We all know that wine has been shown in multiple studies to be beneficial in protecting against heart disease which is also known as the French Paradox.
This has spurred investigations into other common beverages like coffee and tea which are consumed by more people and in larger quantities than wine. How do they fare in this respect?
Tea has been drunk for the last 4000 years and has its origins in China. In the early years, it was regarded as a medicinal plant with therapeutic qualities. Tea has been found to contain catechins, caffeine, theanine, saponins, vitamins and many other minor components. The main therapeutic effects must come from the catechins which are polyphenols and have a strong antioxidant effect. The theanine which is an amino acid gives the tea its full bodied taste and has a relaxing effect for which has been famous for relaxation and a good companion to pass time with.
Coffee on the other hand has an image of a stimulant. The major components of coffee include caffeine, antioxidants and diterpenes which is found in the oil of the bean. Coffee cultivation started in the 15th century in Arabia and the custom of drinking this energizing drink with a wonderful aroma quickly established itself in coffee houses in the Middle East and by the 17th century, it had spread to Europe. Many people have to start their day with their dose of coffee and caffeine.
So in the battle between two ancient beverages, which one comes out on top? Modern scientific methods have been employed to study these two all-time favourites. Both beverages have caffeine as their main component and caffeine has been associated with increased blood pressure, abnormal heart rhythms and increased vascular resistance, all which are actually not good for the body system. However, information on how tea or coffee relate to heart events like stroke, heart attacks, cholesterol plaque formation in the heart arteries is sparse.
Recently, researchers from Johns Hopkins Hospital and the National Institutes of Health in the United States embarked on a study to determine just that. They studied a multi-ethnic population of 6814 men and women and determined the consumption of tea, coffee and other food and caffeine products from a standardised food questionnaire. These people were asked to report the frequency of coffee and tea intake and they were studied for the occurrence of heart events, cardiac diagnoses, hospitalizations, heart procedures and death. Also, many clinical parameters were collected from the participants in this study. The study found that 51% of the participants drank one or more cups of coffee a day and only 13% of them drank one or more cups of tea a day. The participants were followed up for an average of 11 years.
The investigators found that coffee drinkers who drank one or more cups of coffee a day had a higher baseline level of coronary calcium of more than 100. It is well known that the coronary calcium score correlates very strongly with the amount of cholesterol deposits there are in the heart arteries. The higher the score, the more cholesterol there is. The converse was found for tea. In tea drinkers, a lower number of them had a coronary calcium score of 100.
In the follow-up of the participants over time, drinking coffee did not affect the progression of the coronary calcium scores, whilst drinking tea actually helped to reduce coronary calcium score over time, with a 27% reduction in the progression of the score. This means that tea drinking actually retarded the build-up of cholesterol in the heart arteries. This observation is stronger in non-smokers and ex-smokers than in current smokers.
Study participants who drank one or more cups of coffee a day did not have an impact on heart-related events. Those who occasionally drank coffee ie less than one cup a day had a 28% increase in heart related events. Once again, in tea drinkers, those who drank one or more cups of tea a day had a 29% reduction in heart-related events!
In conclusion, from this rather well done study which followed up a group of participants for 11 years found that drinking tea had a beneficial effect in preventing the progression of disease of the heart arteries which then led to a reduction in the occurrence of heart-related events. This is indeed good news for regular tea drinkers and from this shoot-out, it seems that tea has come out on top. The consolation is that regular coffee drinking did not lead to any increase in heart-related events, so it is safe to continue to have your daily coffee fix. The mechanisms of the why this is so is not clear from this study. Tea seems to have a much stronger antioxidant property due to the presence of polyphenols which is also found in wine. Diterpenes in coffee have been found to raise LDL or bad cholesterol levels but depending on the preparation method may not be at significant levels in our cup of coffee. Whatever the underlying cause, I would like to propose a toast to tea drinkers for choosing a superior beverage.
Dr Kenneth Ng