These tiny little gems do indeed pack a potent punch. They rank the highest of any fruit for antioxidants (those free-radical-fighting powerhouses), and one cup delivers 14% of the recommended daily dose of fiber and nearly a quarter of the recommended daily intake of vitamin C. Blueberries are also low in calories — fewer than 100 for a full cup. They owe their distinct hue to their high anthocyanin content, which gives certain fruits and veggies their deep blues and reds. North America is still the leading producer of this beloved blue fruit, accounting for up to 90% of the world’s supply.