Thirteen patients with psoriasis were hospitalized for periods of 4 to 17 weeks and maintained on varying levels of protein intake ranging from 4.0 to 162 gm daily. Local therapy was restricted to a bland cream. All patients improved during the first seven weeks of hospitalization, and only two relapsed thereafter. No significant difference in the degree or rapidity of improvement on the various dietary protein levels was evident. Three patients who improved while on a low-protein intake continued to improve or failed to flare when changed to a high-protein diet. Results of this study fail to support the concept that a low-protein, low-taurine, or low-tryptophan diet is of value in the management of psoriasis.
Zackheim HS, Farber EM. Low-Protein Diet and PsoriasisA Hospital Study. Arch Dermatol. 1969;99(5):580-586. doi:10.1001/archderm.1969.01610230072012