Black Tea
Black tea and its catechins/theaflavins are studied for cardiovascular and metabolic markers. Effects are often modest.
Overview
What is black tea?
Black tea is tea made from the fermented leaves of the Camellia sinensis plant. It contains around 3–4% caffeine in addition to antioxidants.
Dosage
Optimal dose is unknown. Follow manufacturer guidelines or clinician advice.
Effect graph
Effect heatmap
SupplementDEX Database
32 conditions for , and rated at least stars. All purchase bands. No minimum star filter.
Database Snapshot
Most black tea research is concentrated in a handful of conditions.
- Colorectal cancer accounts for 10 of 95 studies (11%).
- Hypercholesterolemia (High cholesterol) accounts for 9 of 95 studies (9%).
- High blood pressure accounts for 8 of 95 studies (8%).
- Sparse coverage remains for Bladder Cancer, Breast Cancer, Cancer (ovarian).
Safety
Safety details were limited in the source article. Use standard caution and clinician guidance for high-dose or therapeutic use.
References
Sources79 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Mental alertness
6 references1.SupplementDEX Database: Mental alertness — Black tea improves attention and self-reported alertness2010
Two double-blind RCTs found black tea improved switch-task accuracy and self-reported alertness versus placebo; benefits were strongest when theanine and caffeine plasma levels were higher.
2.SupplementDEX Database: Mental alertness — Cognitive and physiological effects of an "energy drink": an evaluation of the whole drink and of glucose, caffeine and herbal flavouring fractions2004
In 20 healthy volunteers, a whole energy drink and its caffeine-plus-glucose components improved secondary memory and attention speed versus placebo, suggesting synergy beyond caffeine alone.
3.SupplementDEX Database: Mental alertness — An evaluation of a caffeinated taurine drink on mood, memory and information processing in healthy volunteers without caffeine abstinence2001
In 42 adults with minimal caffeine deprivation, an 80-mg caffeinated taurine drink improved attention and verbal reasoning versus sugar-free and sugar-containing placebos.
4.SupplementDEX Database: Mental alertness — Effect of three caffeine doses on plasma catecholamines and alertness during prolonged wakefulness2000
In 50 sleep-deprived adults, caffeine doses up to 8.6 mg/kg improved alertness (sleep latency, sleepiness, reaction time) and raised adrenaline for 1–4 h versus placebo in a dose-related pattern.
5.SupplementDEX Database: Mental alertness — The effects of a low dose of caffeine on cognitive performance1998
In 8 men, 60 mg caffeine from tea or hot water significantly sped reaction time on CANTAB tests within minutes of consumption, detectable on pattern recognition, delayed match-to-sample, and visual search tasks.
6.SupplementDEX Database: Mental alertness — The effects of black tea and other beverages on aspects of cognition and psychomotor performance1998
In 19 healthy adults, tea (with ~100 mg caffeine) throughout the day prevented the usual afternoon decline in alertness and largely maintained cognitive performance versus caffeine-matched placebo over ~90 min testing periods.
SupplementDEX Database · Cancer (ovarian)
2 references7.SupplementDEX Database: Cancer (ovarian) — Tea consumption and ovarian cancer risk in a population-based cohort2005
In 61,057 Swedish women followed 15.1 years, each additional cup of tea per day was associated with 18% lower epithelial ovarian cancer risk; ≥2 cups/day had HR 0.54 versus seldom/never drinkers.
8.SupplementDEX Database: Cancer (ovarian) — Tea consumption and ovarian cancer risk: a case-control study in China2002
In a Chinese case-control study, increasing green tea frequency and duration reduced ovarian cancer risk (OR 0.23 for >30 years); black and oolong tea associations were not significant.
SupplementDEX Database · Low blood pressure
2 references9.SupplementDEX Database: Low blood pressure — Effect of coffee and tea drinking on postprandial hypotension in older men and women1996
In 171 adults over 50, tea or coffee drinking attenuated postprandial systolic BP drops after meals versus abstaining from caffeine; tea reduced supine systolic fall by 3.8 mmHg in treated hypertensives.
