Guavas are rich in dietary fiber and vitamin C, with moderate levels of folic acid. Having a generally broad, low-calorie profile of essential nutrients, a single common guava (P. guajava) fruit contains about four times the amount of vitamin C as an orange.[6]
However, nutrient content varies across guava cultivars. Although the strawberry guava (P. littorale var. cattleianum) has about 25% of the amount found in more common varieties, its total vitamin C content in one serving (90 mg) still provides 100% of the Dietary Reference Intake.[7]
Guavas contain both carotenoids and polyphenols like (+)-gallocatechin,[8] guaijaverin, leucocyanidin and amritoside[9]–the major classes of antioxidant pigments – giving them relatively high potential antioxidant value among plant foods.[10] As these pigments produce the fruit skin and flesh color, guavas that are red-orange have more pigment content as polyphenol, carotenoid and pro-vitamin A, retinoid sources than yellow-green ones.[11]