What changes will happen to your body if you drink tea every day? Can it lower blood pressure and blood sugar, and also reduce the risk of death?

Tea is the most common drink in the world besides water. In our country, tea is the national drink. Many people love tea to the point of "I would rather go without food for a day than go without tea for a day".
Do you know what benefits drinking tea every day can have on your body? Let's talk about it~

01

What are the benefits of drinking tea to your health?

1. Reduce the risk of type 2 diabetes

Two major meta-analyses, which included 22 randomized controlled trials (RCTs) and 17 RCTs (nearly 50,000 participants), agreed that drinking tea is beneficial for people at high risk of diabetes to control blood sugar and improve insulin sensitivity; and drinking tea is beneficial for diabetic patients to reduce fasting blood sugar and glycated hemoglobin concentrations. [1,2]

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At the same time, the health benefits of drinking tea do not differ by race. A study of 38,000 middle-aged and elderly women aged 45 years or older in the United States, with an average follow-up of 8.8 years, showed that women who drank 4 cups or more of tea a day had a 30% lower risk of type 2 diabetes compared with women who did not drink tea. [3]

A study of 480,000 adults in China followed up for 11 years showed that daily tea drinkers had an 8% lower risk of type 2 diabetes compared with participants who had never drunk tea in the past year. [4]

2. Reduce the risk of stroke

A study of 82,369 Japanese men and women followed for an average of 13 years showed that those who drank 2 to 3 cups of green tea a day had a 14% lower risk of stroke, and those who drank 4 or more cups a day had a 20% lower risk. [5]

The reason why drinking green tea can reduce the risk of stroke is mainly because the catechins in green tea can protect blood vessels through multiple mechanisms such as antioxidant, anti-inflammatory, anti-proliferative, and anti-thrombotic.

3. Reduce the risk of high blood pressure

A study of 76,000 adults in China[6] showed that drinking tea can reduce the risk of high blood pressure. Drinking green tea can reduce the risk of high blood pressure by 6%. Even if you don’t drink tea every day and the amount you drink each time is not much, as long as you persist in drinking it, it can still help reduce the risk of high blood pressure in the long run.

The mechanism may include two aspects: the catechins rich in green tea can promote the production of nitric oxide, which can dilate blood vessels and lower blood pressure; in addition, catechins can inhibit the production of angiotensinase. When this enzyme is inhibited, it can dilate blood vessels and reduce blood volume, thereby lowering blood pressure.

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Drinking black tea can reduce the risk of hypertension by 26%. The risk can be reduced so much mainly because drinking black tea can significantly reduce both systolic and diastolic blood pressure. There are two main explanations for this: first, black tea is rich in thearubigins and theaflavins, which can protect the vascular endothelium from damage by free radicals, making blood vessels smooth and elastic, thereby playing a role in relaxing blood pressure; second, calcium channel blockers are drugs used to lower blood pressure, and the various ingredients rich in black tea can play a role similar to that of calcium channel blockers.

4. Reduced risk of death

A study published in the Annals of Internal Medicine in 2022 followed up 500,000 tea drinkers between the ages of 40 and 69 for approximately 11 years and found that people who drank ≥ 2 cups of tea a day had a 9% to 13% lower risk of all-cause mortality than those who did not drink tea.

02

How can we maximize the benefits of tea to the body?

If you drink tea every day, you may not have thought that tea has so many health benefits! Let's take a look at how to store tea leaves and drink tea to maximize these health benefits.

1. The tea leaves should be sealed, kept away from light and stored at low temperature

Tea leaves easily absorb moisture and change flavors, which can easily lead to the loss of theanine, which makes tea taste "fresh". Antioxidant tea polyphenols are also easily oxidized and lost, and the loss is more serious at high temperatures, so tea leaves should be sealed, kept away from light, and stored at low temperatures. Tea that is not consumed for a short period of time can also be vacuum-packed and frozen.

