It seems as though every day brings yet another study on the effects of caffeine or coffee in particular. Researchers have looked at its effects on almost every aspect of health, from overall mortality to the heart, bones, kidneys, liver, fertility, and more.

Sometimes, separate studies on the same aspect of caffeine consumption have contradictory findings, creating confusion. So, what do you need to know before you take another sip?

An exhaustive analysis of 1,277 existing studies published in Comprehensive Reviews in Food Science and Food Safety found that the potential benefits of drinking moderate amounts of coffee outweigh the risks. In fact, research on caffeine's heart health benefits, published in the journal Circulation, reversed 20-year-old findings to the contrary. But just what is moderate coffee drinking? About four 8-ounce cups a day.

At the other end of the spectrum, research done at the Australian Center for Precision Health has pinpointed the upper end of the safe range, finding that drinking six or more cups a day does pose a danger to heart health. This amount can lead to high blood pressure, a risk factor for heart disease.

Caffeine isn't the only active ingredient in coffee, but tracking caffeine milligrams is a good way to measure intake, with 400 milligrams a day being the limit suggested by the U.S. Food and Drug Administration. One 8-ounce cup of regular brewed coffee has, on average, 80 milligrams.

Always read labels on blended coffee drinks and other caffeinated items to know how much caffeine is in a serving and how many servings it contains. Also check their calorie counts, which may be just as important if you're trying to lose weight.