Tea And Coffee For High Blood Pressure
The role played by tea and coffee in blood pressure is still debated. For years, it was believed that caffeine present in them will have an adverse effect on blood pressure. But, recent research studies suggest that long-term moderate intake of coffee or tea does not have any detrimental effect on healthy individuals. Green tea, hibiscus tea, and black tea have proved their antihypertensive effects.
Hypertension is a major risk factor for cardiovascular disease (CVD). And it is a common condition in American adults.1 The role played by the most popular beverages– tea and coffee, in blood pressure is still debated. For years, it was believed that caffeine present in them will have an adverse effect on blood pressure (BP). But, recent research studies have contradicted these findings.2 The fretting about caffeine in coffee and tea is, thus, slowly fading. Here are the facts about the power of tea and coffee in combating high blood pressure.
Do Coffee And Tea Influence Your Blood Pressure
The daily high intake of caffeine has been associated with the increase in CVD risk factors. However, the long-term moderate intake of coffee or tea does not have any detrimental effect on healthy individuals. In fact, an epidemiological data suggests that black and green tea may reduce the risk of both coronary heart disease and stroke by between 10% and 20%.3
So, what is responsible for the CVD protection exerted by these beverages? Research studies are not yet able to identify the compounds which are capable of it. One factor could be the phytochemicals in them, which may influence the endothelial function, resulting in vascular relaxation. The improved glucose metabolism or the inhibition of oxidative stress may also contribute to it.4 The direct effect of tea components on endothelial-dependent vasodilation, which increases the blood flow, thus, reducing blood pressure, has also been suggested in another study.5
The 2015 edition of Dietary Guidelines for Americans came out with a good news for coffee lovers. According to their recommendations, the consumption of coffee within the moderate range is not associated with increased long-term health risks among healthy individuals.6 Moreover, they point out that consistent evidence relates coffee consumption to reduced risk of cardiovascular disease in healthy people.7 But, the exact causes behind these benefits are still not proven. It could be either caffeine or any other compound present in the coffee.
Impact Of Various Teas And Coffees On Hypertension
These most common beverages are available in different types and forms. However, every tea or coffee may not have the same impact on your blood pressure. Here is a list of them, which you can add to your diet to take control of blood pressure.
1. Green Tea
The long-term consumption of green tea significantly lowers systolic and diastolic blood pressure.8 The catechins in green tea may also improve total and low-density lipoprotein cholesterol. A research has concluded the beneficial effect of green tea on the lining of the blood vessels, resulting in the smooth flow of blood in healthy individuals.9 Thus, it reduces the risk of cardiovascular diseases.
2. Green Coffee
You may have heard the potential of green coffee in helping you with weight loss. Recent research has identified that it could also control your hypertension. The green coffee bean refers to unroasted mature or immature coffee bean. Since it is not roasted, the healthy benefits of chlorogenic acid present in the bean will be maintained. The chlorogenic acids in green coffee bean extract reduce blood pressure in patients with mild hypertension.10 The consumption of green coffee improves arterial elasticity, reducing systolic and diastolic blood pressure in healthy individuals.11 The research study has also shown that black coffee can lower blood pressure.12
3. Decaf Coffee
Wondering whether a decaffeinated coffee is more efficient than a regular coffee in lowering blood pressure? The replacement of regular by a decaffeinated coffee results in a small fall in blood pressure.13 According to another study, decaffeinated coffee has no adverse cardiovascular effects.
4. Black Tea
The consumption of 3 cups of black tea over six months lowers BP in individuals with normal to high-normal range BPs. A research has found that black tea could lower systolic blood pressure and diastolic blood pressure between 2 and 3 mm HG.14 It could be due to the improvement in the endothelial function, which has a positive impact on hypertension. Another possible reason is that tea flavonoids along with caffeine reduce abdominal fatness, thus, positively affecting your blood pressure.15
5. Oolong Tea
This healthy drink is another Chinese tea like green tea, that can influence your blood pressure. The habitual ingestion of moderate strength oolong tea significantly reduces the risk of developing hypertension.16 Studies on animals have concluded that decaffeinated oolong tea also lowers BP. It indicates that substances other than caffeine in the tea may also play a role in regulating the blood pressure.17
6. Hibiscus Tea
The antihypertensive effect of hibiscus tea is beneficial for pre- and mildly hypertensive adults.18 In the clinical trial, about half the group of 65 volunteers was randomly given three cups of hibiscus tea daily and they were allowed to follow their normal diet. According to the findings, those who drank hibiscus tea had a 7.2 point drop in their systolic blood pressure, compared to other participants.19 However, more research is needed to understand the mechanism.