10.SupplementDEX Database: Low blood pressure — The effect of caffeine on postprandial hypotension in the elderly1991
In 7 fit elderly subjects, caffeine with a meal prevented the 14 mmHg postprandial fall in supine systolic BP seen with placebo, maintaining BP near baseline (+9 mmHg at 60 min).
SupplementDEX Database · Myocardial infarction
4 references11.SupplementDEX Database: Myocardial infarction — Inverse association of tea and flavonoid intakes with incident myocardial infarction: the Rotterdam Study2002
In 4,807 Rotterdam Study participants followed 5.6 years, tea drinkers consuming >375 mL/day had 43% lower incident MI risk (RR 0.57) than nondrinkers; flavonoid intake was inversely associated with fatal MI.
12.SupplementDEX Database: Myocardial infarction — Tea consumption and mortality after acute myocardial infarction2002
In 1,900 post-MI patients followed 3.8 years, moderate (OR-derived HR 0.69) and heavy (HR 0.61) tea drinkers had lower mortality than nondrinkers after adjusting for confounders.
13.SupplementDEX Database: Myocardial infarction — Does tea affect cardiovascular disease? A meta-analysis2001
A meta-analysis found each 3 cups/day increase in tea associated with 11% lower myocardial infarction risk, but geographic heterogeneity was substantial and publication bias could not be excluded.
14.SupplementDEX Database: Myocardial infarction — Coffee and tea intake and the risk of myocardial infarction1999
In a case-control study, tea intake >1 cup/day was associated with 44% lower MI risk (OR 0.56) versus nondrinkers; coffee showed no significant association.
SupplementDEX Database · Osteoporosis
5 references15.SupplementDEX Database: Osteoporosis — Coffee and tea consumption on the risk of osteoporosis: a meta-analysis2025
A 2025 meta-analysis of 14 observational studies (562,838 participants) found high-frequency coffee and tea consumption each associated with lower osteoporosis risk (coffee OR 0.79; tea high-frequency OR 0.82).
16.SupplementDEX Database: Osteoporosis — Epidemiological evidence of increased bone mineral density in habitual tea drinkers2002
In 1,037 Taiwanese adults, habitual tea drinking >10 years was associated with 5% higher lumbar spine, hip neck, and Ward triangle BMD; duration of tea consumption was the only independent BMD determinant.
17.SupplementDEX Database: Osteoporosis — Tea drinking and bone mineral density in older women2000
In 1,256 British women aged 65–76, tea drinkers had ~5% higher BMD at lumbar spine, greater trochanter, and Ward's triangle versus non-tea drinkers, independent of milk, smoking, and HRT use.
18.SupplementDEX Database: Osteoporosis — Risk factors for hip fracture in men from southern Europe: the MEDOS study. Mediterranean Osteoporosis Study1999
In the MEDOS study of 730 European men with hip fracture, low BMI, low physical activity, and low sunlight exposure were major reversible risk factors; tea and alcohol consumption contributed modestly to attributable risk.
19.SupplementDEX Database: Osteoporosis — Risk factors for hip fracture in European women: the MEDOS Study. Mediterranean Osteoporosis Study1995
In the MEDOS study of women with hip fracture, low BMI, low milk and calcium intake, and low physical activity and sunlight exposure accounted for ~56% of hip fracture risk; tea consumption was among modifiable factors.
SupplementDEX Database · Parkinson's disease
3 references20.SupplementDEX Database: Parkinson's disease — Parkinson's disease risks associated with cigarette smoking, alcohol consumption, and caffeine intake2002
In 557 western Washington adults, consuming ≥2 cups/day tea or cola was associated with 60% and 40% lower Parkinson disease odds versus nondrinkers; total caffeine intake was not associated with PD.
21.SupplementDEX Database: Parkinson's disease — Prospective study of caffeine consumption and risk of Parkinson's disease in men and women2001
In 88,565 US health professionals followed up to 16 years, caffeine intake was strongly inversely associated with Parkinson disease in men but showed a U-shaped relationship in women, with tea showing a protective trend.
