5 Foods and Supplements to Avoid Mixing with Green Tea

Green tea is rich in antioxidants and offers many health benefits, but it may interact with certain foods and supplements. To get the most out of your cup of green tea, try to avoid consuming iron, dairy, or acidic foods.

1. Iron supplements

Green tea contains plant-derived compounds (polyphenols such as catechins and tannins) that bind to iron, preventing it from being absorbed and used by the body. This leads to low iron levels and iron deficiency.

Avoid drinking green tea when taking an iron supplement. Research shows that drinking green tea containing iron can reduce its absorption by up to 90%.

Talk to a healthcare professional if you want to drink green tea for iron deficiency. Wait at least one to two hours after taking an iron supplement before enjoying your tea.

2. Foods rich in iron

Drinking green tea with iron-rich foods may affect iron absorption. Iron-rich foods include:

• Enriched cereals
• Oysters
• Mussels
• Beef
• Spinach
• Beans
• Lenses

If possible, avoid drinking green tea with meals. Brew a cup an hour or two after eating to minimize the effects on iron absorption. Research shows that drinking green tea at least an hour before an iron-rich meal can improve absorption.

However, eating foods rich in iron and vitamin C can improve iron absorption. Consider adding foods rich in vitamin C to your meal, such as broccoli, red peppers, citrus fruits and strawberries.

3. Folic Acid Supplements

Polyphenols in green tea may inhibit folate absorption. The catechins in green tea bind to folic acid, preventing the body from converting it to folate and absorbing it.

Folate (B9) is a water-soluble vitamin essential for cell growth and neural tube development. Pregnant people need higher levels of folic acid to support healthy fetal development and reduce the risk of neural tube defects, such as spina bifida.

If you are pregnant, ask your doctor if green tea is safe.

4. Caffeine Supplements

Green tea contains caffeine, a natural medicine that stimulates the brain and nervous system. Consuming green tea with caffeine supplements or caffeinated beverages like coffee may cause side effects.

Drinking too much caffeine can cause:

• Increased heart rate
• Higher blood pressure
• Sleep problems
• Nausea
• Headaches
• Anxiety

Experts recommend limiting your daily caffeine intake to less than 400 milligrams. This is the amount found in two to three cups of coffee. A cup of green tea contains about 30 to 50 milligrams of caffeine.

5. Spicy or acidic foods

Green tea contains compounds called methylxanthines that act as stimulants. These compounds also relax the band of muscle called the lower esophageal sphincter (LES). LES prevents stomach acid from flowing back up into the esophagus, causing heartburn and acid reflux.

Drinking green tea may increase your risk of heartburn. Avoid consuming it with spicy or acidic foods, which can lead to heartburn and indigestion.

Who should avoid green tea?

Green tea is generally safe and well tolerated by most healthy adults. However, some groups may need to exercise caution. Talk to your healthcare professional before drinking green tea if you have any of the following health conditions:

• Pregnancy
• Breast-feeding
• Anemia
• Diabetes
• Heart disease
• Kidney disease
• Liver disease
• Stomach ulcers

Due to its caffeine content, children should avoid green tea.

How to minimize interactions

It may still be possible to enjoy green tea despite interactions between foods and supplements. Wait at least one to two hours to drink green tea to avoid absorption problems. Pay attention to the caffeine content so as not to exceed 400 milligrams per day.

Ask your doctor if you are unsure whether any of your medications or supplements interact with green tea. This is especially important for people with anemia, as green tea inhibits iron absorption and could make the condition worse.