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Multispecies probiotic administration reduces emotional salience and improves mood in subjects with moderate depression: a randomised, double-blind, placebo-controlled study.
Baião, R, Capitão, LP, Higgins, C, Browning, M, Harmer, CJ, Burnet, PWJ
Psychological medicine. 2023;53(8):3437-3447
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Plain language summary
Gut microbiota may be able to augment an individual’s mood, brain processing and cognition. Supplements containing live bacteria or a diet high in fibre which act as a substrate for beneficial gut bacteria may be of benefit to individuals with depression or mental illness. This 4-week randomised control trial aimed to determine the effect of a probiotic containing several different gut bacteria species on emotional processing and cognition in people with mild to moderate depression. The results showed that compared to placebo, probiotic intake increased empathy with others and improved some but not all aspects of cognition. Probiotic intake did not affect biological measures of stress but did improve feelings of depression. It was concluded that multispecies probiotics may change the emotional processing of people with depression. This study could be used by healthcare professionals to understand that the use of probiotics may be a good option to reduce the risk of people with mild to moderate depression developing a major depressive disorder.
Abstract
BACKGROUND The potential antidepressant properties of probiotics have been suggested, but their influence on the emotional processes that may underlie this effect is unclear. METHODS Depressed volunteers (n = 71) were recruited into a randomised double-blind, placebo-controlled study to explore the effects of a daily, 4-week intake of a multispecies probiotic or placebo on emotional processing and cognition. Mood, anxiety, positive and negative affect, sleep, salivary cortisol and serum C-reactive peptide (CRP) were assessed before and after supplementation. RESULTS Compared with placebo, probiotic intake increased accuracy at identifying faces expressing all emotions (+12%, p < 0.05, total n = 51) and vigilance to neutral faces (mean difference between groups = 12.28 ms ± 6.1, p < 0.05, total n = 51). Probiotic supplementation also reduced reward learning (-9%, p < 0.05, total n = 51), and interference word recall on the auditory verbal learning task (-18%, p < 0.05, total n = 50), but did not affect other aspects of cognitive performance. Although actigraphy revealed a significant group × night-time activity interaction, follow up analysis was not significant (p = 0.094). Supplementation did not alter salivary cortisol or circulating CRP concentrations. Probiotic intake significantly reduced (-50% from baseline, p < 0.05, n = 35) depression scores on the Patient Health Questionnaire-9, but these did not correlate with the changes in emotional processing. CONCLUSIONS The impartiality to positive and negative emotional stimuli or reward after probiotic supplementation have not been observed with conventional antidepressant therapies. Further studies are required to elucidate the significance of these changes with regard to the mood-improving action of the current probiotic.
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A sympathetic nervous system evaluation of obesity stigma.
Oliver, MD, Datta, S, Baldwin, DR
PloS one. 2017;12(10):e0185703
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Plain language summary
The negative health consequences of obesity are well known. Those classified as obese also suffer from discrimination which has further negative psychological and physiological effects on well-being. The aim of this study was to see if attitudes to obesity can be modified at the physiological and psychological level by priming. 70 people aged 18-53 were randomly assigned to 2 groups. One group was shown images of obesity in negative settings, the other in positive settings. All participants then viewed an actual obesity discrimination incident. Levels of the digestive enzyme salivary alpha amylase (sAA) and skin conductance (SC) were taken as measures of sympathetic nervous system (SNS) activity. Individuals in the negative priming group had significantly more SC arousal and exhibited the highest overall sAA response after viewing the incident when compared to the positively primed group. The authors conclude that clinicians addressing stigma issues should consider the use of positively primed images as a method for reducing the possible long-term physiological consequences of the negative attitudes surrounding obesity.
Abstract
The portrayal of obesity in the media is often one of negativity. Consequently, it may generate an increase in stigma. Obesity stigma, a form of social discrimination, is responsible for many of the negative psychological and physiological effects on individual wellness. These effects not only impact individual health, but also affect the economy, and ultimately, societal wellness. In an attempt to examine the influence of the media on obesity stigma, this study tested the hypothesis that positive priming would lead to a reduction in obesity stigma. To further our understanding of this relationship, we: 1) examined the role of priming on physiological measures (e.g. salivary alpha amylase and skin conductance) in 70 college students by introducing positive and negative media images of individuals with obesity, and 2) assessed psychological measures (e.g. perceived stress, need to belong, and self-esteem, and Body Mass Index). After the priming manipulation, participants read a vignette depicting the discrimination of an individual with obesity and answered subsequent questions assessing participants' attributional blame of obesity. Results of this study revealed that priming affects physiological responding to obesity stigmatization. In conclusion, these findings suggest that incorporating positive media images of individuals with obesity may be an effective tool for reducing stigma and the various physiological consequences associated with it, which in turn, can enhance societal health and wellness.