Green tea and vitamin E enhance exercise-induced benefits in body composition, glucose homeostasis, and antioxidant status in elderly men and women.

OBJECTIVE: To investigate the effects of green tea plus vitamin E in addition to exercise on body composition and metabolic and antioxidant parameters in healthy elderly individuals. DESIGN: Interventional randomized controlled prospective trial. METHODS: For 12 weeks, 22 elderly men and women (age: 71.1 ± 1.2 years; body mass index: 28.3 ± 0.5 kg/m(2) [mean ± SE]) undertook 30 minutes of moderately intense walking 6 d/wk. They were randomly assigned to ingest either green tea plus vitamin E (GTVE; 3 cups and 400 IU, respectively; n = 11) or placebo (n = 11). Data on anthropometrics, fasting insulin and glucose levels, physical fitness, dietary intake, safety parameters, and biomarkers of oxidation status were recorded and analyzed at the start and end of the study. RESULTS: Though dietary intake was unchanged, improved exercise capacity was followed by a significant reduction in body weight and fasting insulin levels in all participants. Additional consumption of GTVE resulted in a twofold increase in serum vitamin E (from 20.4 to 40.6 µmol/L, p < 0.001) and a decrease of men's and women's waist circumferences (from 100.8 and 95.7 to 96.9 and 85.0 cm, p < 0.05 and p < 0.01, respectively) and fasting glucose levels (from 5.30 to 4.98 mmol/L, p < 0.01). Plasma protein carbonyls dropped (from 0.93 to 0.77 nmol/mg protein, p < 0.05), whereas erythrocyte catalase activities increased (from 26.7 to 29.7 U/g hemoglobin, p < 0.05) in the GTVE group only. Oral peroxidase activities were increased in both groups. CONCLUSIONS: A daily dose of GTVE in healthy elderly men and women may improve exercise-induced benefits in body composition and glucose tolerance and may also lower oxidative burden.

Green tea and its major polyphenol EGCG increase the activity of oral peroxidases.

Oral peroxidases (OPO) consist mainly of salivary peroxidase and myeloperoxidase and are involved in oral defense mechanisms. Salivary peroxidase is synthesized and secreted by salivary glands, whereas myeloperoxidase is found in polymorphonuclear leukocytes, which migrate into the oral cavity at gingival crevices. Green tea is the world's second most popular drink after water. Polyphenols are the most biologically active group of tea components. The purpose of our study was to elucidate the interaction between green tea & EGCG (Epigallocatechin 3-gallate), its main polyphenol and OPO. In previous studies we have shown that elderly trained people who drink green tea for 3 months, have a higher level of OPO activity compared to non-drinkers. Thus, we decided to extend our project in order to understand the above observations by studying the interaction of green tea and OPO both in vitro and in vivo. Addition of green tea and black tea infusions (50 µl/ml) and EGCG (50 µM) to saliva, resulted in a sharp rise of OPO activity +280% (p = 0.009), 54% (p = 0.04) and 42% (p = 0.009), respectively. The elevation of OPO activity due to addition of green tea and EGCG was in a dose dependent manner: r = 0.91 (p = 0.001) and r = 0.637 (p = 0.019), respectively. Also, following green tea infusion mouth rinsing, a rise of OPO activity was observed: +268% (p = 0.159). These results may be of great clinical importance, as tea consumer's oral epithelium may have better protection against the deleterious effects of hydroxyl radicals, produced by not removed hydrogen peroxides in the presence of metal ions. Higher OPO activity upon green tea drinking may provide an extra protection against oxidative stress in the oral cavity.

Green tea: a promising natural product in oral health.

Green tea is a leading beverage in the Far East for thousands of years; it is regarded for a long time as a health product. Green tea is important source of polyphenol antioxidants. Polyphenols including epigallocatechin 3 gallate (EGCG) constitute the most interesting components in green tea leaves. Green tea has the potential to protect against various malignant, cardiovascular and metabolic diseases. There is a growing body of evidence pointing a beneficial role of green tea and its polyphenols in oral health. Green tea protects against bacterial induced dental caries. Tea polyphenols possess antiviral properties, believed to help in protection from influenza virus. Additionally, green tea polyphenols can abolish halitosis through modification of odorant sulphur components. Oral cavity oxidative stress and inflammation, consequent to cigarette smoking and cigarettes' deleterious compounds nicotine and acrolein, may be reduced in the presence of green tea polyphenols. Generally, green tea defends healthy cells from malignant transformation and locally has the ability to induce apoptosis in oral cancer cells. All together, there is an increasing interest in the health benefits of green tea in the field of oral health. Nonetheless, there is still a need for more clinical and biological studies to support guidelines for green tea intake as part of prevention and treatment of specific oral pathologies.

Antioxidants in the prevention of atherosclerosis: the importance of proper patient selection.

We wish to comment on the recent publication by Katiski and Manes. We absolutely agree with the reviewers that there has been no consistent protective effect of any single antioxidant or combination against cardiovascular morbidity and mortality. However, one reason why antioxidant trials may have failed to show clinical benefit in these studies may be related to inappropriate patient selection. Thus, we would like to present a recent prospective double blind placebo controlled study (ICARE), which assessed potential cardiovascular benefit from vitamin E in a subgroup of patients with both Diabetes Mellitus (DM) and the Haptoglobin (Hp) 2-2 genotype-agroup with very high oxidative stress. We believe that groups with evidence of a significant pro-oxidative and pro-inflammatory milieu such as the diabetic patients with the Hp 2-2 genotype, may benefit from antioxidants. Thus, better identification of such sub-groups, which will respond favorably to treatment with antioxidants is worthy of investigation.