22.SupplementDEX Database: Parkinson's disease — Association of coffee and caffeine intake with the risk of Parkinson disease2000
In 8,004 Japanese-American men followed 30 years, higher coffee and caffeine intake was linearly associated with lower Parkinson disease incidence; tea was not separately analyzed in this cohort.
SupplementDEX Database · Bladder Cancer
2 references23.SupplementDEX Database: Bladder Cancer — Tea consumption and cancer incidence in a prospective cohort study of postmenopausal women1996
In 35,369 postmenopausal Iowa women followed 8 years, ≥2 cups/day tea was associated with 32% lower digestive tract cancer risk (RR 0.68) and 60% lower urinary tract cancer risk (RR 0.40) versus never/occasional drinkers.
24.SupplementDEX Database: Bladder Cancer — Black tea consumption and cancer risk: a prospective study1986
In 7,833 Japanese-American men, black tea intake >1/day was associated with 4.2-fold higher rectal cancer risk (P=0.0007) but 44% lower prostate cancer risk (P=0.020); no significant associations at other sites.
SupplementDEX Database · Breast Cancer
2 references25.SupplementDEX Database: Breast Cancer — Meta-analysis of black tea consumption and breast cancer risk: update 20132014
A meta-analysis through 2013 found no overall association between black tea consumption and breast cancer risk (OR 0.97); cohort and case-control subgroups also showed no significant benefit.
26.SupplementDEX Database: Breast Cancer — Coffee, tea, and caffeine consumption and breast cancer incidence in a cohort of Swedish women2002
In 59,036 Swedish women followed 508,267 person-years, coffee, tea, and caffeine intake were not associated with breast cancer incidence across consumption levels.
SupplementDEX Database · Colorectal cancer
9 references27.SupplementDEX Database: Colorectal cancer — Green tea, black tea and colorectal cancer risk: a meta-analysis of epidemiologic studies2006
A meta-analysis of 25 studies found green tea associated with 18% lower colorectal cancer risk (OR 0.82) in case-control studies; black tea showed no association (OR 0.99) with substantial heterogeneity.
28.SupplementDEX Database: Colorectal cancer — Tea consumption and the reduced risk of colon cancer -- results from a national prospective cohort study2002
In NHANES I follow-up, habitual tea drinkers in Cohort II had 41–59% lower colon cancer risk at ≥1.5 cups/day versus nondrinkers, predominantly in men; Cohort I showed no significant association.
30.SupplementDEX Database: Colorectal cancer — Tea consumption and risk of cancer of the colon and rectum2001
In 685 colon and 655 rectal cancer cases versus 2,434 controls in Iowa, tea consumption was not associated with colorectal cancer risk overall or by subtype after adjustment for confounders.
31.SupplementDEX Database: Colorectal cancer — Tea consumption and cancer1998
In London men followed from 1967, no dose-response link was found between tea consumption and colon, rectal, or prostate cancer; tea was associated with stomach, lung, and kidney cancer deaths before full adjustment.
32.SupplementDEX Database: Colorectal cancer — Tea and coffee consumption and risk of colon and rectal cancer in middle-aged Finnish men1998
In Finnish men, ≥1 cup/day tea was associated with 2.09-fold higher colon cancer risk (p trend=0.001) but little effect on rectal cancer; coffee showed no protective association.
33.SupplementDEX Database: Colorectal cancer — Coffee and tea intake and risk of cancers of the colon and rectum: a study of 3,530 cases and 7,057 controls1997
In 3,530 Italian colorectal cancer cases and 7,057 controls, ≥4 cups/day coffee lowered colon cancer risk (OR 0.73) but tea intake did not significantly modify colon or rectal cancer risk.
34.SupplementDEX Database: Colorectal cancer — Consumption of black tea and cancer risk: a prospective cohort study1996
In 120,852 Dutch adults followed 4.3 years, black tea consumption was not associated with colorectal cancer risk; initial inverse stomach and lung cancer associations disappeared after adjusting for smoking and diet.
29.SupplementDEX Database: Colorectal cancer — Coffee, tea, tobacco, and cancer of the large bowel1994
In a Stockholm case-control study, ≥6 cups/day coffee lowered colon cancer risk (OR 0.55) but tea ≥2 cups/day lowered rectal cancer risk (OR 0.56); tea was not associated with colon cancer.
