The effect of fermented milk on interferon production in malnourished children and in anorexia nervosa patients undergoing nutritional care

Exploring the gut-brain Axis: Potential therapeutic impact of Psychobiotics on mental health

One of the most challenging and controversial issues in microbiome research is related to gut microbial metabolism and neuropsychological disorders. Psychobiotics affect human behavior and central nervous system processes via the gut-brain axis, involving neuronal, immune, and metabolic pathways. They have therapeutic potential in the treatment of several neurodegenerative and neurodevelopmental disorders such as depression, anxiety, autism, attention deficit hyperactivity disorder, Alzheimer's disease, Parkinson's disease, schizophrenia, Huntington's disease, anorexia nervosa, and multiple sclerosis. However, the mechanisms underlying the interaction between psychobiotics and the abovementioned diseases need further exploration. This review focuses on the relationship between gut microbiota and its impact on neurological and neurodegenerative disorders, examining the potential of psychobiotics as a preventive and therapeutic approach, summarising recent research on the gut-brain axis and the potential beneficial effects of psychobiotics, highlighting the need for further research and investigation in this area.

Probiotic, prebiotic, synbiotic and fermented food supplementation in psychiatric disorders: A systematic review of clinical trials

The use of probiotics, prebiotics, synbiotics or fermented foods can modulate the gut-brain axis and constitute a potentially therapeutic intervention in psychiatric disorders. This systematic review aims to identify current evidence regarding these interventions in the treatment of patients with DSM/ICD psychiatric diagnoses. Forty-seven articles from 42 studies met the inclusion criteria. Risk of bias was assessed in all included studies. Major depression was the most studied disorder (n = 19 studies). Studies frequently focused on schizophrenia (n = 11) and bipolar disorder (n = 5) and there were limited studies in anorexia nervosa (n = 4), ADHD (n = 3), Tourette (n = 1), insomnia (n = 1), PTSD (n = 1) and generalized anxiety disorder (n = 1). Except in MDD, current evidence does not clarify the role of probiotics and prebiotics in the treatment of mental illness. Several studies point to an improvement in the immune and inflammatory profile (e.g. CRP, IL6), which may be a relevant mechanism of action of the therapeutic response identified in these studies. Future research should consider lifestyle and dietary habits of patients as possible confounders that may influence inter-individual treatment response.

Probiotic and prebiotic interventions in eating disorders: A narrative review

AIMS

The review aimed to summarise and discuss findings focused on therapeutic probiotic and prebiotic interventions in eating disorders (ED).

METHODS

Using PubMed/MEDLINE, Cochrane Library, and Web of Science all published studies were retrieved until February 2023, following PRISMA guidelines. From the 111 initial studies, 5 met the inclusion criteria for this review.

RESULTS

All studies included in this narrative review were focused on anorexia nervosa (AN). Three longitudinal, randomised, controlled trials aimed to evaluate interventions with probiotics (Lactobacillus reuteri, yoghurt with Lactobacillus, and Streptococcus) in children and adolescents. These studies primarily emphasised medical outcomes and anthropometric measures following the administration of probiotics. However, the findings yielded mixed results in terms of short-term weight gain or alterations in specific immunological parameters. With a lower level of evidence, supplementation with synbiotics (probiotic + prebiotic) has been associated with improvements in microbiota diversity and attenuation of inflammatory responses.

CONCLUSIONS

Research on probiotics and prebiotics in ED is limited, primarily focussing on anorexia nervosa (AN). Their use in AN regarding medical and anthropometric outcomes needs further confirmation and future research should be warranted to assess their impact on psychological and ED symptomatology, where there is a notable gap in the existing literature.

Effect of lactoferrin in oral nutrition supplement (ONS) towards IL-6 and IL-10 in failure to thrive children with infection

Background

Growth failure due to infection in children is a major health problem throughout the world. It provokes a systemic immune response, with increased interleukin (IL)-6 and reduced IL-10. Lactoferrin (Lf) is a multifunctional iron-binding protein that can be found in whey protein inside formula milk such as oral nutrition supplement (ONS), which is able to upregulate anti-inflammatory cytokines (IL-10) and modulate pro-inflammatory cytokines. We conducted this study to investigate the effect of Lf supplementation in ONS on IL-6 and IL-10 levels in children with failure to thrive and infection.

