We aimed at quantifying the effects of different tea and coffee on weight loss in adults. We searched PubMed, Scopus, CENTRAL and grey literature sources to July 2024. The study excluded cross-over trials without washout period, those in critically ill patients, pregnant or breast-feeding women, multicomponent interventions and active control groups with tea or coffee. A random-effects network meta-analysis with a Bayesian framework was performed to calculate the mean difference (MD) and 95 % credible intervals (CrIs). The certainty of evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation approach, and risk of bias was assessed using Cochrane tool. Twenty-two randomised controlled trials with 1710 participants (average intervention duration = 10 weeks) were included. Green tea was effective for weight loss compared with placebo (MD: −1·23 kg, 95 % CrI: −2·45, −0·02; low certainty evidence) or water (MD: −1·61 kg, 95 % CrI: −2·90, −0·35; very low certainty evidence), while other beverages (coffee, decaffeinated coffee, green coffee, black tea and sour tea) were not. Green tea was effective for weight loss compared with water in sensitivity analysis of healthy individuals (MD: −3·31 kg, 95 % CrI: −5·83, −1·04). Based on very low to low certainty evidence, green tea drinking may result in a small weight loss in adults. This study mainly focused on weight loss effects of green tea and coffee, with limited data on other teas. Only five trials had longer intervention durations, suggesting future research on long-term effects. Most trials had high bias risk and low certainty, requiring more high-quality trials.

Tea can improve the progression of some metabolic diseases through anti-inflammatory and antioxidant effects, but its impact on non-alcoholic fatty liver disease (NAFLD) is still controversial. The aim of this paper is to identify the relationship between tea and NAFLD by Mendelian randomisation (MR) and complete clinical validation using National Health and Nutrition Examination Survey (NHANES) database. MR used data from Genome Wide Association Study, with inverse-variance weighted (IVW) as principal analytical methods. The reliability of the results was verified by a series of sensitivity and heterogeneity tests. Subsequently, clinical validation was conducted using NHANES (2005–2018), involving 22 257 participants, grouped by the type of tea. Green tea drinkers were categorised into four groups (Q1–Q4) by quartiles of green tea intake, from lowest to highest (similar for black tea drinkers and other tea drinkers). Models were constructed by logistic regression to estimate the role of tea consumption (Q1–4) on NAFLD. Finally, using fibrosis-4 index (FIB-4) to evaluate the severity of hepatic fibrosis, the effect of tea consumption (Q1–4) on the degree of hepatic fibrosis was investigated by linear regression. IVW method (OR = 0·43, 95 % CI: 0·21, 0·85, P = 0·01) and weighted median method (OR = 0·35, 95 % CI: 0·14, 0·91, P = 0·03) revealed there was a causal relationship between tea and NAFLD. An array of sensitivity analyses validated the reliability of results. Analysis of NHANES indicated tea drinker present a slightly lower prevalence of NAFLD than non-tea drinker (green tea drinkers: 47·6 %, black tea drinkers: 46·3 %, other tea drinker: 43·2 %, non-tea drinkers: 48·1 %, P < 0·05). After adjusting for confounders, compared with the lowest black tea consumption (Q1), the population with the highest black tea consumption (Q4) was independently related to lower presence of NAFLD (Q4: OR = 0·69, 95 % CI: 0·50, 0·93, P < 0·05), such association remained stable in the overweight subgroup. As further analysed, Q4 also displayed a significant negative correlation with the level of hepatic fibrosis in patients with NAFLD (β = –0·073, 95 % CI: –0·126, −0·020, P < 0·01).Tea reduces the morbidity of NAFLD and ameliorates hepatic fibrosis degree in those already suffering from the disease.