35.SupplementDEX Database: Colorectal cancer — Dietary habits and gastro-intestinal cancers: a comparative case-control study of stomach and large intestinal cancers in Nagoya, Japan1985
A Japanese case-control study of stomach and colorectal cancers found salted foods raised stomach cancer risk and Western-style breakfast raised colon cancer risk; tea and alcohol showed no clear associations.
SupplementDEX Database · Endometrial cancer
1 reference36.SupplementDEX Database: Endometrial cancer — Green tea, black tea consumption and risk of endometrial cancer: a systematic review and meta-analysis2016
A meta-analysis found green tea associated with 22% lower endometrial cancer risk (RR 0.78 per cup/day increment); black tea showed no significant association (RR 0.99).
SupplementDEX Database · Esophageal cancer
2 references37.SupplementDEX Database: Esophageal cancer — Tea drinking and the risk of esophageal cancer: focus on tea type and drinking temperature2020
In a Chinese case-control study, drinking tea >65°C significantly raised esophageal squamous cell carcinoma risk (OR 1.67); black tea consumption was associated with higher risk regardless of amount.
38.SupplementDEX Database: Esophageal cancer — Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies2013
A meta-analysis found green tea associated with lower esophageal cancer risk (OR 0.77 overall; 0.70 in case-control studies), while black tea showed no significant association (OR 1.35).
SupplementDEX Database · Stomach cancer
2 references39.SupplementDEX Database: Stomach cancer — Risk of stomach cancer in relation to consumption of cigarettes, alcohol, tea and coffee in Warsaw, Poland1999
In 464 Warsaw stomach cancer cases and 480 controls, cigarette smoking raised stomach cancer risk in men; daily tea drinking was associated with significantly reduced stomach cancer risk in women but not men.
40.SupplementDEX Database: Stomach cancer — Tea and coffee consumption and the risk of digestive tract cancers: data from a comparative case-referent study in Japan1998
In a Japanese hospital case-referent study, ≥7 cups/day green tea lowered stomach cancer risk (OR 0.69); rectal cancer risk fell with ≥3 cups/day coffee (OR 0.46); black tea associations were not significant.
SupplementDEX Database · Lung cancer
2 references41.SupplementDEX Database: Lung cancer — The consumption of coffee and black tea and the risk of lung cancer2016
In a Montreal case-control study of 1,130 lung cancer cases, black tea consumption was not associated with lung cancer risk after adjusting for smoking (OR 1.05 for daily vs never).
42.SupplementDEX Database: Lung cancer — Coffee and tea consumption and risk of lung cancer: a dose-response analysis of observational studies2012
A dose-response meta-analysis found no consistent linear association between black tea intake and lung cancer risk; coffee showed a significant positive linear relationship with lung cancer in the analysis.
SupplementDEX Database · Diabetes
2 references43.SupplementDEX Database: Diabetes — The effect of an extract of green and black tea on glucose control in adults with type 2 diabetes mellitus: double-blind randomized study2007
In 49 type 2 diabetic adults, 3 months of green/black tea extract (375 or 750 mg/day) did not lower HbA1c versus placebo; mean HbA1c rose ~0.3–0.5% in all arms.
44.SupplementDEX Database: Diabetes — The relationship between green tea and total caffeine intake and risk for self-reported type 2 diabetes among Japanese adults2006
In 17,413 Japanese adults aged 40–65 followed 5 years, ≥6 cups/day green tea (OR 0.67) and ≥3 cups/day coffee (OR 0.58) were inversely associated with self-reported type 2 diabetes; black or oolong tea were not.
SupplementDEX Database · Eczema
1 reference45.SupplementDEX Database: Eczema — Exploring Genetic Association of Tea Intake With Allergic Diseases Among European Population: A Bidirectional Mendelian Randomization Study2024
A Mendelian randomization study in Europeans found genetically predicted higher tea intake associated with lower atopic dermatitis risk (OR 0.71) and allergic asthma (OR 0.50), but not allergic rhinitis.
