Derocha says that the tannins, a class of polyphenol, may also give people an upset stomach , among other potential side effects. Finally, Derocha says that black tea can interfere with mental health drugs, and you should speak to your doctor if you are taking medication or trying a new tea.

Powerful antioxidants in green tea — especially one called epigallocatechin gallate, or EGCG — can help prevent atherosclerosis and plaque buildup in the arteries. And drinking green tea is also associated with a lower risk of cardiovascular diseases, especially in habitual tea drinkers, according to a review published in May in Food Science and Human Wellness.

After surveying , participants in China, scientists found drinking green tea was linked with approximately 25 percent lower risk of living with heart disease or after a stroke, the chance of dying from heart disease and stroke, and general death.

Participants were split between two groups: habitual tea drinkers three times or more a week or not. This might not be doable for everyone. Derocha says that people with caffeine sensitivity should watch how much green tea they drink, just like black tea. A study published in Food Chemistry found that white tea may protect the DNA of normal cells against cell damage from colon cancer , acting as a potential chemotherapeutic agent by inhibiting colon cancer cells.

Regarding heart health, research is limited. White tea does contain caffeine, which can speed your heart rate or increase your risk for high blood pressure.

Oolong tea is crushed tea leaves that have been oxidized for a period of time and then heated to stop the process. A clinical study published in the British Journal of Nutrition found that oolong tea may help lower cholesterol levels in the study population from Shantou, China.

While the results showed that oolong tea was able to increase HDL cholesterol , it was inconsistent with previous studies. Derocha cautions that oolong has a laxative effect and to be wary about what that can do to the body.

Like other teas, it can contradict medications like blood thinners. This herbal tea is notorious for helping people sleep at night because it contains flavanoids, per research.

Sleep is also one of the best tools for dealing with inflammation or healing from an injury, she notes. Getting restful sleep is necessary too.

A study published in March in the Journal of the American Heart Association found that poor sleep quality was associated with increased risk of major cardiovascular diseases. Sometimes the tea works so well that doctors tell patients not to drink chamomile before surgery because it can cause them to be too relaxed and have an adverse effect with anesthesia, says Derocha.

Patients with a coronary artery stent or who are taking aspirin or warfarin blood thinners should consult their doctor before drinking chamomile tea because it may increase the risk for internal bleeding.

Though ginseng has not been officially evaluated by the U. It may even reduce bad breath. A study in the Journal of the American Heart Association found that tea appears to slow the natural decrease in heart-helping HDL cholesterol as a person ages.

Those findings pair well with previous research that suggests tea also reduces low-density lipoprotein, or LDL, known as "bad" cholesterol.

Studies also show tea may reduce blood sugar levels and help prevent type 2 diabetes. Both kinds of tea are loaded with caffeine and antioxidants called polyphenols, which are linked to lower blood pressure and better heart health.

There are some slight differences; black tea, for example, contains more caffeine while green tea has a slightly better antioxidant profile.

Experts are quick to point out, however, that tea's health benefits can be negated if sugar or other unhealthy ingredients are added.

Why is that? While temperature also may seem to be a matter of individual preference, cooler tea may prove to be a healthier choice. Xiang Gao, director of the Nutritional Epidemiology Lab at Pennsylvania State University. Though experts say tea is a safe, natural beverage that is a better choice than processed, sweetened beverages, there can be negative side effects if a person consumes too much.

For example, drinking too much tea could lead to an iron deficiency because tea is rich in tannins, which can bind to iron and keep it from being absorbed in the digestive tract.

Figure 3 depicts the RRs of CAD for the highest vs. lowest total black tea consumption categories, demonstrating an association between the highest black tea consumption and CAD risk summary RR: 0.

We performed subgroup and regression analyses to investigate the sources of heterogeneity. Subgroup analyses were performed according to continent, nationality, study design, and gender Figures 4 , 5. Although no source of heterogeneity was found in the subgroup analysis, we found that studies in the United States, Norway, and the Netherlands supported that black tea drinking could reduce the risk of CAD.

