Iced tea: Drinking the wrong way can cause kidney failure without you knowing it

Iced tea has long been a familiar drink on hot days. Not only does it quench thirst, tea is also healthier than soft drinks or other drinks high in sugar and fat.

However, like any food, drinking iced tea should be done properly and in moderation.

Health benefits of iced tea

According to Everyday Health, Lisa Andrews, owner of Sound Bites Nutrition Center (USA), says that in addition to providing hydration, iced tea has several health benefits.

Iced tea is made from various types of black and green teas. These teas are rich in polyphenols and antioxidants, sometimes even 800-1000% higher than many fruits and vegetables. These compounds offer many benefits such as:

Drinking iced tea also requires the right method and moderation.

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Cardiovascular protection: Helps lower blood pressure, improve cholesterol levels, and reduce atherosclerosis.

Preventing dementia: Caffeine and L-theanine help improve alertness, focus, and reduce stress, which may support the prevention of dementia.

Boosting immunity and detoxification: Antioxidants protect cells and strengthen the immune system. A 2025 study also showed that tea can remove some heavy metals from polluted water.

Beautiful skin, anti-aging: Polyphenols in green tea help protect the skin from UV rays and increase elasticity.

Good for digestion and blood sugar stabilization: Tea supports the gut microbiome, provides manganese which is good for bones, and helps stabilize blood sugar.

Drinking too much iced tea can cause kidney stones and kidney failure.

Despite its many benefits, excessive consumption of iced tea can be harmful.

According to research published in the scientific journal Nutrients , tea, especially black tea, is rich in oxalic acid. Too much oxalic acid can build up in the kidneys, leading to kidney stones and preventing the kidneys from removing waste from the blood.

A study published on the website of the University of Utah School of Medicine (USA) in May 2014 warned about the case of a 56-year-old man at the Veterans Health Care Hospital in Arkansas (USA) who suddenly felt weak and experienced body aches. Doctors discovered that his kidneys were failing and he required dialysis.

Doctors discovered an unexpected culprit: the patient had been drinking approximately 3.8 liters of iced tea every day. Drinking so much tea had caused his kidneys to fail, according to Everyday Health.

Experts explain that drinking iced tea in moderation is still safe. For most people, 2-4 glasses of iced tea a day (240 ml/glass) is fine. And remember not to drink iced tea instead of water.

However, excessive consumption of iced tea can cause health problems. Additionally, drinking too much tea can easily lead to insomnia, rapid heartbeat, frequent urination, and iron deficiency.

How to drink iced tea safely

To take advantage of the benefits, it's best to keep the following two things in mind:

Drink 2-4 glasses per day (240 ml each), avoid drinking too much.

No added sugar or very little sugar. Adding sugar to iced tea can increase the risk of obesity and diabetes.

People with a history of kidney stones should drink plenty of water and consult their doctor.

In summary, iced tea is a good choice if consumed in moderation: it quenches thirst and supports cardiovascular health, brain function, skin, and blood sugar levels. However, remember that drinking too much can lead to kidney stones and even kidney failure. Therefore, moderation is key.

Source: https://thanhnien.vn/tra-da-uong-sai-cach-suy-than-luc-nao-khong-hay-18525090722540712.htm