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Nutr Neurosci. 2016 Nov;19(9):387-395. Epub 2015 Apr 16.

The effects of probiotics on mental health and hypothalamic-pituitary-adrenal axis: A randomized, double-blind, placebo-controlled trial in petrochemical workers.

Author information

a Department of Nutrition, School of Public Health , Iran University of Medical Sciences , Tehran , Iran.
b Research Department of Food Technology Research , National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences , Tehran.
c School of Nutritional Sciences and Dietetics , Tehran University of Medical Sciences , Iran.
d Research Center for Biochemistry and Nutrition in Metabolic Diseases , Kashan University of Medical Sciences , Iran.
e Department of Psychiatry, Roozbeh Hospital , Tehran University of Medical Sciences , Iran.
f Department of Epidemiology and Biostatistics, School of Public Health , Tehran University of Medical Sciences , Iran.



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.


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.


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).


The consumption of probiotic yogurt or a multispecies probiotic capsule had beneficial effects on mental health parameters in petrochemical workers.


Hypothalamic–pituitary–adrenal axis; Mental health; Petrochemical workers; Probiotics

[Indexed for MEDLINE]

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