Chlorogenic acid

Drinking two or more cups of coffee a day was associated with twice the risk of death from cardiovascular disease among people with severe hypertension compared to non-coffee drinkers, in a study of more than 18,600 men and women in Japan. Drinking two or more cups of coffee a day may double the risk of death from cardiovascular disease among people with severe high blood pressure (160/100 mm Hg or higher) but not people with high blood pressure not considered severe, according to research published today in the Journal of the American Heart Association, an open access, peer-reviewed journal of the American Heart Association. In contrast, the study found that one cup of coffee and daily green tea consumption did not increase the risk of death related to cardiovascular disease at any blood pressure measurement, though both drinks contain caffeine. According to the FDA, an 8-ounce cup of green or black tea has 30-50 milligrams of caffeine, and an 8-ounce cup of coffee has closer to 80 to 100 milligrams. Previous research found that drinking one cup of coffee a day may help heart attack survivors by lowering their risk of death after a heart attack and may prevent heart attacks or strokes in healthy individuals. In addition, separate studies have suggested drinking coffee regularly may reduce the risk of developing chronic illnesses, such as Type 2 diabetes and some cancers; may help to control appetite; may help to lower the risk of depression or boost alertness, though it is not clear if this effect is from the caffeine or something else in coffee. On the harmful side, too much coffee may raise blood pressure and lead to anxiety, heart palpitations and difficulty sleeping. "Our study aimed to determine whether the known protective effect of coffee also applies to individuals with different degrees of hypertension; and also examined the effects of green tea in the same population," explained the study's senior author Hiroyasu Iso, M.D., Ph.D., M.P.H., director of the Institute for Global Health Policy Research, Bureau of International Health Cooperation, National Center for Global Health and Medicine in Tokyo, Japan, and professor emeritus at Osaka University. "To the best of our knowledge, this is the first study to find an association between drinking 2 or more cups of coffee daily and cardiovascular disease mortality among people with severe hypertension." High blood pressure, also known as hypertension, occurs when the force of blood pushing against the walls of blood vessels is consistently too high, making the heart work harder to pump blood. It is measured in millimeters of mercury (mm Hg). The current blood pressure guidelines from the American Heart Association and the American College of Cardiology classifies hypertension as a blood pressure reading of 130/80 mm Hg or higher. The blood pressure criteria for this study are slightly different from the ACC/AHA guidelines. Researchers classified blood pressure into five categories: optimal and normal (less than 130/85 mm Hg); high normal (130-139/85-89 mm Hg); grade 1 hypertension (140-159/90-99 mm Hg); grade 2 (160-179/100-109 mm Hg); and grade 3 (higher than 180/110 mm Hg). Blood pressure measures in grades 2 and 3 were considered severe hypertension in this study. Study participants included more than 6,570 men and more than 12,000 women, ages 40 to 79 years at the start of the research. They were selected from the Japan Collaborative Cohort Study for Evaluation of Cancer Risk -- a large, prospective study established between 1988 and 1990 of adults living in 45 Japanese communities. Participants provided data through health examinations and self-administered questionnaires assessing lifestyle, diet and medical history. During nearly 19 years of follow-up (through 2009), 842 cardiovascular-related deaths were documented. The analysis of data for all participants found: "These findings may support the assertion that people with severe high blood pressure should avoid drinking excessive coffee," said Iso. "Because people with severe hypertension are more susceptible to the effects of caffeine, caffeine's harmful effects may outweigh its protective effects and may increase the risk of death." The study found that people with more frequent coffee consumption were more likely to be younger, current smokers, current drinkers, eat fewer vegetables, and have higher total cholesterol levels and lower systolic blood pressure (top number) regardless of the blood pressure category. The benefits of green tea may be explained by the presence of polyphenols, which are micronutrients with healthy antioxidant and anti-inflammatory properties found in plants. The researchers noted that polyphenols may be part of the reason only coffee consumption was associated with an increased risk of death in people with severe high blood pressure despite both green tea and coffee containing caffeine. The research has several limitations: coffee and tea consumption were self-reported; blood pressure was measured at a single point, which did not account for changes over time; and the observational nature of the study could not draw a direct cause-and-effect connection between coffee consumption and cardiovascular disease risk among people with severe high blood pressure. Further study is needed, researchers said, to learn more about the effects of coffee and green tea consumption in people with high blood pressure and to confirm the effects of coffee and green tea consumption in other countries.

