Green tea is known for its various health benefits, which are primarily attributed to its rich composition of antioxidants and nutrients. A green tea shot or a cup of green tea can do wonders! Here is how you will benefit from a cup of green tea. these are just some of the key benefits of green tea:
Green Tea is Rich in Antioxidants
Green tea is loaded with polyphenols like flavonoids and catechins, which are known for their antioxidant properties. These compounds function as powerful antioxidants by scavenging reactive oxygen species, thereby reducing the formation of free radicals in the body. This action helps in protecting cells and molecules from oxidative stress and damage. The antioxidant activity of these polyphenols has been extensively studied and documented, underlining their significance in health and disease prevention.
(Higdon JV, Frei B. Tea catechins and polyphenols: health effects, metabolism, and antioxidant functions. Crit Rev Food Sci Nutr. 2003;43(1):89-143. doi: 10.1080/10408690390826464. PMID: 12587987.)
Green Tea Enhances the Brain Function
Green Tea contains caffeine, a known stimulant, but in lower amounts than coffee.
Green tea’s cognitive-enhancing effects are attributed to two key components: caffeine and L-theanine. Caffeine, a well-known stimulant, operates by inhibiting adenosine receptors (types A1 and A2a) in the brain. This inhibition enhances attention by increasing cholinergic and dopaminergic transmission. This process effectively augments attention and overall cognitive function. On the other hand, L-theanine, an amino acid found in green tea, enhances cognitive function in a different manner. It acts as a glutamate reuptake inhibitor and as a competitive low-affinity glutamate receptor antagonist in the hippocampus. Additionally, it exhibits neuroprotective effects through its action on the gamma-aminobutyric acid (GABA)-A receptors.
(Anas Sohail A, Ortiz F, Varghese T, Fabara SP, Batth AS, Sandesara DP, Sabir A, Khurana M, Datta S, Patel UK. The Cognitive-Enhancing Outcomes of Caffeine and L-theanine: A Systematic Review. Cureus. 2021 Dec 30;13(12):e20828. doi: 10.7759/cureus.20828. PMID: 35111479; PMCID: PMC8794723.)
The combination of caffeine and L-theanine in green tea is particularly noteworthy. Studies have demonstrated that this combination, even in lower doses (such as those found in two cups of tea), can significantly impact cognition and mood. The synergistic effects of these compounds enhance the speed and accuracy of attention switching and improve the ability to ignore distracting information during cognitively demanding tasks. This is indicative of a better focus on attention, improved both in speed and accuracy. This synergistic effect also contributes to maintaining alertness and reducing fatigue across the day, differentiating it from the more acute stimulation effects seen with higher doses of caffeine, such as in coffee. These findings are consistent with the neurochemical effects of L-theanine, which appears to regulate excitatory brain responses and modulate the stimulatory effects of caffeine on the brain.
(Janet Bryan,”Psychological effects of dietary components of tea: caffeine and L-theanine”, Nutrition Reviews, Vol 66/2, 2008-2, 82-90, doi:10.1111/j.1753-4887.2007.00011.x)
Moreover, L-theanine enhances the effects of caffeine on various cognitive tasks, such as information processing, mental fatigue, and tiredness, and importantly, on more complex tasks like sentence verification, word recognition, and sustained attention. The effect of L-theanine in focusing attention is particularly interesting, as it has dual effects on alpha brainwave activity, increasing attention on task-specific information while reducing activity associated with distracting attention.
In summary, the combination of caffeine and L-theanine in green tea offers a unique cognitive benefit, enhancing both basic and complex cognitive functions, while also contributing to overall mental alertness and reducing fatigue. This combination makes green tea a beverage of choice for those seeking to improve cognitive performance and attention, with fewer side effects associated with higher caffeine intake.
Green Tea Increases Fat Burning
Studies on the effects of green tea on metabolic rate and fat burning reveal interesting, though sometimes variable, results.
Green tea has been found to impact lipid metabolism and may have applications in managing obesity and related metabolic disorders. Research suggests that green tea can disrupt lipid emulsification, reduce adipocyte (fat cell) differentiation, enhance thermogenesis (heat production in the body), and decrease food intake, leading to improvements in overall metabolism and a reduction in fat mass.
