The Benefits of Drinking Green Tea Regularly & Important Considerations

Apr 06, 2025 | 0 comments posted by Nature Target

Drinking tea has long been considered a healthy lifestyle habit. Enjoying a cup of tea in your leisure time is not only a relaxing experience but also highly beneficial for overall health. Green tea, in particular, has been widely studied in recent years for its potential role in cancer prevention and anti-aging effects. Some research even suggests that regular green tea drinkers may have better brain health. But what actually happens in the brain of frequent tea drinkers? And how much green tea should one consume daily to achieve optimal brain protection?

Regular Green Tea Consumption Promotes Brain Health

In January 2025, researchers from Kanazawa University in Japan published a study in Nature Food Science that highlighted the advantages of drinking green tea in reducing white matter lesions and preserving brain health.

The study analyzed 8,766 healthy individuals aged 65 and older without dementia. Their daily intake of green tea and coffee was recorded, and three key brain health indicators were evaluated: white matter lesion volume, hippocampal volume, and total brain volume.

White matter is responsible for transmitting information between different brain regions. White matter lesions are considered an early sign of cerebral small vessel disease. Damage to white matter can lead to cognitive decline in mild cases and progress to vascular dementia or Alzheimer's disease in severe cases.

The findings revealed that individuals with higher green tea consumption had significantly smaller white matter lesion volumes. However, no significant correlation was found between green tea intake and hippocampal or total brain volume. Additionally, coffee consumption was not significantly associated with any of these brain health indicators.

How Much Green Tea Should You Drink for Optimal Brain Protection?

Drinking green tea regularly can help protect brain health and prevent white matter lesions, but how much is necessary to achieve the best results? The study found that consuming three cups (approximately 600 ml) of green tea daily reduced white matter lesion volume by 3%, while drinking seven to eight cups (about 1,500 ml) resulted in a 6% reduction.

For green tea enthusiasts, drinking seven to eight cups per day (1,500 ml) offers the best brain protection. However, even consuming around three cups per day (600 ml) provides a notable benefit in slowing brain aging.

Why Does Green Tea Benefit the Brain?

The primary reason lies in its high polyphenol content, particularly epigallocatechin gallate (EGCG), a major catechin compound in green tea. EGCG exhibits strong antioxidant and anti-inflammatory properties. Additionally, it helps inhibit the aggregation of beta-amyloid proteins in the brain, which play a role in neurodegenerative diseases. By reducing white matter lesions and protecting neurons, EGCG contributes to delaying cognitive decline.

Additional Health Benefits of Drinking Green Tea

Lower Risk of Stroke

Drinking two to three cups of green tea daily can reduce the risk of stroke by 14%, while consuming four or more cups lowers the risk by 20%. This effect is mainly due to the catechins in green tea, which provide antioxidant, anti-inflammatory, and antithrombotic benefits, protecting blood vessels in multiple ways.

Anti-Aging Effects

Green tea can help slow the biological aging process. Interestingly, even individuals who do not habitually drink tea but later adopt the habit may still experience anti-aging benefits.

Reduced Risk of Diabetes

Green tea helps regulate blood sugar levels, improve insulin sensitivity, and prevent type 2 diabetes. For individuals already diagnosed with diabetes, drinking green tea regularly can lower fasting blood sugar and glycated hemoglobin levels, aiding in better disease management.

Lower Risk of Cardiovascular Diseases

Regular tea consumption is associated with a reduced risk of cardiovascular and cerebrovascular diseases. The protective effects are particularly significant for habitual green tea drinkers.

Protection Against Fatty Liver Disease

EGCG in green tea supports liver health by reducing damage caused by a high-fat diet, helping to prevent and alleviate fatty liver disease.

Lower Risk of Hypertension

Drinking green tea can decrease the risk of high blood pressure by 6%. Even if not consumed daily, long-term tea drinking can still contribute to lowering hypertension risk.

Important Considerations When Drinking Green Tea

Avoid drinking green tea at night: Green tea can stimulate the nervous system and cause insomnia. If you wish to drink it in the evening, limit your intake and do so at least two hours before bedtime.
Choose high-quality green tea: Opt for green tea varieties rich in polyphenols for maximum health benefits.
Maintain a consistent habit: Drinking green tea daily, ideally after breakfast or lunch, can boost alertness, aid digestion, and provide essential vitamins.
Use the right water temperature: Brew green tea with water at around 80°C (176°F) to avoid destroying polyphenols and reducing its nutritional value.
Pair with healthy snacks: Consuming green tea alongside antioxidant-rich foods like nuts and fruits can enhance its protective effects.
Be mindful of drinking temperature: Avoid consuming excessively hot tea to prevent damage to the mouth and digestive tract. Let the tea cool to a safe temperature before drinking.

Who Should Avoid Drinking Green Tea?

Infants and young children: Green tea contains high levels of polyphenols and caffeine, which may negatively affect brain development in infants and young children.
Individuals with weak digestion: Green tea has a cooling nature and may cause bloating or reduced appetite in those with a weak digestive system.
People taking certain medications: The polyphenols in green tea may interact with some medications. Those on medication or with specific medical conditions should consult a doctor before consuming green tea.
Pregnant women: Tannins in green tea can bind with iron, reducing its absorption and potentially leading to anemia in pregnant women. Excessive consumption should be avoided.

FAQs about Green Tea

Does Green Tea Cause Constipation?

Green tea contains tannins, which can increase the amount of acid in your stomach and may contribute to digestive discomfort in some individuals. Higher acidity levels can sometimes lead to reduced digestive efficiency, potentially slowing down bowel movements. Additionally, tannins have astringent properties that can dry out the intestinal lining and reduce mucus production, making stool harder and more difficult to pass. While green tea generally promotes digestion for many people, those sensitive to tannins may experience constipation as a side effect, especially if consumed in large amounts or on an empty stomach.

Does Green Tea Has Caffeine?

Yes, green tea does contain caffeine, but in relatively small amounts compared to coffee and some other teas. On average, an 8-ounce cup of green tea contains about 29 milligrams (mg) of caffeine, though this amount can vary depending on factors such as the type of green tea, brewing time, and temperature.

Does Green Tea Help Lose Weight?

Green tea may aid in weight loss due to its rich content of bioactive compounds, particularly catechins and caffeine, which have been shown to enhance fat oxidation and boost metabolism.

Does Green Tea Help With Digestion?

Yes, green tea can help improve digestion due to its rich content of antioxidants and polyphenols, particularly catechins, which have been shown to support gut health. These compounds can enhance the production of digestive enzymes, making it easier for the body to break down food efficiently.

Does Green Tea Help You Sleep?

Green tea contains L-theanine, an amino acid known for promoting relaxation and reducing stress, which may help improve sleep quality. However, it also contains caffeine, a stimulant that can interfere with sleep, especially for individuals sensitive to it. The effects of green tea on sleep can vary depending on a person’s tolerance to caffeine and the amount consumed. To enjoy the calming benefits of L-theanine without the risk of caffeine-induced alertness, opting for decaffeinated green tea before bed is a better choice for those looking to improve their sleep.