Differential Effects of Sulfur Amino Acid-Restricted and Low-Calorie Diets on Gut Microbiome Profile and Bile Acid Composition in Male C57BL6/J MiceOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
Researchers compared how sulfur amino acid restriction (SAAR, low methionine without cysteine) affects the gut microbiome and bile acids in male mice, versus a 12% low calorie diet (LCD) matched for calories but not methionine, and a control diet (CD).
How was it studied?
Male 21-week-old C57BL6/J mice were fed CD (0.86% methionine), SAAR (0.12% methionine), or LCD for 10 weeks. Fecal microbiome was profiled by 16S rRNA sequencing and plasma bile acids by UPLC-MS/MS.
What did they find?
Beta diversity differed between SAAR and LCD and between LCD and CD, but not between CD and SAAR. Firmicutes, Clostridiaceae, and Turicibacteraceae were more abundant, while Verrucomicrobia was less abundant, in SAAR than LCD. Secondary bile acids and the secondary to primary bile acid ratio were lower in SAAR than LCD, and SAAR favored glycine over taurine conjugation of bile acids.
Why it matters
SAAR and calorie restriction both extend lifespan in mice, but this study shows they alter the gut microbiome and bile acid metabolism through distinct pathways. This suggests SAAR's longevity effects are not simply a byproduct of reduced calorie intake.