Daily intake ofLactobacillus caseiShirota increases natural killer cell activity in smokers

Abstract

Dietary probiotics supplementation exerts beneficial health effects. Since cigarette smoking reduces natural killer (NK) activity, we evaluated the effect of Lactobacillus casei Shirota (LcS) intake on NK cytotoxic activity in male smokers. The double-blind, placebo-controlled, randomised study was conducted on seventy-two healthy Italian blue-collar male smokers randomly divided for daily intake of LcS powder or placebo. Before and after 3 weeks of intake, peripheral blood mononuclear cells were isolated and NK activity and CD16 þ cells' number were assessed. Daily LcS intake for 3 weeks significantly increased NK activity (P,0·001). The increase in NK activity was paralleled by an increase in CD16 þ cells (P,0·001). Before intake, NK cytotoxic activity inversely correlated with the number of cigarettes smoked (R 20·064). LcS intake prevented the smoke-dependent expected NK activity reduction. The analysis of the distribution of changes in smoke-adjusted NK activity demonstrated that the positive variations were significantly associated with LcS intake, while the negative variations were associated with placebo intake (median value of distributions of differences, 20·98 lytic unit (LU)/10 7 cells for LcS v. 24·38 LU/10 7 cells for placebo, P¼ 0·039). In conclusion, 3 weeks of daily LcS intake in Italian male smokers was associated with a higher increase in cytotoxic activity and CD16 þ cells' number in comparison to the placebo intake group.

Effect of Probiotics on Central Nervous System Functions in Animals and Humans: A Systematic Review

“…[56][57][58] In healthy male smokers, a 3-week intervention with L. casei showed no effect on STAI score. 59 In children with ASD, a 3-week intervention with L. plantarum did not change the DBC score.…”

“…Fifteen studies tested healthy participants with respect to anxiety, depression, distress levels, mood state, and behavior problems. 39,[51][52][53][54][55][56][57][58][59][60][61][62] The measurement tools included the General Health Questionnaire (GHQ), the Depression Anxiety and Stress Scale (DASS), the Leiden Index of Depression Sensitivity-Revised (LEIDS-r), the Positive and Negative Symptom Scale (PANSS), the State-Trait Anxiety Inventory (STAI), the Development Behavior Checklist (DBC), the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI), the Hopkins Symptom Checklist (HSCL-90), the Hospital Anxiety and Depression Scale (HADS), the Perceived Stress Scale (PSS), the Coping Checklist (CCL) (also used to counter the stress of daily life), and the questionnaire-based Profile of Mood State (POMS). Due to the different questionnaires, scales, and their combinations used in these studies, we only report here whether the probiotics treatment improved mental health/mood.…”

“…39,50 The immune system could be improved by the probiotic L. casei, with evidence of reduced pro-inflammatory cytokines (TNF-a, IL-6, and IL-12), increased regulatory cytokines (eg, IL-10), and increased natural killer cell activity in smokers. 55,59 Only one study in humans investigated metabolites of the tryptophan pathway but did not find any significant change by probiotics. 52 Many of the human studies looked at bowel function, and they did find reduced difficulties in bowel movement, IBS severity, and symptoms in patients.…”

“…[55][56][57][58] Also, in two studies, one in male smokers and one in children with ASD, the intervention periods were 3 weeks, shorter than the effective period, which seems to be 4 weeks, that can make a measurable effect. 59,60 Also, caution is warranted when drawing conclusions from the human studies that used psychological questionnaires and/or scales rather than behavioral or neuropsychological experiments, resulting in subjective biases. The clinical efficacy of probiotic interventions and guidelines for their administration in diseases such as diarrhea, allergies, IBS, and inflammatory bowel disease has been addressed in previous reviews.…”

Microbiome and Probiotics inHealth and HIV Infection

“…Over the past 20 years, the increasing interest on probiotics use in healthy subjects has sprung in researches both in food and pharmaceuticals companies, thanks to probiotics effects on cell proliferation and activity [1], homeostasis of the immune system [2], modulation of host's microbiota and related improvement of host's health by limiting pathogens colonization and controlling inflammatory gut disorders [3,4], and on metabolic disorders [5].…”