Methods

We performed a quasi-experimental pre- and post-study in children aged 12-60 months old with failure to thrive due to infectious illness. The subjects received 400 ml of oral nutritional supplements (ONS, 1 ml equivalent to 1 kcal) each day for 90 days, and their parents received dietary advice and medication based on the underlying illness. Blood was drawn to measure IL-6 and IL-10 before and after the intervention.

Results

There were 75 subjects recruited and divided into group-1 and group-2 based on age. The incidence of undernutrition was 37.33%. Lf in ONS intervention improved body weight and body length. Lf also reduced IL-6, although there was not a significant difference before and after the intervention. However, the IL-6 reduction was significantly higher in subjects with undernutrition compared with subjects with weight faltering. Pre-intervention IL-6 levels were higher in children with stunting than in children with normal stature. There was a greater change in IL-6 in children with severe stunting than in children with normal stature or stunting. IL-10 was significantly reduced after the intervention.

Conclusions

In addition to improving body weight and length, Lf supplementation in ONS improved immune response homeostasis by balancing IL-6 and IL-10 levels and by improving the IL-6/IL-10 ratio.ClinicalTrials.gov number ID: NCT05289674, dated May 3 rd 2022.

[The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders]

The Therapeutic Potential of Prebiotics and Probiotics in Child and Adolescent Psychiatric Disorders Abstract: This short review summarizes the literature available on therapeutic interventions with prebiotics and probiotics and their potential use in psychiatric disorders in childhood, adolescence, and adulthood. Most studies of children and adolescents are done on ADHD and autism spectrum disorders, whereas single reports exist largely on positive effects on cognitive symptoms and quality of life. Initial studies regarding anorexia nervosa point to a potential effect of weight gain and reduction of gastrointestinal symptoms. To date, the effects of prebiotics and probiotics in depression, bipolar disorder, anxiety disorders, and schizophrenia have been mainly investigated in adults. The best reported evidence exists for depression, whereas the effects on depressive symptomatology are small. Positive effects are seen on gastrointestinal symptoms in these disorders. Given these positive effects, the mixed literature reports may result from very heterogeneous study designs. Nevertheless, the high potential of prebiotics and probiotics may be seen for minors with mental health problems. Further studies that include child and adolescent psychiatric populations and reflect the complexity of the gut-brain axis are urgently needed.

Gut-Associated Lymphatic Tissue in Food-Restricted Rats: Influence of Refeeding and Probiotic Supplementation

Anorexia nervosa (AN) is a severe and often chronic eating disorder that leads to alterations in the gut microbiome, which is known to influence several processes, such as appetite and body weight regulation, metabolism, gut permeability, inflammation, and gut-brain interactions. Using a translational activity-based anorexia (ABA) rat model, this study examined the effect of chronic food starvation, as well as multistrain probiotic supplementation and refeeding, on the structure of the gut and gut-associated lymphatic tissue (GALT). Our results indicated that ABA had an atrophic influence on intestinal morphology and increased the formation of GALT in the small bowel and colon. Higher formation of GALT in ABA rats appeared to be reversible upon application of a multistrain probiotic mixture and refeeding of the starved animals. This is the first time that increased GALT was found following starvation in the ABA model. Our results underscore a potential role of gut inflammatory alterations in the underlying pathophysiology of AN. Increased GALT could be linked to the gut microbiome, as probiotics were able to reverse this finding. These results emphasize the role of the microbiome-gut-brain axis in the pathomechanisms of AN and point to probiotics as potentially beneficial addendum in the treatment of AN.

