Tea is one of the most popular beverages worldwide. The most popular varieties are green, black, and oolong tea—all made from the leaves of the tea plant.

There's nothing more satisfying or soothing than sipping a hot cup of tea, and its benefits go beyond that. For centuries, tea has been used for its therapeutic properties in traditional medicine.

Additionally, modern research suggests that the plant compounds in tea may help reduce the risk of chronic diseases like cancer, obesity, diabetes, and heart disease.

While drinking tea in moderation is a very healthy choice for most people, consuming more than 3-4 cups (710-950 milliliters) daily can have some negative effects.

1. Reduces Iron Absorption

Tea is rich in a type of compound called tannins. Tannins can bind to iron in certain foods, making it harder for your body to absorb.

Iron deficiency is one of the most common nutritional deficiencies in the world, and excessive tea consumption may worsen the condition if your iron levels are low.

Studies show that tannins in tea are more likely to hinder the absorption of plant-based iron than animal-based iron. Therefore, if you're following a strict vegan or vegetarian diet, you may need to pay extra attention to how much tea you consume.

The exact amount of tannins in tea may vary depending on the type and how it's brewed.

2. Causes Stomach Issues

Excessive tea consumption can sometimes lead to digestive discomfort. The caffeine in tea can increase stomach acid production, potentially causing acid reflux or heartburn.

Additionally, the tannins found in tea can irritate the stomach lining, leading to nausea and other digestive issues when consumed on an empty stomach.

If you already suffer from digestive issues like acid reflux, irritable bowel syndrome (IBS), or ulcers, drinking large amounts of tea may worsen your symptoms.

3. Can Lead to Sleep Disruptions

Most types of tea contain caffeine, a natural stimulant that can affect your sleep. While some teas, such as chamomile or peppermint, are naturally caffeine-free, other popular varieties like black, green, and oolong tea do contain varying amounts of caffeine.

Consuming too much caffeine, especially later in the day, can interfere with your ability to fall asleep and disrupt the quality of your sleep. If you're sensitive to caffeine, even small amounts can cause insomnia or difficulty staying asleep.

4. May Increase Anxiety

Caffeine is known to stimulate the central nervous system, which can lead to feelings of jitteriness or anxiety. While moderate tea consumption might provide an energy boost, excessive intake can worsen anxiety symptoms.

If you're prone to anxiety or stress, consuming too much caffeinated tea could intensify these feelings and make it harder to relax or unwind.

5. Can Stain Your Teeth

While tea is less likely to stain your teeth than coffee, it can still contribute to discoloration over time. The tannins in tea can stick to the surface of your teeth, leaving behind stains, particularly if you drink it regularly.

If you want to minimize staining, consider drinking tea through a straw or rinse your mouth with water afterward. Regular brushing and professional dental cleanings can also help keep your teeth bright.

6. Affects Calcium Absorption

Consuming large amounts of tea may interfere with calcium absorption in your body. The caffeine in tea can increase the excretion of calcium through urinary output, which may contribute to a decrease in skeletal density over time.

While moderate tea consumption is unlikely to cause significant issues, consuming excessive amounts regularly could potentially increase your risk of developing conditions like osteoporosis.

7. May Cause Dehydration

Though tea is a liquid, it can act as a mild diuretic due to its caffeine content. This means that drinking too much tea may increase urination, which can lead to dehydration if you're not also drinking enough water.

To stay hydrated, it's essential to balance your tea intake with plenty of water, especially if you're consuming caffeinated varieties.

8. Interferes with Medications

Certain compounds found in tea, including caffeine and tannins, may interact with some medications, affecting their effectiveness. For example, tea can interfere with the absorption of certain antibiotics or medications used to treat iron deficiencies.

If you're on any medication, it's a good idea to check with your doctor or pharmacist to ensure that tea won't interfere with your treatment plan.

9. Increases Risk of Kidney Stones

Tea, especially black tea, contains oxalates—compounds that can contribute to the formation of kidney stones. When consumed in excessive amounts, the oxalates in tea may increase your risk of developing kidney stones, particularly if you're already prone to them.

If you're at risk for kidney stones or have a history of them, it's wise to limit your tea intake, particularly black tea.