Bioavailability - the proportion of a nutrient that is absorbed and used by the body - varies considerably depending on whether foods are of animal or plant origin. This review summarises data from Chungchunlam and Moughan (2024) on the bioavailability of thirteen vitamins and choline, an essential nutrient related to the B vitamins, in major food sources. Animal-sourced foods are the almost exclusive sources of preformed vitamin A (retinol and retinyl esters, 74% bioavailable) and vitamin B12 (65%), and provide all B vitamins with high bioavailability (biotin: 89%; vitamin B6: 83%; thiamin: 82%; pantothenic acid: 80%; folate and niacin: 67%). Plant-based foods are the main sources of vitamin C (76%) and provitamin A carotenoids (β-carotene, 16%). These data show that animal-sourced foods - particularly offal and red meat - provide vitamins with, for the most part, generally high bioavailability. They also confirm the value of a diversified diet, supported by a nutritional complementarity already demonstrated by modelling: to meet all nutrient-based recommendations, the contribution of animal protein to total protein intake must represent at least 45 to 60% depending on age and sex.