This amazing spice contains a number of bioactive components, which raise its medicinal value. In traditional medicine, it is well-known for its blood pressure-lowering effect. Studies indicate that through blockade of voltage-dependent calcium channels, ginger reduces blood pressure.20 By blocking calcium channels, calcium influx will be reduced, relaxing vascular muscles. However, more human studies about the hypotensive effect of ginger need to be conducted for a conclusive result.21
8. Nettle Tea
Various studies on animals have suggested that nettle may lower blood pressure. But, there is a lack of research to determine its effect on humans.22 Moreover, University of Maryland warns that stinging nettle can interact with drugs for high blood pressure such as ACE inhibitors, beta-blockers, and calcium channel blockers.23
9. Garlic Tea
This medicinal plant, particularly in the form of the standardizable and highly tolerable aged garlic extract, lowers BP in hypertensive individuals. The polysulfides in garlic contribute to its BP reduction potential.24 Research studies have suggested that garlic preparations are good at reducing blood pressure in individuals with hypertension.25
10. Basil Tea
This medicinal herb used in traditional Chinese medicine is efficient in treating cardiovascular diseases including hypertension. The crude extract of basil helps in lowering systolic and diastolic BP. This may be because of its component eugenol, which acts as a calcium channel blocker, resulting in lower blood pressure. 26 However, the antihypertensive effect is short term as BP returns to normal within two minutes. Other studies on animals have also suggested the ability of basil in reducing hypertension.27
11. Lemon Tea
Auraptene, an ingredient in citrus fruits like lemons has proved its positive effect on hypertension in animal studies. It could reduce the mean systolic blood pressure in hypertensive rats.28 It also contains potassium, which helps you regulate blood pressure.29 However, there is a lack of human studies about the impact of lemon on blood pressure.
Is There A Recommended Intake For Each?
According to the American Medical Association Council on Scientific Affairs, moderate tea or coffee drinking is not likely to be harmful to your health as long as you have other good health habits. Reference Daily Intake (RDI) is this:30
- Four 8 oz cups of brewed or drip coffee.
- Five servings of tea, which is about 165 to 235 mg of caffeine.
- Ten 8 oz cups of coffee a day is considered excessive intake.
As mentioned earlier, the Dietary Guidelines for Americans, a government advisory committee, have also said that moderate coffee ingestion is safe. And according to them, moderate consumption is this:
- Within the range of 3 to 5 cups of coffee a day, or up to 400 mg of caffeine per day.31
- However, pregnant women are recommended not to consume more than 200mg of caffeine a day, which is equivalent to about two mugs of instant coffee or about two and a half mugs of tea.32
More research studies are needed to close the debate on the pros and cons of tea and coffee consumption. But for now, moderate consumption is considered safe for healthy individuals.
References [ + ]
|1.||↑||Peng, Xiaoli, Rui Zhou, Bin Wang, Xiaoping Yu, Xiaohong Yang, Kai Liu, and Mantian Mi. “Effect of green tea consumption on blood pressure: A meta-analysis of 13 randomized controlled trials.” Scientific reports 4 (2014).|
|2.||↑||Crippa, Alessio, Andrea Discacciati, Susanna C. Larsson, Alicja Wolk, and Nicola Orsini. “Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis.” American journal of epidemiology (2014): kwu194.|
|3, 4.||↑||Bøhn, Siv K., Natalie C. Ward, Jonathan M. Hodgson, and Kevin D. Croft. “Effects of tea and coffee on cardiovascular disease risk.” Food & function 3, no. 6 (2012): 575-591.|
|5.||↑||Ras, Rouyanne T., Peter L. Zock, and Richard Draijer. “Tea consumption enhances endothelial-dependent vasodilation; a meta-analysis.” PLoS One 6, no. 3 (2011): e16974.|
|6, 31.||↑||Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Office of Disease Prevention and Health Promotion.|
