likewise people who drink wine in moderation have lower risk of heart disease
though the point here is little to do with drinking caffeine in moderation
Except substances in coffee are known to have positive influences such as reducing diabetes risks, as well as numerous other health risks. You can give caffeine to house flies or earth worms and they will live longer on average. that isn't due to Caffeine drinking earth worms having better lifestyles and working out at the gym, it is chemical reaction the caffeine creates that changes the physiology of the worm so it will live longer. The same is true for humans because when the studies are done external factors like socioeconomic status, lifestyle, education, career, geographic location are accounted for. You are probably also thinking of this form a UK perspective where there is a more obvious social divide between regular coffee drinkers and tea drinkers. In the US everyone drinks coffee, tea is pretty rare. In fact tea drinkers in the US are probably more liekly to be extra health conscious. Go to a supermarket here an there is an entire aisle of coffee, including a long stretch of whole beans to buy in bulk form dozens and dozens of different cofee produces. Shoved at the end is small selection of disappointing tea bags, half of which are specially designed for ice-tea!. So even if a study totally ignored external factors, the population as whole is not especially biased.



