Benzoic acid and gut function in pigs and lab cells
What it found
In pigs and pig gut cells, benzoic acid improved digestion, absorption and gut barrier measures at some doses, but too much damaged gut health.
The authors say the right dose for people still needs to be worked out.
What they found
Animal and lab studies
Nutrient digestion
In pigs and piglets, 0.5% benzoic acid in feed increased the digestibility of dry matter, crude protein, energy and minerals. In lactating sows, 2% benzoic acid raised the digestibility of organic matter, protein, fat and fibre.
Digestive enzymes
In piglets, benzoic acid raised the amounts of trypsin, lipase and amylopsin in the pancreas and boosted several digestive enzyme activities in the jejunum. It also lowered the pH in the stomach and jejunum in some studies, though not in all.
Gut barrier
In piglets and pig intestinal cells, benzoic acid improved gut barrier measures, including villus height, gut wall integrity and the proteins that seal the gaps between gut cells. It also lowered markers of gut leakage in the blood.
Gut bacteria
In piglets, 0.5% benzoic acid increased helpful bacteria such as Lactobacillus and Bifidobacterium and reduced harmful ones such as E. coli in the gut. But higher doses (0.85% and 1%) cut Lactobacillus too, and in broilers 0.25-0.75% had no effect on gut bacteria.
Too much benzoic acid
In piglets, excess benzoic acid in feed damaged the liver, spleen and lungs and harmed the gut lining. In lab tests, excess benzoic acid stopped pig intestinal cells from multiplying.
What the authors conclude
“The supplementing dose of BA should be 0.2-0.5% in feeds.”
Also in their conclusions
- They conclude that benzoic acid can improve gut functions, including digestion, absorption and barrier, which helps explain the growth and health benefits seen in animal studies.
- They say the supplementing dose should be 0.2-0.5% in feeds, but the dose for use in human foods still needs to be determined.
- They call for more research on how benzoic acid affects gut functions, especially the underlying mechanisms.
How it was done
Benzoic acid is widely used as a preservative in foods and feeds, and recent studies suggested it could improve growth and health, at least partly by helping gut functions. The authors wanted to summarise what is known about how it affects the gut.
They pulled together studies that used piglets, growing pigs, lactating sows, weaned rabbits and pig intestinal cells (IPEC-1) as models, because pig gut physiology is similar to humans. Doses in the studies ranged from 0.2% to 2% benzoic acid in feed.
What it can’t tell you
- Most of the studies were in pigs and pig gut cells, so they cannot show what happens in people.
- The studies used different doses, diets and animals, so it is not clear which dose would help or harm human gut health.
- The review did not find enough evidence on how benzoic acid affects the immune system in the gut.
Who paid
- Authors work at
- Sichuan Agricultural University, China; Chinese Ministry of Education, China; Oklahoma State University, USA
The paper
- Title
- Benzoic Acid Used as Food and Feed Additives Can Regulate Gut Functions
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Mao X, Yang Q, Chen D, Yu B, He J (2019). Benzoic Acid Used as Food and Feed Additives Can Regulate Gut Functions. BioMed research international. doi:10.1155/2019/5721585Free full textPubMed 30931328DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error