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One Major Side Effect of Having Too Much Caffeine, According to Doctors

Two doctors explain how the stimulant could cause breast tenderness.
FACT CHECKED BY Joseph Neese

Drinking too many cups of coffee each day may make you feel more anxious, susceptible to acid reflux, and increase your heart rate. If you identify as a woman, it may also make your breasts sensitive.

"Large amounts of caffeine can lead to changes in your hormone levels. This may lead to cyst formation and therefore tenderness," Dr. Jill Hechtman, MD, a board-certified OBGYN, and scientific advisor to Nightfood, says. "Caffeine can also dilate some vessels causing swelling and tenderness."

In general, Hechtman advises that you limit your caffeine consumption to less than 400 milligrams per day, or a maximum of four, 8-ounce cups of coffee. Consuming anything above 600 milligrams of caffeine in a day isn't considered healthy. While there's limited research on caffeine and breast tenderness, one study from researchers at Duke University suggests that too much of the stimulant could be a cause of breast pain.

"They studied 147 patients, and of those that reduced their caffeine, 61% reported a decrease or absence of breast pain," says Sophia Yen, MD, MPH, and founder and CEO of Pandia Health—the only women-founded, women-led, doctor-led birth control delivery service.

Aside from caffeinated beverages like coffee, energy drinks, and soda, chocolate could also be a culprit when it comes to breast tenderness—especially if eaten in excess. Cheese, meat, and wine may also yield a similar effect in some women, Hechtman adds. Food aside, breast tenderness may also be brought on by stress.

It's important to note that breast tenderness triggered by excessive caffeine intake isn't a cause for concern. More specifically, caffeine isn't a risk factor for breast cancer, though there may be a small association between breast tissue density and caffeine intake.

Premenopausal women who had a high coffee intake also had a higher percentage of breast density, according to one 2018 study published in the scientific journal Breast Cancer Research and Treatment that looked at 4,130 healthy women. Simply put, having dense breasts just means that you have more fibrous or glandular tissue than fatty tissue.

"Women with dense breasts have a higher risk of breast cancer," says Yen, adding that half of women 40 years and older have dense breasts. Breasts that are predominantly made of dense tissues can hide cancers on mammograms. Similar to tumors, fibrous and glandular tissue can appear white on an X-ray.

According to the Centers for Disease Prevention and Control, breast density is assigned one of four categories on a mammogram:

  1. 10% of women have mainly fatty breasts,
  2. 40% have breasts with dense tissue scattered throughout,
  3. 40% have "evenly dense" breasts,
  4. 10% have extremely dense breasts.

The best way to combat breast cancer is to regularly screen for it starting at age 40. However, if breast cancer runs in your family, you can begin screening as early as five years before the age a family member who was diagnosed. For example, if your mom was diagnosed with breast cancer at 35, you can get your first mammogram at age 30.

For more information on how caffeine can affect your body, be sure to check out the Side Effects of Drinking Caffeine, According to Science. And don't forget to sign up for our newsletter to get all of the latest news delivered straight to your inbox.

Cheyenne Buckingham
Cheyenne Buckingham is the news editor of <Eat This, Not That!, specializing in food and drink coverage, and breaking down the science behind the latest health studies and information. Read more
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