Functional Food Center, School of Life Sciences, Oxford Brookes University, Oxford, United Kingdom.
Nutr Res. 2010 Jan;30(1):14-20. doi: 10.1016/j.nutres.2009.11.005.
Epidemiological studies have shown that populations consuming fruits, vegetables, tea, cocoa, and red wine have lower incidences of cardiovascular disease, certain cancers, and eye disease. These health effects have largely been attributed to the polyphenol content of the foods and drinks studied. Black tea is rich in a range of polyphenolic compounds that could potentially have health-promoting properties. The scale of consumption of tea in the United Kingdom means that it could be an appropriate vehicle for increasing the antioxidant activity and polyphenol content of human plasma. However, it is common practice in the United Kingdom to add milk to tea, and some studies have suggested that this may decrease the overall antioxidant capacity. The objective of the present study was to analyze and compare the antioxidant capacity of 5 brands of tea and to test the hypothesis that the addition of different volumes of whole milk, semiskimmed, and skimmed milk may affect the antioxidant capacity. Each of the teas analyzed was a significant source of antioxidants. The addition of 10, 15, and 20 mL of whole, semiskimmed, and skimmed bovine milk to a 200-mL tea infusion decreased the total antioxidant capacity of all the brands of tea. Skimmed milk decreased the total antioxidant capacity of the tea infusion significantly (P < .05) more than either whole milk or semiskimmed milk. We conclude that black tea is a valuable source of antioxidants and that the effect of milk on the total antioxidant capacity may be related to the fat content of the milk.
流行病学研究表明，食用水果、蔬菜、茶、可可和红酒的人群心血管疾病、某些癌症和眼部疾病的发病率较低。这些健康影响主要归因于所研究的食物和饮料中的多酚含量。红茶富含多种具有潜在健康促进特性的多酚化合物。英国的饮茶量很大，因此红茶可能是提高人体血浆抗氧化活性和多酚含量的合适载体。然而，在英国，往茶里加牛奶是一种常见做法，一些研究表明，这可能会降低整体抗氧化能力。本研究的目的是分析和比较 5 种茶的抗氧化能力，并验证往茶中添加不同量的全脂奶、半脱脂奶和脱脂奶是否会影响抗氧化能力这一假设。分析的每种茶都是抗氧化剂的重要来源。往 200 毫升茶浸液中加入 10、15 和 20 毫升全脂、半脱脂和脱脂牛奶，会降低所有品牌茶的总抗氧化能力。脱脂奶比全脂奶或半脱脂奶更显著地降低了茶浸液的总抗氧化能力（P<.05）。我们得出结论，红茶是抗氧化剂的重要来源，而牛奶对总抗氧化能力的影响可能与牛奶的脂肪含量有关。
