Evidence: calming / anxiety nutrition in dogs (L-theanine, tryptophan, alpha-casozepine)
Source: Europe PMC (Europe PubMed Central) REST search — first-hand peer-reviewed abstract records, pulled 2026-07-22. Query: (("calming" OR L-theanine OR tryptophan OR "alpha-casozepine") AND dog AND (diet OR nutrition)) AND HAS_ABSTRACT:"Y". The cluster returns 5 records in Europe PMC; 6 representative studies are extracted below. Abstract text is verbatim from source; each study is traceable by PMID.
Studies
- PMID 42004292 (2024, Veterinary evidence) — In adult dogs is supplementary tryptophan in the diet effective in reducing signs of anxiety?. <h4>Pico question</h4>In adult dogs, is dietary supplementation with tryptophan compared with no dietary tryptophan supplement effective in reducing signs of anxiety?<h4>Clinical bottom line</h4><h4>Category of research< *[CC BY — Open Access, verbatim with attribution.]*
- PMID 41976013 (2026, Animals : an open access journal from MDPI) — Plant-Derived Functional Ingredients in Pet Nutrition: Phytochemical Classification, Mechanisms, Efficacy, and Application in Dogs and Cats.. This review classifies plant-derived functional ingredients in pet food according to phytochemical groups and application forms, including direct oral supplementation and incorporation into complete diets. *[CC BY — Open Access, verbatim with attribution.]*
- PMID 36978793 (2023, Antioxidants (Basel, Switzerland)) — Dietary Strategies for Relieving Stress in Pet Dogs and Cats.. A variety of physical, emotional, and mental factors can induce a stress response in pet dogs and cats. *[CC BY — Open Access, verbatim with attribution.]*
- PMID 42193745 (2026, Animals : an open access journal from MDPI) — The Digestibility of Vegan and Vegetarian Diets for Dogs and Cats.. There is growing interest in vegan and vegetarian (veg*n) diets for dogs and cats, due to factors including pet health, environmental sustainability and farmed animal welfare. *[CC BY — Open Access, verbatim with attribution.]*
- PMID 41301986 (2025, Animals : an open access journal from MDPI) — Investigation of the Digestibility, Fecal Characteristics, and Palatability of Oil Mil By-Products as a Plant-Based Protein Source in Canine Diets.. This study investigates the digestibility, fecal characteristics, and palatability of plant-based protein sources in canine diets. *[CC BY — Open Access, verbatim with attribution.]*
Source text: pdf-raw/evidence/europepmc_canine_anxiety_calm_nutrition_2026-07-22.txt (Europe PMC first-hand abstracts, pulled 2026-07-22).
License & attribution
Mixed licensing per COPYRIGHT_POLICY §3: Open Access (CC BY / CC BY-NC / CC BY-NC-ND) studies are reproduced verbatim with attribution under their specific CC license; non-Open-Access studies are paraphrased as derived fact summaries (numbers and proper nouns preserved, sentences rewritten). Original records:
- https://pubmed.ncbi.nlm.nih.gov/42004292/
- https://pubmed.ncbi.nlm.nih.gov/41976013/
- https://pubmed.ncbi.nlm.nih.gov/36978793/
- https://pubmed.ncbi.nlm.nih.gov/42193745/
- https://pubmed.ncbi.nlm.nih.gov/41301986/
Cleaning removal log (2026-08-05, codebuddy)
PMID 41828608 — Lab-model organism: rat metabolomics/obese-rat study; dogs only incidentally named (prior work), actual subject is rats.