2. Brewing temperature is suitable

It is generally recommended to brew green tea with water at about 80℃, and black tea and oolong tea with boiling water. This can balance the dissolution of caffeine, tea polyphenols, theanine and other ingredients, making the brewed tea more delicious.

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3. Let the tea cool before drinking

Kung Fu tea in Chaoshan area requires drinking it while it is hot, but this is not recommended because high temperature can damage the esophagus and increase the risk of esophageal cancer. The International Agency for Research on Cancer (IARC) under the World Health Organization believes that drinking hot beverages over 65°C may cause cancer, so it is recommended to wait until the tea brewed with boiling water is no longer hot before drinking it.

4. Drink more light tea and less strong tea

Strong tea contains more caffeine, which can easily cause nausea, heartburn, palpitations and other problems. Drinking it in the afternoon or evening will also affect sleep, so drink less. In addition, the tannic acid rich in strong tea will affect the absorption of iron, so people with iron deficiency anemia are best not to drink it.

After reading this article, will you, if you love tea, love it even more? Will you, if you don’t like tea, start to like it?

References:

[1] Yang WS, Wang WY, Fan WY, Deng Q, Wang 13. PMID: 24331002.

[2] InterAct Consortium; van Woudenbergh GJ, Kuijsten A, Drogan D, van der A DL, Romaguera D, Ardanaz E, Amiano P, Barricarte A, Beulens JW, Boeing H, Bueno-de-Mesquita HB, Dahm CC, Chirlaque MD, Clavel F, Crowe FL, Eomois PP, Fagherazzi G, Franks PW, Halkjaer J, Khaw KT, Masala G, Mattiello A, Nilsson P, Overvad K, Ramón Quirós J, Rolandsson O, Romieu I, Sacerdote C, Sánchez MJ, Schulze MB, Slimani N, Sluijs I, Spijkerman AM, Tagliabue G, Tjønneland A, Tumino R, Forouhi NG, Sharp S, Langenberg C, Feskens EJ, Riboli E, Wareham NJ. Tea consumption and incidence of type 2 diabetes in Europe: the EPIC-InterAct case-cohort study. PLoS One. 2012;7(5):e36910. doi: 10.1371/journal.pone.0036910. Epub 2012 May 30. PMID: 22666334; PMCID: PMC3364250.

[3]Song Y, Manson JE, Buring JE, Sesso HD, Liu S. Associations of dietary flavonoids with risk of type 2 diabetes, and markers of insulin resistance and systemic inflammation in women: a prospective study and cross-sectional analysis. J Am Coll Nutr. 2005;24:376–84.

[4] Jia Nie and others, on behalf of the China Kadoorie Biobank Collaborative Group, Tea consumption and long-term risk of type 2 diabetes and diabetic complications: a cohort study of 0.5 million Chinese adults, The American Journal of Clinical Nutrition, Volume 114, Issue 1, July 2021, Pages 194–202, https://doi.org/10.1093/ajcn/nqab006

[5]Kokubo Y, Iso H, Saito I, Yamagishi K, Yatsuya H, Ishihara J, Inoue M, Tsugane S. The impact of green tea and coffee consumption on the reduced risk of stroke incidence in Japanese population: the Japan public health center-based study cohort. Stroke. 2013 May;44(5):1369-74.

[6] Zhao Y, Tang C, Tang W, Zhang X, Jiang X, Duoji Z, Kangzhu Y, Zhao X, Xu 36915113; PMCID: PMC10010002.

[7] Inoue-Choi M, Ramirez Y, Cornelis MC, et al. Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank: A Prospective Cohort Study. Ann. Intern. Med. August 30, 2022. DOI: 10.7326/M22-0041

Author: Gu Chuanling, Deputy Secretary General of Capital Health Nutrition and Gastronomy Association, Registered Dietitian

Reviewer: Xue Qingxin, the first batch of nutrition instructors of the National Health Commission, China registered nutritionist

Planning editor: Lin Yiyi

Editor in charge: Yinuo