A single dose of tea with or without milk increases plasma antioxidant activity in humans

Leenen, R.; Roodenburg, Annet J. C.; Tijburg, Lilian B.M.; Wiseman, Sheila A.

doi:10.1038/sj.ejcn.1600900

Cited by 284 publications

(175 citation statements)

References 21 publications

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“…It allows the substantial measuring of the blood concentration of antioxidants as agents able to reduce the iron from its ferric (Fe3+) to its ferrous (Fe2+) form. The test provides a global measurement of many antioxidants including uric acid, ascorbic acid, α-tocopherol, glutathione, carotenoids and so on [32]. The results obtained in our study indicate a signifi cant decrease in FRAP concentration (p<0.05) after exercise in June, before antioxidant supplementation was implemented (Table 1).…”

Section: Discussionsupporting

confidence: 60%

Effects Of Rose-Hip And Grapeseed Dietary Supplementation On Serum Oxidative Stress Parameters In Dogs Before And After Physical Exercise

Kukovska¹,

Celeska

Ruskovska

et al. 2015

Acta Veterinaria

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The aim of this study was to evaluate the effects of 60 days of rose-hip and grapeseed dietary supplementation of a balanced home-cooked diet on serum oxidative stress parameters: ROMs, MDA and FRAP in army service dogs before and after regular physical exercise. The dogs were fed a balanced cooked diet as instructed by army standards until the initial blood sampling in June. Thereon the dogs were randomly allotted to 4 groups according to the dietary regime: dogs maintained on a balanced cooked diet according to army standards, branded dry dog food, cooked diet with added 500 mg rose-hip extract, and cooked diet with added 100 mg grapeseed extract for a 60 day period from June to September after which all 4 groups were fed the standard cooked meal diet. Sampling was performed at the beginning of the experiment (June), 60 days from the start of the treatment (September) and finally 60 days after the end of supplementation (November). Statistical analysis of the results included descriptive statistical parameters: mean (M), standard deviation (SD), and variation coefficient (CV%). In order to test the statistical significance of the differences between treatments a multifactor variance test (ANOVA) was performed for ROM, MDA and FRAP and the combined effects of diet, exercise and time period were observed. The initial (in June) increase in MDA and ROMs after exercise indicates the presence of oxidative stress 30 minutes after exercise. However, the antioxidative effects of rose-hip and grapeseed extracts are not conclusive, as multifactor ANOVA testing of time, diet, and exercise factors did not reveal for MDA statistically significant differences either at 60 days of supplementation nor 60 days after withdrawal of the supplements. Only one distinct exception was recorded for the prolonged antioxidative effects reflected in significantly decreased (p<0.01) ROMs before and after exercise in dogs fed the branded dry food 60 days after the end of such dietary regime (November). FRAP values tend to be higher (p>0.05) after exercise compared to before exercise in all experimental groups in November, indicating on a possible redistribution and upregulation of endogenous antioxidants during the experiment.

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Section: Discussionsupporting

confidence: 60%

Effects Of Rose-Hip And Grapeseed Dietary Supplementation On Serum Oxidative Stress Parameters In Dogs Before And After Physical Exercise

Kukovska¹,

Celeska

Ruskovska

et al. 2015

Acta Veterinaria

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“…Some studies indicate a decrease in antioxidant potential of tea after adding milk [31], others signal an increase in the antioxidant value [32]. There are also studies known where no change in the antioxidant properties of tea was observed after adding milk [33].…”