The effect of tomato-derived lycopene on low carotenoids and enhanced systemic inflammation and oxidation in severe obesity.

BACKGROUND: Fat tissue mediates the production of inflammatory cytokines and oxidative products, which are key steps in the development of type 2 diabetes and atherosclerosis. Antioxidant-rich diets protect against chronic diseases. Antioxidants may interfere with pro-inflammatory signals. OBJECTIVES: To investigate the effect of the potent tomato-derived antioxidant carotenoid, lycopene, on plasma antioxidants (carotenoids and vitamin E), inflammatory markers (C-reactive protein, interleukin-6, tumor necrosis factor-alpha) and oxidation products (conjugated dienes). METHODS: Eight obese patients (body mass index 37.5 +/- 2.5 kg/m2) were compared with a control group of eight lean, age and gender-matched subjects (BMI 21.6 +/- 0.6 kg/m2), before and after 4 weeks of lycopene supplementation (tomato-derived Lyc-O-Mato) (30 mg daily). RESULTS: Plasma carotenoids were significantly reduced in the obese compared to control subjects (0.54 +/- 0.06 vs. 0.87 +/- 0.08 microg/ml, P < 0.01). CRP levels were significantly higher (6.5 vs. 1.1 mg/L, P = 0.04) in obese vs. controls, as were IL-6 and conjugated dienes (3.6 and 7.9-fold, respectively). CRP, IL-6 and conjugated dienes correlated with BMI, while IL-6 and conjugated dienes correlated inversely with carotenoids (P < 0.05). Following lycopene treatment, a significant elevation of plasma carotenoids (1.79 vs. 0.54 microg/ml) and specifically lycopene (1.15 vs 0.23 microg/ml) (P < 0.001) occurred in the treatment vs. the placebo group, respectively. Markers of inflammation and oxidation products were not altered by lycopene. CONCLUSIONS: Obese patients showed abnormally higher markers of inflammation and oxidation products and lower plasma carotenoids. The lack of reduction of pro-inflammatory markers could be attributed to the short period of the study and the small number of participants. More studies are needed on the protective qualities of natural antioxidant-rich diets against obesity-related co-morbidities.

Vitamin E supplementation reduces cardiovascular events in a subgroup of middle-aged individuals with both type 2 diabetes mellitus and the haptoglobin 2-2 genotype: a prospective double-blinded clinical trial.

OBJECTIVE: Clinical trials of vitamin E have failed to demonstrate a decrease in cardiovascular events. However, these studies did not address possible benefit to subgroups with increased oxidative stress. Haptoglobin (Hp), a major antioxidant protein, is a determinant of cardiovascular events in patients with Type 2 diabetes mellitus (DM). The Hp gene is polymorphic with 2 common alleles, 1 and 2. The Hp 2 allelic protein product provides inferior antioxidant protection compared with the Hp 1 allelic product. We sought to test the hypothesis that vitamin E could reduce cardiovascular events in DM individuals with the Hp 2-2 genotype, a subgroup that comprises 2% to 3% of the general population. METHODS AND RESULTS: 1434 DM individuals > or = 55 years of age with the Hp 2-2 genotype were randomized to vitamin E (400 U/d) or placebo. The primary composite outcome was myocardial infarction, stroke, and cardiovascular death. At the first evaluation of events, 18 months after initiating the study, the primary outcome was significantly reduced in individuals receiving vitamin E (2.2%) compared with placebo (4.7%; P=0.01) and led to early termination of the study. CONCLUSIONS: Vitamin E supplementation appears to reduce cardiovascular events in individuals with DM and the Hp 2-2 genotype (ClinicalTrials.gov NCT00220831).

[Plasma anti-oxidants and rheumatoid arthritis].

We present a clinical study aimed to compare plasma antioxidant vitamins, vitamin E, beta-carotene and vitamin A. The study consisted of a group (15 patients) with rheumatoid arthritis (RA) compared to a healthy control group. There was a significant decrease in plasma vitamin E, beta-carotene and vitamin A (vitamin E 30.4 +/- 4.9 VS 43.6 +/- 8.2 micrograms/ml, beta-carotene 0.73 +/- 0.26 VS 1.02 +/- 0.22 micrograms/ml and vitamin A 0.22 +/- 0.07 VS 0.46 +/- 0.15 microgram/ml, P < 0.01 patients VS control, respectively). Supplementation of Dunaliella (natural)--beta-carotene to the RA patients for 3 weeks, resulted in a significant increase in plasma vitamin E (47.9 +/- 5.5 micrograms/ml) beta-carotene (0.87 +/- 0.21 microgram/ml) and vitamin A (0.55 +/- 0.15 microgram/ml). There were no changes in the activity indexes of RA. Low plasma antioxidant vitamins in patients with RA are consistent with the observation that oxidative processes occur in the inflammed joints. The validity of antioxidant vitamins as supplementary therapy for RA is not clear.