Propionic acid

Propionic acid (E 280) is a monobasic, unpleasantly pungent smelling, saturated, slightly corrosive organic acid (fatty acid), which can be detected in humans in urine and sweat, among other things.

Propionic acid and its salts (propionates) sodium propionate(E 281), calcium propionate(E 282) and potassium propionate(E 283) are authorised as food additives. They have an antimicrobial effect against certain types of bacteria, yeast and mould, e.g. they prevent bread from going mouldy. Propionic acid occurs naturally in small amounts in certain types of cheese. Maximum levels of 1.0 to 3.0 g/kg of food apply to the various products.

Propionic acid is used as preservative in cosmetic formulations under the INCI designation"propionic acid".

Propionic acid is found in various plants in their essential oils. In the large intestine, propionic acid is formed by bacteria, especially in high-fibre diets. This process breaks down indigestible food components. This process produces short-chain fatty acids such as acetic, propionic and butyric acid. These are absorbed in the large intestine and thus become systemically effective.

Propionic acid and immune system: New observations on the effects of short and long chain fatty acids on the immune system. In particular, propionic acid and its salts lead to the production and activation of regulatory T cells and to the downregulation of inflammatory and autoimmunological reactions. Propionic acid, benzoates and curcumin are able to suppress the Th1 type of the immune response in vitro in a dose-dependent manner. This anti-inflammatory effect could cause a shift of the Th1/Th2-type immune balance to a Th2-dominated immune response.

For example, it has been shown that nutritively supplied fatty acids have a positive influence on the course of multiple sclerosis (Haghikia A et al. 2015). In contrast, long-chain fatty acids promote inflammatory processes in the intestinal wall (increased production of interleukin-17 and gamma interferon). Long-chain fatty acids seem to have an unfavourable influence on the course of multiple sclerosis (source: Press Release Ruhr-University Bochum, 21.10.2015). Cumulative doses of propionic acid, on the other hand, have a neurotoxic effect and aggravate autistic phenomena.

Propionic acid and skin: Propionibacterium acnes, an important component of the skin microbiome, forms propionic acid. This is of great importance for PH skin and its antimicrobial effect. The proliferation of Propionibacterium acnes (e.g. in acne vulgaris) leads to increased local propionic acid concentration and consecutive cytological and immunological effects.

1. Chambers, Edward S (2014) Effects of targeted delivery of propionate to the human colon on appetite regulation, body weight maintenance and obesity in overweight adults. In: Good microbiota: 1744-1754
2. El-Ansary AK et al (2012)Etiology of autistic features: the persisting neurotoxic effects of propionic acid. J Neuroinflammation 9:74.
3. Haghikia A et al. (2015) Dietary Fatty Acids Directly Impact Central Nervous System Autoimmunity via theSmall
   Intestine. Immunity 43:817-829.
4. Maier E et al (2010) Food preservatives sodium benzoate and propionic acid and colorant curcumin suppress Th1-type immune response in vitro. Food Chem Toxicol 48:1950-1956.
5. Press Release Ruhr-University Bochum, 21.10.2015
6. Tax G et al (2016) Propionic Acid Produced by Propionibacterium acnes Strains Contri-butes to Their Pathogenicity. Acta Derm Venereol 96:43-49.