Drinking tea or coffee can reduce the risk of premature death - but which is best for you?
New research shows drinking coffee or a cuppán tae can reduce the risk of premature death. But which is best for you, asks Victoria Lambert
Reading this with a mug of coffee in your hand? Then you have permission to feel smug. The latest pan-European research, led by epidemiologist Dr Marc Gunter of Imperial College, London - following a study of more than half a million people over 16 years - has shown that those who drank the most coffee had a reduced risk of premature death from any cause.
But what if you're reaching for a cuppán tae instead? Don't panic: a compound in black tea could help gut bacteria fight infections and prevent severe influenza, say scientists at the Washington University School of Medicine in the latest issue of the journal, Science.
It's good to know that the nation's two favourite hot drinks can be healthy - but which one would be best for you?
Best for… longer life? Tea
The latest study on coffee backs up evidence from the National Institutes of Health, published in the New England Journal of Medicine in 2012, which reported that, compared with men who did not drink coffee, men who drank six or more cups per day had a 10pc lower risk of death, whereas women in this category of consumption had a 15pc lower risk.
But regular tea drinkers have also been found to live longer than average. An Australian study published in The Journal of Clinical Nutrition in 2015 showed that women in their 70s and 80s lived longer if they had the equivalent of two cuppas a day. This may be due to a unique compound in tea that can change the body's genetic code.
Weronica Ek, from Uppsala University, whose study was published in Human Molecular Genetics in May, found that regular tea (but not coffee) drinking is associated with epigenetic changes in 28 different gene regions known to interact with cancer or oestrogen metabolism.
Best for… antioxidants? Coffee
Both coffee and tea contain lots of antioxidants called polyphenols, nutrients that can help to reduce inflammation and repair cellular damage. Dr Bob Arnot, whose latest bestseller The Coffee Lover's Diet reveals how to get the most health benefits from the drink, explains: "We know now that the driving force behind many illnesses such as heart disease and stroke is inflammation, which is something polyphenols can help with. And coffee contains two and a half times more polyphenols than tea on average."
But he also warns there is a staggering difference between brands, thanks to methods of roasting, and even among types of beans from different countries. "If you want to get the most polyphenols (and thus the most benefit) from drinking coffee, choose beans grown at high altitude, such as Nyeri in Kenya.
"Better still is dark Greek or Turkish roast, as these retain higher levels of polyphenols than lighter French or Italian roasts," says Dr Arnot. "But for the very best health, you want varieties of polyphenols. So do drink tea, too."
Best for… heart health? Tea
Be still your (rapidly beating) heart: both coffee and tea have been linked with reduced cardiovascular diseases. Dutch research, published in Arteriosclerosis, Thrombosis, And Vascular Biology: Journal Of The American Heart Association in 2010, found that drinking more than six cups of tea per day was associated with a 36pc lower risk of heart disease compared to those who drank less than a single cup of tea per day. Coffee drinkers with a modest two-to-four cups per day had a 20pc lower risk of heart disease compared to those drinking less than two or more than four cups.
"The poly-phenols may help your heart," says Dr Arnot. "But if you are a slow caffeine metaboliser, it can lead to increased blood pressure and a higher pulse rate. Know your caffeine tolerance level and how much goes into the average shop-bought coffee. No one should have more than 400mg of caffeine a day (equivalent to four espressos). Anyone who finds caffeine particularly affects them - ie, that it disturbs their sleep - should have no more than 200mg a day." One Starbucks Caffe Americano Venti contains 300mg of caffeine.
Best for… the digestive system? Coffee
Researchers at the University of Southern California (USC) Norris Comprehensive Cancer Center of Keck Medicine reported last April that coffee consumption decreases the risk of colorectal cancer.
"We found the more coffee consumed, the lower the risk," said Dr Stephen Gruber, Director of the USC Norris Comprehensive Cancer Center and senior author of the study.
The indication of decreased risk was seen across all types of coffee, both caffeinated and decaffeinated.
Best for… weight loss? Tea (as long as it's green)
Black coffee has been the staple of many a dieter's regime, but it may be doing more harm than good. An April 2011 study from the University of Guelph reveals not only that a healthy person's blood sugar levels spike after eating a high-fat meal, but the spike doubles after having both a fatty meal and caffeinated coffee, jumping to levels similar to those of people at risk for diabetes. Ultimately, said researchers in the Journal Of Nutrition, saturated fat and fat combined with caffeinated coffee hinder the body's ability to clear sugar from the blood, and having high blood sugar levels can take a toll on our body's organs. There are a number of small studies that indicate the use of green tea in supporting weight management, says Euan MacLennan, a medical herbalist with a central London NHS General Practice. "In a study carried out with 35 obese men and women, it was found that those who drank four cups of green tea daily for two months lost significantly more weight than those who consumed a placebo.
Best for… lowering cholesterol? Tea
Drinking coffee may be raising your cholesterol. According to US research from the Baylor College of Medicine published in the July 2007 edition of journal Molecular Endocrinology, a compound found in coffee called cafestol elevates cholesterol by hijacking a receptor in an intestinal pathway critical to its regulation. Cafetiere, or French press coffee, boiled Scandinavian brew and espresso contain the highest levels of the compound, which is removed by paper filters used in most other brewing processes. If your cholesterol is high, stick to Barry's.
Best for… alertness? Tea
We drink coffee to pep us up, but that feeling may be an illusion, say researchers from the University of Bristol. A June 2010 study, published in Neuropsychopharmacology, reports that frequent coffee drinkers develop a tolerance to both the anxiety-producing effects and the stimulatory effects of caffeine. Frequent consumers may feel alerted by coffee, but the evidence suggests this is the reversal of the fatiguing effects of acute caffeine withdrawal. And given the increased propensity for anxiety and raised blood pressure induced by caffeine consumption, there is no net benefit.
However, MacLennan, who is herbal director at Pukka Herbs, quotes Portuguese research published in Frontiers In Bioscience in 2011 which suggested compounds found in green tea can cross the brain-blood barrier to reach neural tissue. "They can help to protect neurons (nerve cells)," he says, "and reduce the decline in brain function. Studies also suggest that L-theanine, the 'relaxing' amino acid in green and matcha tea, may have benefits for memory and reducing the decline in cognitive function as we get older."
Best for… improving bone strength? Tea
Studies have long linked black tea with improved bone strength, but, says MacLennan, the benefits of green tea may be even greater.
He cites research from Texas, published in 2013 in the American Journal Of Clinical Nutrition: "It found that the epigallocatechin gallate (EGCG) compound, which is abundant in green tea, can decrease the numbers of osteoclasts in the body - these are the cells that break down bone - and increase the numbers and activity of osteoblasts, the cells that build bone. Green tea may also be helpful if you need to speed up the healing process of a broken bone."
Coffee may not boost bone strength, but according to a report by the Society for Experimental Biology, by sports scientists at Coventry University in June 2012, caffeine does boost the power of older muscles.