World Federation of Societies of Biological Psychiatry (WFSBP) guidelines update 2023 on the pharmacological treatment of eating disorders

OBJECTIVES

This 2023 update of the WFSBP guidelines for the pharmacological treatment of eating disorders (EDs) reflects the latest diagnostic and psychopharmacological progress and the improved WFSBP recommendations for the assessment of the level of evidence (LoE) and the grade of recommendation (GoR).

METHODS

The WFSBP Task Force EDs reviewed the relevant literature and provided a timely grading of the LoE and the GoR.

RESULTS

In anorexia nervosa (AN), only a limited recommendation (LoE: A; GoR: 2) for olanzapine can be given, because the available evidence is restricted to weight gain, and its effect on psychopathology is less clear. In bulimia nervosa (BN), the current literature prompts a recommendation for fluoxetine (LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1). In binge-eating disorder (BED), lisdexamfetamine (LDX; LoE: A; GoR: 1) or topiramate (LoE: A; GoR: 1) can be recommended. There is only sparse evidence for the drug treatment of avoidant restrictive food intake disorder (ARFID), pica, and rumination disorder (RD).

CONCLUSION

In BN, fluoxetine, and topiramate, and in BED, LDX and topiramate can be recommended. Despite the published evidence, olanzapine and topiramate have not received marketing authorisation for use in EDs from any medicine regulatory agency.

Gastrointestinal symptoms, gut microbiome, probiotics and prebiotics in anorexia nervosa: A review of mechanistic rationale and clinical evidence

Recent research has revealed the pivotal role that the gut microbiota might play in psychiatric disorders. In anorexia nervosa (AN), the gut microbiota may be involved in pathophysiology as well as in the gastrointestinal (GI) symptoms commonly experienced. This review collates evidence for the potential role of gut microbiota in AN, including modulation of the immune system, the gut-brain axis and GI function. We examined studies comparing gut microbiota in AN with healthy controls as well as those looking at modifications in gut microbiota with nutritional treatment. Changes in energy intake and nutritional composition influence gut microbiota and may play a role in the evolution of the gut microbial picture in AN. Additionally, some evidence indicates that pre-morbid gut microbiota may influence risk of developing AN. There appear to be similarities in gut microbial composition, mechanisms of interaction and GI symptoms experienced in AN and other GI disorders such as inflammatory bowel disease and functional GI disorders. Probiotics and prebiotics have been studied in these disorders showing therapeutic effects of probiotics in some cases. Additionally, some evidence exists for the therapeutic benefits of probiotics in depression and anxiety, commonly seen as co-morbidities in AN. Moreover, preliminary evidence for the use of probiotics in AN has shown positive effects on immune modulation. Based on these findings, we discuss the potential therapeutic role for probiotics in ameliorating symptoms in AN.

Psychobiotics: the Influence of Gut Microbiota on the Gut-Brain Axis in Neurological Disorders

Nervous system disorders are one of the common problems that affect many people around the world every year. Regarding the beneficial effects of the probiotics on the gut and the gut-brain axis, their application along with current medications has been the subject of intense interest. Psychobiotics are a probiotic strain capable to affect the gut-brain axis. The effective role of Psychobiotics in several neurological disorders is documented. Consumption of the Psychobiotics containing nutrients has positive effects on the improvement of microbiota as well as alleviation of some symptoms of central nervous system (CNS) disorders. In the present study, the effects of probiotic strains on some CNS disorders in terms of controlling the disease symptoms were reviewed. Finding suggests that Psychobiotics can efficiently alleviate the symptoms of several CNS disorders such as autism spectrum disorders, Parkinson’s disease, multiple sclerosis, insomnia, depression, diabetic neuropathy, and anorexia nervosa. It can be concluded that functional foods containing psychotropic strains can help to improve mental health.

A systematic review of in vitro cytokine production in eating disorders

BACKGROUND

Eating disorders (EDs) have been associated with alterations in cytokine concentrations and production. This review examines whether in vitro cytokine production (i) is altered in people with EDs compared to healthy participants; and (ii) changes in response to treatment?

METHODS

Using PRISMA guidelines, we systematically reviewed articles reporting group comparisons or longitudinal assessments of spontaneous and/or stimulated cytokine production in vitro in people with EDs.

