Tea For Your Health – Latest Newsletter
Update for Health Professionals & Media – May 2014
In this issue:
- Update on tea and health research
- Flavonoid antioxidant benefits and content in beverages
- Caffeine in context
Tea and Health Research
Every day, new medical evidence from the international scientific community lends credibility to tea’s healthy properties. Not only does tea taste delicious and is easy to make, it’s also good for healthier hearts, sharper minds and smaller waistlines. Below are some highlights of the latest scientific research presented at the Fifth International Scientific Symposium on Tea & Human Health in 2012 and published by the American Journal of Clinical Nutrition in December 2013 (1).
Tea Flavonoids (Polyphenols)
Teas from the Camellia sinensis plant contain a group of compounds called flavonoids which were originally studied because of their antioxidant properties, but are now known to have multiple, or pleotrophic effects in the body that go beyond antioxidant properties. This may help explain the breadth of their health promoting and disease fighting benefits. New research shows that flavonoids in tea may help ward off the sustained inflammatory process and vascular damage linked to chronic human conditions associated with aging including heart disease (1) and decline in memory and cognition (2,3). Since flavonoids are the largest group of polyphenolic compounds, these two words are often used interchangeably. Although some plants may contain several different polyphenols, flavonoids are the major source of polyphenols in the average diet. Fresh brewed tea is a natural source of flavonoids that are released when the tea leaves come in contact with boiling water. “Tea is the second most consumed beverage in the world next to water, and about one-third of the weight of a tea leaf is flavonoids. This makes tea a key dietary source of flavonoids” confirms Louise Roberge, President of the Tea and Herbal Association of Canada. The updated client resource titled “Polypehnol Rich Beverages” shows the important role tea plays in contributing polyphenols and flavonoids to the diet, and is available to download at http://www.tea.ca/tea-health/resource-materials/.
Caffeine in Context
Caffeine occurs naturally in coffee, tea and chocolate, and is added to some soft drinks and medications. On average, there is about 34mg of caffeine in a cup of black tea, which is about one-third the amount in a cup of coffee. The amount of caffeine in tea will depend on the water temperature, the number of tea leaves brewed and the length of time the leaves are steeped. The hotter and darker coloured your tea, the more caffeine it may have. The amount of caffeine is not affected by whether you use a tea bag or loose leaves to make your tea (4). Products containing caffeine are used and enjoyed by many people throughout the world. The Caffeine Meter resource is provided to assist your clients in understanding the contribution of various foods to caffeine intake. Health Canada states that for the average adult, moderate daily caffeine intake at levels of 400 mg/day is not associated with any adverse effects (5). Specific advice on moderating caffeine intake applies to women who are pregnant or breastfeeding (300 mg/day) and children (45-85 mg/d) (5).
(1) Hertog MGL, et al. Dietary antioxidant flavonoids and risk of coronary artery disease the Zutphen Elderly Study Lancet 1993;342:1007-11
(2) Mandel SA, et al. Targeting multiple neurodegenerative disease etiologies with multimodal-acting green tea catechins. J Nutr 2008;138:1578S
(3) Kelly SP, et al. L-Theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance. J Nutr 2008;138:1572S-7S
(4) Dietitians of Canada – EatRight Ontario, Tea Time, Retrieved from http://www.eatrightontario.ca/en/Articles/Antioxidants/Tea-Time.aspx#.U1daPvldV8E (April 2014)
(5) Health Canada, Caffeine in Food. 2012-02-16, Retrieved from www.hc-sc.gc.ca/fn-an/securit/addit/caf/food-caf-aliments-eng.php (April 2014)
Download a pdf version of Tea for Your Health Newsletter May 2014 .