Black tea rich polyphenol content—including flavonoids and catechins—contributes to its numerous health benefits by providing powerful antioxidant and anti-inflammatory properties. These compounds help combat oxidative stress, which is linked to various chronic conditions.
Research suggests that drinking three or more cups of black tea daily may be associated with a lower risk of several chronic diseases.1 Including black tea as part of a balanced diet can be a simple yet effective way to enhance overall well-being.
1. It’s Nutritious
The nutrition profile of black tea varies depending on the specific type of tea, the brew method, and whether it is freshly made or ready to drink. In general, the nutrition breakdown includes:
- Low caffeine content: A 16-ounce bottle of store-bought black tea contains 52 milligrams (mg) of caffeine, whereas a freshly brewed 8-ounce cup has 47 mg.23
- Polyphenols: Black tea contains six groups of polyphenols, compounds in plants with health benefits.4 Polyphenol content depends on how the tea is brewed. Generally, polyphenols comprise about 3% to 10% of the compounds in black tea.1 Specifically, black tea contains a polyphenol called flavonoids, which contribute to the tea’s color, taste, and benefits. Theaflavins, a specific type of flavonoid, are common in black tea and confer many health benefits.4
- Other healthy compounds: Black tea is packed with other health-supporting compounds, such as the amino acid L-theanine, which helps you feel relaxed. A cup of black tea contains 20 mg to 40 mg of L-theanine.5 An 8-ounce cup of freshly brewed black tea also contains 0.5 mg of manganese (32% of the daily value), an essential trace mineral that supports metabolism and has antioxidant properties.2
2. It Has Antioxidant Properties
Antioxidants like catechins look for harmful and unstable molecules (free radicals) in the body. Free radicals damage cells and contribute to the development of chronic conditions. Catechins in black tea neutralize free radicals to minimize damage.4
Drinking three cups of black tea daily raises antioxidant levels in the body.6 Some research shows that the body’s antioxidant capacity increases within 30 to 60 minutes after drinking a glass of black tea.7
3. It Increases Alertness and Cognitive Function
Theaflavins in black tea limit the production of inflammatory molecules and prevent the weakening and breakdown of nerve cells.
Some research indicates that black tea prevents the formation of aging-related amyloid proteins. Amyloid proteins affect cognitive function and contribute to cognitive decline.8
One large meta-analysis observed a 29% reduction in the risk of all-cause dementia with regular tea drinking. However, researchers did not differentiate between the different types of tea. Instead, they highlighted the beneficial compounds of tea that support cognitive health.8 Additional research observed a lower risk of cognitive disorders with tea drinking, especially among women.9
Other research suggests that black tea enhances mental alertness, planning capacity, and concentration.4 Animal studies show that tea’s polyphenols improve learning and memory.8 Some evidence in humans suggests that black tea may reduce short- and long-term memory issues.4
4. It May Help Digestive Health
Black tea’s health benefits may be due to its interaction with the gut microbiome during metabolism.10 Microbiota breaks down polyphenols from tea for absorption.11
Emerging research suggests drinking four to five glasses of black tea daily may influence microbial diversity.12 Black tea potentially contributes to the colonization of beneficial bacteria and inhibits the growth of harmful bacteria.11
Black tea’s antimicrobial properties may prevent diarrhea. However, more research is needed to understand its effect on gut microbiota and its role in diarrhea prevention and recovery.10
5. It May Assist Blood Sugar Control
Polyphenols in black tea may improve the body’s insulin sensitivity, helping lower blood sugar (glucose) levels.13 Still, evidence yields conflicting results on the benefits of black tea for blood sugar control.
One study found a potential link between regularly drinking at least one cup of black tea daily and a reduced risk of developing type 2 diabetes. Polyphenols in black tea may contribute to this reduced risk.4
Another study noted that drinking black tea after a sugar-rich meal minimized the subsequent increase in blood sugar in healthy individuals and people with prediabetes. Black tea may block the absorption of carbohydrates by inhibiting the activity of enzymes involved in breaking down carbohydrates.13
Still, not all evidence shows the benefit of black tea in reducing blood sugar. One meta-analysis observed no significant effects of black tea on blood sugar levels.14
6. It May Benefit Heart Health
Population studies indicate that drinking more black tea may protect against heart disease. Black tea influences cholesterol levels and blood pressure to support heart health.15 Tea flavonoids influence blood vessels to improve blood flow, possibly reducing heart disease risk.
Igho-Osagie E, Cara K, Wang D, et al. Short-term tea consumption is not associated with a reduction in blood lipids or pressure: a systematic review and meta-analysis of randomized controlled trials. J Nutr. 2020;150(12):3269-3279. doi:10.1093/jn/nxaa295
- Blood pressure: Research conflicts on the effects of black tea on blood pressure. One analysis observed a trend toward lower blood pressure with three cups of black tea daily for at least six months.16 Another large analysis found a decrease in blood pressure with just two cups of tea daily, but the study did not separate black and green tea. One thing to note: Caffeine in black tea may still negatively affect blood pressure despite the beneficial effects of flavonoids.17
- Cholesterol: Regularly drinking black tea reduces low-density lipoprotein (LDL) or “harmful cholesterol” levels, particularly among individuals with a high risk of heart disease. Polyphenols in black tea may suppress how much cholesterol the body produces.18 The effects of black tea on triglyceride levels are less clear and may differ depending on gender.19 Although promising, other research has found that drinking five cups of black tea daily did not significantly impact cholesterol levels.16
- Theobromine: Theobromine is a compound in black tea with potential heart health benefits. According to some research, theobromine may positively influence cholesterol levels, reducing LDL and increasing high-density lipoprotein (HDL) or good cholesterol levels. However, the benefit may depend on the individual. Moreover, studies use a therapeutic dose of 500 mg of theobromine daily, far above the 4.75 mg in an 8-ounce cup of freshly brewed black tea.220
7. It May Help Fight Dental Plaque
Cavities (dental caries) result from plaque accumulation on the teeth. Plaque is a biofilm produced from saliva and bacteria. Cavities occur when large quantities of bacteria exist on teeth, causing tooth enamel to break down.21
Theaflavins in black tea have antibacterial properties that damage bacterial cell membranes to fight dental plaque and reduce cavities.21
Preliminary research in rats indicates that black tea reduces the development of cavities.21 However, research in humans is less conclusive.