RESULTS

Twelve studies were included. Cross-sectional results were mixed in anorexia nervosa. Only one study measured cytokine production in bulimia nervosa. Two longitudinal studies showed that daily yoghurt consumption increases phytohemagglutinin-stimulated interferon-γ production in anorexia nervosa.

CONCLUSION

The mixed results could be accounted for by variations in experimental design. Our findings suggest that cytokine production could possibly be modulated through dietary interventions. However, due to the methodological heterogeneity and shortcomings of the included studies, it seems unreasonable to draw further conclusions.

Can prebiotics and probiotics improve therapeutic outcomes for undernourished individuals?

It has become clear in recent years that the human intestinal microbiota plays an important role in maintaining health and thus is an attractive target for clinical interventions. Scientists and clinicians have become increasingly interested in assessing the ability of probiotics and prebiotics to enhance the nutritional status of malnourished children, pregnant women, the elderly, and individuals with non-communicable disease-associated malnutrition. A workshop was held by the International Scientific Association for Probiotics and Prebiotics (ISAPP), drawing on the knowledge of experts from industry, medicine, and academia, with the objective to assess the status of our understanding of the link between the microbiome and under-nutrition, specifically in relation to probiotic and prebiotic treatments for under-nourished individuals. These discussions led to four recommendations:   (1) The categories of malnourished individuals need to be differentiated To improve treatment outcomes, subjects should first be categorized based on the cause of malnutrition, additional health-concerns, differences in the gut microbiota, and sociological considerations. (2) Define a baseline "healthy" gut microbiota for each category Altered nutrient requirement (for example, in pregnancy and old age) and individual variation may change what constitutes a healthy gut microbiota for the individual. (3) Perform studies using model systems to test the effectiveness of potential probiotics and prebiotics against these specific categories These should illustrate how certain microbiota profiles can be altered, as members of different categories may respond differently to the same treatment. (4) Perform robust well-designed human studies with probiotics and/or prebiotics, with appropriate, defined primary outcomes and sample size These are critical to show efficacy and understand responder and non-responder outcomes. It is hoped that these recommendations will lead to new approaches that combat malnutrition. This report is the result of discussion during an expert workshop titled "How do the microbiota and probiotics and/or prebiotics influence poor nutritional status?" held during the 10th Meeting of the International Scientific Association for Probiotics and Prebiotics (ISAPP) in Cork, Ireland from October 1-3, 2012. The complete list of workshop attendees is shown in Table 1.

Effects of enteral immunonutrition on the maintenance of gut barrier function and immune function in pigs with severe acute pancreatitis

BACKGROUND

This study evaluated the effects of enteral immunonutrition (EIN) supplemented with glutamine, arginine, and probiotics on gut barrier function and immune function in pigs with severe acute pancreatitis (SAP).

METHODS

The model was induced by retrograde injection of 5% sodium taurocholate and trypsin via the pancreatic duct. After induction of SAP, 18 pigs were randomly divided into 3 groups, in which either parenteral nutrition (PN), control enteral nutrition (CEN), or EIN was applied for 8 days. Serum and pancreatic fluid amylase concentration was determined. Intestinal permeability (lactulose to mannitol ratio) was measured by high-performance liquid chromatography, and plasma endotoxin was quantified by the chromogenic limulus amebocyte lysate technique. Samples of venous blood and organs were cultured using standard techniques. Pancreatitis severity and villi of ileum were scored according to histopathologic grading. Plasma T-lymphocyte subsets were measured by flow cytometry, and immunoglobulins (Igs) were determined via enzyme-linked immunosorbent assay.

RESULTS

There were no significant differences in serum and pancreatic fluid amylases concentrations or in pancreatitis severity between any 2 of the 3 groups. Compared with PN and CEN, EIN significantly decreased intestinal permeability, plasma endotoxin concentration, and the incidence and magnitudes of bacterial translocation, but increased ileal mucosal thickness, villous height, crypt depth, and percentage of normal intestinal villi. Significant differences were found in CD3+, CD4+ lymphocyte subsets, the ratio of CD4+: CD8+ lymphocyte subsets, and serum IgA and IgG, but not IgM, between any 2 of the 3 groups.

