Which Tea Is Good For High Blood Pressure?

High blood pressure (hypertension) is generally managed by maintaining a lifestyle healthy for the heart, such as regular exercise and a low-sodium diet. Medication may also be required to help reduce blood pressure.

Some people use natural medications and supplements to help manage their blood pressure, including herbal teas. But, what tea is good for high blood pressure? 

Some animal-model studies and clinical trials have observed the antihypertensive effects of certain teas.¹ Most evidence points toward the consumption of both black and green tea being linked with reduced blood pressure, despite a few studies showing negative results.

What is considered high blood pressure (hypertension)? 

Hypertension is a common condition that can develop when your blood flows at a higher-than-normal pressure through your arteries. Two numbers make up your blood pressure – your systolic and diastolic numbers.

• Systolic blood pressure (SBP): Pressure when your heart ventricles are pumping blood out of your heart.

• Diastolic blood pressure (DBP): Pressure between your heartbeats as your heart fills with blood.

Throughout the day, your blood pressure changes based on your activities. A normal blood pressure, for most adults, is less than 120/80mm Hg (millimeters of mercury). The 120 is your systolic blood pressure (SBP), and the 80 is your diastolic blood pressure (DBP). 

Consistent 130mm Hg or higher systolic readings, or 80mm Hg or higher diastolic readings, are considered high blood pressure.

How many Americans have high blood pressure?

Almost 50% of adults in the US have hypertension or are taking hypertension medication.

Approximately one in three adults in the US with hypertension don't even know they have it and aren't receiving treatment to keep their blood pressure under control.

Hypertension was a main or contributing cause of death for more than 515,000 people in the US in 2019.

Which types of tea are good for high blood pressure? 

So, what kind of tea is good for high blood pressure? Here are some teas that research claims to be effective at reducing hypertension. 

Green tea

Green-tea consumption decreases SBP and DBP significantly, according to a meta-analysis.² There were some limitations within this analysis which suggests you should view the results as promising instead of conclusive.

Black tea

Like with green tea, research shows black tea can help reduce blood pressure,³ and it may also have properties that help protect the heart. 

Hibiscus tea

Another meta-analysis⁴ shows that drinks made with Hibiscus sabdariffa L. also effectively lowered SBP and DBP. Although this finding shows promise, it requires more research.

A few randomized clinical trials confirmed the hypotensive effect of Hibiscus sabdariffa L. For instance, a randomized controlled trial⁵ investigated the effects of 10g of Hibiscus sabdariffa L. extract per day for four weeks in people with hypertension. After the protocol period, these people experienced a significant reduction in both SBP and DBP.

Oolong tea

Oolong tea's benefits on blood pressure haven't been studied on their own. However, antioxidants in oolong tea are the same as green and black tea. Therefore, it's quite possible that oolong tea shares similar benefits for hypertension. 

However, its effects on blood pressure specifically need more research.

Relationship between tea and blood pressure levels 

Researchers have documented the effects of tea⁶ when it comes to regulating blood pressure.

The benefits of tea are frequently linked to the beverage being rich in polyphenolic substances or flavonoids. Flavonoids can play a significant role in controlling and treating hypertension.

The antihypertensive effects of consuming tea have become a popular topic for research. Clinical studies⁶ have tried to describe tea’s role in decreasing blood pressure.

Both black and green teas are brewed from the Camellia sinensis shrub's leaves, but green tea comes from unfermented leaves and has more antioxidants. The oxidation during black tea's fermentation process decreases its antioxidant levels.

Certain polyphenols (catechins) in black and green teas help relax the smooth muscle lining blood vessels, which could result in lower blood pressure.

These catechins include:

• Epicatechin (EC)

• Epicatechin gallate (ECG)

• Epigallocatechin (EGC)

• Epigallocatechin gallate (EGCG)

• Gallocatechin gallate (GCG)

• Catechin gallate (CG)

• Catechin (C)

• Gallocatechin (GC)

Until now, the molecular mechanism that contributes to the impact on blood pressure hasn't been explained.

Not only this, but tea also has L-theanine, an amino acid proven to decrease blood pressure in people under stress.⁷

Reasons to talk with your doctor about herbal tea for high blood pressure 

If you're looking into which herbal tea is good for high blood pressure, your first step should be a discussion with your doctor or healthcare professional. 

Some reasons you should talk with your doctor first about herbal tea for hypertension include:

May contain caffeine

For people who don't regularly consume caffeine, it can temporarily increase blood pressure. 

Herbal tea blocks a certain hormone in your body that keeps your blood vessels open so your blood can pass through easily. This can increase your blood pressure temporarily, but there is no sufficient evidence that it will increase your blood pressure in the long term.

May interact with medication

The British Journal of Clinical Pharmacology published a research review⁸ reporting that various herbal supplements, including green tea, can interact with certain prescription medicines. This can cause some medications to become less effective or even very harmful or fatal.

Black tea contains caffeine that can interact with different supplements and medications.

Some of these medications include:

• Antibiotics: Certain types of antibiotics affect how your body breaks down caffeine

• Adenosine: This medication is given before cardiac stress testing

• Ephedrine: This medication is a stimulant, like caffeine, and if you take them together, it may trigger side effects

• Carbamazepine (Tegretol): Consuming caffeine while taking this medication could reduce its ability to prevent seizures

Anyone taking medications should consult with their doctor about how much caffeine they're consuming through coffee and tea. It could affect how their medicine works and may even put them at risk of side effects.

Some supplements, which may be found in certain herbal teas, can cause negative effects for people taking high blood pressure medication.

These supplements include: 

• Ephedra (ma huang)

• St. John's wort

• Licorice (Glycyrrhiza glabra)

• Garlic

• Ginseng (Panax ginseng and Panax quinquefolius)

• Yohimbine

Just because herbal supplements and teas are ‘natural’ doesn't mean they're always safe. 

Always check with your doctor before taking any type of herbal supplement or herbal tea.

May contain toxic elements

All types of brewed tea contain minerals that can be poisonous⁹ when consumed in excess.

For instance, aluminum and lead can be found in tea. When consumed in larger doses, they can be toxic to humans. Some teas contain minor traces of cadmium and arsenic, but not in quantities that can cause harm.

There are high levels of manganese in black tea. Your body requires this mineral, but when taken in excess, it can be toxic.

The longer a tea is brewed, the higher concentration levels there will be of these toxic elements. You can reduce the risk by brewing your tea for no longer than three minutes.

The lowdown

Dealing with a hypertension diagnosis can be frustrating, but it's a manageable condition through medication, exercise, and other lifestyle changes. 

Drinking tea may be a healthy habit you can add to your lifestyle to help manage your blood pressure levels which you should discuss with your doctor. 

Remember to consume any teas in moderation since most contain caffeine (including green tea, which contains naturally-occurring caffeine).  And, as you've read, caffeine can have its own interactions and effects.

Tea is meant to be enjoyed. For people with high blood pressure, it may just provide them with added benefits.