title: The effects of probiotics on mental health and hypothalamic-pituitary-adrenal axis: A randomized, double-blind, placebo-controlled trial in petrochemical workers.
abstract: OBJECTIVE
  The aim of this study was to determine effects of probiotic yogurt and multispecies probiotic capsule supplementation on mental health and hypothalamic-pituitary-adrenal axis in petrochemical workers.
  
  
  METHODS
  The present randomized double-blind, placebo-controlled trial was conducted on 70 petrochemical workers. Subjects were randomly divided into three groups to receive 100 g/day probiotic yogurt + one placebo capsule (n = 25) or one probiotic capsule daily + 100 g/day conventional yogurt (n = 25) or 100 g/day conventional yogurt + one placebo capsule (n = 20) for 6 weeks. Mental health parameters including general health questionnaire (GHQ) and depression anxiety and stress scale (DASS) scores were measured. Fasting blood samples were obtained at the beginning and 6 weeks after the intervention to quantify hypothalamic-pituitary-adrenal axis.
  
  
  RESULTS
  After 6 weeks of intervention, a significant improvement of GHQ was observed in the probiotic yogurt (18.0 ± 1.5 vs. 13.5 ± 1.9, P = 0.007) and in the probiotic capsule group (16.9 ± 1.8 vs. 9.8 ± 1.9, P = 0.001), as well as a significant improvement in DASS scores in the probiotic yogurt (23.3 ± 3.7 vs. 13.0 ± 3.7, P = 0.02) and the probiotic capsule group (18.9 ± 3.2 vs. 9.4 ± 4.0, P = 0.006). However, there was no significant improvement in the conventional yogurt group (P = 0.05 for GHQ and P = 0.08 for DASS).
  
  
  CONCLUSIONS
  The consumption of probiotic yogurt or a multispecies probiotic capsule had beneficial effects on mental health parameters in petrochemical workers.
authors: a Department of Nutrition, School of Public Health , Iran University of Medical Sciences , Tehran , Iran.
authors: Ali Akbar
authors: AA
authors: Mohammadi
authors: a Department of Nutrition, School of Public Health , Iran University of Medical Sciences , Tehran , Iran.
authors: Shima
authors: S
authors: Jazayeri
authors: b Research Department of Food Technology Research , National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences , Tehran.
authors: Kianoush
authors: K
authors: Khosravi-Darani
authors: c School of Nutritional Sciences and Dietetics , Tehran University of Medical Sciences , Iran.
authors: Zahra
authors: Z
authors: Solati
authors: c School of Nutritional Sciences and Dietetics , Tehran University of Medical Sciences , Iran.
authors: Nakisa
authors: N
authors: Mohammadpour
authors: d Research Center for Biochemistry and Nutrition in Metabolic Diseases , Kashan University of Medical Sciences , Iran.
authors: Zatollah
authors: Z
authors: Asemi
authors: c School of Nutritional Sciences and Dietetics , Tehran University of Medical Sciences , Iran.
authors: Zohre
authors: Z
authors: Adab
authors: c School of Nutritional Sciences and Dietetics , Tehran University of Medical Sciences , Iran.
authors: Mahmoud
authors: M
authors: Djalali
authors: e Department of Psychiatry, Roozbeh Hospital , Tehran University of Medical Sciences , Iran.
authors: Mehdi
authors: M
authors: Tehrani-Doost
authors: f Department of Epidemiology and Biostatistics, School of Public Health , Tehran University of Medical Sciences , Iran.
authors: Mostafa
authors: M
authors: Hosseini
authors: a Department of Nutrition, School of Public Health , Iran University of Medical Sciences , Tehran , Iran.
authors: Shahryar
authors: S
authors: Eghtesadi
mesh_terms: D000328:Adult; D001007:Anxiety / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D001644:Bifidobacterium / Q000254:growth & development / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D003863:Depression / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D004311:Double-Blind Method; D064806:Dysbiosis / Q000178:diet therapy* / Q000209:etiology / Q000382:microbiology / Q000523:psychology; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007492:Iran / Q000453:epidemiology; D007778:Lactobacillus / Q000254:growth & development / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D000066388:Oil and Gas Industry; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D019936:Probiotics; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D013315:Stress, Psychological / Q000097:blood / Q000382:microbiology / Q000503:physiopathology / Q000523:psychology; D000078329:Workforce; D015014:Yogurt / Q000382:microbiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers
keywords: Hypothalamic–pituitary–adrenal axis; Mental health; Petrochemical workers; Probiotics