Health benefits of coffee and tea

Christopher Thomas

Christopher Thomas has written 125 posts in this blog.

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Is coffee good for us?

Coffee is the most widely-consumed stimulant in the world. Coffee was, and largely still is, viewed as a tonic with revitalizing properties for the sick and the weary. However, coffee is not a health drink. It is clearly addictive and there are many better sources of phytonutrients. But what effects is the coffee fix having on our health?

In fact, the effects of coffee are mixed, probably because coffee is a complex mixture of different compounds from the bean as well as generated or excluded in the processes of fermentation, roasting and preparation. Some of these may be beneficial for human health, like vitamins, antioxidants and minerals. Others, like acrylamide and diterpene are noxious chemicals. Coffee beans grown using sustainable organic practices and in the absence of synthetic pesticides herbicides and fertilizers also have number of positives for the coffee drinker.

The most well known component is caffeine, the main stimulant in coffee.  It acts by blocking receptors in the brain whose job it is to dull brain activity. So by preventing dulling, it stimulates. This may seem useful on Monday mornings or when we’d rather be in bed. But it also increases our blood pressure and metabolism, stiffens our arteries and makes us pee more.  If we drink caffeine regularly, even as little as a cup a day, we can suffer withdrawal symptoms if we stop. The more coffee we drink, the more likely we will experience the need for a cup! Some of the feeling we get from our morning ‘fix’ of coffee is relief of this withdrawal.

How does coffee impact our health?

Overall, a regular moderate intake of coffee (2-3 cups a day) does not appear to be harmful to health. Black coffee (not lattes) may slightly reduce the risk of heart disease, diabetes, Parkinson’s disease, Alzheimer’s disease, hip fracture and liver disease. For heart disease and diabetes, at least, this is not the caffeine, as the same benefits are also seen in those who drink decaffeinated coffee, especially when prepared in the absence of chemical solvents (e.g. the Swiss Water method). It could be that there is something about coffee drinkers that protects them (e.g. they have less stress in the mornings, the social ritual, or even the stress of daily withdrawal).

Health benefits of tea

Tea is second only to water in its global consumption. In western countries, the most widely drunk tea is black tea, prepared from leaves that have been fermented and oxidized. About half of the adult population drinks 2 to 3 cups a day. By contrast, oolong tea is partially oxidized and green tea is minimally processed before drying. This creates a range of different flavors, astringencies and caffeine content (which is generally greater the less processing). In each case, the tea leaf is then steeped in hot or boiling water to release the complex mixture of chemicals contained within.

The health properties of tea are readily confused with the stimulant effects of its caffeine content. Black teas contain about half the caffeine of most coffees, while many green teas contain more caffeine than coffee.  Contained within the tea leaf are also a number of beneficial compounds including flavonoid antioxidants (catechins or tannins, vitamins and minerals. Some, but not all, of these are lost or transformed during prolonged drying and oxidization required to make to make the tea leaves black. Adding milk to black tea may also reduce the availability of antioxidants.  Nonetheless, health benefits have been described in adults drinking 2-3 cups of black tea a day. For example, a regular cup of tea is associated with a small reduction in the risk of heart attacks and strokes. Tea drinking may also improve bone density and reduce the risk of fractures in women.

Green tea and prevention of disease

Green teas have a greater antioxidant potential, and with it, potentially greater benefits for human health. A number of studies have shown that the intake of green tea is associated with reduced rates of some cancers, heart disease and cognitive decline with advancing age. It should be remembered to never brew green tea with boiling water, as this can damage some of its antioxidants, as well as increase the release of caffeine and other bitter tasting compounds. Because not everyone likes the taste or has time to drink three cups a day, extracts are available that can be taken in pill form, standardized to contain 80% total polyphenols and 55% epigallocatechin gallate.

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