(Dinh TC, Thi Phuong TN, Minh LB, Minh Thuc VT, Bac ND, Van Tien N, Pham VH, Show PL, Tao Y, Nhu Ngoc VT, Bich Ngoc NT, Jurgoński A, Thimiri Govinda Raj DB, Van Tu P, Ha VN, Czarzasta J, Chu DT. The effects of green tea on lipid metabolism and its potential applications for obesity and related metabolic disorders – An existing update. Diabetes Metab Syndr. 2019 Mar-Apr;13(2):1667-1673. doi: 10.1016/j.dsx.2019.03.021. Epub 2019 Mar 15. PMID: 31336539.)
Further investigations into the anti-obesity effects of green tea in both human and molecular studies have shed light on the mechanisms by which green tea components, particularly epigallocatechin gallate (EGCG), influence weight management. These studies indicate that green tea may play a role in reducing obesity through various pathways, including influencing fat metabolism.
(Huang, J., Wang, Y., Xie, Z. et al. The anti-obesity effects of green tea in human intervention and basic molecular studies. Eur J Clin Nutr 68, 1075–1087 (2014). doi: 10.1038/ejcn.2014.143)
It’s important to note that while some studies show positive results regarding green tea’s impact on metabolic rate and fat burning, not all studies are conclusive or agree on the extent of these effects. This variability may be due to differences in study design, population, dosage, and other factors. As such, while green tea may be a beneficial addition to a weight management or health-focused diet, it should not be considered a standalone solution for weight loss or metabolic enhancement. It’s always best to approach weight management with a comprehensive strategy that includes diet, exercise, and lifestyle changes.
Green Tea has Anticancer Properties
The relationship between green tea consumption and cancer prevention, particularly for types like breast, prostate, and colorectal cancer, has been a subject of significant research interest. The antioxidants in green tea, especially catechins, are believed to play a key role in this potential protective effect. These catechins are powerful antioxidants, which are thought to inhibit cancer cell proliferation.
In a comprehensive review by the Cochrane Database of Systematic Reviews, various studies, both experimental and nonexperimental (observational), were analyzed to assess the association between green tea consumption and cancer risk. This review included 142 completed studies and two ongoing studies. The results from experimental studies suggested some evidence of a beneficial effect of green tea at some cancer sites, but the findings were limited by the small number and size of the studies, and inconsistencies with the results of cohort studies. The nonexperimental studies, involving over 1.1 million participants, showed a lower overall cancer incidence in those with the highest intake of green tea compared to the lowest, although the evidence was considered of low certainty. No association was found between green tea consumption and cancer-related mortality. The review highlighted that while some evidence of green tea’s beneficial effect on certain types of cancer emerged, the overall findings were inconsistent, providing limited evidence for a significant impact of green tea consumption on cancer risk.
(Filippini T, Malavolti M, Borrelli F, Izzo AA, Fairweather-Tait SJ, Horneber M, Vinceti M. Green tea (Camellia sinensis) for the prevention of cancer. Cochrane Database Syst Rev. 2020 Mar 2;3(3):CD005004. doi: 10.1002/14651858.CD005004.pub3. PMID: 32118296; PMCID: PMC7059963.)
Another review from epidemiologic studies also examined the preventive effects of green tea on cancer. These studies suggested that the highest category of green tea consumption compared to the lowest showed a decreased risk ratio for most site-specific cancers. However, the results varied across different cancer types and study designs. For some cancer sites such as esophageal, prostate, urinary tract cancer, and leukemia, the results were conflicting between cohort studies and case-control studies. This review also emphasized the limitations of these findings due to methodological factors and the variability in green tea consumption patterns across different populations.
(Yuan JM. Cancer prevention by green tea: evidence from epidemiologic studies. Am J Clin Nutr. 2013 Dec;98(6 Suppl):1676S-1681S. doi: 10.3945/ajcn.113.058271. Epub 2013 Oct 30. PMID: 24172305; PMCID: PMC3831544.)
These findings indicate that while there is some evidence suggesting green tea might have cancer-preventive properties, particularly due to its antioxidant components, the overall evidence remains mixed and inconclusive. More robust, well-conducted research, especially randomized controlled trials, are needed to draw definitive conclusions on the potential cancer-preventive effects of green tea consumption.