Figure 3. Forest plot: Summary relative risks RRs of coronary artery disease CAD for comparing the highest black tea consumption with the lowest black tea consumption. Figure 4. Forest plot: results of subgroup analysis of black tea consumption and coronary artery disease CAD risk.

A Forest plot of black tea consumption and CAD risk after subgroup analysis stratified by continent. B Forest plot of black tea consumption and CAD risk after subgroup analysis stratified by country.

Figure 5. Subgroup analysis of black tea intake and coronary artery disease CAD risk. A Forest plot of subgroup analysis stratified by the study design. B Forest plot of subgroup analysis stratified by gender. The difference in follow-up time could explain We created a funnel plot to evaluate the publication bias Figure 6.

We also used Egger's test to assess publication bias quantitatively Figure 6. Figure 6. Funnel plot and Egger's test analyses to detect publication bias of studies on black tea consumption and coronary artery disease CAD risk. A Funnel plot: used to detect the publication bias studies.

B Egger chart: used to detect the publication bias of studies. Therefore, we established a regression model using the regression coefficients of the nonlinear regression equation and plotted the non-linear dose-response meta-analysis graph. Figure 7. Twenty-four studies investigated the relationship between the highest vs.

the lowest categories of green tea consumption and CAD risk. The pooled results showed the association between highest green tea consumption and CAD risk summary RR: 0.

We used subgroup and regression analyses to account for the heterogeneity. We also did subgroup analysis according to gender, continent, nationality, study design, and gender Figures 9 , Figure 8.

Forest plot: Summary relative risks RRs of coronary artery disease for comparing the highest green tea consumption with the lowest green tea consumption. Figure 9. Forest plot: results of subgroup analysis of green tea consumption and coronary artery disease CAD risk.

A Forest plot depicting green tea consumption and CAD risk after subgroup analysis stratified by continent. B Forest plot showing green tea consumption and CAD risk after subgroup analysis stratified based on country. Figure Forest plot depicting the subgroup analysis of green tea intake and coronary artery disease CAD risk.

A Subgroup analysis forest plot stratified by the study design. B Forest plot of subgroup analysis based on gender. A funnel plot Figure 11 and Egger's test Figure 11 were used to assess publication bias, with the result of Egger's test indicating that bias may exist. Funnel plot and Egger's test analyses to detect publication bias of studies on green tea consumption and coronary artery disease CAD risk.

A Funnel plot: used to detect studies on green tea consumption and CAD risk publication bias. B Egger chart: used to detect studies evaluating green tea consumption and CAD risk publication bias.

Our findings revealed that the RR of these two models decreased as the number of green tea cups consumed per day increased. Tea is a traditional and popular beverage worldwide; regular tea consumption as part of a healthy habitual dietary pattern may substantially impact public health.

To our knowledge, this is by far the largest meta-analysis assessing the association between tea consumption and its preventive effect on CAD. In this systematic review and meta-analysis of 35 observational studies, the pooled analysis showed that both black and green tea consumption might significantly reduce the risk of CAD.

The dose-response relationship between green tea consumption and prevention of CAD based on linear and non-linear models revealed that the risk of CAD gradually decreased as green tea consumption increased. The concept that tea intake may help prevent coronary artery disease has received much interest among medical professionals and the general public.

