Drinking on average seven cups of tea a day could raise the risk of prostate cancer by 50% researchers say in a new study which began in 1970. The study, which was led by Dr Kashif Shafique, looked at the drinking, eating and lifestyle habits of 6,000 men over the last 37 years. This study appears to argue against previous research that suggested drinking tea could have health benefits as it found that men who drank lots of tea were more likely to develop prostate cancer, than those who did not. In fact, those who drank seven or more cups a day had a 50 per cent higher risk of contracting the disease than men who had three or fewer. The study which was conducted at the University of Glasgow tracked the health of participants aged between 21 and 75 who were asked to complete a health questionnaire about what they drank, eat etc. They also had to attend a medical screening examination. Just under a quarter of the 6,016 men were heavy tea drinkers, consuming seven or more cups a day. Of these, 6.4 per cent went on to develop prostate cancer over the next 37 years.
Conversely, researchers also found that the subjects who drank the most tea were more often teetotal and led healthier lifestyles. This means that they may have been at a less risk from other competing causes of death and had more time to develop develop prostate cancer, the journal Nutrition and Cancer reports. Dr Shafique said: “Most previous research has shown either no relationship with prostate cancer for black tea, or some preventive effect of green tea. We don’t know whether tea itself is a risk factor or if tea-drinkers are generally healthier and live to an older age, when prostate cancer is more common anyway.” In another twist, Dr Shafique added that those who were drinking the most tea were also less likely to be overweight or drink alcohol, and more likely to have healthy cholesterol levels.”However, we did adjust for these differences in our analysis and still found that men who drank the most tea were at greater risk of prostate cancer,” he said. So what is in black tea that causes the greater risk of developing prostate cancer? Dr Shafique could not answer and said that his team was ‘unaware of any constituent of black tea that may be responsible for carcinogenic activity in prostate cells’. It is thought that black tea has many health benefits and drunk in moderation can help to control inflammation, reduce excess blood clotting and limit narrowing of the arteries, due to the flavonoids in the tea These are antioxidant compounds that are essential for health and well being.
Head of research at The Prostate Cancer Charity, Dr Kate Holmes, said: ‘Whilst it does appear that those who drank seven or more cups of tea each day had an increased risk of developing prostate cancer, this did not take into consideration family history or any other dietary elements other than tea, coffee and alcohol intake. It is therefore unclear as to whether there were other factors in play which may have had a greater impact on risk.” Dr Carrie Ruxton of the Tea Advisory Panel, looked more closely at the study from Glasgow and concluded that out of 6000 men, 92 men in the Glasgow study drank more than seven cups a day and went on to develop prostate cancer. She commented: “We’re lacking the complete picture because we don’t know what other dietary factors were involved. Other research suggests tea has a protective or neutral effect on prostate cancer, and the authors acknowledge there is no known ingredient in tea that is cancer-causing. Tea-drinking may be a marker for some sort of behaviour that can raise the risk of prostate cancer, but the study does not show it is a cause.”
Everything in moderation we say.