Methionine-Supplemented Low-Protein Diet Extends Mouse Healthspan and Links to Lower Human Disease Risk

Researchers published in *Cell Metabolism* a study testing a low-protein, methionine-supplemented longevity diet (LDMM) in mice. Four groups received standard, Western, ketogenic, or LDMM diets. LDMM mice showed longer healthspan, reduced fat without loss of lean mass, and ate comparable calories. Analysis of >200,000 humans linked high animal-protein (high methionine) intake to higher obesity and twice the Type 2 diabetes rate despite lower calories.

Low-Protein, Amino Acid-Supplemented ‘Longevity Diet’ Tied to ExtendedUSC Annenberg

The work was led by Valter Longo and Maura Fanti at USC’s Leonard Davis School of Gerontology, with collaborators from the University of Toronto, Harvard, and the Keck School of Medicine. Funding: National Institute on Aging (grant AG084485), NIH (grant GR1045540), USC Edna Jones Chair Fund. Longo holds equity in L-Nutra and co-holds patents on the fasting-mimicking diet licensed to USC.

Low-Protein, Amino Acid-Supplemented ‘Longevity Diet’ Tied to Extended

LDMM mice had higher GLP-1, FGF21, and growth hormone, hormones tied to glucose regulation and energy use. The diet lowered frailty scores and fat mass. In the human cohort, the highest animal-protein consumers showed greater obesity and double the Type 2 diabetes prevalence versus low-animal-protein eaters, despite lower calories.

Low-Protein, Amino Acid-Supplemented ‘Longevity Diet’ Tied to Extended

Longo said the results “challenge the dogma that calorie reduction is necessary to lose weight”. Fanti called the coordinated hormone shifts “genuinely encouraging” and announced plans for a controlled human trial. The authors note that human data are observational and species-specific pathway differences may affect translation. Longo’s equity in L-Nutra and related patents pose a potential conflict.

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The study notes species-specific pathway regulation and lacks interventional human data, a gap the upcoming trial will address.

Low-Protein, Amino Acid-Supplemented ‘Longevity Diet’ Tied to Extended

• “We expected different diets to produce different outcomes, but what really impressed us was how modulating just a single amino acid, methionine, in the longevity diet could produce such dramatic metabolic changes,” — Maura Fanti, Research Associate, USC Leonard Davis School of Gerontology

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• “There are, of course, differences in how these pathways are regulated between mice and humans, but seeing such coordinated changes across multiple metabolic hormones is genuinely encouraging, and we’re very curious to know whether effects of similar magnitude would be seen in human studies,” — Maura Fanti, USC Leonard Davis School of Gerontology

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• “This challenges the dogma that calorie reduction is necessary to lose weight, but it also tells us that we need to have clear understanding of the mechanisms,” — Valter Longo, USC Leonard Davis School of Gerontology

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• “Too little methionine caused frailty, but too much methionine abolished the benefits of this diet, which was otherwise based on the diet of long-lived populations like the traditional Italian and Okinawa diets. … These results indicate that overall protein intake may be less important than specific amino acid intake.” — Valter Longo, USC Leonard Davis School of Gerontology

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