Green Tea Protects the Brain from Aging
Green tea catechins, particularly epigallocatechin gallate (EGCG), have shown potential in neuroprotection, which may be beneficial for neurodegenerative diseases like Alzheimer’s and Parkinson’s. These catechins exhibit anti-inflammatory and antioxidant properties, helping to prevent excessive production of cytokines and inflammatory pathways. They may also inhibit tau protein phosphorylation, amyloid-beta aggregation, and release of apoptotic proteins, lower alpha-synuclein levels, and boost dopamine levels. These effects could influence the progression of neurodegenerative disorders. The review also highlights the mechanisms of catechins in various neurodegenerative and cognitive diseases, emphasizing their biological, pharmacological, antioxidant, and metal chelation abilities and their ability to activate diverse cellular pathways in the brain.
(Afzal O, Dalhat MH, Altamimi ASA, Rasool R, Alzarea SI, Almalki WH, Murtaza BN, Iftikhar S, Nadeem S, Nadeem MS, Kazmi I. Green Tea Catechins Attenuate Neurodegenerative Diseases and Cognitive Deficits. Molecules. 2022 Nov 6;27(21):7604. doi: 10.3390/molecules27217604. PMID: 36364431; PMCID: PMC9655201.)
Green Tea Kills Bacteria
Some studies show that the catechins in green tea can kill bacteria and inhibit viruses like the influenza virus, potentially lowering your risk of infections. Green tea catechins, particularly epigallocatechin-3-gallate (EGCG), have been studied for their potential antiviral and antibacterial effects. Research indicates that these catechins can combat various viruses, including the influenza virus. The mechanisms underlying these effects involve inhibiting different stages of viral invasion and replication. These findings suggest that green tea catechins could play a role in reducing the risk of infections caused by certain viruses.
(Xu J, Xu Z, Zheng W. A Review of the Antiviral Role of Green Tea Catechins. Molecules. 2017 Aug 12;22(8):1337. doi: 10.3390/molecules22081337. PMID: 28805687; PMCID: PMC6152177.)
Green Tea Improves Dental Health
The catechins in green tea also have biological effects. Some studies show that they can inhibit the growth of bacteria in the mouth, reducing the risk of bad breath and dental issues. Studies have shown that catechins found in green tea, particularly epigallocatechin-3-gallate (EGCG), exhibit antibacterial activity against Streptococcus mutans, a primary bacterial agent in the formation of dental caries. The antibacterial effect of green tea catechins was evaluated using disc diffusion and minimum inhibitory concentration (MIC) tests at various concentrations. These findings indicate that catechins in green tea can be potent anti-cariogenic agents, potentially reducing bacterial presence in the oral cavity and assisting in the development of dental care products like mouthwash and toothpaste.
(Hattarki SA, Bogar C, Bhat KG. Green tea catechins showed antibacterial activity on streptococcus mutans -An in vitro study. Indian J Dent Res. 2021 Apr-Jun;32(2):226-229. doi: 10.4103/ijdr.ijdr_512_21. PMID: 34810394.)
Green Tea. Lowers Risk of Type 2 Diabetes
Green tea seems to improve insulin sensitivity and reduce blood sugar levels.
Research indicates that green tea consumption can have a positive effect on glycemic control and insulin sensitivity. A systematic review and meta-analysis of randomized controlled trials, which included 27 studies with a total of 2194 subjects, assessed the impact of green tea on fasting blood glucose (FBG), fasting blood insulin (FBI), hemoglobin A1c (HbA1c), and homeostatic model assessment of insulin resistance (HOMA-IR). The studies varied in terms of green tea catechins intake, ranging from 80 to 1344 mg/day, and the duration of the trials ranged from 3 weeks to 12 months.