The meta-analysis by Wang et al. Consistent with findings from a meta-analysis by Wang et al. Concerning the biological mechanisms involved in the prevention of CAD, studies have shown that tea is high in antioxidant polyphenols catechins, flavonols, theaflavins, and thearubigins that protect the cardiovascular system 6 , 57 , Studies have shown that catechin may promote nitric oxide production and enhance endothelial function 60 , Moreover, green tea contains more catechin polyphenols than black tea, and catechins have been shown to have vascular protective benefits through various pathways, including antioxidative, antihypertensive, anti-inflammatory, anti-proliferative, anti-thrombogenic, and lipid-lowering properties Moderate tea consumption enhances endothelium-dependent vasodilation and significantly decreases blood pressure, which is beneficial for the cardiovascular system Furthermore, tea drinking may reduce low-density lipoprotein cholesterol LDL-c and delay the formation of atherosclerosis Tea's antioxidant and antithrombotic properties are significant in preventing CAD In line with our findings, a dose-response meta-analysis of 22 prospective observational studies 65 examining the relationship between tea consumption and major cardiovascular outcomes found that increasing tea consumption by three cups per day was associated with a lower risk of coronary heart disease, cardiac death, stroke, and cerebral infarction.

However, the main limitation of the meta-analysis by Zhang et al. Another systematic review and meta-analysis 66 evaluating the link between tea consumption and CVD risks found that an increase in daily tea intake by one cup Nonetheless, in the present study increasing green tea intake by one cup per day did not result in a statistically significant decrease in the risk of CAD.

To the best of our knowledge, the present study is the first to report these findings. As previously mentioned, catechins present in both green and black tea have cardioprotective qualities 60 , The catechin concentration of partly fermented black tea is about half that of green tea 67 , which may explain the discrepancy in the dose-response relationship between black tea and green tea.

Furthermore, a recent double-blind, randomized, placebo-controlled cross-over study 68 found that black tea may significantly raise central systolic blood pressure compared to green tea and placebo. Because black tea contains more caffeine than green tea, this effect could be attributed to caffeine.

Therefore, we speculate that caffeine has a more significant impact on raising blood pressure and increases the risk of CAD when the dosage of black tea exceeds 4—6 cups.

In subgroup analysis, we found a noteworthy and significant finding that there was a substantial inverse correlation between green tea drinking and the incidence of CAD in Asian populations but not in Western ones. Due to a lack of relevant gene sequencing data, we could not explain this variance from an ethnic or genetic viewpoint, although the influence of varied cooking techniques may play a role.

Orientals prefer to boil tea with only hot water; however, in the west, high-lipid components such as milk are added to tea, which may elevate blood cholesterol and reduce the decrease the benefit of catechins 69 , In addition, Orientals treat tea drinking as a self-cultivation practice, and this emotional recognition may also affect blood pressure 68 , This study has the following strengths.

Firstly, this systematic review and meta-analysis assessing the association between tea consumption and the risk of CAD are the largest to date, with more than two times the number of studies included in the previous meta-analysis.

Secondly, we demonstrated a novel finding of a significant inverse association between green tea consumption and CAD risk in Asian populations but not in Western populations. Thirdly, we performed a dose-response analysis to investigate the linear and non-linear relationships, which may help quantify these possible associations' linkages.

In addition, the majority of the studies included in this analysis are prospective studies, which would reduce the recall bias to a certain extent.

There are several limitations of this meta-analysis. Firstly, the quantity of antioxidant components such as flavonoids in tea varies depending on tea variety and region of origin, and the size of cups was not stated in detail in some research; therefore, we tried our best to avoid potential confounding bias from cup size.

Secondly, this meta-analysis is based on observational studies, which are prone to bias. We cannot rule out uncontrolled confounders, such as fruit and vegetable consumption, socioeconomic status, and education level, as a possible explanations for the observed link between tea consumption and CAD risk.

Thirdly, measurement mistakes in food and nutrient consumption estimations are unavoidable, and measurement errors may result in underestimating the relationship between tea consumption and CAD risk. Finally, all the articles included are in English, which may indirectly restrict the range of countries where the studies originated, so the findings may not be generalized to other areas of the world.

In conclusion, the data presented in this study demonstrated that black tea and green tea had preventive effects on CAD. Green tea drinking could effectively reduce the risk of CAD in the Asian population Chinese and Japanese , but not in Europeans and Americans. More than 4—6 cups of black tea consumption may promote CAD.