CONCLUSIONS

EIN maintained gut barrier function and immune function in pigs with SAP.

Immunomodulatory effects of probiotics in different stages of life

The immunomodulatory properties of lactic acid bacteria (LAB) and foods containing them (e.g., fermented milks) is a topic currently under investigation. Individuals could potentially benefit from the inclusion of LAB in the diet at different times during the life cycle. One of the most accepted specific uses of probiotic bacteria is the prevention of atopic eczema in infants with family history of the disease who receive the probiotic bacteria early, through supplementation of the gestating mother and orally after birth. Immune enhancing effects have also been suggested to be beneficial in diarrhoea treatment, especially in children infected with rotavirus and in malnourished patients, infants and adolescents, whose capacity to produce IFN-gamma can be increased after LAB-containing yoghurt intake. Regarding young people and adults, investigations have been conducted exploring the immunomodulation by LAB in subjects under stressful situations, in the prevention of urinary tract infections in fertile women and in the treatment of allergy. However, the beneficial effects of probiotics in these conditions remain controversial and the scientific evidence provided so far is not considered to be conclusive. The elderly population has been the focus of investigations aimed at identifying the capacity of probiotics to counteract the immunosenescence process by increasing phagocytic and natural killer (NK) cell activities and to protect against infection. The mechanisms involved in the different effects attributed to LAB remain to be clarified. Moreover, considering that the immunomodulatory properties are strain-specific, defining the optimal dose of a certain bacteria or combination of bacteria strains and the duration of treatment for a desired effect in a target population group is essential in order to substantiate health claims.

Probiotic, as well as conventional yogurt, can enhance the stimulated production of proinflammatory cytokines

BACKGROUND

Lactic acid bacteria have been shown to stimulate the secretion of cytokines by lymphocytes and monocytes in a strain-dependent manner. Therefore, in this study, the effect of a daily intake of probiotic yogurt on cytokine production in young healthy women was compared with that of a conventional product.

METHODS

For 2 weeks each, subjects consumed 100 g, then 200 g of either a probiotic or a conventional, commercially available yogurt, both containing Lactobacillus bulgaricus and Streptococcus thermophilus with additional Lactobacillus casei DN 114 001 in the probiotic product. Cytokine production in blood culture following stimulation with phytohaemmaglutinin and lipopolysaccharide was measured using Cytometric Bead Array and enzyme-linked immunosorbent assay.

RESULTS

Stimulated production of tumour necrosis factor-alpha increased significantly following consumption of conventional or probiotic yogurt (+63% and +24% compared with baseline, respectively, P < 0.001). There was also a significantly higher production of interleukin (IL)-1beta in the conventional (+40%, P = 0.006) and of interferon gamma in the probiotic group (+108%, P < 0.05). IL-10 decreased following consumption of the probiotic product, but increased significantly after intake cessation (+129%, P < 0.001). No significant differences in cytokine responses between the conventional and the probiotic yogurt were observed.

CONCLUSION

Both conventional and probiotic yogurt enhanced the stimulated production of pro-inflammatory cytokines.

Daily Intake of Probiotic as well as Conventional Yogurt Has a Stimulating Effect on Cellular Immunity in Young Healthy Women

BACKGROUND/AIMS

The aim of this work was to study the effects of daily yogurt consumption on the cellular immunity of young healthy women and to compare a conventional with a probiotic product.

METHODS

33 young healthy women (22-29 years) consumed 100 g/day of either probiotic or conventional commercially available yogurt for 2 weeks and 200 g/day for another 2 weeks followed by a 2-week washout period with no fermented food at all. Before the intervention and after each phase, a complete white blood count was done, the percentage of activated CD69+ T lymphocytes after stimulation of whole blood with pokeweed mitogen was determined as well as the natural cytotoxicity of peripheral blood mononuclear cells against a human erythroleukemic target cell line (K562). All analyses were done by flow cytometry.

