Table 5.
Epidemiological data and clinical trials with green tea.
| Disease | Compound/Component | Effect | Reference |
|---|---|---|---|
| Prevention | |||
| AML Hospital-based case–control study (n = 111 cases and 439 controls) |
Tea | Regular and high daily intake of tea reduced the risk of adult AML among males and females in New York | [112] |
| Leukemia Hospital-based case–control study (n = 107 cases and 110 orthopedic controls) |
Green tea | The frequency, longer duration and higher quantity of green tea intake reduced the risk of ALL and CML/CLL in Southeast China | [119] |
| Leukemia Hospital-based matched case–control study (n = 107 cases and 110 inpatient controls) |
Green tea | High consumption of green tea reduced the risk of adult leukemia | [120] |
| Leukemia Population-based case–control study (n = 252 cases and 637 controls) |
Tea | The highest intake of tea, especially green tea, reduces the risk of leukemia in Southwestern Taiwan | [121] |
| AML NIH–AARP cohort (n = 338 cases and n = 491,163 people) |
Tea | No association with consumption of tea and risk of leukemia in US | [115] |
| Childhood acute leukemia Population-based case–control study (n = 190 cases and 842 controls) |
Tea | No association with consumption of tea and risk of leukemia in Southern Taiwan | [113] |
| Hematologic malignancies Population-based case–control study (n = 41,761) |
Green tea | Green tea consumption reduces the risk of hematologic malignancies—lymphoid and myeloid neoplasms—in Japan | [116] |
| Leukemia Meta-analysis |
Tea | High tea consumption reduces the risk of leukemia, indicating a protective role of tea against leukemia | [122] |
| De novo MDS Hospital-based case–control (n = 208 cases and 208 controls) |
Tea | Regular and high intake of tea reduces the risk of MDS in China | [109] |
| Adult leukemia Hospital-based case–control (multicenter) (n = 442 cases and 442 outpatient controls) |
Green tea | The regular daily intake of green tea reduces the risk of leukemia regardless of GSTM1 and GSTP1 polymorphic status in China | [[114] |
| AML and MDS Population-based cohort study (n = 95,807) |
Green tea | No association between green tea consumption and the risk of MDS and AML in Japan | [110] |
| Adult leukemia Population-based cohort study (n = 651 cases and 1771 controls) |
Tea | A protective effect of tea intake on the risk of AML in Italy | [117] |
| Hematologic neoplasm Community-based prospective study (n = 110,585 individuals) |
Green tea | A protective effect of tea intake against hematologic neoplasm, specifically of AML and follicular lymphomas in Japan | [118] |
| Cancers Meta-analysis of observational studies. |
Tea | The tea consumption was associated with a lower risk of cancer, like leukemia, showing a protective effect | [111] |
| Clinical trials | |||
| Patients with low-grade B-cells malignancies (n = 4) |
Oral ingestion of products containing tea polyphenols by their own initiative | An objective clinical response | [124] |
| Asymptomatic Rai stage 0 to II CLL (phase I trial) (n = 33) |
Polyphenon E—6 months 2000 mg twice per day | Reduction in absolute number of lymphocytes and lymphadenopathy in most patients | [125] |
| Asymptomatic Rai stage 0 to II CLL (phase II trial) (n = 42) |
Polyphenon E—6 months 2000 mg twice per day | Reduction in absolute number of lymphocytes and lymphadenopathy in most patients | [126] |
| Patients with Rai stage 0 CLL (n = 12 per group) |
Green tea extract—6 months four capsules/day for the first months and six capsules/day for the following 5 months (400 mg of green tea total concentrate per capsule) |
Reduction in the absolute number of B-lymphocytes, circulating Treg cells and IL-10 and TGF-β serum levels | [127] |
| 48-year-old man with CLL (n = 1) |
1200 mg/day of EGCG | Patient achieved a complete clinical and molecular regression, 20 years after a diagnosis, without conventional therapy and using EGCG | [128] |
| Elderly acute myeloid leukemia patients with myelodysplasia-related changes (AML-MRCs) (n = 10) |
Green tea extract—6 months (1000 mg/day—4 capsules/day) |
Reduction in the immunosuppressive profile by ↓ Treg cells, CXCR4+ Treg cells and mRNA expression of TGF-β and IL4, and activation of cytotoxic phenotype by ↑ CD8+ T-cells, natural killer cells and classical monocytes in bone marrow and/or peripheral blood | [123] |