Duyun compound green tea (DCGT) is a healthy beverage with lipid-lowering effect commonly consumed by local people, but its mechanism is not very clear. We evaluated the effect of DCGT treatment on bile acids (BA) metabolism of mice with high-fat diet (HFD) – induced hyperlipidaemia by biochemical indexes and metabolomics and preliminarily determined the potential biomarkers and metabolic pathways of hyperlipidaemia mice treated with DCGT as well as investigated its lipid-lowering mechanism. The results showed that DCGT treatment could reduce HFD – induced gain in weight and improve dyslipidaemia. In addition, a total of ten types of BA were detected, of which seven changed BA metabolites were observed in HFD group mice. After DCGT treatment, glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic acid were significantly down-regulated, while hyodeoxycholic acid, deoxycholic acid and chenodeoxycholic acid were markedly up-regulated. These results demonstrated that DCGT treatment was able to make the BA metabolites in the liver of hyperlipidaemia mice normal and alleviate hyperlipidaemia by regulating the metabolites such as glycocholic acid, tauroursodeoxycholic acid and taurochenodeoxycholic, as well as the BA metabolic pathway and cholesterol metabolic pathway involved.

The present study aimed to assess the longitudinal associations of coffee and tea consumption with metabolic syndrome and its component conditions in a group of Australian older adults who participated in the Blue Mountains Eye Study (n 2554, mean age: 64 years, 43 % female). Participants’ coffee and tea intake were measured using a validated food frequency questionnaire. Hazard ratios (HRs) over a 10-year period were estimated using Cox hazard regression models adjusting for lifestyle factors. Results showed that coffee consumption was not associated with the incidence of metabolic syndrome, high fasting glucose, high triglycerides, central obesity, high blood pressure and low HDL-cholesterol (HDL-C). Tea consumption was not associated with incidence of metabolic syndrome and the component conditions except for the risk of having low HDL-C, in which a nominally inverse association was observed (multivariate-adjusted HR at 2–3 cups/d: 0⋅48, 95 % CI 0⋅26, 0⋅87, P = 0⋅016; 4 cups/d or more: 0⋅50, 95 % CI 0⋅27, 0⋅93, P = 0⋅029). After stratifying for fruit consumption (Pinteraction between tea and fruit = 0⋅007), consuming four cups of tea per day was nominally associated with lower incidence of metabolic syndrome among those with high fruit consumption (multivariable-adjusted HR: 0⋅44, 95 % CI 0⋅20, 0⋅93, P = 0⋅033). Our results did not support a significant association between tea and coffee consumption and metabolic syndrome. Tea consumption may be associated with a lower risk of having low HDL-C, while high tea and fruit consumption together may be associated with a lower risk of developing metabolic syndrome.

The present study examines how alcohol intake from wine and non-wine alcoholic beverages (non-wine) in g/d, as well as cups of coffee and tea included as continuous covariates and mutually adjusted are associated with all-cause, cancer, non-cancer and CVD mortality. Consumption was assessed in 354 386 participants of the UK Biobank cohort who drank alcohol at least occasionally and survived at least 2 years after baseline with 20 201 deaths occurring over 4·2 million person-years. Hazard ratios (HR) for mortality were assessed with Cox proportional hazard regression models and beverage intake fitted as penalised cubic splines. A significant U-shaped association was detected between wine consumption and all-cause, non-cancer and CVD mortality. Wine consumption with lowest risk of death (nadir) ranged from 19 to 23 g alcohol/d in all participants and both sexes separately. In contrast, non-wine intake was significantly and positively associated in a dose-dependent manner with all mortality types studied except for CVD in females and with the nadir between 0 and 12 g alcohol/d. In all participants, the nadir for all-cause mortality was 2 cups coffee/d with non-coffee drinkers showing a slightly increased risk of death. Tea consumption was significantly and negatively associated with all mortality types in both sexes. Taken together, light to moderate consumption of wine but not non-wine is associated with decreased all-cause and non-cancer mortality. A minor negative association of coffee consumption with mortality cannot be excluded whereas tea intake is associated with a consistently decreased risk of all mortality types studied.