RESULTS

In the probiotic group only, the numbers of cytotoxic T lymphocytes (CD3+CD16+CD56+) increased significantly (+30.8% with p = 0.001, +22.1 and +32.7% with p = 0.002, for T2, T3 and T4 compared to T1). There were no major changes for other cell populations, and all remained within the physiological range. In both groups, the expression of CD69 on T lymphocytes increased after yogurt consumption, especially on CD8+ (conventional: T2 +23%, T3 +27.2%, probiotic: T2 +15.7%; T3 +10.8% compared to T1) and to a lesser extent on CD4+ (conventional: T2 +7.7%, T3 +14.9%, probiotic: T2 +4% compared to T1. The cytotoxic activity also augmented following the intake, this effect persisting after cessation of consumption. However, there were no significant differences between the probiotic and the conventional yogurt group.

CONCLUSION

Daily yogurt intake has a stimulating effect on cellular immune functions, but in this study the probiotic product did not perform better than the traditional one.

Reversal in fatigued athletes of a defect in interferon gamma secretion after administration of Lactobacillus acidophilus

BACKGROUND

Fatigue and impaired performance in athletes is well recognised and has been loosely linked to "overtraining". Reduced concentration of IgA in the saliva and increased shedding of Epstein Barr virus (EBV) have been associated with intense training in elite athletes.

OBJECTIVE

To determine whether athletes presenting with fatigue and impaired performance had an immune defect relevant to defective containment of EBV infection, and whether a probiotic preparation (Lactobacillus acidophilus) shown to enhance mucosal immunity in animal models could reverse any detected abnormality.

RESULTS

The fatigued athletes had clinical characteristics consistent with re-activation of EBV infection and significantly (p = 0.02) less secretion of interferon (IFN) gamma from blood CD4 positive T cells. After one month of daily capsules containing 2 x 10(10) colony forming units of L acidophilus, secretion of IFNgamma from T cells had increased significantly (p = 0.01) to levels found in healthy control athletes. A significant (p = 0.03) increase in salivary IFNgamma concentrations in healthy control athletes after the one month course of L acidophilus demonstrated in man the capacity for this probiotic to enhance the mucosal IFNgamma concentration.

CONCLUSION

This is the first evidence of a T cell defect in fatigued athletes, and of its reversal following probiotic therapy.

Yoghurt accelerates the recovery of defence mechanisms against Streptococcus pneumoniae in protein-malnourished mice

Experiments studied the effect of yoghurt on the recovery of defence mechanisms against Streptococcus pneumoniae respiratory infection in malnourished mice. Weaned mice were malnourished with a protein-free diet (PFD) for 21 d. Malnourished mice were made replete with a balanced diet (BD), yoghurt, or the BD with supplemental yoghurt (BD + Y) for 7, 14 or 21 d. The normal control (NC) group was fed the BD whereas malnourished control (MC) mice consumed only the PFD. Mice were challenged with pneumococci at the end of each dietary treatment. MC mice showed increased susceptibility to pneumococcal infection. Blood leucocytes, phagocyte activity and serum and bronco-alveolar anti-pneumococcal IgG and IgA were significantly lower in the MC than in the NC group. Repletion of malnourished mice with the BD for 21 d was necessary to obtain a response to infection similar to that of NC mice; however, administration of the BD + Y for 14 d was enough to normalise the immune defence mechanisms. Histological examination of MC lungs showed progressive loss of alveolar architecture. Lung injuries were significantly less pronounced in NC mice. Mice treated with the BD + Y for 14 d showed histological signs similar to the NC group. The present study showed that administration of yoghurt to malnourished mice induced an early recovery of the immunological parameters studied. Despite the uncertainties about the mechanisms involved and about the human relevance of the effects observed in animal models, the present study provides a strong rationale for the hypothesis that yoghurt consumption by malnourished hosts will accelerate the recovery of the immune mechanisms involved in the protection against respiratory infections.

