1.
Effect of aerobic exercise, slow deep breathing and mindfulness meditation on cortisol and glucose levels in women with type 2 diabetes mellitus: a randomized controlled trial.
Obaya, HE, Abdeen, HA, Salem, AA, Shehata, MA, Aldhahi, MI, Muka, T, Marques-Sule, E, Taha, MM, Gaber, M, Atef, H
Frontiers in physiology. 2023;14:1186546
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Plain language summary
Stress is considered to be an important factor in type 2 diabetes mellitus (T2DM) and aerobic exercise can help modulate the stress response as well as being important in the management of diabetes. Mindfulness meditation and deep breathing have also been shown to have positive effects on both stress and T2DM. This 6-week single-blind, randomised, controlled trial evaluated the effect of 10 min slow deep breathing and 10 min mindfulness meditation following a 40 min aerobic exercise programme, compared to the 40 min aerobic exercise alone, on fasting blood glucose (FBG) and cortisol levels in 58 stressed women with T2DM. FBG and cortisol levels improved in both groups but more so in the group who received the deep breathing and mindfulness meditation in addition to the exercise intervention: 20% vs 30% reduction in cortisol and 10% vs 15% reduction in FBG. The authors conclude that adding slow deep breathing and mindfulness meditation to an exercise programme may be useful in the management of stressed women with T2DM and reduce their cardiometabolic risk.
Expert Review
Conflicts of interest:
None
Take Home Message:
Practitioners could consider slow deep breathing and mindfulness meditation, added to aerobic exercise, as potentially useful components of the T2DM management program for stressed women.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Stress, a key factor for Type 2 diabetes mellitus (T2DM), stimulates the hypothalamus-pituitary-adrenal gland (HPA) and triggers parasympathetic nerve withdrawal, leading to increased circulating cortisol levels and higher levels of blood glucose. Exercise is a key intervention that can modulate the HPA axis and help manage stress.
Methods
Fifty-eight women (aged between 40-50), diagnosed with T2DM for at least 5 years but medically stable with moderate to high stress scores were randomised to either aerobic training (AT) or aerobic exercise combined with slow deep breathing and mindfulness meditation (DMM) training three times weekly over 6-weeks.
AT group performed aerobic exercise on a treadmill at an intensity of 60%– 75% of the maximum heart rate for a total of 40 min, including a 5 minute warm up and 5 min cool down.
AT + DMM group performed a combination of aerobic exercise as per the AT group followed by a total of 10 minutes of diaphragmatic slow, deep breathing; and mindfulness meditation.
Results
Both groups showed a change from baseline in serum cortisol to p<0.0001
At 6 weeks in the AT + DMM group, the primary outcome of serum cortisol (nmol/L) levels was 12.59 nmol/L [95% CI 4.45-6.52] a decrease of 30.29% and the fasting blood glucose levels (secondary outcome) was 136.37mg/dl (95% CI: 9.19–2.6) a decrease of 14.54%
In the AT group performing only aerobic exercise decreased serum cortisol levels by 20.16% and FBG levels decreased by 9.97%.
Conclusion
This study showed that combining slow deep breathing and mindfulness meditation with aerobic exercise reduced the serum cortisol (p = 0.01) and FBG levels (p = 0.001) in women with T2DM compared to when only aerobic training was performed.
Clinical practice applications:
Consider a combined therapy approach with diaphragmatic breathing exercises and aerobic exercises that targets both the endocrine and autonomic nervous systems, as this may have a synergistic effect to assist with maintaining normal blood sugar levels and cortisol levels in individuals with T2DM.
Considerations for future research:
Future research is needed to determine the most effective combination of therapies for managing both FBG and serum cortisol levels in individuals with T2DM.
