Karim Maghraby, M.B. B.Ch, M.Sc
Director, Nutritional Psychology Research Library (NPRL)

Microbiota-Gut-Brain Axis/DMHR

Microbiota-induced epigenetic alterations in depressive disorders are targets for nutritional and probiotic therapies

Major depressive disorder (MDD), being a complicated condition in nature, affects 280 million individuals globally and is a primary cause of disability. Numerous environmental variables, including medicines, nutrition, and microorganisms, have a role in the pathophysiology of depression disorders. The host immune system, genetics, and epigenetics are some of the contributors to the intricate underlying causes of depression. Alterations to intestinal microbiota and their metabolites affect how people with depressive disorders respond to stress and behave in social situations by influencing immune cell maturation and brain neurogenesis, which is mediated by epigenetic changes. In this study, Nohesara et al. (2023) address the possible contributions of dysregulated gut permeability to the emergence of depressive illnesses through changes in metabolites generated from the gut microbiota that have epigenetic consequences. In addition, the authors discuss how changes in the makeup of the gut microbiota might lead to epigenetic changes that can cause depressive illnesses. Focus is shed on the potential benefits of microbiota-derived metabolites, such as probiotics, butyrate (which acts as an epigenetic modifier), polyphenols, medications (such as antibiotics, antipsychotics, and antidepressants), maternal diet, and fecal microbiota transplantation, in mitigating depressive-like behaviors through altering the epigenetic landscape. Lastly, the authors review the difficulties and potential solutions connected to current treatment techniques for depressive disorders via microbiome-related epigenetic changes. 

Diet, Depression and Anxiety

Eating disorders symptoms and depressive symptoms in Chinese Tibetan university students: a network analysis.

The awareness of eating disorders, or EDs, continues to rise in tandem with the growing recognition of depression as a worldwide public health problem. The symptoms of EDs and other mental health issues, such as depression, commonly coincide. Still, there is a dearth of research on the symptoms of depression and EDs in Tibetan students studying in China. To determine the relationship network between EDs and symptoms of depression, Wu et al. (2023) recruited students from two colleges (Tibetan n = 2,582, Han n = 1,743) to conduct their study. Study participants completed the Patient Health Questionnaire-9 (PHQ-9) and the Eating Attitude Test-26 (EAT-26). The three main symptoms found through preliminary network analysis were “fatigue,” “desire to slim,” and “calorie awareness.” Suicide, appetite, anhedonia, body fat awareness, guilt, and food preoccupation, however, belonged to ‘bridge’ symptoms, i.e., symptoms that provide the links between the pathology of EDs and depression. The study found no discernible gender disparities in the network model. On the other hand, differences between the various ethnic groups were noted in the network structure. The authors deduce that preventing and managing EDs and symptoms of depression may be facilitated by concentrating intervention efforts on issues such as the individual’s pursuit of the ideal body type and the appetite issues that some students experience potentially due to moving away from home, adjusting to a new university environment, or adjusting to the diet made available by their school canteens. This may bring forth favorable outcomes by assisting students in maintaining mental and physical health. The authors conclude that their study sheds light on the role environmental impact plays in elevated levels of depression. 

Micronutrients and Mental Health

Efficacy and safety of a vitamin-mineral intervention for symptoms of anxiety and depression in adults: A randomised placebo-controlled trial “NoMAD.”

The costs of Depression and anxiety are rising. In an adult community environment, Blampied et al. (2023) looked at whether micronutrients (vitamins and minerals) reduced the symptoms of anxiety and Depression. For ten weeks, participants (n = 150) who reported functionally hindering symptoms of anxiety or Depression received either micronutrients or a placebo. The Generalised Anxiety Disorder Scale-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), and Clinical Global Impression-Improvement Scale (CGII) were used as the primary outcome measures. Participants were also monitored online with routine phone calls with a professional psychologist. The authors noted no significant adverse events or increased suicide thoughts throughout the study, and participants showed a low dropout rate (8.7%). The results revealed that the micronutrient group improved considerably more quickly on the PHQ-9 and the GAD-7. Further analysis demonstrated that participant characteristics impacted time-by-group interactions; for those from lower socioeconomic categories, younger individuals, and those who had already attempted medical treatment, micronutrients offered the quickest benefit relative to placebo. With 49% of the micronutrient group and 44% of the placebo group being recognized responders on the CGII, there were no group differences at the end-point. Participants taking micronutrients had noticeably more bowel movements than those taking a placebo. The authors recognize the limitations to the generalizability of their results due to the improvement under placebo and the lack of official diagnosis. Nevertheless, all subjects improved despite having little contact with a doctor, albeit changes with micronutrients manifested more rapidly. Participants in particular subgroups responded less well to the placebo, indicating the areas where micronutrients may be most useful as a treatment. (CNP Article in Nutritional Psychology on this study can be found here). 