The dose-response relationship of green tea showed that the risk of CAD gradually decreased with increased green tea consumption. Notably, the consumption of green tea in the Asian population is more popular than in western countries. Extrapolation of these results to the global population should be done with caution since the majority of studies included in the meta-analysis are from Asian nations, and few studies from other countries have been published.

Therefore, further multi-center prospective studies should be conducted to examine the impact of tea drinking on the risk of CAD. XY, HD, RD, MG, and JS: conception and design of the study. XY, ZZ, RD, and YQ: acquisition and analysis of the data.

XY, HD, RD, and JS: interpreted the results. XY, HD, and ZZ: drafted the manuscript. XY, HD, RD, ZZ, MG, YQ, and JS: review and editing. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The handling editor declared a shared parent affiliation with the authors at the time of review. All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers.

Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. Benjamin EJ, Virani SS, Callaway CW, Chamberlain AM, Chang AR, Cheng S, et al. Heart disease and stroke statistics update: a report from the American heart association.

doi: PubMed Abstract CrossRef Full Text Google Scholar. Wang C, Li X, Sun W, Li J, Wang Y, Bao X, et al. Weekly variation in quality of care for acute ST-segment elevation myocardial infarction by day and time of admission: a retrospective observational study. BMJ Qual Saf. Report on cardiovascular health and diseases in China an updated summary.

Biomed Environ Sci. PubMed Abstract CrossRef Full Text. Roth GA, Mensah GA, Johnson CO, Addolorato G, Ammirati E, Baddour LM, et al. Global burden of cardiovascular diseases and risk factors, — update from the GBD study. J Am Coll Cardiol. Ikeda A, Iso H, Yamagishi K, Iwasaki M, Yamaji T, Miura T, et al.

Plasma tea catechins and risk of cardiovascular disease in middle-aged Japanese subjects: The JPHC study.

Chieng D, Kistler PM. Coffee and tea on cardiovascular disease CVD prevention. Trends Cardiovasc Med. Keller A, Wallace TC. Tea intake and cardiovascular disease: an umbrella review. Ann Med. Tang GY, Meng X, Gan RY, Zhao CN, Liu Q, Feng YB, et al. Health functions and related molecular mechanisms of tea components: an update review.

Int J Mol Sci. Liu C, Guo Y, Sun L, Lai X, Li Q, Zhang W, et al. Six types of tea reduce high-fat-diet-induced fat accumulation in mice by increasing lipid metabolism and suppressing inflammation. Food Funct. de Koning Gans JM, Uiterwaal CSPM, van der Schouw YT, Boer JMA, Grobbee DE, Verschuren WMM, et al.

Tea and coffee consumption and cardiovascular morbidity and mortality. Arterioscler Thromb Vasc Biol. Mukamal KJ, Alert M, Maclure M, Muller JE, Mittleman MA.

The Eat It or Leave It? series from American Heart Association News covers the science behind foods and drinks, with an expert look at the health pros and cons. This story is part of Eat It or Leave It? American Heart Association News covers heart disease, stroke and related health issues. Not all views expressed in American Heart Association News stories reflect the official position of the American Heart Association.

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Next to water, tea is one of the most popular beverages in the world, and at just a couple of calories per serving, it's loaded with flavonoids that make it one of the world's healthiest beverages as well.

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Learn more. Show navigation Hide navigation. Sub menu. Tea drinkers live longer 09 Jan Topic s : Nutrition, Malnutrition and Heart Disease. Disclosures : None. References 1 Wang X, Liu F, Li J, et al.

About the European Society of Cardiology The European Society of Cardiology brings together health care professionals from more than countries, working to advance cardiovascular medicine and help people lead longer, healthier lives.

About the European Journal of Preventive Cardiology The European Journal of Preventive Cardiology is the world's leading preventive cardiology journal, playing a pivotal role in reducing the global burden of cardiovascular disease.

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