This is not the case with animal food sources, where we only eat the meat and leave out the bones, which are in fact full of minerals. (fitnessandpower.com)
This diet provided them with amino acids, the building blocks of protein they needed and could only get from animal food sources. (eukanuba.com)
The primary source of B12 is found in animal food sources, although both plants and animals can't produce this nutrient for themselves. (drvitaminsolutions.com)