Food Dish — Where food, science and regulation meet
Green Tea: The beverage that packs a huge health punch
Green tea is made with the leaves of Camellia sinensis that have undergone minimal oxidation during processing. It has high levels of flavonoids, plant metabolites that are responsible for a number of plant-related functions, including pigmentation, UV filtration and chemical messaging. The mean content of flavonoids in a cup of green tea is higher than in food and drinks we traditionally associate with having a health-contributing nature, including fresh fruits, vegetable juices or wine.
The health benefits of green tea
Flavonoids – and specifically catechins – have antioxidant and vascular protective effects, and have been studied widely for their potential health benefits, including anti-cancer activity and improvement of cardiovascular health and neurological function. Epigallocatechin gallate (EGCG), the most abundant catechin in green tea (and not present in black tea), has also been studied for potential use in the treatment of AIDS-related dementia, Chronic Fatigue Syndrome, autoimmune diseases and endometriosis.
Some of the latest research on the effect of catechins in humans looks at the link to body composition, particularly body fat distribution. Catechins and caffeine (also contained in green tea) have been proposed as being able to affect how energy and fat are used in the body. The link is thought to relate to the EGCG and caffeine content of green tea’s induction of thermogenesis – the process of heat production in organisms – and stimulation of fat oxidation, which boosts metabolic rate.
Other possible health benefits of green tea include: reducing or delaying the onset of Parkinson’s disease, treating low blood pressure, treating high blood pressure, reducing abnormal cell development caused by human papilloma virus infection, and the prevention of stroke, osteoporosis and diabetes.
And this is just a drop in the bucket – there is a lot of research looking at the health benefits of green tea. However, the food and beverage industry does not yet appear to be getting the advantages of health-benefit labelling of green tea or green tea products.
Permitted label claims in Canada
In Canada, green tea has been approved by the Natural Health Products Directorate (NHPD) as a non-medicinal ingredient in vitamin and mineral supplements (recommended for the maintenance of good health), as an antioxidant (for the maintenance of good health), and in a body wash recommended for the treatment of acne.
In addition, Health Canada has approved function claims that can be used on the labelling of green tea products. Function claims relate to the specific beneficial effects that the consumption of a food at levels consistent with normal dietary patterns has on the normal functions or biological activities of the body. Such claims portray a positive contribution to health and the maintenance of a physiological function, or to physical or mental performance.
Approved function claims for green tea link its consumption in specified amounts – one cup or 250 mL – to the protection of blood lipids from oxidation, an antioxidant effect in blood, and increased antioxidant capacity in the blood. This list of acceptable function claims can be updated as new claims for green tea are presented to, and found to be acceptable by, Health Canada.