Tea contains polyphenols such as flavonoids, anthocyanidins, flavanols and phenolic acids which in laboratory studies have reported to promote antioxidant enzyme formation, reduces excess inflammation, slow cancer cell proliferation and promote apoptosis. Evidence from epidemiological studies on the effect of tea consumption on prostate cancer (CaP) incidence has been conflicting. We analysed data from 25 097 men within the intervention arm of the 155 000 participant Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Histologically confirmed cases of prostate cancer were reported in 3088 men (12·3 %) during the median 11·5 year follow-up. Tea consumption was assessed with a FFQ. Baseline characteristics were compared between groups using χ2 and Kruskal–Wallis tests. Cox regression models were used to assess associations between tea intake and CaP incidence. There was no statistical difference between the risk of CaP between men who never drank tea to those who drank tea at any quantity. Amongst tea drinkers, those in the highest third of consumption group had a small but significantly lower risk compared with those in the lowest third (11·2 % v. 13·2 % hazard ratio 1·16; (95 % CI 1·05, 1·29), P = 0·004). This pattern persisted with adjustments for demographics and lifestyle. In conclusion, among tea drinkers, there was a small positive association between drinking tea and a reduced risk of prostate cancer. It does not support starting to drink tea, if men previously did not, to reduce the risk. Further research is needed to establish whether tea is justified for future prospective nutritional intervention studies investigating CaP prevention.

The existing literature has demonstrated that both ethnic and economic factors affect a vote decision in African democracies. I show that there is a meaningful interaction between the two cleavages in their influence on voting. In particular, I argue for political salience of agricultural subsectors that shape the electoral consequences of economic performance in the context where agricultural policy affects the livelihood of the majority population. Relying on the analyses of the 2007 and 2013 elections in Kenya, I illustrate how likely an individual, who is attached to a politically coherent ethnic group, votes for a candidate, the majority of whose ethnic members engage in the same industry as the voter himself regardless of the candidate's ethnicity. The results show that the sector factor reinforces the positive and negative effects of ethnic communities on incumbent support, and also explains voting by ethnic minorities whose motives for voting are not ethnic.

Consumption of a high-fat diet increases fat accumulation and may further lead to inflammation and hepatic injuries. The aim of the study was to investigate the effects of Camellia oleifera seed extract (CSE) on non-alcoholic fatty liver disease (NAFLD). After a 16-week NAFLD-inducing period, rats were assigned to experimental groups fed an NAFLD diet with or without CSE. At the end of the study, we found that consuming CSE decreased the abdominal fat weight and hepatic fat accumulation and modulated circulating adipokine levels. We also found that CSE groups had lower hepatic cytochrome P450 2E1 and transforming growth factor (TGF)-β protein expressions. In addition, we found that CSE consumption may have affected the gut microbiota and reduced toll-like receptor (TLR)-4, myeloid differentiation primary response gene 88, toll/IL-1 receptor domain-containing adaptor-inducing interferon-β (TRIF) expression and proinflammatory cytokine concentrations in the liver. Our results suggest that CSE may alleviate the progression of NAFLD in rats with diet-induced steatosis through reducing fat accumulation and improving lipid metabolism and hepatic inflammation.

Farmer training is important to improve weed management practices in tea cultivation. To explore the group characteristics of tea growers, we interviewed 354 growers in Guizhou Province, China. Sixty-one percent of the respondents planted tea for companies or cooperative groups, and 56% managed tea gardens larger than 10 ha. Self-employed tea growers tended to be older and smallholders, and to apply herbicides and conduct weed control less frequently (P < 0.05). Approximately 87% of the respondents conducted weed control two to four times yr−1, 83% spent between $200 and $2,000 ha−1 yr−1 for weed control, and 42% thought weed control costs would decrease by 5 years from this study. Twenty-eight species were mentioned by the respondents as being the most serious. According to canonical correspondence analysis, latitude, altitude, being self-employed or a member of a cooperative, having training experience in tea-garden weed management, and frequency and cost of weed control in tea gardens had significant (P < 0.05) influence on the composition of most troublesome weed species listed by respondents. Among the respondents, 60% had had farmer’s training on weed management in tea gardens. Of these, a significant number (P < 0.05) tended to think weed control costs would decrease, and a nonsignificant number (P > 0.05) tended to conduct weed control more frequently and have lower weed management costs in their tea gardens.