46.SupplementDEX Database: Infant cognitive development — Impact of tea and coffee consumption during pregnancy on children's cognitive development2025
In 1,423 Chinese mother-child pairs, maternal tea drinking throughout pregnancy was associated with higher child cognition, fine motor, and gross motor scores at ~36 months versus tea only in the first trimester; coffee showed no association.
SupplementDEX Database · All-cause mortality
1 reference47.SupplementDEX Database: All-cause mortality — Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank: A Prospective Cohort Study2022
In 498,043 UK Biobank adults followed 11.2 years, drinking ≥2 cups/day tea was modestly associated with lower all-cause mortality (HR 0.87–0.89 for 2–7 cups) and lower CVD, ischemic heart disease, and stroke mortality.
SupplementDEX Database · Atherosclerosis
1 reference48.SupplementDEX Database: Atherosclerosis — Tea flavonoids may protect against atherosclerosis: the Rotterdam Study1999
In 3,454 Rotterdam Study participants, tea drinkers consuming >500 mL/day had 69% lower odds of severe aortic atherosclerosis versus nondrinkers; associations were stronger in women.
49.SupplementDEX Database: Chronic obstructive pulmonary disease (COPD) — Tea Consumption and Risk of Chronic Obstructive Pulmonary Disease in Middle-Aged and Older Singaporean Adults2021
In 4,617 Singaporean adults aged ≥55, ≥3 cups/day tea was associated with lower prevalent COPD (OR 0.77) and lower 4.5-year COPD incidence (OR 0.35), with strongest trends for green tea.
50.SupplementDEX Database: Coronary heart disease (CHD) — Dose-Response Relation between Tea Consumption and Risk of Cardiovascular Disease and All-Cause Mortality: A Systematic Review and Meta-Analysis of Population-Based Studies2020
A meta-analysis of 39 cohort studies found each cup/day of tea associated with ~4% lower CVD mortality, ~2% lower CVD events, ~4% lower stroke risk, and ~1.5% lower all-cause mortality.
51.SupplementDEX Database: Coronary heart disease (CHD) — Black tea—helpful or harmful? A review of the evidence2007
A review of epidemiologic and clinical studies concluded ≥3 cups/day black tea relates to coronary heart disease risk reduction, with moderate caffeine intake improving mental performance and no credible evidence of harm at typical intakes.
52.SupplementDEX Database: Coronary heart disease (CHD) — Tea consumption and the prevalence of coronary heart disease in Saudi adults: results from a Saudi national study2003
In 3,430 Saudi adults, drinking >6 cups/day tea (>480 mL) was associated with 51% lower CHD prevalence versus nondrinkers (OR 0.49) after adjusting for cardiovascular risk factors.
53.SupplementDEX Database: Coronary heart disease (CHD) — Catechin intake might explain the inverse relation between tea consumption and ischemic heart disease: the Zutphen Elderly Study2001
In 806 Zutphen elderly men, higher catechin intake (mainly from black tea) was inversely associated with ischemic heart disease mortality (RR 0.49 highest vs lowest tertile) but not stroke.
54.SupplementDEX Database: Coronary heart disease (CHD) — Coffee and tea consumption in the Scottish Heart Health Study follow up: conflicting relations with coronary risk factors, coronary disease, and all cause mortality1999
In 11,000 Scottish adults followed 7.7 years, tea consumption showed inverse associations with coronary morbidity and mortality before adjustment; relationships became neutral or reversed after multivariable adjustment.
55.SupplementDEX Database: Coronary heart disease (CHD) — Antioxidant flavonols and ischemic heart disease in a Welsh population of men: the Caerphilly Study1997
In 1,900 Welsh men, flavonol intake was not inversely associated with IHD incidence; heavy tea drinkers (>1.2 L/day) had 2.4-fold higher total mortality, possibly related to milk added to tea.
56.SupplementDEX Database: Coronary heart disease (CHD) — Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study1993
In 805 Zutphen elderly men followed 5 years, highest flavonoid intake tertile (mainly from tea) had 58% lower coronary heart disease mortality (RR 0.42) than the lowest tertile, independent of major risk factors.
