Time for coffee and tea
Tea and Cardiovascular Disease
After water, tea is the most consumed drink in the world. There are three main types of tea;
1. Black tea is the most consumed and is mainly drank in the western countries
2. Green Tea represents about 20% of tea consumption, and is mainly consumed in China and Japan
3. Oolong tea is drank mainly in Taiwan and parts of China and represents about 2% of all tea drank.
Drinking green tea is known to have many health benefits, this is mainly down to the antioxidants that they contain. As teas are manufactured differently they have different antioxidants. Fermented black teas have partially oxidised components such as flavonols and theaflavins, whereas green tea has unoxidised catechins. In addition to this tea also contains many other components such as vitamins and minerals. One of the conditions in which tea is thought to be beneficial is that of cardiovascular disease. This is not too big a surprise as a persons diet is known to have a large impact upon cardiovascular diseases.
There are many aspects that lead to cardiovascular disease and it is well known that that eating fatty foods and smoking leads to higher risks of getting the diseases.
The first step in the development of cardiovascular disease is atherosclerotic plaques appearing in the arteries, these protrude out from the inner surface and lead to a narrowing of the lumen resulting in a reduction of the blood flow.
One of the key steps in the formation of cardiovascular disease is the depositing of low density lipoproteins on the arterial walls, these become modified by oxidation and this leads to inflammatory reactions and the accumulation of monocyte macrophages; this results in fatty foam cells and atherosclerotic plaques.
It is widely reported that tea has many antioxidant properties and it is therefore thought that they may help to limit the oxidation of lipoproteins involved in the disease. Some of the properties of tea polyphenols that are thought to be help in fighting cardiovascular disease include anti-oxidant capabilities, anti-inflammatory properties, lipid lowering abilities and vasculoprotective properties. Some components in green tea have been shown to improve arterial function and to positively impact the development of damaging atherosclerosis.
Many cohort studies have shown that there is a correlation between tea consumption and the risk of developing cardiovascular diseases. A study has suggested that drinking two cups of tea a day can reduce the risk of developing the condition by as much as 44%. Further studies have suggested that the more tea drank the lower the risk of cardiovascular disease.
In vivo experiments using rats have found that green tea is able to lower the levels of triglycerides and cholesterol content in the blood, and increase the activity of the enzymes in the liver. In addition green tea has also been shown to increase enzymes in the aorta that are known to be involved in the bodies defence mechanisms against free radicals.