Most of us reach for a pale, light beer at happy hour when watching our calories. But new research shows a nutritional benefit to opting for a heavier, darker beer: iron. The study, which was published in the Journal of the Science of Food and Agriculture, examined 40 types of beer from around the world and found that, on average, dark beers have free iron content of 121 parts per billion (ppb) compared to 92 ppb in pale beers and 63 ppb in non-alcoholic beers.

Iron is an essential mineral that is need to make a part of blood cells. Iron helps carry oxygen from the lungs to the muscles and other organs, so when your iron intake is low, oxygen circulates more slowly, which can leave you feeling tired, sluggish and irritable.

While iron is found in meat, beans, grains and some veggies, it's estimated that only 65 to 70 percent of all Americans meet their daily recommended intake. Because of menstruation, women are particularly prone to low iron. While getting all of your iron from dark beer isn't a good idea (drink responsibly!), this new research can definitely make you feel a little healthier about enjoying that darker brew the next time you're out.