(Xu, R., Bai, Y., Yang, K. et al. Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials. Nutr Metab (Lond) 17, 56 (2020). https://doi.org/10.1186/s12986-020-00469-5)
Another meta-analysis that reviewed 17 randomized controlled trials with a total of 1133 subjects found that green tea consumption significantly reduced fasting glucose and HbA1c concentrations. Specifically, green tea was observed to lower fasting glucose by -0.09 mmol/L and HbA1c by -0.30%. Additionally, in studies with high Jadad scores, green tea was found to significantly reduce fasting insulin concentrations by -1.16 μIU/mL. These results suggest that green tea may have favorable effects on decreasing fasting glucose and HbA1c concentrations, with a significant reduction in fasting insulin concentrations observed in high-quality trials.
(Liu K, Zhou R, Wang B, Chen K, Shi LY, Zhu JD, Mi MT. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013 Aug;98(2):340-8. doi: 10.3945/ajcn.112.052746. Epub 2013 Jun 26. PMID: 23803878.)
These findings indicate that green tea, particularly due to its catechin content, can be beneficial in improving glucose control and enhancing insulin sensitivity, which are important factors in managing and preventing diabetes. However, it’s important to consider that the effects might vary based on the dosage of green tea catechins, the duration of consumption, and individual differences among subjects.
Green Tea Reduces Risk of Cardiovascular Disease
Scientific studies have provided evidence supporting the benefits of green tea in reducing cholesterol levels and aiding cardiovascular health. Here’s a summary of the key findings:
1. Lowering Cholesterol Levels: Research indicates that green tea consumption can significantly lower total cholesterol and low-density lipoprotein (LDL) cholesterol levels. This has been observed in various studies and meta-analyses, where results from individual trials were pooled using random-effect models. These findings highlight the effectiveness of green tea in managing cholesterol profiles, which is a crucial factor in cardiovascular health.
2. Reducing LDL Oxidation: Green tea not only lowers LDL levels but also helps in reducing the oxidability of LDL particles. Oxidized LDL is a key factor in the development of atherosclerosis, a condition that can lead to cardiovascular diseases. The catechins in green tea, particularly epigallocatechin gallate (EGCG), play a significant role in this protective effect.
3. Observational Studies on Cardiovascular Disease Risk: A large body of observational studies has suggested that regular consumption of green tea is associated with a reduced risk of cardiovascular diseases. This is likely due to the combined effects of improved lipid profiles, reduced LDL oxidation, and other heart-healthy benefits of green tea’s components.
4. Impact on HDL and Triglycerides: While the effects of green tea on HDL (high-density lipoprotein) cholesterol and triglycerides are also studied, the results are not as consistently significant as those for total and LDL cholesterol.
It’s important to note that these benefits are typically observed with regular and long-term consumption of green tea. The studies vary in terms of the form of green tea used (such as beverage or capsules) and the dosage, but the overall trend supports its beneficial role in lipid metabolism and cardiovascular protection.
References
1. Lowering Total and LDL Cholesterol: A meta-analysis published in the American Journal of Clinical Nutrition examined the effect of green tea on serum lipid profiles, including total and LDL cholesterol. The study concluded that green tea intake significantly reduces total cholesterol and LDL cholesterol levels in adults. (Zheng, X. X., Xu, Y. L., Li, S. H., Liu, X. X., Hui, R., & Huang, X. H. (2011). Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials. American Journal of Clinical Nutrition, 94(2), 601-610. https://pubmed.ncbi.nlm.nih.gov/21715508/)
2. Reducing LDL Oxidation: Another study investigated the effects of green tea catechins on LDL oxidation, a process that contributes to atherosclerosis. The study found that green tea catechins can prevent LDL oxidation, thus potentially reducing the risk of cardiovascular diseases. (Suzuki-Sugihara, N., Kishimoto, Y., Saita, E., Taguchi, C., Kobayashi, M., Ichitani, M., … & Kondo, K. (2016). Green tea catechins prevent low-density lipoprotein oxidation via their accumulation in low-density lipoprotein particles in humans. Nutrition Research, 36(1), 16-23. https://pubmed.ncbi.nlm.nih.gov/26773777/)
3. Impact on Cardiovascular Disease Risk: A review of multiple studies highlighted the association between green tea consumption and reduced risk of cardiovascular disease. This is attributed to the combined effects of improved lipid profiles and other cardiovascular protective properties of green tea. (Naito, Y., & Yoshikawa, T. (2009). Green tea and heart health. Journal of Cardiovascular Pharmacology, 54(5), 385-390. https://pubmed.ncbi.nlm.nih.gov/19668087/)
These studies provide a strong scientific basis for the beneficial effects of green tea on cholesterol levels and cardiovascular health. They highlight the importance of regular green tea consumption as part of a healthy lifestyle for cardiovascular disease prevention.
