Drinking two cups of coffee a day could add years to your life, according to new research. The world's most popular beverage boosts the heart - increasing longevity, scientists said.
Its benefits apply both to healthy individuals - and those with cardiovascular disease, a study found. In the biggest analysis of its kind, scientists tracked more than 400,000 Britons for at least a decade.
Senior author Professor Peter Kistler, of the Baker Heart Institute, Melbourne, Australia, said: "Because coffee can quicken heart rate, some people worry that drinking it could trigger or worsen certain heart issues. This is where general medical advice to stop drinking coffee may come from.
"But our data suggest that daily coffee intake shouldn’t be discouraged, but rather included as a part of a healthy diet for people with and without heart disease. We found coffee drinking had either a neutral effect—meaning that it did no harm—or was associated with benefits to heart health."
Optimum effects were identified in people who glugged two to three cups a day. They had a 10 to 15 per cent lower risk of developing coronary heart disease, heart failure a heart rhythm problem or dying for any reason.
This was compared to peers who never touch the black stuff. Coffee beans are packed with over 100 nutritious plant chemicals. They dampen oxidative stress and inflammation and improve insulin sensitivity and metabolism, explained Prof Kistler. The biologically active compounds also block absorption of fat into the gut and molecules linked to abnormal heart rhythms.
Overall, participants who downed less than two cups or more than three cups fared less well. However, the risk of stroke or heart-related death was lowest among those who drank one cup of coffee a day.
Drinking coffee was also associated with a lower risk of death for people who had been diagnosed with an arrhythmia, or irregular heart beat. For example, those with AFib (atrial fibrillation) where the heart beats rapidly were nearly 20 per cent less likely to die than non-coffee drinkers if they had one cup a day.
Prof Kistler said: "Clinicians generally have some apprehension about people with known cardiovascular disease or arrhythmias continuing to drink coffee. So they often err on the side of caution and advise them to stop drinking it altogether due to fears that it may trigger dangerous heart rhythms. But our study shows that regular coffee intake is safe and could be part of a healthy diet for people with heart disease."
Prof Kistler added: "There is a whole range of mechanisms through which coffee may reduce mortality and have these favourable effects on cardiovascular disease. Coffee drinkers should feel reassured that they can continue to enjoy coffee even if they have heart disease. Coffee is the most common cognitive enhancer - it wakes you up, makes you mentally sharper and it's a very important component of many people's daily lives."
The international team used data from the UK BioBank - looking at consumption ranging from up to a cup to more than six cups a day.
They compared levels with heart rhythm problems (arrhythmias), cardiovascular disease and total and heart-related deaths. In many cases, coffee significantly reduced risks to heart health - regardless of exercise, alcohol, smoking, diabetes and high blood pressure.
The researchers followed 382,535 men and women with an average age of 57 without known heart disease. Secondly, they included 34,279 individuals who had some form of cardiovascular illness at the outset.
Among these, coffee intake of two to three cups a day was also linked with lower odds of dying compared with never touching it. Importantly, consuming any amount did not increase the risk of heart rhythm problems including AFib or atrial flutter.
This is often what clinicians are concerned about, said Prof Kistler. Of the 24,111 people included in the analysis who had an arrhythmia at baseline, drinking coffee was associated with a lower risk of death.
For example, people with AFib who drank one cup of coffee a day were nearly 20 per cent less likely to die than non-coffee drinkers. A third analysis of instant, ground, caffeinated or decaf coffee again found two to three daily cups was best. Lower death rates were seen across all types.
Decaf did not have favourable effects against arrhythmia cases but reduced cardiovascular disease - with the exception of heart failure. It suggests caffeinated coffee is preferable across the board - and there are no benefits to choosing decaf over caffeinated coffees, said Prof Kistler.
Cardiovascular disease is the world's number one killer - claiming an estimated 17.9 million lives each year. Drinking coffee has also been linked with combating cancer, dementia , diabetes and depression.
People are normally advised to drink no more than four cups a day - about 400mg. Caffeine is a stimulant - and can trigger insomnia and even muscle tremors.
The results were presented at an American College of Cardiology meeting in Washington DC.