Abstract
Background: Aerobic exercise combined with breathing exercise can be an integral part of diabetes mellitus treatment. This single-center, randomized, parallel-group study investigated the effect of the combination of aerobic exercise with slow deep breathing and mindfulness meditation on the glucose and cortisol levels of women with type 2 diabetes mellitus (T2DM). Materials and Methods: Fifty-eight middle-aged women with T2DM (mean age: 45.67 ± 2.92 years) were randomly assigned to either the aerobic training group (AT: n = 29; mean age [46.1 ± 2.7 years]) or the aerobic exercise combined with slow deep breathing and mindfulness meditation (AT + DMM: n = 29; mean age [45.24 ± 3.14 years]). Aerobic exercise was performed at 60%-75% of the maximum heart rate. The women in each group were asked to perform the training three times weekly over a 6-week period. The duration of each session was 40 min for the AT group and 60 min for the AT + DMM group. The two groups were asked to perform aerobic exercise at 60%-75% of the maximum heart rate. Their fasting blood glucose (FBG) and serum cortisol levels were measured at the baseline and after the 6 weeks. Results: Compared with the AT group, the group undertaking 6 weeks of aerobic training combined with slow, deep breathing exercises and mindfulness meditation showed significantly lower levels of FBG (p = 0.001) and cortisol levels (p = 0.01) than the AT group. Conclusion: The addition of slow deep breathing and mindfulness meditation to aerobic exercise can better control the glucose and cortisol levels of women with T2DM and thereby improve their outcomes and decrease their cardiometabolic risk.
2.
Effects of acute sleep loss on leptin, ghrelin, and adiponectin in adults with healthy weight and obesity: A laboratory study.
van Egmond, LT, Meth, EMS, Engström, J, Ilemosoglou, M, Keller, JA, Vogel, H, Benedict, C
Obesity (Silver Spring, Md.). 2023;31(3):635-641
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Plain language summary
A lack of sleep may be a risk factor for weight gain. Leptin is an adipocyte-derived hormone that activates satiety networks within the brain. Ghrelin, as opposed to leptin, is mainly produced by the stomach and it acts as a hunger hormone, signalling fuel status to the central nervous system. Some studies have found either no alterations or higher leptin and lower ghrelin blood levels following experimental sleep deprivation. The aim of this study was to investigate whether blood concentrations of leptin, ghrelin, and adiponectin are affected by acute total sleep deprivation in a sex- and weight-specific manner. This study is a laboratory study based on blood samples from 44 participants, mainly university students. Results show that: - acute total sleep deprivation is linked to lower serum levels of the adipokine leptin and higher blood levels of ghrelin. - following sleep deprivation, serum adiponectin levels were elevated. - the drop in serum leptin was larger in women after total sleep deprivation; however, there wasn’t a significant association between biological sex and experimental condition. - the increase in blood levels of adiponectin was slightly more pronounced among women, whereas there weren’t any differences in the effects of sleep loss on plasma ghrelin. Authors conclude that acute total sleep deprivation shifts the endocrine balance from the satiety hormone leptin toward the hunger-promoting hormone ghrelin. However, further investigation in larger samples focusing on their findings linked to sex- and weight-specific differences in leptin, ghrelin, and adiponectin are needed.
Expert Review
Conflicts of interest:
None
Take Home Message:
Sleep deprivation may shift the balance of appetite controlling hormones causing an increase in hunger and decreased satiety and therefore resulting in increased food intake. These changes may be more pronounced in biological females.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Sleep deprivation may contribute to weight gain and obesity through its effect on the hormonal pathways promoting hunger and satiety. Research has also linked chronic sleep loss with an increase in the brain reward response to food, thus driving an increase in daily food intake. Leptin and ghrelin are hormones involved in the control of food intake. Some research has associated alterations in these hormones following sleep loss, whilst others have not.
This study aimed to investigate whether biological sex and weight status affect fasting serum levels of leptin, ghrelin and adiponectin following chronic sleep deprivation in a supervised laboratory setting.
Methods
This randomised crossover design study included n=44 mixed sex participants with a mean age of 24.9 years. A total of 19 of the participants were classed as obese, with the remaining n= 25 participants were considered normal weight. Participants completed 2 nights in experimental sessions under continuously supervised conditions in a laboratory. One night was spent awake and the other asleep. Fasting blood samples were taken the morning after each session to measure levels of leptin, ghrelin and adiponectin.
Results
Serum levels of leptin after one night’s sleep loss were around 7% lower than those measured after sleep (17.3 = +/-2.6 vs 18.6 +/- 2.8 ng/mL, p = 0.037). Adjustments using sex-stratified analysis showed significantly lower levels of serum leptin in women (25.8 +/_4.3 vs 28.1 +/_ 4.7 ng/mL, p = 0.030) but not for men (10.1 +/_ 2.4 vs 10.6 +/_ 2.3 ng/mL, p = 0.458). However, when comparing individual participant differences between sleep and wake sessions, the results were not significant. Additionally, no significant differences were found between normal weight and obese participants.
