Does Black Tea Affect Cancer Risk?
Key Takeaways:
There’s not enough evidence to know if black tea reduces the overall risk of cancer in people.
Studies in people only have convincing evidence that black tea lowers the risk of oral cancer. For other cancers, including breast cancer, evidence is mixed.
Some studies have found that black tea may actually raise breast cancer risk, but more studies are needed to be sure.
Black tea is a popular drink across the world. Some people drink tea for its health benefits.
Studies suggest that people who drink black tea live longer. Black tea contains compounds that help fight inflammation, which has been linked to many chronic health conditions, and can improve heart health. Black tea may also lower the risk of some cancers.
One reason why experts think black tea could affect cancer risk is that it contains a lot of antioxidants, including polyphenols. These compounds protect against harmful molecules in the body called free radicals. Free radicals can cause oxidative stress, which hurts cells and DNA, raising the risk of cancer.
What the research shows
Many studies have looked at the effects of black tea on people, but their results are still far from conclusive when it comes to cancer.
Cancer risk
It’s not clear if drinking black tea affects the risk of cancer. Some studies found no link between black tea and cancer, while others suggest drinking black tea may increase or decrease risk. For example, one large study of nearly 500,000 adults in the United Kingdom found no evidence that black tea affects cancer risk. And a 2013 meta-analysis found no link between black tea and breast cancer.
Some studies have found that black tea may lower the risk of specific types of cancer. The most convincing evidence suggests that drinking black tea may lower the risk of oral cancer. There’s also some evidence black tea may lower the risk of breast, endometrial, liver, and biliary tract cancer. A large study found a lower breast cancer risk for women who drank at least five cups of black tea per week compared to those who drank none.
Other studies show that drinking at least a cup of black tea per day was linked to higher breast cancer risk.
If black tea does raise breast cancer risk, sex hormones may play a role. One study found that drinking black tea was linked to both overall breast cancer risk and an even higher risk of estrogen- or progesterone-receptor positive breast cancer.
Overall, it’s unclear if black tea affects risk for cancer, including breast cancer. If there’s an effect, you would likely have to drink black tea at least once daily to experience it.
Cell and animal studies
Studies in cells and animals are an important early step in research. But you can’t draw conclusions about how things will work in people based on these studies. For example, adding black tea to cells in a lab dish can’t tell researchers how it will be absorbed or broken down in your body. And cancer can behave differently in a mouse than it does in a person. These studies are valuable, though, because they help researchers find promising leads and decide if they should test these leads in people.
Studies in cells and animals show that black tea may be able to fight cancer. For instance, lab studies have found that black tea can kill breast cancer cells. Also, many animal studies have found that components of black tea protect against cancer development by fighting oxidative stress and inflammation, and by limiting tumor growth and metastasis.
Other uses
One of the most common claims about black tea is that it can improve heart health. Research supports this, but more studies are needed to be sure.
The study of almost 500,000 people in the U.K., for example, found that black tea was linked to a lower risk of death from cardiovascular disease, ischemic heart disease, and stroke. Meta-analysis studies havae also found that drinking black tea can lower cholesterol and blood pressure.
Other studies suggest black tea may help with focus and attention, blood sugar levels, and the gut microbiome.
Safety, risks, and side effects
Some studies suggest that drinking black tea at least once daily may raise breast cancer risk. But there isn’t enough research yet to be sure. If you’re worried, talk to your doctor.
Drinking tea and other beverages that are too hot can raise your risk of esophageal cancer. Let your tea cool a bit before you drink it. Some experts recommend waiting until the temperature is below 140 degrees Fahrenheit. (Water boils at 212 degrees Fahrenheit.)
Be aware that a cup of black tea contains about 50 milligrams of caffeine. For most people, a maximum of 400 milligrams of caffeine per day is safe. But caffeine can interact with some medications. It may harm people with some conditions, like schizophrenia and insomnia. Ask your doctor before taking caffeinated foods and drinks, including tea.
Should you drink black tea?
If you like to drink black tea and are worried about cancer, there’s no reason to change your behavior. There isn’t enough evidence that drinking black tea changes the risk of breast cancer and most other cancers. Drinking black tea may improve your health in other ways, such as by improving your heart health, reducing inflammation, and more.