By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – Here is a great argument for eating plenty of fruits and vegetables.

READ MORE: Suspect Accused Of Shooting Into Northeast Philadelphia Bar, Killing 21-Year-Old Woman Arrested

We know an apple a day was good for you – but now we know exactly how good. A single daily serving of fruits or vegetables is linked to a 5% lower risk of dying early – from any cause.

READ MORE: Philadelphia Police Asking For Public's Help In Obtaining Cell Phone Video Of July 4 Parkway Shooting That Injured 2 Officers

Think about that. All you have to do is add a single serving every day.

But even more interesting – each fruit or vegetable that you add to your daily intake is tied to a 5 percent additional drop in that risk, up to five servings a day.

MORE NEWS: Philadelphia Mayor Jim Kenney Walks Back Comments After Saying He'll 'Be Happy' When He Is No Longer Mayor

The information is from the NIH and Harvard – two very reliable sources.