Higher levels of ghrelin were found following sleep deprivation in both sexes and weight sub-groups (839.4 +/-77.5 vs 741.4+/-63.2 pg/mL, p= 0.003). Adiponectin was also found to be elevated in all participants regardless of biological sex or weight status (7.5 +/- 0.6 vs 6.8 +/- 0.6ug/mL, p= 0.003). However, ghrelin was observed to increase slightly more in participants with obesity, whereas elevations in adiponectin were slightly greater in those of normal weight.
Conclusion
In this study, sleep loss was associated with lowered levels of leptin and higher levels of ghrelin. Analysis between biological sexes indicated that there may be a greater decrease in leptin in females. Serum levels of adiponectin were also found to be elevated after sleep deprivation for both sexes with a slightly larger increase in women. These changes may result in increased hunger and food intake and decreased satiety. No significant differences were found between normal weight and obese participants.
Notes: The authors reported no conflicts of interest.
Clinical practice applications:
Sleep deprivation may lead to lower levels of leptin in both sexes with a greater decrease for females. Ghrelin and adiponectin levels may be increased in both men and women after sleep loss with a slightly larger increase in adiponectin for women. This could lead to an increase in appetite, food consumption and therefore weight gain, particularly in women.
Considerations for future research:
- Larger studies are needed to investigate sex and weight status related differences in serum levels of ghrelin, leptin and adiponectin.
- It may be beneficial for blood samples to be taken at different points during the day to allow for fluctuations in hormone levels.
- Food intake should be measured to monitor any increases in food intake.
Abstract
OBJECTIVE This study investigated whether blood concentrations of leptin, ghrelin, and adiponectin are affected by acute total sleep deprivation in a sex- and weight-specific manner. METHODS A total of 44 participants (mean age 24.9 years; 20 women; 19 with obesity) participated in a crossover design, including one night of sleep deprivation and one night of sleep in the laboratory. After each night, fasting blood was collected. RESULTS After sleep deprivation, fasting levels of leptin were lower (mean [SE], vs. sleep: 17.3 [2.6] vs. 18.6 [2.8] ng/mL), whereas those of ghrelin and adiponectin were higher (839.4 [77.5] vs. 741.4 [63.2] pg/mL and 7.5 [0.6] vs. 6.8 [0.6] μg/mL, respectively; all p < 0.05). The changes in leptin and adiponectin following sleep loss were more pronounced among women. Furthermore, the ghrelin increase was stronger among those with obesity after sleep loss. Finally, the sleep loss-induced increase in adiponectin was more marked among normal-weight participants. CONCLUSIONS Acute sleep deprivation reduces blood concentrations of the satiety hormone leptin. With increased blood concentrations of ghrelin and adiponectin, such endocrine changes may facilitate weight gain if persisting over extended periods of sleep loss. The observed sex- and weight-specific differences in leptin, ghrelin, and adiponectin call for further investigation.
3.
Enhancing Night and Day Circadian Contrast through Sleep Education in Prediabetes and Type 2 Diabetes Mellitus: A Randomized Controlled Trial.
García-Serrano, C, Pujol Salud, J, Aran-Solé, L, Sol, J, Ortiz-Congost, S, Artigues-Barberà, E, Ortega-Bravo, M
Biology. 2022;11(6)
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Diabetes mellitus is a chronic condition that occurs when blood glucose levels increase because the body cannot produce enough insulin or cannot effectively use the insulin it produces. Type 2 diabetes mellitus (T2DM) is the most common type of diabetes. It is a chronic metabolic disease that can be controlled when its pathophysiological factors are neutralised. The aim of this study was to analyse the effect of a sleep hygiene intervention in the management of impaired fasting glucose (IFG) and T2DM. This is an experimental study based on a parallel clinical trial using blocked randomization with equal allocation ratio. A total of 69 participants were included in the analysis (31 and 38 from the control and intervention groups, respectively). Results show a significant improvement in all the measured sleep parameters (sleep quality, time and efficiency). Furthermore, it also demonstrates that sleep health educational intervention, delivered during the regular check-ups of patients with T2DM or IFG, has a positive metabolic effect and is feasible as a complementary therapy in primary care settings. Authors conclude that sleep education improves T2DM metabolic management.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Sleep has a restorative function that benefits glucose metabolism.
