Leucine stabilized mitochondrial proteins in cells and worms; this is not a human diet trial

What the research found

Study (cells and Caenorhabditis elegans). Qiaochu Li, Thorsten Hoppe, and colleagues at the University of Cologne’s CECAD aging center report that the essential amino acid leucine slows breakdown of proteins on the outer mitochondrial membrane by reducing activity of the quality-control protein SEL1L, so mitochondria can raise energy output when nutrients are plentiful. ScienceDaily carried the university account on 3 October 2026. The page’s journal line reads Nature Cell Biology 2025; 27(11):1889; doi 10.1038/s41556-025-01799-3. In the worms, problems breaking leucine down disrupted mitochondria and were linked to fertility problems. In human lung cancer cells, some mutations in leucine metabolism helped the cancer cells survive. Li cautioned that SEL1L also clears damaged proteins, so changing that balance could have costs. Leucine is abundant in dairy, meat, beans, and lentils. This is laboratory and animal work, not a test of a high-leucine diet or a supplement in people. Educational notes. This is not a reason to load leucine.

Evidence level: Animal study. Results in animals or cells often don't carry over to people.

Read the original at University of Cologne / Nature Cell Biology