One study observed less cavity-inducing bacteria in the mouths of people who regularly drink tea, suggesting black tea may reduce dental plaque. However, habitual black tea consumption did not prevent cavities.22
8. It May Reduce Stress
L-theanine is a compound found naturally in black tea that may improve attention and reduce stress. In healthy adults, taking 200 mg of L-theanine daily—the amount of L-theanine in eight cups of black tea—for four weeks improves stress-related symptoms like anxiety and sleep.2324
Reaching 200 mg of L-theanine from black tea is likely unrealistic without supplementation. Still, L-theanine in black tea may provide calming benefits.
Some research indicates that consuming caffeine and L-theanine together—like in black tea—may result in mental alertness and a feeling of calm. Generally, caffeine and L-theanine have opposing effects. However, when consumed together, particularly during stressful moments, these two compounds may counteract each other.5
Additionally, an older study noticed lower stress levels and more relaxation following a high-stress task among individuals who drank four cups of black tea daily for six weeks compared to those who consumed a placebo.25
9. It May Have Anti-Inflammatory Effects
Black tea’s anti-inflammatory properties influence its effects on various health conditions like heart disease and cancer.
Regularly drinking black tea reduces markers of cell damage and inflammation. Specifically, tea drinking is associated with lower levels of c-reactive protein, an inflammatory marker.7
10. It May Benefit Skin Health
Aging and environmental factors like sunlight exposure and air pollution affect skin health and make skin more susceptible to issues.26 Polyphenols in black tea contain antioxidant properties that reduce skin damage and inflammation.2728
Preliminary animal research shows a potential anti-wrinkle effect of black tea extract when applied directly to the skin. Black tea extract reduced skin damage and improved anti-wrinkling processes in mice exposed to ultraviolet radiation.27
Other research in mice observes increases in skin moisture and collagen with oral administration of black tea extract.26
Despite the promise of black tea on animal skin health, additional research in humans is necessary.
Is Black Tea Safe for Me?
Drinking four or fewer glasses of black tea daily is considered safe for most people.6 Black tea’s most negative effects are due to its caffeine content, which exceeds recommended limits.
- Allergy: Do not consume black tea if you are allergic to it or its parts.
- Interactions: Some medications interact with caffeine, slowing its metabolism. Ephedrine (used for low blood pressure), quinolone antibiotics, and oral contraceptives can increase caffeine’s effects. Asthma medications and nicotine may amplify caffeine’s impact. Black tea can also reduce iron absorption, so drink it between meals if you’re taking an iron supplement.29
- Added sugar content: Sugar or other sweeteners are often added to black tea to reduce bitterness. The U.S. Dietary Guidelines for Americans recommend limiting added sugar to less than 10% of daily calories to reduce the risk of chronic conditions like heart disease and type 2 diabetes.30 On a 2,000-calorie diet, 10% amounts to 50 grams or 12 teaspoons of sugar. If you add sugar to your tea, do so mindfully and always use a measuring spoon.
- Caffeine content: The primary safety concern with black tea is its caffeine content. The maximum amount not associated with any adverse effects in healthy, non-pregnant people is 400 mg or less daily (roughly eight cups of black tea).31
- Reduced nutrients: Due to its tannin content, tea can decrease the absorption of key nutrients such as iron.32 Drinking tea one hour before or after meals is suggested.
- Precautions: Pregnant and breastfeeding individuals should limit caffeine to 200 mg daily (about four cups of black tea).3133 Children under 12 should avoid caffeine, while those ages 12 to 18 should limit it to 100 mg per day.34
Does Adding Milk Make My Tea Less Healthy?
It’s unclear whether adding milk affects the benefits of black tea. Some research indicates that milk may impact the bioavailability and activity of black tea polyphenols.28 Other research suggests that the polyphenols are unaffected by milk.1 One large study found that adding milk or sugar to black tea did not negatively affect the association between black tea and the lower risk of all-cause mortality.35
How to Prepare Black Tea
Aim for two to four 8-ounce (250 milliliters) cups of tea daily to reap its health benefits.8
Pour boiling water over one tea bag or 1 to 2 teaspoons of loose tea. Pour the water when it starts to boil because overboiling can make the tea taste flat. Steep the tea for three to five minutes. Do not judge a tea’s readiness based on color. Color develops more quickly than flavor.36
Reduce the brew time for a milder tea flavor. Conversely, increase the brew time for a more pungent taste and more components like theanine.
Black tea should be stored in a dark, cool place. Teabags can be kept in the pantry for 18 to 36 months from purchase. Loose-leaf tea maintains freshness for two years in the pantry and six to 12 months when opened.37
Summary
Black tea is a popular, relatively safe beverage rich in polyphenols. Its high polyphenol content confers potential health benefits that support heart health, cognitive function, blood sugar, and oral and digestive health.
Incorporate black tea into your routine to reap its health benefits. Aim for two to four cups per day, depending on other sources of caffeine you may consume.
