This week,I want to look at tea and coffee as beverages and whether they are suitable to include as part of a healthy balanced diet.
Green tea
We have already looked at some benefits of green tea in the stress blog, looking at its Theanine content which helps us to adapt to stress .
Green tea has many other health giving properties and it features in many anti cancer regimes. It contains hundreds of chemical compounds which give it its distinctive aroma and flavour. One class predominates and that is the polyphenols also called catechins which possess both antifungal and antibacterial properties. One of the catechins called EGCG (epigallocatechin gallate) gives green tea its anti cancer label. It has been shown to inhibit the growth of cancerous cells in vitro (in the lab).
Another possible mode of activity that green tea may help with is to suppress angiogenesis. Angiogenesis is when the cancer cell develops its own blood supply for nourishment. As little as 4 cups a day has shown to be sufficient.
In 2004 the Mayo clinic complete their own research study on green tea and concluded that green tea was hugely beneficial at stopping cancer in its tracks. Quite a bold statement I think but non the less shows perhaps that green tea is beneficial as part of a balanced diet. Another important studies in 2009 by The Tohoko School of Medicine, printed in the American Journal of Epidemology, carried research out over a nine year period using 42.000 people and found that by drinking at least 5 cups of green tea a day resulted in a 40% reduction in the spread of cancer cells.
Green tea has 4 times less caffeine than black tea. (We will look at the effects of caffeine later when we look at coffee). To benefit from green tea the brewing time is important. The longer the tea brews the more catechins are released. So those of you who like the bag left in as they drink their tea will be getting greater benefits of catechins. Gyokuro is considered the connoisseurs among the finest green teas in the world.
What about black tea?
Interestingly enough black tea starts out as green. The difference is that the roasting time is longer leaving the tea blackened and the longer process destroys some of the benefits that are found in green tea. It is like all food the more processing the lower the nutritional value. Having said that Darjeeling black tea contains a significant level of catechins more than the common or garden black teas that we usually drink. I have included below a recipe for green tea poached pears, which is quite novel and something you may like to try.
And now coffee
When I looked into coffee I got some surprising and quite mixed results. Many articles that I found were very much in favour of coffee as a regular drink.
The effects of coffee
The reasons were mainly because of its stimulating, motivating effects. It has been described as a ‘mood enhancer’, because its greatest effects are exerted on the brain and mind, acting on the central nervous system. In one article it was described as a “pleasure drug” by the author. This is mainly due to the caffeine content.
Coffee is said to be beneficial because it is high in antioxidants and as we know they have important health protective effects.
Reportedly coffee is of great importance in the American diet because it is their main source of antioxidants. The reason being is that they simply do not eat sufficient fresh fruits and vegetables!!!!!.
Other virtues have been bestowed on coffee, it is reported to enhance analgesic medication especially for patients with migraines and headache on painkillers. That is why some of the over the counter headaches who take pain killing drugs contain caffeine.
According to research papers as recent as 2009 and 2011 coffee is also supposed to reduce the risk of type 2 diabetes by up to a half which was observed in people who drank over 7 cups a day. I might suggest that they must be very wired and I can think of other more positive ways to avoid diabetes, like eating a wholefood low sugar diet.
In 2008 coffee was linked, in Africa, to a reduced incidence of oral and esophageal cancers.
Other research have reported that coffee drinkers were less likely to get liver cancer and prostate cancer. Without more detail on the research it is difficult to comment further. It would be interesting to know what their diets were like generally despite the coffee.
Perhaps coffee isn’t as good as it seems…...
However if we look a little deeper coffee may not seem as beneficial as these articles would like us to believe.
Let’s first of all look at the way the body deals with coffee. I
Coffee blocks our calming neurotransmitters: It takes forty five minutes for 99% of the caffeine to be absorbed with the maximum effect wearing off after about three hours. As soon as caffeine enters the body it is already being metabolised by the liver and broken down into three compounds called theophylline, theobromine and paraxanthine. These compounds are known to affect our body chemistry. They bind to our calming neurotransmitters in the brain (adenosine and dopamine) making them unavailable for use and it is this which causes feelings of alertness and energy, which is obviously one way in which caffeine works.
Coffee also has a diuretic effect. Once the caffeine compounds have been excreted out of the body you can expect a crash in mood and energy. Until you have your next cup of course!!!.
It’s addictive and stimulates release of stress hormones As you can see, this could easily become very addictive. It is worth remembering here that if the body is stimulated in this way it automatically signals the release of the stress hormone cortisol and as we know from our stress blogs that cortisol can lower the function of the immune system and cause our blood sugar and possibly our blood pressure levels to rise, which is not ideal. Having said that a 12 year study concluded that the link between high blood pressure caused by coffee was very weak and inconclusive which is interesting. I wonder if the research was sponsored by the coffee industry!
Are some coffee’s better than others?
So if we decided to drink coffee, despite its negative impact on stress and the fact that caffeine dependence and withdrawal is well documented, which is the best?
Instant coffee does contain more acrylamide than filtered. Acrylamide is a chemical compound that develops in the roasting process. Which has been linked to being a probable carcinogen.
Decaffeinated coffee So is decaffeinated coffee any better? Well you would think so but it really depends how the caffeine has been removed. There are several methods that are commonly used to remove the caffeine. The use of chemical solvents such as trichloroethylene or methylene chloride are the most common. These would be best avoided simply because of the chemical components that would be left in the coffee. As we know any chemicals in the diet are a burden on our normal cell metabolism.
However another method that is used is called the Swiss water process, which involves soaking the raw beans in water to remove the caffeine. As no chemicals are involved this is the better option. I know that Clipper decaffeinated coffee uses the Swiss method and someone told me that Taylor’s coffee is the same but I have not come across that one yet.
So what’s the bottom line on drinking coffee?
I must admit that I do occasionally drink Clipper decaffeinated and really enjoy it but I do make sure that it is occasional and that I also drink plenty of water and herbal teas throughout the day. My general advice to people is that the occasional cup of coffee is fine but I do see some people totally addicted or on 6 or 7 cups a day which is a little alarming and we do discuss ways of perhaps reducing the amount to reduce levels of cortisol production and calm down the system.
Green Tea Poached Pears.
400mls of unsweetened apple juice.
2 green tea bags
2 star anise
1 cinnamon stick
Rind of 1 lemon.
4 firm pears, peeled halved and the core cut out.
A handful of frozen berries.
Natural yogurt or nut cream to serve.
1.Place the apple juice. Tea bags, spices and lemon rind in a large pan, bring to the boil then add the pear halves and simmer for 12-15 min till the pears are soft.
2.Lift the pears out and turn the heat up. Add the berries and boil for a few minutes until the liquid becomes syrupy. Discard the tea bags.
3. Serve the pears with the syrup poured over them
See also my Stress blog (June 2013)
and Antioxidants blog (Aug 2012)
Blog originally written by Caroline June 2013