Opinions on that reverse every couple of years. Go ahead and drink all you want until somebody finds some actual facts.
1. You can expect to pee once for every cup of coffee. Maybe you won't, but you should expect to.
2. Drink eight or so cups of coffee per day and your hair will turn white a few years earlier than it otherwise would.
3. Coffee keeps you awake. It also makes you sleepy. Go figure.
For one thing, coffee is more complex than it looks. A cup of coffee may contain as many as five hundred naturally occurring chemicals. Yet, most studies focus on just one ingredient, the stimulant caffeine.
In some people, caffeine can cause sleeplessness and irritability or make it difficult to concentrate.
Still, there are a few cautions that a coffee drinker may wish to note. The Times of London recently cited this finding from a Dutch report: “Coffee in which the boiling water and grounds are mixed directly can increase cholesterol levels by 10 per cent, compared with drinking filtered coffee or no coffee at all.” Cholesterol is a well-known contributor to heart disease. In another issue, The Times quoted a leading British nutritionist as saying: ‘Regular coffee drinkers should always have a fresh cup and avoid a stewed or boiled brew.’
If the experts agree on anything when it comes to coffee, it is moderation. Doctors generally recommend that people should drink no more than six cups (or four mugs) of coffee in a day. Those with such health problems as heart or kidney disease or high blood pressure should have less than that. And pregnant women or those who breast-feed their babies should have no more than one cup a day.