Effects of a nutritional intervention with yogurt on lymphocyte subsets and cytokine production capacity in anorexia nervosa patients

BACKGROUND

The benefits of probiotic therapy in immunocompromised subjects still need strong scientific evidences.

AIM OF THE STUDY

To assess the effects of yogurt on certain immunological parameters in anorexia nervosa (AN) patients during refeeding.

METHODS

A parallel 10-week nutritional intervention with yogurt was conducted on a group of patients with AN and on a group of healthy adolescents (HA). In total, 16 AN patients and 16 HA consumed 375 g/d of yogurt containing L. bulgaricus and S. thermophilus (groups AN-y and HA-y, respectively). The control groups for AN patients (n = 14) and healthy subjects (n = 19) consumed 400 ml/d of semi-skimmed milk (groups AN-c and HA-c, respectively). Blood lymphocyte subsets were assessed by flow cytometry and the in vitro production of IL-2, IFN-gamma, IL-1, IL-6 and TNF-alpha by PHA-stimulated PBMC was measured by ELISA.

RESULTS

A significant combined effect of time and nutritional intervention was found for the CD8+ subset and IFN-gamma production, both in HA and AN patients. The CD8+ subset showed a significant increase after 10 weeks in HA-c and AN-c. As a consequence, the CD4+/CD8+ ratio was significantly lower in AN-c than in AN-y after treatment. A significant increase in IFN-gamma production was found after yogurt intake in AN-y, while it decreased significantly in AN-c.

CONCLUSION

The findings suggest that the inclusion of yogurt in the refeeding therapy of AN patients may exert positive effects on the immunological markers related to the nutritional status of these patients, such as the CD4+/CD8+ ratio and the production of IFN-gamma by lymphocytes.

The effect of milk fermented by yogurt cultures plus Lactobacillus casei DN-114001 on the immune response of subjects under academic examination stress

BACKGROUND

A suppressed immune response has been documented in students under examination stress.

AIMS

The current study aimed to evaluate the effect of milk fermented with yogurt cultures plus Lactobacillus casei DN-114001 (Actimel) on the immune system of subjects under academic examination stress.

METHODS

University students were allocated to one of two groups, receiving during 6 weeks (3 weeks prior to, as well as the 3-week duration of the examination period) either: a) a glass of semi-skimmed milk each day (control group, n=63) or b) two 100mL portions per day of fermented milk (treatment group, n=73). Anxiety and immunological measurements were monitored at baseline (Phase 0) and study end (Phase 1).

RESULTS

The results were expressed as the differences between the data obtained from Phase 0 and Phase 1. This was calculated by subtracting Phase 1 results from the Phase 0 and it is denominated "Treatment effect". Mean (+/- SE) anxiety increased significantly (P<0.05) over the 6-week study in all students, from 40.74+/-2.50 to 61.19+/-2.64 (in percentiles). There was no significant treatment effect since this increase was similar in the control and the treatment groups (21.65+/-5.09 vs 19.14+/-3.67, respectively). However, there was a significant treatment effect (P<0.05) on the mean change in absolute number of lymphocytes during the 6-week study, which decreased in the control group (-0.04+/-0.12 cells x 10(3)/mm(3)) and increased in the treatment group (0.37+/-0.11 cells x 10(3)/mm(3)). There was also a significant treatment effect (P<0.05) on the change in absolute numbers of CD56 cells during the 6-week study. Mean absolute CD56 cells significantly decreased (P<0.05) in the control group (-51.97+/-21.33 cells/mm(3)),while remaining similar in the treatment group (17.29+/-17.27 cells/mm(3)). During the study, mean serum cortisol increased 4.30+/-0.98 microg/dL in the control group, and 1.75+/-1.05 microg/dL in the treatment group and no significant differences were found between both values (P=0.062).

CONCLUSIONS

Milk fermented with yogurt cultures plus Lactobacillus casei DN-114001 was able to modulate the number of lymphocytes and CD56 cells in subjects under academic examination stress.