Some Common Sense about Tea and Health

What is Common Sense?

We all love a great tea.  Clearly, tea for many is an important part of a great life, and an important part in the big picture of a healthy diet and healthy lifestyle.  For tea drinkers interested in tea as part of an overall health regime, there are several important considerations, such as caffeine level, fluoride level, and the level of general and specific antioxidants.
 
Beyond this specific approach of the kinds of biologically active compounds found in teas, and how they interact with the body as part of your diet and general lifestyle, there is also what some would term a wider or more holistic  set of considerations as to the entire sensory experience of drinking teas - the taste, aroma and feeling the tea imparts, as well as the whole experience of brewing and enjoying a great cup of tea.  Perhaps just as important as the level of antioxidants or ECGC present in a particular tea, the sense of well being and fun you create from drinking your favorite tea may be the best medicine in creating a wonderful, healthy and long life.

It's All Good

All teas are made from the same plant, Camellia sinensis, from black teas, oolong, green to white teas, including first blush and top drawer teas.

Dietary polyphenols and health: defining the nutritional context

Polyphenols are the most abundant antioxidants in our diet. The large number of studies already published illustrates the wide diversity of their biological effects and suggests a protective role against a variety of diseases. However, few of the documented effects have been validated in a nutritional context. Most authors have used high polyphenol doses which could only be reached through drug administration.
 
The biological effects associated to food consumption could be very different from those observed in these studies. It is therefore essential to characterize precisely dietary intake, metabolism, and tissue exposure to polyphenols. Researchers at the Linus Pauling Institute are currently constructing a comprehensive database and food composition table for polyphenols, based on the analysis of the scientific literature. More than 500 phenolic compounds are already included with over 40,000 content values. Such a database will allow estimating the dietary intake of all these compounds. Beyond intake, the bioavailability of several polyphenols representative of different classes found in food has been compared in animal and human experiments.
 
The nature and concentrations of the main metabolites have been determined in plasma and tissues. Altogether, these studies have provided the range of polyphenol concentrations and intake levels which should not be exceeded in in vitro or in vivo studies to be nutritionally relevant. We also showed that 15 phenolic metabolites, estimated by tandem mass spectrometry in urine samples from 154 human subjects, can be used as biomarkers of polyphenol intake, useful for epidemiological studies. This approach is now extended to a wider variety of phytochemicals using a metabolomic approach and a QT of mass spectrometer. Such a metabolomic approach should also lead to the discovery of the still missing robust markers of effects for polyphenols.

Overview of flavonoids in human health

Flavonoids are dietary compounds which have some health implications. All are antioxidant in vitro, but their action in vivo is more complex. Although there are many flavonoids in nature, only a few are important in Western diets, including some catechins, procyanidins, flavonols (e.g. quercetin), flavanones (e.g. hesperidin, naringenin), and anthocyanins. In addition, the non-flavonoid but related phenolic acids (e.g. caffeic and ferulic acids) and isoflavones are also important. Researchers hypothesize that dietary flavonoids and phenolics are “lifespan essential” since they have multiple actions in vivo which combine to reduce the risk of chronic disease (especially cardiovascular and other inflammatory diseases).
 
Different classes of flavonoids may have different effects and mechanisms, but human studies are generally not done on pure compounds, so it can be difficult to ascribe an effect in vivo to an individual flavonoid. They are not needed for growth and development, but are needed for stress protection, which includes returning or partially returning a biomarker back to optimal. For this reason, it is not always possible to observe an effect in studies of young, healthy volunteers. In addition, a flavonoid must be bioavailable in order to exert an effect in vivo, and this aspect is also discussed in relation to the bioefficacy.

EGCG - the Secret Sauce

If you have read much about the health benefits of tea, you may have heard of EGCG, also known Epigallocatechin gallate. EGCG is the main active and water-soluble component of green tea - there is more EGCG found in green tea than any other type of catechin, and it is known for being the potent antioxidant of the catechin group.
 
EGCG accounts for 9-13% of green tea in net weight.  Because of its peculiar stereochemical structure, EGCG possesses much stronger anti-oxidant activities and plays an important role in preventing cancer and cardiovascular diseases.

Other Great News

One of the more remarkable aspects of the scientific research is the breathtakingly wide number of health claims that appear to have some level of support in the scientific literature - from possible protection against cancer and heart disease to guarding against excessive anxiety and depression.  Tea has even been shown to help fight tooth decay and keep your breath fresh - breathtaking, indeed.

The Big Picture

Whether you drink tea for fun or as part of an overall diet and health regimen, you can take heart knowing that there is a growing body of scientific research demonstrating the health benefits of all kinds of high quality teas, from black, oolong and pu-erh to green and white teas.  Whatever your pleasure in a great tea, just knowing that you are drinking one of the most widely enjoyed brews in the world, and widely recognized as one of the healthiest things you can do for both your mind and body.