• Crohn's disease;
  • orofacial granulomatosis;
  • phenolic acids



Orofacial granulomatosis (OFG) is a rare disease of unknown cause. A cinnamon- and benzoate-free diet is successful in up to 72% of patients. Phenolic acids are among the chemical constituents restricted in this diet, which avoids some but not all of these structurally similar compounds. The present study aimed to: (i) develop a novel diet low in phenolic acids; (ii) implement this in a small clinical trial; and (iii) assess its nutritional adequacy.


A literature review identified 10 papers quantifying phenolic acids from which 91 10-mg phenolic acid exchanges were devised. A phenolic acid exclusion diet with precautionary micronutrient supplementation was designed and implemented in 10 patients. Phenolic acids were excluded for 6 weeks and were reintroduced at a rate of one exchange every second day for 6 weeks. Wilcoxon matched pairs tests analysed disease outcomes measured by an oral disease severity scoring tool at weeks 0, 6 and 12. Nutritional adequacy was assessed, excluding micronutrient supplementation, at weeks 0 and 6, and compared intakes with dietary reference values.


The diet was nutritionally inadequate for a range of micronutrients. Seven of 10 patients responded. Mean [standard deviation (SD)] severity scores improved from week 0–6 [20.8 (9.39) and 10.1 (5.72); = 0.009] and were maintained in five patients who completed the reintroduction [6.6 (3.13) and 7.2 (5.54); = 0.713].


A low phenolic acid diet with micronutrient supplementation holds promise of a novel dietary treatment for OFG. Further work is required in larger studies to determine long-term outcomes.