Section: Influence Of Additives On the Antioxidant Properties Of Teamentioning

confidence: 99%

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Bartoszek

Polak

Chorążewski

2017

Eur Food Res Technol

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including tea; these methods are based on different mechanisms, using a variety of detection techniques and are therefore not standardized. Hence, the comparison of the antioxidant capacity values obtained in different laboratories is not possible. On the other hand, the antioxidant capacity values obtained in the same laboratory through the use of different methods and parameters are also not consistent, due to the use of different interactions. Therefore the research is leading to the modification of existing methods and new methods are constantly sought. Recently, an EPR method based on a new semi-empirical mathematical model were proposed [5]. This method allows for a quick and precise determination of the antioxidant capacity of food products. In this paper this method was applied to tea. Tea is one of the most widely consumed beverages in the world [7]. It is valued both for the taste and for the health benefits associated with its antioxidant content [1,[7][8][9][10]. All varieties of tea are produced from young, tender leaves of Camellia sinensis (L.) (family Theaceae). Through using a wide variety of methods, different types of tea are produced: unfermented (green and white), partially fermented (oolong) and fermented (black and red). Green tea is produced through treating the leaves with hot steam and subsequently drying them. In such conditions, polyphenol oxidation is inactivated, which prevents the oxidation of polyphenols. As a result, the raw material remains rich in flavonols such as: catechin, epicatechin, epigallocatechin, flavonoids and simple phenolic acids [7,11]. Fermentation is necessary in order to produce black tea. This process consists of enzymatic oxidation by endogenous polyphenol oxidases and peroxidases of tea polyphenols, namely colorless flavonols that are partially converted into theaflavins and thearubigins, responsible for the characteristic aroma and color of the black and oolong teas. About 75% of the catechin contained in leaves undergoes enzymatic oxidation [12]. AbstractThe antioxidant properties of different types of tea-green, black and earl grey-were investigated using the EPR spectroscopy method based on a new semi-empirical mathematical model and on a single EPR spectroscopy measurement. The obtained values of the antioxidant capacity were correlated with the bioactive ingredient content identified through the NMR spectroscopy. Moreover, an attempt was made to determine what impact on the antioxidant properties of tea does adding sugar, milk, lemon and honey have. All studied teas exhibited antioxidant properties. The best DPPH free radical scavengers were green teas. Adding sugar, milk and lemon juice to tea did not significantly impact the antioxidant properties of the infusion; adding honey, however, caused an increase in the total antioxidant capacity of the infusion. The aromatic proton content correlates positively with the antioxidant capacity value.

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“…This may decrease the bioavailability and antioxidant potential of polyphenols in vivo (14)(15)(16)(17)(18), thus negating the antiathersclerotic benefit of black tea. In contrast, others report no masking effects of milk addition on increases in plasma antioxidant potential (19) and concentrations of catechins (20) or flavonols (21) after the consumption of black tea. However, interpretation of such studies is difficult as they consider different polyphenolic tea components and use antioxidant assay systems differing in choice of oxidation source, target, and type of measurement used (2,22,23).…”

Section: Introductionmentioning

confidence: 98%

Effects of Infusion Time and Addition of Milk on Content and Absorption of Polyphenols from Black Tea

Kyle

Morrice

McNeill

et al. 2007

J. Agric. Food Chem.

131

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Epidemiological studies assessing the health benefits of drinking black tea are equivocal. Such disparity may reflect an inability of semiquantitative assessment to consider how infusion time and addition of milk affect the bioavailability of potentially beneficial antioxidant polyphenols. Six brands of tea demonstrated similar increases in antioxidant capacity and total phenolic and catechin contents with increasing infusion time. These results were unaffected by the addition of milk. Consumption of black tea (400 mL) was associated with significant increases in plasma antioxidant capacity (10%) and concentrations of total phenols (20%), catechins (32%), and the flavonols quercetin (39%) and kaempferol (45%) (all p < 0.01) within 80 min. This was unaffected by adding milk. Infusion time may therefore be a more important determinant in the absorption of polyphenols from black tea. Observational studies assessing the health benefits of tea consumption require recording of brewing methods as well as frequency of consumption.

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A single dose of tea with or without milk increases plasma antioxidant activity in humans

Cited by 284 publications

References 21 publications

Effects Of Rose-Hip And Grapeseed Dietary Supplementation On Serum Oxidative Stress Parameters In Dogs Before And After Physical Exercise

Effects Of Rose-Hip And Grapeseed Dietary Supplementation On Serum Oxidative Stress Parameters In Dogs Before And After Physical Exercise

Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

Effects of Infusion Time and Addition of Milk on Content and Absorption of Polyphenols from Black Tea

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