Dampened Muscle mTORC1 Response Following Ingestion of High-Quality Plant-Based Protein and Insect Protein Compared to Whey.
Level 5 - mechanism / opinion, no new human data
Preclinical animal laboratory experiment
PubMed 33919313 · doi:10.3390/nu13051396
What was done
C57BL/6J mice were administered an oral gavage of different protein solutions: whey protein, a pea-rice protein blend matched to whey for total protein content or leucine content, insect (worm) protein matched for total protein, or a saline control. Blood samples were collected at 30, 60, 105, and 150 minutes post-gavage to assess aminoacidemia. Skeletal muscle samples were collected at 60 and 150 minutes post-gavage to measure activation of downstream kinases in the mTORC1 signaling pathway.
What was found
No numerical values, effect sizes, or variance statistics are reported in the abstract. Ingestion of the pea-rice plant protein blend resulted in a lower postprandial increase in blood leucine compared to whey, which coincided with dampened skeletal muscle mTORC1 activation at both acute and 150-minute time points. Matching total leucine content of the plant blend to whey did not rescue the attenuated rise in plasma amino acids or the lower mTORC1 response. Insect protein produced downstream mTORC1 kinase activation similar to plant protein despite lower postprandial aminoacidemia; both plant and insect proteins induced lower mTORC1 activation than whey.
Why it matters
This study shows that alternative protein sources elicit lower acute mTORC1 signaling in rodent muscle compared to whey, and that simply matching total leucine content is insufficient to rescue the attenuated signaling response.
Limits
The study was conducted in a mouse model with an acute gavage protocol, limiting direct translation to human physiology and chronic muscle mass adaptations. Downstream muscle protein synthesis rates were not reported, only signaling kinases. The abstract omits sample sizes (n) and all exact quantitative data, confidence intervals, and p-values.
Cited by
- supports Plant-based protein sources generally contain lower amounts of bioavailable leucine than animal-based sources.