Green Tea for MPNs

Daily consumption of hot green tea or its extract, epigallocatechin-3-gallate (EGCG), has been reported to inhibit JAK/STAT pathway across multiple blood cancers and autoimmune conditions. A 2018 study found that EGCG reduces JAK2 expression in chronic myeloid leukemia (CML) cells. EGCG supplementation induced complete molecular remission in a chronic lymphocytic leukemia case (2015). Furthermore, EGCG has been found to inhibit specific IFN-γ pathways and JAK2 in alopecia areata patients (an autoimmune disorder that causes hair loss) (2018). It also demonstrated potential in vitiligo (an autoimmune skin condition) treatment by inhibiting JAK2 activity (2015). Green tea reduced obesity associated inflammation by inhibiting JAK2/STAT3 in mice (2020).

A 2020 study investigated the effects of green tea (GT) consumption on patients with indolent low-grade B-cell lymphomas and leukemias (LGBCL) and monoclonal gammopathy of undetermined significance (MGUS). The authors were inspired by previous research that demonstrated the beneficial effects of EGCG, on patients with asymptomatic CLL. 11 patients with various types of LGBCL and MGUS were advised to drink two bags of GT in hot water daily. Results showed improvements in disease biomarkers and lymphadenopathy for all patients. For example, six CLL patients had reductions in absolute leukocyte count (ALC), with percentages ranging from 37% to 74%. Patients with Waldenstrom macroglobulinemia, MGUS, splenic Marginal zone lymphoma, and follicular lymphoma also experienced significant improvements. The study suggested that low-dose EGCG in GT may help delay the onset of therapy for these conditions, reducing the need for immunosuppressive treatment and associated toxicities. 

The 2013 Phase 2 trial evaluated the clinical efficacy of green tea extract Polyphenon E in patients with early-stage chronic lymphocytic leukemia (CLL). The study included 42 previously untreated patients with asymptomatic, Rai stage 0 to II CLL and an absolute lymphocyte count (ALC) ≥ 10 × 10(9)/L. Participants received Polyphenon E, containing a standardized dose of epigallocatechin gallate (EGCG) (2000 mg per dose), twice daily for up to six months. The trial reported clinical activity, with 13 patients (31%) experiencing a sustained reduction of ≥ 20% in ALC, and 20 out of 29 patients (69%) with palpable adenopathy experiencing at least a 50% reduction in the sum of the products of all lymph node areas. Overall, 29 patients (69%) met the criteria for a biologic response, exhibiting either a sustained decline ≥ 20% in ALC and/or a reduction ≥ 30% in the sum of the products of all lymph node areas during the six months of active treatment. The study concluded that daily oral EGCG was well-tolerated by CLL patients, and the majority experienced durable declines in ALC and/or lymphadenopathy.

Several studies have demonstrated the potential longevity benefits of green tea. Zhao et al. (2017) found that green tea intake was inversely associated with all-cause and CVD mortality in Chinese adults, particularly among never-smokers. In a pooled analysis of eight Japanese cohort studies, Abe et al. (2019) observed that higher green tea consumption was associated with a decreased risk of all-cause mortality, heart disease, and cerebrovascular disease mortality. A dose-response meta-analysis by Tang et al. (2015) revealed that green tea consumption was significantly inversely associated with CVD and all-cause mortality. Overall, these findings suggest that regular green tea consumption may contribute to a lower risk of mortality due to various causes, particularly CVD.

Green tea and its extract, EGCG, extended the lifespan of mice, fruit flies and C elegans, though not every experiment showed statistically-significant life extension (2021, 2014, 2012).