Coffee and longevity – debate continues

By Dr. Ananya Mandal, MDMay 13 2019

Coffee prevents deaths

There have been studies saying coffee drinking increases longevity and general health and also studies to the contrary. Now, the latest research shows that drinking at least two cups of coffee per day can increase the life expectancy of consumers by up to around two years. The results of the large and fairly conclusive study titled, “Coffee consumption and all-cause and cause-specific mortality: a meta-analysis by potential modifiers,” were published in the latest issue of the European Journal of Epidemiology.

The study analysed previous studies on benefits of drinking coffee by looking at 40 studies that included around 3,852,651 participants of which there were 450,256deaths. They noted that drinking coffee reduced all-cause mortality or risk writing that it decreased death rates, “irrespective of age, overweight status, alcohol drinking, smoking status, and caffeine content of coffee”.  They compared consumption of four cups of coffee per day and found that it was responsible for more reduction in cause specified death as well as deaths due to all causes when compared to consumption of no coffee. Coffee consumption was also associated with reduced risk of getting and dying due to cancers, diabetes, lung disease and heart disease. They analyzed subjects and the effects coffee had on them by correcting for other factors such as age, obesity and lifestyle choices. The study authors noted that coffee was more likely to reduce risk of death among those from Europe and Asia than Americans.

The authors quantify according to their findings;

• 3.5 cups of coffee per day reduced risk of all-cause death best
• 2.5 cups per day reduced risk of deaths due to heart disease best
• 2 cups per day reduced risk of cancer deaths best

Image Credit: NOBUHIRO ASADA / Shutterstock

These amounts seem to be of optimum benefit. More consumption than this did not change the findings.

Authors write that coffee has been connected to a reduced risk of prostate cancer, Alzheimer’s disease and Parkinson’s disease. Astrid Nehlig, a research director at France’s National Institute of Health and Medical Research in a statement said, “It is difficult to calculate, but my feeling is that drinking coffee possibly adds another couple of years to your life.” He added that more focus and attention could be the reason behind this longevity.

Authors concluded, “Moderate coffee consumption (e.g. 2-4 cups/day) was associated with reduced all-cause and cause-specific mortality, compared to no coffee consumption.”

Six or more cups harmful

In yet another study from Australian researchers, it was found that there was an optimum amount of coffee that was beneficial. The new study was published this month in the journal American Journal of Clinical Nutrition and was titled, “Long-term coffee consumption, caffeine metabolism genetics, and risk of cardiovascular disease: a prospective analysis of up to 347,077 individuals and 8,368 cases.”

Researchers from the University of South Australia in their study published this month set out to ascertain the amount of coffee that was beneficial for health. They noted that drinking six or more cups of coffee per day could be harmful for health and raise the risk of heart disease by up to 22 percent.

The researchers write that one in six persons are suffering from heart disease in Australia. The World Health Organization calls cardiovascular disease the leading cause of death as well as one of the most preventable causes of death. Dr Ang Zhou and Professor Elina Hyppönen of the Australian Centre for Precision Health looked at the long term effects of coffee consumption and heart disease. They explain that research shows that excess coffee can harm the heart by raising blood pressure.

They write that this is the first study that outlines the upper limit of coffee consumption in terms of benefit and harm. Prof Hyppönen in a statement said, “Coffee is the most commonly consumed stimulant in the world -- it wakes us up, boosts our energy and helps us focus -- but people are always asking 'How much caffeine is too much?'” She added, “Most people would agree that if you drink a lot of coffee, you might feel jittery, irritable or perhaps even nauseas -- that's because caffeine helps your body work faster and harder, but it is also likely to suggest that you may have reached your limit for the time being. We also know that risk of cardiovascular disease increases with high blood pressure, a known consequence of excess caffeine consumption.”

On this study Prof Hyppönen said, “In order to maintain a healthy heart and a healthy blood pressure, people must limit their coffees to fewer than six cups a day -- based on our data six was the tipping point where caffeine started to negatively affect cardiovascular risk.”

The team used data from the UK Biobank including 347,077 participants aged 37-73 years. They in addition also looked at the caffeine-metabolizing gene (CYP1A2). People with this gene could metabolize coffee faster than others. The team found that even carriers of this gene could not safely consume more caffeine than others while maintain a healthy heart. Hyppönen said, “An estimated three billion cups of coffee are enjoyed every day around the world. Knowing the limits of what's good for you and what's not is imperative. As with many things, it's all about moderation; overindulge and your health will pay for it.”

Part of a healthy diet

A similar study on genetic variation and effects of coffee was published last year August by authors E Loftfield and colleagues in the journal JAMA Internal Medicine titled, “Association of Coffee Drinking With Mortality by Genetic Variation in Caffeine Metabolism: Findings From the UK Biobank.”

This team looked at genetic variations at “AHR, CYP1A2, CYP2A6, and POR” genes. They looked at genetic data from 498,134 participants, their coffee consumption and the risk of all-cause deaths. Over 10 years of follow-up they noted 14,225 deaths.

Their results showed that “Coffee drinking was inversely associated with mortality, including among those drinking 8 or more cups per day and those with genetic polymorphisms.” They wrote that “coffee drinking can be a part of a healthy diet”.

Protects heart

Authors Z. Gaeini and colleagues this month also published an article comparing coffee drinking and tea drinking in the journal Nutrition Metabolism. Their study was titled, “Tea, coffee, caffeine intake and the risk of cardio-metabolic outcomes: findings from a population with low coffee and high tea consumption.”

This team included participants of the Tehran Lipid and Glucose Study (2006-2008 to 2012-2014). They looked at effects of coffee and tea drinking among Iranian populations on heart disease and kidney disease. They followed up their participants for an average of six years and noted that coffee had protective effects on heart disease. Tea consumption on the other hand was found to be detrimental to the heart in Iran. They added that it could be due to the “additives or artificial colors in tea consumed in Iran, and sweets or sugar that mostly consumed accompanied by tea”.