8 Teas That Can Help or Harm Your Heart

“Black tea has cardio-protective benefits that can improve blood vessel function and blood flow,” says Guy L. Mintz, MD, director of cardiovascular health and lipidology at the Sandra Atlas Bass Heart Hospital at North Shore University Hospital in Manhasset, New York.

Grace Derocha, RD, national spokesperson for the Academy of Nutrition and Dietetics, warns that the tannins, a class of polyphenols, may cause an upset stomach or other side effects.

“Tannins in black tea can also decrease iron absorption from plant-based foods,” Derocha says. “That's why there's tea time. You’re not supposed to have tea with your meals for a reason.”

Finally, Derocha says that black tea can interfere with mental health medication, so you should speak to your doctor if you are taking medication or trying a new tea.

For your heart health, it pays to go green.

Because green tea is made from steamed tea leaves and is less highly processed than black or oolong tea, it offers more health benefits, according to Derocha. “Steamed tea leaves have a higher concentration of EGCG, an antioxidant that helps prevent plaque buildup in our arteries,” she says.

However, it’s worth noting that these benefits are strongest with regular tea drinkers, and more so for those drinking more than one cup of green tea a day. But remember that green tea has caffeine ‚— though usually less than black tea — and the amount depends on how long it steeps.

White tea is harvested from the young buds of the tea plant and only briefly processed.

Regarding heart health, research is limited. Mintz says that while white tea does have antioxidant effects, there aren’t any specific studies exploring the link between the two.

As with green and black tea, oolong tea is made from Camellia sinensis plant leaves. The difference is in the processing. For oolong tea, crushed leaves are oxidized for a period of time and then heated to stop the process.

“It’s not a weight loss cure or supplement,” says Derocha. “That’s not how you want to sell anything because it could be dangerous for people.”

If you’re unsure how oolong tea will affect you, Derocha recommends speaking with a doctor. Like other teas, it may be contraindicated with medications like blood thinners.

Sometimes the tea works so well that doctors tell patients not to drink chamomile before surgery because it can have an adverse effect with anesthesia, says Derocha.

However, people 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.

“Just like with black tea, pharmacists and doctors want to know what herbal teas you drink,” says Derocha. This way they can ensure that there aren’t any contraindications with your medications..

“Ginseng is trickier because it can come in tea or capsule form,” says Derocha, who adds that ginseng supplements are sometimes touted as “miracle capsules” but with little proof of doing anything miraculous or with the approval of the FDA. If you want the potential benefits of ginseng, it is safer in tea form.

As with most teas, talk to your doctor if you’re taking blood thinners like warfarin or antiplatelet drugs such as clopidogrel (Plavix).

You may have heard that St. John’s wort, usually found in capsule form, can help treat symptoms of depression. But be wary of drinking this tea if you have a heart condition. And there is no evidence that St. John’s wort tea has significant cardiovascular benefits.

The organization also notes that while there has been extensive research on St. John’s wort for depression, the interactions with some medications can be life-threatening.

It’s important to note that because St. John’s wort is a dietary supplement, the FDA has not reviewed it for effectiveness or safety in the way it reviews drugs.

Derocha says ginseng tea is a safer option than St. John’s wort tea and that black and green teas are still the best and safest options for heart health.

But that doesn’t mean we shouldn’t drink it, notes Derocha.

“We talk about [eating] a rainbow of color with fruits and vegetables and getting a little bit of color from everything because there's a variety of nutrition that you'll get,” she says. “I feel the same way about tea. I think we should have red, black, white, and green tea because you'll get different perks.”

Fancy Tea Lattes Have No Heart Health Benefits

Creamy, foamy, frothy sweet tea lattes may be delicious. But for heart health and other health benefits, you’re better off drinking your tea plain. You’ll avoid a lot of calories with plain tea, too.

“A lot of patients will drink fancy tea lattes, and what they're going to get from that is a lot of sugar, calories, and carbs,” says Mintz. “In that case, you’re doing nothing for yourself.”