The hidden dangers of your green tea addiction

To round out this week of “New World” discoveries, let’s talk about a beverage that’s hit the mainstream in recent years.

I’m talking about green tea, of course. In fact, I recently read that Walt Disney World® has started offering a frozen green tea concoction for a mere $5.69 plus tax. One reviewer said it tastes like a “grassy milkshake.” And, of course, Starbucks has been offering its own pricey twist on green tea for years now.

But in my view, you—and your wallet—are far better off skipping green tea and opting for another type of tea (or black coffee) instead. Here’s why…

Too much of a good thing

 Green tea and black tea come from the same plant—Thea sinensis also called Camellia sinensis.

 And—yes—some studies have found that constituents in these teas support certain aspects of your health, such as your cardiovascular heath, immune system, and cognitive function.

But you’d have to drink a staggering eight cups or more of green (or black) tea daily to reach the right amounts found to confer the health benefits in those studies.

And—by the time you drink enough green tea to potentially gain any benefits, you’ve put yourself on the threshold of potentially being poisoned. In fact, both black and green tea contains tannic acid (which irritates the gastrointestinal tract) and oxalic acid (which is toxic to the kidneys). And the New England Journal of Medicine recently profiled a case that showed just how quickly these constituents can reach toxic levels…

Poisoned by home-brewed tea

The case study introduced us to a 56-year-old man who went to the emergency room at the Veterans’ Administration Hospital in Little Rock, Arkansas. The man reported intense aches and pains, fatigue and weakness. Blood testing showed excessively high levels of a waste product called creatinine, which is associated with kidney failure. The man actually required immediate dialysis to reduce the toxic creatinine, since the kidneys weren’t working. (As you may recall, some ignorant doctors recently tried to blame a similar set of symptoms on a vitamin D “overdose.”)

In the meantime, urine testing found that the man’s oxalate crystals were at more than double the normal limit. And a biopsy of the kidneys found oxalate crystals throughout the renal tissue.

As a Medical Examiner, I encountered this same kind of poisoning when people ingested ethylene glycol, the deadly chemical found in antifreeze. (They ingested it either accidently or intentionally to commit suicide and even administered it to others to commit homicide.)

In this case, the culprit wasn’t antifreeze, but iced tea. In fact, the doctors determined that the man’s high oxalate levels were caused by drinking 16 eight-ounce glasses of home-brewed iced tea daily.

Black and green tea more dangerous than you might think

Tea is the second most consumed beverage in the world, after water. And it’s popularity is definitely on the rise in the U.S., thanks in no small part to all of the new retail offerings that make the drink seem like some kind of “superfood.”

One kidney expert said that two to three glasses of tea daily would be considered safe, provided you don’t also eat significant quantities of high-oxalate foods, such as peanuts, rhubarb, spinach, star fruit, and wheat bran. (Other fruits, such as blackberries, blueberries, and raspberries, also contain oxalate, but in lower amounts.)

The expert’s advice is sound advice, as two to three glasses of tea a day probably won’t get you into trouble. But then, at the same time, it’s nowhere near the amounts really required to prevent chronic disease. And you’re not doing yourself any favors—health-wise—by drinking that amount either. So, why drink it at all?

In my view, it’s high time to give up your green or black tea habit in favor of other herbal brews, such as rooibos, a type of red tea that I’ve talked about before.

Or—you can stick with coffee. Studies link two to three cups of coffee daily with six impressive health benefits. Including short-term benefits, such as increased energy and improved mental focus, as well as long-term reductions in risk of cancer, dementia, heart disease, and other chronic diseases.

P.S. I’m not a fan of the so-called “superfoods” touted by the mainstream. But I’m all for certain native-grown “wonder weeds.” In fact, I discussed my favorite uses for them in the September 2018 issue of my monthly newsletter, Insiders’ Cures (“Ten free ‘superfoods’ growing right in your backyard”). Subscribers have access to all of my past content in the archives. So if you haven’t already, consider signing up today. Click here now!


“The Man Who Almost Died From Drinking (Too Much) Tea.” The Atlantic, 4/6/2015. (