Tea Drinking Habits That May Affect Your Health: 5 Side Effects to Know

Tea can be part of a healthy diet, but how much you drink, when you drink it and what you add to it can affect how your body responds. Drinking too much tea may contribute to caffeine-related problems such as poor sleep, restlessness and stomach upset, while tea consumed with meals can reduce the absorption of non-haem iron.

For most healthy adults, moderate tea consumption is not considered inherently harmful. The concern is more relevant when tea intake is high, the drink contains a lot of added sugar, or someone already has a condition or nutritional deficiency that can be affected by caffeine or reduced iron absorption.

What are the 5 major side effects of drinking too much tea?

The effects vary from person to person, but excessive tea intake can potentially contribute to:

1. Sleep problems and restlessness
2. Anxiety, shakiness or a fast heartbeat
3. Stomach discomfort
4. Reduced iron absorption
5. Frequent urination and other caffeine-related effects

These effects are largely associated with caffeine, while the impact on iron absorption is linked to tea's polyphenolic compounds. Mayo Clinic notes that excessive caffeine can cause insomnia, nervousness, frequent urination, fast heartbeat, tremors and stomach upset.

Can drinking tea every day be bad for you?

Not necessarily. Tea contains polyphenols and other compounds that have been studied for potential health effects, and the National Center for Complementary and Integrative Health notes that tea contains substances including polyphenols and caffeine.

The important distinction is between moderate everyday consumption and excessive intake. Drinking several cups throughout the day may be tolerated by many adults, but people who are sensitive to caffeine may experience symptoms at much lower amounts.

Tea drinking habits: what may help and what may cause problems?

Does drinking too much tea cause iron deficiency?

Tea can reduce the absorption of non-haem iron, the type of iron found mainly in plant foods and many fortified foods. Research reviewed in PubMed found clear evidence that tea drinking limits non-haem iron absorption, although the effect on overall iron status varies between people.

This does not mean that everyone who drinks tea will develop anaemia. The concern is greater for people who already have low iron intake or are otherwise at risk of iron deficiency.

For people taking iron supplements, Mayo Clinic advises avoiding tea or coffee within an hour of taking the supplement because both can interfere with iron absorption.

Is drinking too much tea bad for your kidneys?

There is not enough evidence to say that ordinary tea drinking directly damages healthy kidneys. In fact, observational research has found associations between moderate tea consumption and some kidney outcomes, but these studies do not prove that tea itself prevents kidney disease.

The question becomes more complicated with people who already have kidney disease, take certain medicines, or consume extremely large quantities of caffeinated beverages.

Tea is also one of several dietary sources of oxalate, which can be relevant to people who are prone to certain types of kidney stones. Mayo Clinic lists tea among foods that can be high in oxalates, while also emphasising that kidney-stone risk depends on several factors, including hydration and overall diet.

So the claim that “tea is bad for your kidneys” is too broad. The amount consumed and an individual's health history matter.

What are the side effects of milk tea?

Milk tea deserves a separate discussion because the potential issue is not simply the presence of milk.

A typical cup of milk tea may contain tea, caffeine, milk and added sugar. If several cups are consumed every day, the added sugar and total calorie intake can become more important than the tea itself.

Research has also examined how adding milk changes the relationship between tea consumption and health outcomes. One large observational study found a different association between tea consumption and acute kidney injury depending on whether milk or sweeteners were added, but this type of research cannot establish that milk tea causes or prevents kidney problems.

Can tea affect your skin?

There is not strong evidence that ordinary tea drinking directly causes acne or skin damage in everyone.

Searches for “side effects of tea on skin” often produce claims that tea causes pimples, pigmentation or dull skin, but these should not be presented as established facts without specific evidence. The relationship can also be affected by what is added to the tea, overall diet, sleep and individual skin conditions.

Green tea itself contains polyphenols that have been investigated for various potential health effects, although much of the research concerns extracts or specific compounds rather than ordinary cups of tea.

Does drinking tea on an empty stomach cause problems?

Some people report nausea or stomach discomfort after drinking strong tea on an empty stomach. Caffeine can contribute to gastrointestinal symptoms in sensitive people, although individual responses vary.

If tea consistently makes you feel nauseous, acidic or uncomfortable, drinking it after food or reducing the strength and quantity may help. Persistent digestive symptoms should not automatically be attributed to tea.

How much caffeine is too much?

For most healthy adults, up to 400 mg of caffeine per day is generally considered an amount that is not associated with negative effects, although individual sensitivity varies considerably. Importantly, caffeine content differs between tea types, serving sizes and brewing methods.

Someone who gets headaches, insomnia, anxiety, tremors or a racing heartbeat after tea may need less caffeine than someone who experiences no symptoms at the same intake.

Pregnant or breastfeeding people and those taking certain medicines should discuss their caffeine intake with a healthcare professional rather than relying on a general limit.

What are the benefits of drinking tea every day?

Tea isn't simply a beverage associated with side effects. Tea leaves contain polyphenols and other compounds that have been studied for potential health effects. The evidence varies by tea type and by the health outcome being studied.

For green tea specifically, NCCIH says studies have found a small reduction in total cholesterol and LDL cholesterol, although many studies of green tea products involve extracts rather than ordinary brewed tea.

That is why it is better to avoid both extremes: tea is neither a universal health drink nor automatically harmful.

What tea habits should you change?

If tea is a daily part of your routine, a few practical changes can reduce potential problems:

1. Avoid excessive caffeine, particularly if you experience insomnia, anxiety or palpitations.
2. Don't take tea alongside iron supplements. Leave at least an hour, as advised by Mayo Clinic.
3. Consider having tea between meals if you are at risk of iron deficiency. A review recommends this approach and suggests waiting at least an hour after eating.
4. Watch the sugar in milk tea, especially if you drink multiple cups daily.
5. Avoid late-evening caffeinated tea if it affects your sleep.
6. Pay attention to your own symptoms rather than assuming a fixed number of cups is suitable for everyone.

Tea drinking habits: Quick Q&A

Is drinking tea every day healthy?

Moderate tea consumption can generally fit into a healthy diet, and tea contains polyphenols and other compounds that have been studied for potential health benefits. The effects depend on the type and amount of tea and individual factors.

What happens if you drink too much tea?

Too much caffeinated tea can cause insomnia, nervousness, shakiness, increased urination, a fast heartbeat and stomach upset, particularly in caffeine-sensitive people.

Is tea bad for your kidneys?

Ordinary tea consumption has not been established as a direct cause of kidney damage in healthy people. Kidney health is influenced by many factors, and people with kidney disease or a history of kidney stones may need individual dietary advice.

Does milk tea have side effects?

Milk tea can contribute to caffeine intake and, depending on preparation, significant added sugar. The health impact therefore depends on how much is consumed and what is added to each cup.