Drinking coffee regularly may keep type 2 diabetes away from women who had diabetes during pregnancy. Replacing artificially sweetened and sugar-sweetened beverages with caffeinated coffee also reduces the risk, by 10% for a cup of artificially sweetened beverage, and 17% for a cup of sugar-sweetened one. The prevalence of type 2 diabetes is projected to continue rising and one in three Singaporeans currently has a risk of developing diabetes in their lifetime. Several early-life cardiometabolic complications make identifying high-risk populations and application of diabetes preventive strategies paramount. Among the high-risk groups are women who experienced diabetes during pregnancy, commonly known as gestational diabetes mellitus or gestational diabetes. Compared to the general healthy female population, these women may face a ten-fold higher risk of developing type 2 diabetes. Current known research has found that, instead of artificially- and sugar-sweetened drinks, drinking two to five cups of either caffeinated or decaffeinated coffee a day is potentially a healthier substitute in delaying the onset or preventing type 2 diabetes. This is likely due to the bioactive components in coffee, such as polyphenols, which are naturally-occurring plant micronutrients. Bioactive components are types of chemicals found in small amounts in plants and certain foods, such as fruits, vegetables, nuts, oils, and whole grains, and may promote good health. This common and popular drink appears to reduce the risk of type 2 diabetes in the general population. However, whether it may also be beneficial among women who had gestational diabetes remained unknown. To investigate this, Professor Cuilin Zhang, Director of the Global Centre for Asian Women's Health (GloW) and a professor in the Department of Obstetrics and Gynecology at the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), with her team at GloW, in collaboration with the Harvard T.H. Chan School of Public Health and the National Institutes of Health (NIH), examined the roles of long-term coffee consumption after the complicated pregnancy and subsequent risk of type 2 diabetes among women with a history of gestational diabetes. The team further examined coffee consumption with type 2 diabetes by replacing commonly consumed sugary drinks with coffee. Findings from this study, "Habitual coffee consumption and subsequent risk of type 2 diabetes in individuals with a history of gestational diabetes -- a prospective study" was recently published in the American Journal of Clinical Nutrition. In their study, the researchers followed more than 4,500 predominantly white female participants who had a history of gestational diabetes, for over 25 years, and examined the associations of long-term coffee consumption with subsequent risk of type 2 diabetes. The consumption of caffeinated coffee among women after their pregnancies, was discovered to have a linear inverse association with the risk of type 2 diabetes. Compared to those who did not drink caffeinated coffee at all, among those who drank one cup of caffeinated coffee or less, two to three cups, and four and more cups a day, the risk of type 2 diabetes was reduced by 10%, 17%, and 53% respectively. Interestingly, decaffeinated coffee was not associated with the risk of type 2 diabetes in their study. However, this null finding might be due to the relatively small number of women who consumed decaffeinated coffee, so that the study was not able to detect a significant association. More importantly, replacing artificially sweetened and sugar-sweetened beverages with caffeinated coffee also reduces the risk, by 10% for a cup of artificially sweetened beverage, and 17% for a cup of sugar-sweetened one. "Thus far, the overall findings suggest that caffeinated coffee, when consumed properly (two to five cups per day, without sugar and whole-fat/high-fat dairy), could be incorporated into a relatively healthy lifestyle for certain population," noted Professor Zhang. "The beneficial roles of coffee have been consistently suggested across diverse populations, including Asians. Coffee is a popular beverage choice in Singapore, but local coffee drinking culture and behaviours may vary among individuals, such as brewing methods, drinking frequency, and other condiments contained in the coffee. Thus, more studies are needed to examine the roles of coffee consumption in the local context with major health outcomes," concluded Professor Zhang. Adding on to Professor Zhang's point, Dr Jiaxi Yang, the first author of the study and a postdoctoral research fellow at GloW and the Department of Obstetrics and Gynecology at NUS Medicine, said, "Although coffee presents as a potentially healthier alternative to sweetened beverages, the health benefits of coffee vary and much depend on the type and the amount of condiments, like sugar and milk, that you add into your coffee." Dr Yang is currently leading the working group of Nutrition and Lifestyle at GloW. However, concerns should be given when coffee is taken in excessive amounts. It also needs to be emphasised that certain groups should be careful about drinking coffee. Not much is known about the effects of coffee on pregnancies, foetuses and children.