Green Tea, Weight Loss and Longevity
Some studies suggest that green tea can help in losing weight, though the effect is usually modest. Given green tea’s effects on preventing chronic diseases, it’s not surprising that green tea drinkers are likely to live longer than non-drinkers.
The Best Green Teas
The “best” green tea for you: This depends on your personal preference, including taste, quality, and specific health benefits you’re looking for. There are a few regions and brands known for producing high-quality green tea:
Japanese Green Teas:
Japan is famous for its green teas, with Matcha and Sencha being particularly popular. Matcha is a powdered green tea used in traditional Japanese tea ceremonies, known for its rich flavor and health benefits. Sencha, the most commonly drunk tea in Japan, is appreciated for its delicate balance of sweetness and bitterness.
Chinese Green Teas
China, the birthplace of tea, offers a vast variety of green teas. Longjing (Dragon Well) from Hangzhou is highly prized for its quality and unique flavor. Other notable Chinese green teas include Bi Luo Chun (Green Snail Spring), Mao Feng, and Gunpowder Green Tea.
Darjeeling and Assam Green Teas from India
While better known for black teas, these regions in India also produce high-quality green teas with distinctive flavors.
Korean Green Teas
Korean green teas, like Jeju Island green tea, are also known for their quality and unique taste profiles.
How To Buy The Best Green Tea:
When looking to buy the best green tea, consider these tips:
– Buy from Reputable Sources: Specialty tea shops or online retailers with good reputations are usually the best places to buy high-quality green tea.
– Look for Freshness: The fresher the tea, the better the flavor and health benefits. Look for information on harvest dates.
– Organic Options: If you prefer organic products, there are many organic green teas available which are grown without the use of pesticides.
– Loose Leaf vs. Bagged: Generally, loose leaf teas offer better quality and flavor than bagged teas.
Many of these teas can be bought online from specialty tea shops or large e-commerce platforms. When purchasing online, it’s helpful to read customer reviews and product descriptions carefully to ensure you’re getting a high-quality product. Remember, the best tea is one that suits your taste preferences and meets your health goals.
Loose Leaf Green Tea or Green Tea Bags?
In short: Loose leaf green tea wins hands down!
When comparing loose leaf green tea to green tea bags, there are several reasons why loose leaf tea is often considered a better option:
Quality and Flavor: Loose leaf green tea is generally of higher quality than tea bags. Tea bags often contain smaller pieces of leaves, dust, and fannings, while loose leaf teas are typically whole or broken leaves, leading to a more flavorful and aromatic cup of tea.
Antioxidant Content: Loose leaf green tea contains more antioxidants compared to tea bags. The smaller pieces in tea bags are more prone to oxidation, which can reduce the antioxidant content.
Variety: There’s a wider selection of loose leaf green teas available, particularly in specialty tea shops. This variety includes teas from different regions and producers, offering a broader range of flavors and qualities.
Caffeine and Theanine Content: The process of chopping green tea leaves for bags can cause the tea to lose some of its caffeine. Furthermore, loose leaf tea has more theanine, which promotes calmness and aids concentration.
Freshness: Loose leaf tea is often fresher than tea bags because it’s not pre-packaged, reducing the likelihood of it becoming stale.
Sustainability: Loose leaf tea is more sustainable than tea bags as it doesn’t produce waste that ends up in landfills.
Economical: High-quality loose leaf tea can be infused multiple times, offering better value for money. Although tea bags may seem convenient and sometimes cheaper, they might not always offer the same cost-effectiveness when considering quality and reusability.
However, the choice between loose leaf tea and tea bags can also depend on personal preference, particularly when it comes to convenience. Tea bags offer ease of use and are ideal for quick preparation, especially in an office setting or while traveling.
If you are looking for the best cup of green tea in terms of health benefits, flavor, and sustainability, loose leaf tea is the recommended option. But if convenience is a priority, high-quality tea bags can still be a good choice.