INFLUENCE OF TEA AND COFFEE ON HUMAN HEALTH
What are the effects of tea and coffee on our health?
Let’s look at a few studies that were published in Tea & Coffee magazine.
Coffee and Strokes
An American study performed by the Harvard Medical School and the Harvard School of Public Health in Boston researched 83,000 women and found that women that drink five to seven cups of coffee a week were 12% less likely to have a stroke than those who had one cup a month.
However, it found that the beneficial effect was not due to caffeine, because people who drank tea or other caffeinated drinks did not have a similar fall in the incidence of strokes. These effects come from the anti-oxidants contained in coffee, which reduce inflammations and improve the functioning of blood vessels. However, the study also pointed out that coffee’s positive effects only apply to healthy individuals. Those that suffer from insomnia, anxiety, high blood pressure and heart problems should be aware that consuming coffee can worsen their problems.
Tea and the Brain
A joint study performed by experts from Norway and Great Britain proved that drinking tea and wine and consuming chocolate every day could lead to an improvement in older people’s cognitive functions. Scientists focused on the links between the cognitive functions of the brain in older people and consumption of chocolate, wine and tea, which are rich in flavonoids. They found that people aged 70-74 consuming chocolate, wine or tea had a significantly better average test result and less poor recognition performances than a similar group of persons not consuming chocolate, tea or wine. And a cup of tea or glass of wine is enough, more is not necessarily better.
Coffee and Dementia
According to Scandinavian researchers, if you are middle-aged, then drinking three to five cups of coffee a day can help prevent or slow down the start of dementia and Alzheimer’s disease by up to 70%. Specialists compared records of 1,409 people aged 65–79 in Finland and Sweden and checked them against research in 1972, 1977, 1982 and 1987. The study showed that those who drank coffee in middle age had a lower risk of dementia or Alzheimer’s disease. The lowest risk was found among average consumers of coffee, in comparison with people who only drank a little coffee. Previous studies showed that coffee improves the memory and that caffeine reduces the risk of Parkinson’s disease.
Scientists tried to describe the link between coffee and tea consumption in middle age and dementia/Alzheimer’s disease in later life, because the long-term effect of caffeine on the central nervous system was not known. The pathological trends leading to Alzheimer’s disease can occur decades before the clinical symptoms of the disease occur.
According to scientists, however, drinking tea did not have the same effect.
Tea and Breast Cancer
Women who are under fifty and regularly drink tea are less likely to get breast cancer. Nevertheless, according to one Florida study tea does not offer protection against the disease to older women. The study compared the medical records and lifestyle of 5,000 women aged 20-74 that were treated for breast cancer and compared them to data for women who did not have breast cancer.
The results showed that women aged under 50 that drink three or more cups of tea a day have a 37% lower chance of contracting cancer than those that do not drink tea at all. The effect is appreciably higher for lobular breast cancer, which affects one woman in ten suffering from breast cancer. In this case drinking tea reduces the risk of cancer by 66%. Regular consumption of tea, in particular in higher quantities, can reduce the incidence of breast cancer in young women. As tea is the most widespread drink in the world, this makes it the best candidate to prevent breast cancer, says the study.
Coffee and Cancer
Six cups of coffee a day can reduce the risk of some types of cancer by about 30%. However, in this regard only coffee with caffeine is beneficial, as the effect has not been found with decaffeinated coffee. Scientists studied more than 90,000 women aged 50-79 and their coffee habits. They compared coffee consumption with the number of women diagnosed to have basal-cell carcinoma, which is a mild form of cancer appearing on the face or throat and is only occasionally life-threatening. They found that the consumption of six or more cups of caffeinated coffee a day reduced the incidence of cancer by 31%.
Tea and Bortezomib
Green tea can have beneficial, positive effects against cancer, but when it is drunk together with the frequently used anti-cancer medicine Velcade, also known as bortezomib, it can suppress the medicine’s effect. Bortezomib (marketed as Velcade) is a substance that, in a quite unique way, inhibits the cloning of tumour cells. It blocks the proteasome, i.e. the cellular system, which is responsible for dealing with liquidation of proteins not needed for a cell.
Experts from the University of Los Angeles found that some elements contained in green tea can prevent bortezomib from destroying malign tumour cells. They have pointed out, however, that the negative effects of green tea occurred only for patients treated with bortezomib, not those who were treated with other anti-cancer drugs. Therefore, people using this medicine should refrain from drinking green tea and products containing green tea, especially those that are very concentrated. Bortezomib fights against cancer by killing tumour cells. And scientists found that some polyphenols and other elements of green tea do not allow bortezomib “to do its job.” Polyphenols contained in green tea have the potential to cancel out the therapeutic functions of bortezomib. However, according to the study, it is not all bad for green tea. Green tea is a tried-and-tested beneficial plant and it has been proved that it improves the anti-cancer effects of other drugs.
Black Tea and Parkinson’s Disease
One Singapore study showed that drinking black tea reduces the risk of Parkinson’s disease in the Chinese population. The first study of its type in Asia started fifteen years ago and monitored the life and diet habits of more than 63,000 Singapore Chinese. On average one cup of black tea a day was linked to a fall in the risk of disease by 70%. Green tea was not found to have an effect on Parkinson’s disease.