- Sleep education should emphasise that maintaining a regular and sufficient sleep schedule and establishing a series of routines and habits in the hours prior to going to sleep would prevent early awakenings.
- Education is an important part of clinical practice.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
The aim of this study was to analyse the effect of a sleep hygiene intervention in the management of impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM).
Methods
This experimental parallel open-label clinical trial included 69 adults with IFG or T2DM.
The intervention was individual informative education which aimed to develop skills to improve sleep, which consisted of:
1. Information: Reading of the educational sheet (9 tips for a healthy sleep) with subsequent discussion.
2. Verification: checking participants understood the advice.
3. Participant information: One telephone call after 1 month was made as educational reinforcement of the intervention.
The controlled group received no educational intervention. The main outcome variable measured was levels of HbA1c (%) 3 and 6 months post intervention. Secondary outcomes were fasting glucose (mg/dL) 3 and 6 months post intervention, Pittsburgh Sleep Quality Index (PSQI), declared sleep hours and sleeping efficiency 3 months post intervention.
Results
- . 84.2% participants from the intervention group and 14.0% in the control group reported a change in sleep habits.
- 3 months after the intervention, the control group did not report any change, while the intervention group reported a statistically significant improvement in all three: PSQI (−2.97 ± 2.93), hours of sleep (1.00 [0.00; 2.00] hours) and sleep efficiency (6.74 ± 12.9%).
- The intervention group achieved a significant reduction in 3 months post intervention fasting glucose levels (−14.69; CI 95%: −28.15, −1.22) and HbA1c levels (−0.39; 95% CI: −0.73, −0.05), as well as a reduction in 6 months post intervention HbA1c levels (−0.66; 95% CI: −0.96, −0.36).
Conclusion
- The results show a significant improvement in all the measured sleep parameters (sleep quality, time and efficiency).
- The PSQI score improvement in the intervention group was 3.6 points higher than the control group.
- The median sleep time in the intervention group was increased by 1.5 h, doubling the number of participants who reported sleeping more than 6 h.
Clinical practice applications:
- An educational intervention in sleep hygiene and circadian contrast may help to increase sleep quality, time and efficiency.
- The educational intervention helped lower HbA1c levels in patients with IFG and T2DM.
- Sleep education helps to improve T2DM metabolic management.
- The 9 tips for a healthy sleep, were developed from the latest guidelines from the American Academy of Sleep Medicine, the National Health Service, and the Health Department of Catalonia.
Considerations for future research:
- The open-labelled intervention and the use of subjective variables related to sleep quality could lead to biassed self-reports in the intervention group so further studies are required.
- Future studies should gather baseline parameters closer to the start of the intervention rather than wait 3 months to assess the immediate outcomes of the intervention.
- Future research could take the same approach with diet and exercise education.
Abstract
BACKGROUND Evidence supports a causal relationship between circadian disturbance and impaired glucose homeostasis. METHODS To determine the effect of an educational intervention delivered by primary care nurses to improve sleep hygiene, a parallel, open-label clinical trial in subjects aged 18 and older with impaired fasting glucose (IFG) or type 2 diabetes mellitus (T2DM) was performed. Study variables were sex, age, fasting glucose, glycated haemoglobin A1c (HbA1c), Pittsburgh Sleep Quality Index (PSQI), sleep duration and efficiency, body mass index, antidiabetic treatment, diet and physical exercise. An individual informative educational intervention was carried out following a bidirectional feedback method. The intervention aimed to develop skills to improve sleep through nine simple tips. An analysis of covariance was performed on all the mean centred outcome variables controlling for the respective baseline scores. RESULTS In the intervention group, PSQI dropped, the duration and quality of sleep increased, and a decrease in fasting glucose and in HbA1c levels was observed. CONCLUSION The proposed intervention is effective for improving sleep quality, length and efficiency, and for decreasing fasting glucose and HbA1c levels in only 3 months. These findings support the importance of sleep and circadian rhythm education focused on improving IFG and T2DM.
4.
Gut feelings: A randomised, triple-blind, placebo-controlled trial of probiotics for depressive symptoms.
