How to maximize the health benefits of coffee

The health benefits of coffee have been hotly debated for centuries. Scientific studies reported in the media often yield contradictory results, only adding fuel to the fire. But we may finally have some clarity about just how good coffee is for us and

how much we should be drinking.

Several recent meta-analyses show that drinking coffee does indeed offer many health perks. "These are huge studies which look at all the studies, so we can actually say something definitive," medical contributor Dr. Holly Phillips told "CBS This Morning." "From these we can say this: for most people, moderate coffee drinking is not harmful."

Moderate is defined as three to five cups per day. Studies have linked drinking java in this amount to a decreased risk of Alzheimer's disease, diabetes, heart disease, and evenmelanoma. Drinking coffee has also been shown to lower the risk of death from all causes.

Of course, these benefits do not extend to the super-sized, flavored and sugar-filled drinks at many popular coffee chains. "By cups, we mean small 8-ounce cups of coffee, black or almost black," Phillips said. "We're not talking about the 32-ounce mocha frappuccino."

But heavy java drinkers beware: consuming coffee does come with diminishing returns. "There's a U-shaped relationship, meaning if you have less than one or two cups a day, the benefits are weaker, but it also drops off if you have more than five or six cups a day," Phillips said.

So exactly what is it about coffee that makes it so good for us?

"We often think of coffee just as a vehicle to get caffeine into our body, but we forget that the coffee bean itself has a hundred different compounds and tons of antioxidants," Phillips said. "Some studies have even shown that Americans get more antioxidants from their coffee than from fruits and vegetables."

Finally, since most studies have been done on caffeinated coffee, the health benefits of decaf are not as clear, although Phillips said drinking decaf is definitely not harmful.