Sodium butyrate

October 11, 2021
If you eat right, I will help your gut bacteria.
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Sodium butyrate—more properly sodium butanoate—is a salt of butyric (butanoic) acid. If it comes into contact with even a trace of moisture, it emits a faint odor of its foul-smelling conjugate acid.

The butyrate ion, along with the analogous propionate ion, is purported to enhance gut health in humans and many other animal species. But you don’t have to take it as a supplement. Bacteria in the gut produce butyrate from dietary fiber, especially the fiber from legumes and nuts.

Two recent reports illustrate the benefits of butyrate. Yanfen Bai and Thomas J. Mansell* at Iowa State University (Ames) wrote, “The short-chain fatty acid [anion] butyrate plays critical roles in human gut health, affecting immunomodulation, cell differentiation, and apoptosis, while also serving as the preferred carbon source for colon cells.” To assist in studies of butyrate for therapeutic applications, the researchers developed a high-throughput biosensor that responds to intracellular concentrations.

In another account, Sanne Verhoog at the University of Bern (Switzerland) and collaborators there and at other institutions in Switzerland, Turkey, Germany, and the United States reviewed 29 studies about how dietary factors influence the populations of two beneficial gut bacteria, Akkermansia muciniphila (11 studies) and Faecalibacterium prausnitzii (25 studies). The studies involved a total of 1444 participants. Supplementation with several substances, including sodium butyrate, increased the abundance of A. muciniphila, whereas diets low in fermentable saccharides that produce butyrate lowered the quantity of the bacterium. (Butyrate was not considered in the case of F. prausnitzii.)

Sodium butyrate hazard information*

Hazard class** GHS code and hazard statement
Acute toxicity, oral, category 4 H302—Harmful if swallowed Chemical Safety Warning
Skin corrosion/irritation, category 1B H314—Causes severe skin burns and eye damage Chemical Safety Warning
Serious eye damage/eye irritation, category 1 H318—Causes serious eye damage Chemical Safety Warning
Specific target organ toxicity, single exposure, respiratory tract irritation, category 3 H335—May cause respiratory irritation Chemical Safety Warning
Germ cell mutagenicity, category 2 H341—Suspected of causing genetic defects Chemical Safety Warning
Short-term (acute) aquatic hazard, category 3 H402—Harmful to aquatic life

*Compilation of selected safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. 
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MOTW updates

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See this week's MOTW updates below.

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Sodium butyrate 
fast facts

CAS Reg. No. 156-54-7
Butanoic acid, sodium salt (1:1)
Empirical formula C4H7NaO2
Molar mass 110.09 g/mol
Appearance White crystals or powder
Melting point 250–253° C
Water solubility 0.5–100 g/La

a. A wide range of solubilities are reported in the literature. Readers are invited to submit the generally accepted value to

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