A Randomized, Placebo-Controlled Study on the Safety and Efficacy of Daily Ingestion of Green Tea (Camellia sinensis L.) cv. “Yabukita” and “Sunrouge” on Eyestrain and Blood Pressure in Healthy Adults

Abstract

The green tea (Camellia sinensis L.) cultivar “Sunrouge” contains anthocyanins, catechins and flavonols. To determine whether ingesting green tea containing anthocyanins improves visual function and blood pressure (BP) in healthy adults, a randomized, double-blind, placebo-controlled study was performed. A total of 120 healthy subjects, aged between 20 and 60 years and with a systolic BP (SBP) value of ≤125 and <155 and a diastolic BP (DBP) value <95, or a DBP of ≤75 mmHg and <95 mmHg and a SBP <155 mmHg, were randomly assigned to one of three groups. For 12 weeks, the placebo group received barley extract without catechin; another group received “Sunrouge” extract containing 11.2 mg anthocyanin and 323.6 mg epigallocatechin-3-O-gallate (EGCG); and a third group received “Yabukita” extract containing 322.2 mg EGCG. Home BP, accommodation ability, visual analog scale questionnaires for eyestrain, and metabolic-associated markers were analyzed at weeks 0, 4, 8, and 12 of the intake period. The ingestion of “Sunrouge” tea significantly improved accommodation ability and eyestrain in subjects younger than 45 years and in subjects who operated visual display terminals every day. It also elevated BP. “Yabukita” tea ingestion significantly increased serum adiponectin levels. No adverse effects were observed. We conclude that long-term intake of “Sunrouge” tea containing anthocyanins and flavonols might improve visual function.

Bioactive Compounds and Their Effect on Blood Pressure—A Review

“…The results of this study showed no significant BP or visual improvement in the “Yubukita” group. Moreover, the “Sunrouge” group showed an increase in blood pressure (SBP of 123.3 ± 12.9 mmHg at baseline, compared to 129.8 ± 12.7 mmHg after 12 weeks, p < 0.01 and DBP of 77.1 ± 8.5 mmHg at baseline, compared to 82.4 ± 8.2 mmHg after 12 weeks, p < 0.01) at bedtime, as well as improvement of the eye accommodation ability in subjects below the age of 45 [ 87 ].…”

Effect of flavonoid intake on circulating levels of adiponectin and leptin: A systematic review and meta‐analysis of randomized controlled clinical trials

“…Additionally, flavonoids from tea catechin were effective for increasing serum adiponectin levels, and dietary supplements rather than whole foods intervention were effective in increasing adiponectin levels. Although existing evidence from RCTs suggests that flavonoid intervention could elevate adiponectin levels (Bell et al, 2011; Hussain et al, 2017; Maeda‐Yamamoto et al, 2018), there is evidence of null effects (Brull et al, 2017; Hsu, Liao, Lin, Tsai, Huang, & Chou, 2011; Liu et al, 2014). Our meta‐analysis suggests that flavonoids with an intervention duration longer than 12 weeks might be required to observe the improved effects on adiponectin post‐flavonoid intervention.…”

“…However, results from human randomized controlled trials (RCTs) are controversial with regard to the effects of flavonoid intake on circulating adiponectin and leptin levels. On the one hand, evidence suggests that flavonoid intervention could elevate adiponectin levels (Bell, Canale, & Bloomer, 2011; Capomolla et al, 2019; Huang, Liu, Wang, Huang, & Hsu, 2018; Hussain, Habib Ur, & Akhtar, 2017; Maeda‐Yamamoto et al, 2018) and/or reduce leptin levels (Kani et al, 2017; Lee, Cha, Lee, & Yim, 2016; Wu et al, 2005); on the other hand, there are also evidences reporting null effects on adiponectin (Brull et al, 2017; Hsu, Liao, Lin, Tsai, Huang, & Chou, 2011; Liu et al, 2014; Miyawaki et al, 2018) and/or leptin (Gholamrezayi et al, 2019; Jeong et al, 2020; Mirmiran, Hosseini, Hosseinpour‐Niazi, & Azizi, 2019). Similarly, evidence from meta‐analyses has remained inconsistent.…”

Exotic Medicinal Plants Used in Brazil with Diuretic Properties: A Review

“…The data obtained showed that after three weeks of administering the capsules of C. sinensis, there was a decrease in blood pressure and cholesterol. Unlike the previous study, Maeda-Yamamoto et al [41] evaluated the consumption of two types of green tea for twelve weeks to assess visual function and blood pressure. According to the data obtained, there was no decrease in blood pressure.…”