Chahwan, B, Kwan, S, Isik, A, van Hemert, S, Burke, C, Roberts, L
Journal of affective disorders. 2019;253:317-326
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Depression is a debilitating psychiatric disorder that is the leading cause of disability world-wide. Multiple causes of depression have been identified, including genetic, neurological, inflammatory, personality, cognitive, and environmental factors. The aim of this study was to investigate the effectiveness of the multispecies probiotic Ecologic® Barrier for reducing symptoms in adults with mild to severe levels of depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial. Participants were randomly allocated into two groups; probiotic and placebo. 71 participants with depressive symptoms were recruited and allocated sequentially over 12 months. Results indicate that all participants across both probiotic and placebo groups exhibited a reduction in depressive symptoms over the time-period of the trial. Thus, the routine involved with daily preparation and consumption of the probiotic and scheduled appointments, as well as involvement in these behaviours with the aim of seeking improvement in depressive symptoms had positive impacts on mood, irrespective of whether the probiotic or placebo was consumed. Authors conclude that their findings offer evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression.
- The study suggests that probiotics, rather than having a direct effect on depressive symptoms, potentially act on immune system activity, inflammation and gut barrier integrity which contribute to the expression of depression.
- Probiotics may be a useful adjunct to potentiate the effects of other therapies, such as CBT.
- This study points to the validity of managing physical health as part of mental health treatment.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
With evidence suggesting that decreased gut barrier function and inflammation are correlated with depression, this study set out to determine the effect of consumption of probiotic supplements on depressive symptoms from a sample of 71 participants with depression. The study was a triple-blinded parallel, placebo-controlled randomised clinical trial conducted over 8 weeks in Australia. Pre and post intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota were compared alongside psychological variables and gut microbiota composition to non-depressed, placebo and probiotic groups. All the clinical trial participants demonstrated an improvement in symptoms – participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group. Probiotics did not significantly alter the microbiota of depressed individuals, however a significant correlation was found between Ruminococcus gnavus and one of the metrics for depression.
Clinical practice applications:
This study was small and carried out over a short period of time. While significant results were found, which signify potential considerations for clinical practice, the results from this study do not offer evidence that the probiotics used had a direct effect on depressive symptoms – they suggest that probiotics potentially act on cognitive processes contributing to depression which may include immune system activity, inflammation, and gut barrier integrity. Overall, this study offers evidence to indicate that probiotic consumption can exert change on cognitive patterns associated with depression. In clinical practice, probiotics may be a useful adjunct to potentiate the effects of therapies, such as CBT. Finally, the use of probiotics promotes the concept of managing physical health as part of mental health treatment.
Considerations for future research:
These preliminary results are promising and offer a number of future research and clinical avenues to build upon. The results do however, indicate that a longer trial may be needed to fully assess the effects of probiotics on mood and the mechanisms by which probiotics may be influencing this. The study also suggests that further research using a range of concentrations in a dose response study may be warranted to determine the optimal dose; a greater dose over a longer period may produce detectable changes in microbiota as well as further differences in psychological data.
Abstract
BACKGROUND Depression is the leading cause of disability worldwide; with evidence suggesting that decreased gut barrier function and inflammation are correlated with depressive symptoms. We conducted a clinical trial to determine the effect of consumption of probiotic supplements (Winclove's Ecologic® Barrier) on depressive symptoms in a sample of participants with mild to severe depression. METHOD 71 participants were randomly allocated to either probiotic or placebo, which was, consumed daily over eight weeks. Pre- and post-intervention measures of symptoms and vulnerability markers of depression as well as gut microbiota composition were compared. Clinical trial participants were also compared on psychological variables and gut microbiota composition to a non-depressed group (n = 20). RESULTS All clinical trial participants demonstrated improvement in symptoms, suggesting non-specific therapeutic effects associated with weekly monitoring visits. Participants in the probiotic group demonstrated a significantly greater reduction in cognitive reactivity compared with the placebo group, particularly in the mild/moderate subgroup. Probiotics did not significantly alter the microbiota of depressed individuals, however, a significant correlation was found between Ruminococcus gnavus and one depression metric. LIMITATIONS There was a high attrition rate, which may be attributed to weekly monitoring visits. Additionally, modulation of the gut microbiota may need more specific testing to distinguish subtle changes. CONCLUSIONS While microbiota composition was similar between all groups, probiotics did affect a psychological variable associated with susceptibility to depression. Further research is needed to investigate how probiotics can be utilised to modify mental wellbeing, and whether they can act as an adjunct to existing treatments.