|7.||↑||Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Office of Disease Prevention and Health Promotion.|
|8.||↑||Liu, Gang, Xue-Nan Mi, Xin-Xin Zheng, Yan-Lu Xu, Jie Lu, and Xiao-Hong Huang. “Effects of tea intake on blood pressure: a meta-analysis of randomised controlled trials.” British Journal of Nutrition 112, no. 07 (2014): 1043-1054.|
|9.||↑||Alexopoulos, Nikolaos, Charalambos Vlachopoulos, Konstantinos Aznaouridis, Katerina Baou, Carmen Vasiliadou, Panagiota Pietri, Panagiotis Xaplanteris, Elli Stefanadi, and Christodoulos Stefanadis. “The acute effect of green tea consumption on endothelial function in healthy individuals.” European Journal of Cardiovascular Prevention & Rehabilitation 15, no. 3 (2008): 300-305.|
|10.||↑||Watanabe, Takuya, Yoichi Arai, Yuki Mitsui, Tatsuya Kusaura, Wataru Okawa, Yasushi Kajihara, and Ikuo Saito. “The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension.” Clinical and experimental hypertension 28, no. 5 (2006): 439-449.|
|11, 12.||↑||Revuelta-Iniesta, Raquel, and Emad AS Al-Dujaili. “Consumption of green coffee reduces blood pressure and body composition by influencing 11β-HSD1 enzyme activity in healthy individuals: a pilot crossover study using green and black coffee.” BioMed research international 2014 (2014).|
|13.||↑||van Dusseldorp, Marijke, Paul Smits, Theo Thien, and Martijn B. Katan. “Effect of decaffeinated versus regular coffee on blood pressure. A 12-week, double-blind trial.” Hypertension 14, no. 5 (1989): 563-569.|
|14, 15.||↑||Hodgson, Jonathan M., Ian B. Puddey, Richard J. Woodman, Theo PJ Mulder, Dagmar Fuchs, Kirsty Scott, and Kevin D. Croft. “Effects of black tea on blood pressure: a randomized controlled trial.” Archives of internal medicine 172, no. 2 (2012): 186-188.|
|16.||↑||Yang, Yi-Ching, Feng-Hwa Lu, Jin-Shang Wu, Chih-Hsing Wu, and Chih-Jen Chang. “The protective effect of habitual tea consumption on hypertension.” Archives of internal medicine 164, no. 14 (2004): 1534-1540.|
|17.||↑||Tanida, Mamoru, Nobuo Tsuruoka, Jiao Shen, Yoshinobu Kiso, and Katsuya Nagai. “Effects of oolong tea on renal sympathetic nerve activity and spontaneous hypertension in rats.” Metabolism 57, no. 4 (2008): 526-534.|
|18.||↑||McKay, Diane L., Edward Saltzman, Chung-Yen Chen, and Jeffrey B. Blumberg. “Hibiscus sabdariffa L. tea (Tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults.” Circulation 118, no. Suppl 18 (2008): S_1123-S_1123.|
|19.||↑||Study Shows Consuming Hibiscus Tea Lowers Blood Pressure. United States Department of Agriculture.|
|20.||↑||Ghayur, Muhammad Nabeel, and Anwarul Hassan Gilani. “Ginger lowers blood pressure through blockade of voltage-dependent calcium channels.” Journal of cardiovascular pharmacology 45, no. 1 (2005): 74-80.|
|21, 26.||↑||Tabassum, Nahida, and Feroz Ahmad. “Role of natural herbs in the treatment of hypertension.” Pharmacognosy reviews 5, no. 9 (2011): 30.|
|22, 23.||↑||Stinging nettle. University of Maryland Medical Center.|
|24.||↑||Ried, Karin, and Peter Fakler. “Potential of garlic (Allium sativum) in lowering high blood pressure: mechanisms of action and clinical relevance.” Integrated blood pressure control 7 (2014): 71.|
|25.||↑||Ried, Karin, Oliver R. Frank, Nigel P. Stocks, Peter Fakler, and Thomas Sullivan. “Effect of garlic on blood pressure: a systematic review and meta-analysis.” BMC cardiovascular disorders 8, no. 1 (2008): 13.|
|27.||↑||Umar, Anwar, Guzelnur Imam, Wuliya Yimin, Parhat Kerim, Ibadet Tohti, Bénédicte Berké, and Nicholas Moore. “Antihypertensive effects of Ocimum basilicum L.(OBL) on blood pressure in renovascular hypertensive rats.” Hypertension research 33, no. 7 (2010): 727-730.|
|28.||↑||Razavi, Bibi Marjan, Ebrahim Arasteh, Mohsen Imenshahidi, and Mehrdad Iranshahi. “Antihypertensive effect of auraptene, a monoterpene coumarin from the genus Citrus, upon chronic administration.” Iranian journal of basic medical sciences 18, no. 2 (2015): 153.|
|29.||↑||Lemon. Better Health.|
|30.||↑||Caffeine in the diet. MedlinePlus.|
|32.||↑||Healthy hydration guide. British nutrition Guide.|