Background/Objectives: Mood disorders include symptoms of depression, anxiety, and or stress, and have increased in prevalence. Green tea and its bioactive components (epigallocatechin gallate [EGCG] and L-theanine) have been investigated for their health benefits and neuroprotective properties. As adults seek integrative and alternative treatment modalities, it is relevant to determine the effects of natural and non-pharmacological treatments on humans. This study aimed to assess current evidence from published randomized controlled trials testing the effects of green tea, green tea extracts, or its bioactive compounds on mood disorder symptomology and brain-derived neurotrophic factor (BDNF). Methods: We searched PubMed, Cochrane Library, PsycINFO, Embase, Google Scholar, and ClinicalTrials.gov, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and utilizing predetermined inclusion and exclusion criteria. Results: A total of 445 studies were identified, 395 screened, and thirteen met inclusion criteria. Seven used one of the bioactive compounds found in green tea for intervention, while six used green tea extract, matcha, or traditional green tea. Mood disturbance was assessed with several tools, with studies reporting improvements in depressive (n = 4), anxiety (n = 6), stress (n = 5), and sleep (n = 1) symptoms. No studies found a statistically significant effect of green tea or its bioactive compounds on BDNF. Conclusions: Our findings suggest green tea, GTE, L-theanine, and EGCG may improve mood disorder symptomology, particularly symptoms of depression; no evidence to date reports effects on BDNF.

Background: Previous research indicates that gastrointestinal discomfort from milk consumption may be attributable to A1 β-casein, rather than lactose intolerance alone. A2 milk (free of A1 β-casein) consumption may result in fewer symptoms compared to conventional milk containing both A1/A2 β-casein. Objective: In this five-week, double-blind, double-crossover study, we assessed the physiological responses to doses escalating in volume of lactose-free conventional milk (Lactaid), A2 milk, and lactose-free A2 milk in fluid milk-avoiding participants. Methods: Each milk type was consumed over three separate weeks with three increasing doses across five days per week, >one week washout. Gastrointestinal symptoms, blood glucose, and breath gases were monitored for twenty-four, two-, and three-hours post-consumption, respectively. Sensory evaluation was completed for each sample. Results: Fifty-three participants consented and were randomized, with forty-eight participants completing the study. Overall, symptoms were minimal. On Days 1 and 3, lower ratings of bloating and flatulence were observed in A2 compared to lactose-free A2. Breath hydrogen responses reflected lactose content, but were higher in lactose-free A2 than Lactaid on Day 5. Thirty-three participants were deemed lactose-intolerant and had higher fasting and average breath hydrogen for all samples. The only symptom corresponding to the increase in breath hydrogen among these participants was flatulence after A2 consumption. Surprisingly, flatulence was apparently higher for lactose-tolerant individuals when consuming Lactaid compared to A2. Conclusions: These findings suggest that adults who avoid conventional fluid milk consumption may experience minimal GI discomfort from lactose-free and/or A1-free milks.