Dear Editor,
Small, short-chain fatty acids (SCFAs) (acetic acid, propionic acid, and butyric acid: conjugate bases, acetate, propionate, and butyrate) as well as the alpha-hydroxy acid, L-lactic acid (conjugate base, L-lactate) are important energy substrates and signaling molecules in the central nervous system (CNS) [1, 2].L-lactic acid is produced by glycolysis [3] and gut microbes [4] and is released in large quantities during exercise [5].Within the CNS, L-lactate has been shown to be a rapid, excitatory signaling molecule [6-8], displaying both neuroprotective [9] and neurotoxic [10, 11] properties depending on concentration and time.