Natural products have been studied regarding their effectiveness on Inflammatory Bowel Disease (IBD).To examine the effects of Mastiha (Pistacia lentiscus var. Chia) on clinical course and amino acid (AA) profile of patients in remission.This is a randomised, double-blind, placebo-controlled clinical trial.Patients (n = 68) were randomly allocated to Mastiha (2.8 g/day) or placebo adjunct to stable medication. Free AAs were identified applying Gas Chromatography-Mass Spectrometry in plasma. Medical-dietary history, Inflammatory Bowel Disease Questionnaire, Harvey-Bradshaw Index, Partial Mayo Score, biochemical, faecal and blood inflammatory markers were assessed. Primary endpoint was the clinical relapse rate at 6 months. Secondary endpoints included variations in free AAs, inflammatory biomarkers and quality of life. Statistical significance was set at 0.05.Concerning AAs and biochemical data, alanine (p = 0.006), valine (p = 0.047), proline (p = 0.022), glutamine (p < 0.001) and tyrosine (p = 0.043) along with total cholesterol (p = 0.032) and LDL cholesterol (p = 0.045) increased only in placebo group compared with baseline and the change between the study groups was significantly different. Inflammatory markers had not a significantly different change between the two groups, even serum IL-6, faecal calprotectin and faecal lactoferrin increased only in the placebo group. Although Mastiha was not proven superior to placebo in remission rate (17.6% vs. 23.5%, p = 0.549), attenuation in increase of free AAs levels in verum group is reported.Mastiha inhibited an increase in plasma free AAs seen in patients with quiescent IBD. Since change of AAs is considered an early prognostic marker of disease activity, this indicates a potential role of Mastiha in remission maintenance.