SupplementDEX Database · Dementia
1 reference57.SupplementDEX Database: Dementia — Consumption of coffee and tea and risk of developing stroke, dementia, and poststroke dementia: A cohort study in the UK Biobank2021
In 365,682 UK Biobank participants followed 11.4 years, 2–3 cups/day coffee plus 2–3 cups/day tea was associated with 32% lower stroke and 28% lower dementia risk versus non-consumers.
SupplementDEX Database · Depression
2 references58.SupplementDEX Database: Depression — Habitual tea consumption was associated with lower levels of depressive symptoms among older Chinese: Guangzhou Biobank Cohort Study2022
In 10,014 older Chinese adults, regular tea consumption was associated with lower Geriatric Depression Scale scores and 49% lower odds of depressive symptoms (GDS ≥8) versus never-drinkers, across green, black, and oolong tea.
59.SupplementDEX Database: Depression — Effects of black tea consumption and caffeine intake on depression risk in black tea consumers2021
In 491 Turkish adults (30.1% depressed by BDI), black tea consumption up to 4 cups/day and caffeine intake of 450–600 mg/day were associated with lower depression risk versus lower intake levels.
SupplementDEX Database · Diarrhea
1 reference60.SupplementDEX Database: Diarrhea — The Effect of Black Tea (Camellia sinensis (L) Kuntze) on Pediatrics With Acute Nonbacterial Diarrhea: A Randomized Controlled Trial2017
In 120 children with acute nonbacterial diarrhea, black tea tablets plus standard treatment increased the proportion with formed stool after 24 h and reduced defecation frequency versus standard treatment alone.
61.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Effectiveness of black tea versus placebo in subjects with hypercholesterolemia: A PRISMA systematic review and meta-analysis2019
A PRISMA meta-analysis of 6 hypercholesterolemia RCTs found no significant differences in total cholesterol, LDL, HDL, or triglycerides with black tea versus placebo in the short term.
62.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Black tea consumption and serum cholesterol concentration: Systematic review and meta-analysis of randomized controlled trials2015
A meta-analysis of 10 RCTs (411 adults) found black tea significantly lowered LDL cholesterol by 4.64 mg/dL versus control; total cholesterol and HDL were unchanged.
63.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Effect of black tea consumption on blood cholesterol: a meta-analysis of 15 randomized controlled trials2014
A meta-analysis of 15 RCTs found black tea did not significantly change total, HDL, or LDL cholesterol overall; a random-effects LDL reduction of 4.56 mg/dL was not significant (p=0.12).
64.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Green and black tea for the primary prevention of cardiovascular disease2013
A Cochrane review of 11 short-term RCTs (821 participants) found black tea lowered LDL by 0.43 mmol/L and blood pressure modestly over 6 months; no clinical cardiovascular events were reported.
65.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — A 6-month randomized pilot study of black tea and cardiovascular risk factors2007
In 31 older adults with cardiovascular risk factors, 6 months of 3 glasses/day black tea did not significantly change lipids, inflammatory markers, blood pressure, or oxidative stress versus water control.
66.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Black tea consumption reduces total and LDL cholesterol in mildly hypercholesterolemic adults2003
In 15 mildly hypercholesterolemic adults, 5 servings/day black tea for 3 weeks on a controlled diet reduced total cholesterol by 6.5%, LDL by 11.1%, apoB by 5%, and lipoprotein(a) by 16.4% versus caffeine-matched placebo.
67.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Regular ingestion of black tea improves brachial artery vasodilator function2002
In 21 adults with mild hyperlipidemia, 5 cups/day black tea for 4 weeks increased endothelium-dependent brachial artery dilation by 2.3% and endothelium-independent dilation by 4.2% versus hot water control.
68.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — No effect of consumption of green and black tea on plasma lipid and antioxidant levels and on LDL oxidation in smokers1998
In smokers consuming 900 mL/day black or green tea for 4 weeks, neither tea nor isolated green tea polyphenols (3.6 g/day) changed plasma lipids or ex vivo LDL oxidation; green tea polyphenols lowered plasma vitamin E.
