Propionic acid and blood sugar hormones in a small human trial
What it found
In 28 healthy adults, a single dose of propionic acid raised several hormones that counter insulin, especially under low blood sugar conditions.
It also increased the body's own glucose production when blood sugar was mildly low.
What they found
Studies in people
Hormones at rest
At rest, propionic acid increased glucagon and norepinephrine compared with placebo. It did not significantly change glucose, insulin, epinephrine, or endogenous glucose production.
Hormones during normal blood sugar clamp
During a clamp that kept blood sugar normal, propionic acid increased glucagon, norepinephrine, and epinephrine. It did not significantly affect endogenous glucose production.
Hormones during low blood sugar clamp
During a clamp that kept blood sugar mildly low, propionic acid increased norepinephrine and epinephrine. It also increased endogenous glucose production. The rise in glucagon was not statistically different from placebo.
Glucose and insulin
Blood glucose and insulin levels were similar with propionic acid and placebo under both clamp conditions.
Timing of hormone changes
The increase in norepinephrine came 30 minutes before the increase in glucagon, which the authors say fits with animal studies suggesting sympathetic activation comes first.
What the authors conclude
“Oral consumption of PA leads to inappropriate activation of the insulin counterregulatory hormonal network.”
Also in their conclusions
- They conclude that consuming propionic acid activates the insulin counterregulatory hormonal network, increasing glucagon, norepinephrine, and epinephrine, and under mild hypoglycemia this is enough to raise endogenous glucose production.
- They note that the amount of propionic acid given is similar to what people commonly eat in processed foods.
- They call for future studies to find out whether long-term consumption of processed foods containing propionic acid could have harmful metabolic effects.
How it was done
The authors wanted to understand how the food preservative propionic acid affects glucose metabolism in people, since previous animal and small human studies suggested it might disrupt metabolism.
They ran a randomized, placebo-controlled crossover trial in 28 healthy men and women. Each person had two visits, separated by at least a week, and took either propionic acid (as calcium propionate) or a placebo. They measured glucose, insulin, glucagon, norepinephrine, epinephrine, and endogenous glucose production for 2 hours after the dose, both at rest and during a hyperinsulinemic clamp (with normal or mildly low blood sugar).
What it can’t tell you
- This was a short study in healthy people, so it cannot show what happens with long-term consumption or in people with obesity or diabetes.
- The study did not measure blood levels of propionic acid, so it cannot confirm how much was actually absorbed.
- The small sample size means some effects might have been missed.
Who paid
- Funding
- Funded by NIDDK NIH HHS; NCATS NIH HHS; NHLBI NIH HHS (from the PubMed record).
- Conflicts
- Competing interests: None declared.
- Authors work at
- Brigham and Women's Hospital, USA; University of Virginia, USA; University of Miami Miller School of Medicine, USA
The paper
- Title
- Acute effects of the food preservative propionic acid on glucose metabolism in humans
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Adler GK, Hornik ES, Murray G, et al (2021). Acute effects of the food preservative propionic acid on glucose metabolism in humans. BMJ open diabetes research & care. doi:10.1136/bmjdrc-2021-002336Free full textPubMed 34312159DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error