Sugar, Ultra-Processed, & Hyper-Palatability

Social, clinical, and policy implications of ultra-processed food addiction

Addiction is becoming understood scientifically. Even though the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) does not list food addiction as a disorder, studies on the subject have expanded significantly over the past 20 years. The Yale Food Addiction Scale (YFAS), created to quantify food addiction by evaluating DSM-5 criteria for drug use disorder in the context of food intake, is used extensively in this research. Gearhardt et al. (2023) present a recent analysis of two systematic reviews, including 281 studies from 36 countries, which revealed that 14% of adults and 12% of children worldwide have YFAS-measured food addiction. However, the degree of suggested addiction in children is unprecedented. This claimed prevalence is comparable to the levels of addiction documented for other legal drugs in adults (14% for alcohol and 18% for tobacco). YFAS found that the prevalence of food addiction approaches 32% in obese patients undergoing bariatric surgery and above 50% in patients with binge eating disorders in populations with clearly established clinical diagnoses. According to the YFAS, food addiction is linked to key elements of addiction, including mood dysregulation, impulsivity, reward-related brain dysfunction, worsened physical and mental health, and decreased quality of life. The authors conclude that convergent and consistent evidence supports the validity and clinical applicability of food addiction; nevertheless, it is less clear what kinds of foods are addictive. Despite the ambiguity, labeling certain foods as addictive may encourage study and change public perceptions of regulation. 

Diet and the Parent-Child Relationship (Child and Adolescent Research Library)

Emotional eating following a laboratory mood induction: The interaction between parental feeding practices and child temperament.

The preferential ingestion of palatable meals (sugar- and fat-rich) is seen commonly in emotional eater (EE) children. Although the exact nature of EE development is unknown, EE may be influenced by the eating habits of parents as well as a child’s temperament. These interaction effects on EE have yet to be empirically investigated. Furthermore, rather than focusing on particular negative emotions like boredom, which has never been studied in this context, most studies have examined EE in reaction to a general “negative” mood. In order to predict the number of calories consumed by children aged 4–5 years in a laboratory setting, this study by Stone et al. (2023) sought to investigate the interactions between parent-reported non-responsive feeding practices (such as the use of food items as rewards, restricting certain foods due to negative health impacts, or using food for emotional control), induced mood conditions (boredom, sadness, control), and parent-reported child temperament (negative affect, effortful control, surgency). According to the results, children who participated in the control group ingested considerably fewer total calories than the bored children. Furthermore, compared to the control condition, children of parents who reported frequent use of food for emotion regulation and children with high negative affect consumed significantly more calories from sweet food when bored. Similarly, children with high negative affect and parents who reported infrequent use of food as a reward also consumed significantly more calories from sweet food when bored. The authors conclude that children’s snack food intake is potentially predicted by their emotions of boredom and that non-responsive feeding practices and negative affect in children are significant factors in the manifestation of this connection.

Diet and Beneficial Microbes

Inulin-type fructans and 2’fucosyllactose alter both microbial composition and appear to alleviate stress-induced mood state in a working population compared to placebo (maltodextrin): the EFFICAD Trial, a randomized, controlled trial.

The reciprocal interaction between the gut and the brain, as well as the ways in which the prebiotics oligofructose and 2’fucosyllactose can change the makeup of microorganisms and mood, are subjects of growing attention. However, much remains to be learned about how oligopeptide and 2’fucosyllactose might alter the gut flora to enhance mood. In this 5-week, 4-arm, parallel, double-blind, randomized, placebo-controlled study by Jackson et al. (2023), the authors assessed how oligofructose and 2’fucosyllactose, both separately and in combination with maltodextrin, affected the microbiological makeup and psychological condition of a working population. Ninety-two healthy people who suffered from mild to moderate depression and anxiety were recruited for this study. The subjects were randomized to receive 8 g/d of oligofructose plus 2 g/d of maltodextrin, 10 g/d of maltodextrin, 8 g/d of oligofructose plus 2 g/d of 2’fucosyllactose, or 2 g/d of 2’fucosyllactose plus 8 g/d of maltodextrin. Bowel habits, gastrointestinal symptoms, and emotional state indicators were among the secondary results, while the main measurements were modifications in the microbial load (fluorescence in situ hybridization-flow cytometry) and composition (16S ribosomal RNA sequencing). Analysis of the results revealed that the oligofructose and oligofructose/2’fucosyllactose treatments resulted in substantial increases in a number of bacterial taxa, including Bacteroides, Bifidobacterium, Roseburia, and Faecalibacterium prausnitzii. The bacterial taxa changed in a very diverse way when 2’fuscoyllactose was added. Between oligofructose, oligofructose/2’fucosyllactose combination, and 2’fucosyllactose interventions, significant improvements in Positive and Negative Affect Schedule scores, cortisol awakening response, State-Trait Anxiety Inventory Y1 and Y2, and Beck Depression Inventory were observed. All mood state metrics were improved with both the oligofructose alone and the oligofructose/2’fuscosyllactose combination treatments, outperforming the solo 2’fuscosyllactose and maltodextrin. The authors comment that their study’s findings suggest that oligofructose and oligofructose/2’fucosyllactose combination can improve mood state metrics and change the microbial makeup in a positive way. To comprehend the essential microbiological distinctions that distinguish between individual responses to 2’fucosyllactose supplementation, more research is required.