TEA KNOWLEDGE Tea plant History of the tea Tea Processing Tea Classification Tisanes Health benefits Brewing Guide Origins of our tea

There are many health benefits associated with tea, especially green and white tea. However, it is important to remember that in the human based studies that show these health benefits there are external factors that could have an effect on the results of the research. For example, a lot of the studies have been carried out in the East where increased consumption of fish and soy proteins and a decreased consumption of diary are normal.

Green tea has been linked to numerous health benefits including a decreased risk of cancer, heart disease, liver damage, diabetes and tooth decay. It is also connected to aiding weight loss.

• Cancer

What makes green tea different to black tea are the anti-oxidants present in the tea. In the process of oxidising, black tea loses the Catechin Polyphenols that give green and white tea their anti-oxidant properties. The anti-oxidant present in green tea is Epigallocatechin Gallate (EGCG). It is EGCG that has been linked with slowing down the growth of cancer cells. A study in Japan with 500 Japanese women who had either Stage 1 or Stage 2 breast cancer showed that an increase in the consumption of green tea before and after surgery was associated with a lower recurrence of the cancer.

• Heart Disease

EGCG has also been found to be effective in lowering total cholesterol. A study has shown that EGCG is twice as powerful as resveratrol, the phytoalexin found in wine that has been linked to the healthy hearts of the French! In Japan 240 participants, both male and female, were given varying amounts of green tea extract. The participants who ingested the highest amounts of extract found that they lost the most body fat and weight and that their LDL (bad) cholesterol was lowered. Some research suggests that the consumption of 3 cups of tea a day can reduce the rate of heart disease by 11%. However, the US Food and Drug Administration (FDA) will not allow tea makers to declare their tea as being able to reduce the risk of heart disease as they do not believe that there is sufficient evidence to support the claim.

• Diabetes

Green tea has been tied to the regulation of blood glucose levels and can therefore be used as an aid to those with diabetes. A small scale study showed that a daily supplement of green tea helped to control the haemoglobin A1c (HbA1c) of people who have borderline diabetes. However green tea should not be used as a substitute to any medication that has been prescribed by a doctor.

• Liver Disease

A population based study showed that men who drank 10 cups or more of green tea a day were less likely to develop liver disorders. Green tea has also been found to help protect the liver against the toxins found in alcohol that have adverse effects on the liver.

• Tooth Decay

Green tea can trigger the muscles and tissues in the body to tighten. This means that it can help to prevent tooth decay as it provides sufficient contraction of the gums to keep the teeth firm and tight. In a study of 940 men, it was found that those who drank more green tea had greater periodontal health than those who didn't.

• Weight Loss

Green tea is often promoted and sold in health food shops and on websites as a weight loss supplement. This is because it has been found that drinking green tea can increase your metabolism and help to burn fat. A study carried out at Birmingham University showed that fat oxidation rates rose by 17% after the ingestion of a green tea extract compared with the ingestion of a placebo. In another short term study a group of students aged 19-37 years were asked to consume 4 cups of commercial green tea a day but to maintain their normal eating habits. After 14 days the participants found that their systolic and diastolic blood pressure and fasting cholesterol had dropped and they had reduced their amount of body fat and body weight.

The list of health benefits from tea is actually quite astounding but we must not forget that the key to a healthy body can not solely rely on green tea. One must have a balanced diet and get regular exercise.

Oolong tea is more and more frequently being promoted as a weight loss drink. While I would not recommend buying these drinks solely for the purpose of loosing weight (as quite often the drinks contain poor quality Oolong at an expensive price), the research does suggest a link between weight loss and Oolong that is different to that with Green tea and weight loss.

There have been a number of studies into weight loss and Oolong. One such study took 102 women and had them consume Oolong tea regularly for six weeks which ended up resulting in a loss of body fat for all the women involved. Another study was done to establish whether the weight loss was linked to the caffeine in the tea or something else. This study involved four different drinks; a full strength Oolong tea, a half strength Oolong tea, caffeinated and non caffeinated water. The Energy Expenditure (EE) of each participant was measured after each 24hours of consuming one of the beverages. The results showed that EE was higher after drinking the full strength Oolong or the caffeinated water, participants burned an average of 67 calories more per day when drinking the full strength Oolong compared with the other drinks. Perhaps most substantial was the fact that after drinking the full strength Oolong, fat oxidation had increased by 12% versus the caffeinated water. This result shows that it is not the caffeine in Oolong tea that aids in weight loss but something else entirely. It is believed that it is the polymerized polyphenols which are highest in Oolong tea compared to other teas such as green tea that aid in weight loss.

Research also shows that Oolong tea has an affect on health similar to that of Green Tea. It can help those with type 2 Diabetes; can help to lower blood pressure, aid in preventing tooth decay and support skin treatment.

Black tea may not be as high in antioxidants is green, white or oolong tea but they are still present in the drink and still provide the same benefits just perhaps not at the same level. Some speculation has been circling about whether the addition of milk to black tea could mean that the positive effects of the beverage are counteracted. The research carried out states that the protein known as casein may be unbeneficial so perhaps it is worth while to occasionally enjoy your black tea without milk as you may find the taste pleasurable and will benefit from the reduced diary consumption.
A study by the Netherlands National Institute of Public Health and the Environment found a correlation between the consumption of black tea and reduced risk of heart disease. The study that consisted of 552 male participants over a 15 year period found that men who drank four or more cups of black tea a day compared to those who only drank one to three cups a day had a lower risk of heart disease. Another study, carried out in Boston found similar results but over a shortened period. This study comprised of 66 male participants who were either given four cups of black tea or water for four months. The results showed that drinking black tea could have a reverse affect on abnormal blood vessels and it was even stated that a change could be seen in the blood vessels two hours after drinking a cup of black tea.

As white tea is picked before the bud fully opens, it is the youngest of the leaves used to make tea. It also undergoes the least amount of processing with green tea following it at a close second. As white tea is hardly processed at all it contains the highest level of polyphenols. Polyphenols are a rich anti-oxidant that helps to fight cancer. Research into white tea has shown that it can help to boost your immune system and fight off unfriendly bacteria. One study that was carried out by the Paul Linus Institute compared how green tea and white tea would combat the mutation of cells that leads to cancer. In all cases they found that white tea was more effective than green tea.

Another study into white tea showed that it may help to prevent wrinkles and pigmentation of the skin. The study involved using a white tea based cream and not the drink white tea. The effects showed that skin left untreated by the white tea cream developed DNA damage but the skin that was treated with the cream had limited damage. This was explained by the high levels of antioxidants present in the white tea.

The research into white tea is not yet as extensive as that for green tea. The findings however do show white tea to perhaps be better for you than green tea.

Pu Erh tea may be processed differently to other teas but it still contains the same antioxidants and therefore still carries many of the same health benefits. In particular research has been done into the digestive and weight loss properties of Pu Erh tea as well as its ability to lower cholesterol levels in the blood. Traditionally in China, Pu Erh tea is used to counteract the negative affects of alcohol. There is not much research to support this fact but it has been used for this purpose in China for hundreds of years.