirosh:
“The dramatic increase in the incidence of obesity and diabetes over the past 50 years suggests the involvement of contributing environmental and dietary factors. One such factor that warrants attention is the ingredients in common foods. We are exposed to hundreds of these chemicals on a daily basis, and most have not been tested in detail for their potential long-term metabolic effects,”
Indeed, nearly half a billion people suffer from diabetes around the world. This is expected to increase by 40 percent by the year 2040. What is causing this?
Other research has found that probiotics reduce the risk of diabetes and glucose problems. Other research finds probiotics help prevent type-2 diabetes.
Meanwhile, another batch of research has pointed to propionates causing behavioral issues and intestinal issues in children.
For example, a 2002 study from Australia2 tested 27 children with prior behavioral issues. Their behavioral issues had lessened after a change to the Royal Prince Alfred Hospital diet, which excludes food additives including salicylates, amines and glutamates.
The researchers then challenged the children with calcium propionate. This caused a worsening of their behaviors in 52 percent of the children. They had increased levels of irritability, restlessness, inattention and sleep disturbance according to the researchers.
Yes, propionate is typically produced from natural sources, notably certain yeasts and bacteria that produce it to fight off other microorganisms.
But this doesn’t mean that it is necessarily healthy as a common food additive. For example, a 2014 study exposed calcium propionate to human blood cells (lymphocytes).3 They found that the propionate produced genetic changes in the blood cells, which they described as “genotoxic.”
Three other food preservatives were also tested. They also produced genotoxic effects on the blood cells.
There are healthy alternatives to propionates. A 2008 study tested the calcium propionate against the healthy probiotic Lactobacillus plantarum4 as a preservative in bread loaves. The researchers found the Lactobacillus probiotic was as effective as the propionate in preventing spoilage.
I should note that a number of bread brands don’t contain preservatives. While they may not have the same shelf life, they can simply be refrigerated to lengthen the bread’s storage life. And let’s not forget homemade bread. Yum.
1. Amir Tirosh, Ediz S. Calay, Gurol Tuncman, Kathryn C. Claiborn, Karen E. Inouye, et al. The short-chain fatty acid propionate increases glucagon and FABP4 production, impairing insulin action in mice and humans. 24 April 2019. Science Translational Medicine Volume 11 Issue 489
2. Dengate S, Ruben A. Controlled trial of cumulative behavioural effects of a common bread preservative. J Paediatr Child Health. 2002 Aug;38(4):373-6.
3. Yilmaz S, Unal F, Yüzbaşıoğlu D, Celik M. DNA damage in human lymphocytes exposed to four food additives in vitro. Toxicol Ind Health. 2014 Nov;30(10):926-37. doi: 10.1177/0748233712466132.
4. Valerio F, De Bellis P, Lonigro SL, Visconti A, Lavermicocca P. Use of Lactobacillus plantarum fermentation products in bread-making to prevent Bacillus subtilis ropy spoilage. Int J Food Microbiol. 2008 Mar 20;122(3):328-32. doi: 10.1016/j.ijfoodmicro.2008.01.005.
5. Adams C. The Gluten Cure: Scientifically Proven Natural Solutions to Celiac Disease and Gluten Sensitivities. Logical Books, 2017.
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