Short-Chain Fatty Acid Profiles in Amyotrophic Lateral Sclerosis: Longitudinal Effects of Disease and Mediterranean Diet Intervention

<b>Background</b>: Amyotrophic lateral sclerosis (ALS) evolution is influenced by many dietary factors, biochemical and hormonal inter-relations and gut microbiota. This study focuses on dynamics by conducting a plasmatic quantitative analysis of six of the main short-chain fatty acids (SCFAs) for ALS patients and the shifts in circulating SCFA profiles during ALS progression as well as their potential responsiveness or change due to dietary modulation. <b>Methods</b>: A 12-month prospective study in parallel with control group determinations was conducted. The patients diagnosed with ALS were evaluated at the start of the study (T0) followed by a six-month observation time frame (T1) and after another six months of a Mediterranean diet intervention (T2). Plasma SCFAs were determined using liquid chromatography coupled to mass spectrometry to showcase the plasmatic profiles. Correlation between plasma levels of SCFAs and patients' clinical characteristics next to correlations between plasma SCFA levels at T1 and T2 were performed. <b>Results</b>: A significant increase between control group and patients at T0 was observed for acetic, propionic, butyric and hydroxy-butyric acid. Hexanoic acid levels stagnated and 4-methyl-valeric acid concentrations decreased. Evolutions from T1 and T2 impacted acetate, propionate and 4-methyl-valerate. <b>Conclusions</b>: The study offers a better understanding regarding the differences in SCFA levels in ALS patients. The Mediterranean diet may impact the levels of acetic and propionic acid, indicating the modulation of SCFA production by gut microbiota.