69.SupplementDEX Database: Hypercholesterolemia (High cholesterol) — Effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit1997
In 65 adults in a 4-week crossover trial, 6 mugs/day black tea did not significantly change serum cholesterol, blood pressure, or bowel habit versus a caffeine-matched placebo drink.
SupplementDEX Database · High blood pressure
5 references70.SupplementDEX Database: High blood pressure — The effect of black tea supplementation on blood pressure: a systematic review and dose-response meta-analysis of randomized controlled trials2021
A meta-analysis of 13 tea RCTs found black tea supplementation significantly lowered systolic BP by 1.04 mmHg and diastolic BP by 0.59 mmHg versus control.
71.SupplementDEX Database: High blood pressure — The effects of regular consumption of green or black tea beverage on blood pressure in those with elevated blood pressure or hypertension: A systematic review and meta-analysis2020
A meta-analysis of 5 RCTs (408 adults with elevated BP or hypertension) found regular tea reduced systolic BP by 4.81 mmHg and diastolic by 1.98 mmHg; green tea effects appeared more pronounced than black tea.
72.SupplementDEX Database: High blood pressure — The effect of black tea on blood pressure: a systematic review with meta-analysis of randomized controlled trials2014
A meta-analysis of 11 black tea RCTs (378 subjects, 4–5 cups/day) found regular intake reduced systolic BP by 1.8 mmHg and diastolic by 1.3 mmHg versus control.
73.SupplementDEX Database: High blood pressure — Effects on blood pressure of drinking green and black tea1999
In normotensive and hypertensive adults, black and green tea caused acute BP increases after ingestion versus caffeine alone, but 7 days of 5 cups/day tea did not significantly change 24-h ambulatory BP versus caffeine.
74.SupplementDEX Database: High blood pressure — Tea consumption: relationship to cholesterol, blood pressure, and coronary and total mortality1992
In 19,089 Norwegian adults aged 35–49 followed 12 years, ≥1 cup/day tea drinkers had lower serum cholesterol and systolic BP; coronary death RR was 0.64 (95% CI 0.38–1.07) versus <1 cup/day.
75.SupplementDEX Database: Kidney stones (nephrolithiasis) — Effect of Black Tea Consumption on Urinary Risk Factors for Kidney Stone Formation2021
In 10 healthy men, replacing fruit tea with 1.5 L/day black tea (86 mg/day oxalate) for 5 days did not significantly change 24-h urinary oxalate, citrate, or calcium oxalate supersaturation.
76.SupplementDEX Database: Kidney stones (nephrolithiasis) — Beverage use and risk for kidney stones in women1998
In 81,093 Nurses' Health Study women followed 8 years, each 240-mL/day tea was associated with 9% lower kidney stone risk; higher total fluid intake reduced stone risk overall.
SupplementDEX Database · Pancreatic cancer
1 reference77.SupplementDEX Database: Pancreatic cancer — Cigarette smoking, alcohol, tea and coffee consumption and pancreas cancer risk: a case-control study from Opole, Poland1993
In an Opole, Poland case-control study, lifetime tea consumption showed a strongly significant inverse trend with pancreatic cancer risk (p<0.001 among directly interviewed subjects); alcohol showed null associations.
78.SupplementDEX Database: Pregnancy-induced hypertension — The association between maternal tea consumption and the risk of pregnancy induced hypertension: A retrospective cohort study in Lanzhou, China2022
In 10,452 Chinese pregnant women, tea consumption during pregnancy was associated with higher odds of pregnancy-induced hypertension (OR 1.44), gestational hypertension (OR 1.86), and early-onset preeclampsia (OR 2.93), especially black tea.
SupplementDEX Database · Stroke
1 reference79.SupplementDEX Database: Stroke — Dietary flavonoids, antioxidant vitamins, and incidence of stroke: the Zutphen study1996
In 552 Zutphen men followed 15 years, flavonoid intake (70% from black tea) was inversely associated with stroke incidence; drinking ≥4.7 cups/day tea versus <2.6 cups/day had stroke RR 0.31 (95% CI 0.12–0.84).