Minerals make bones hard, but without collagen they can become brittle and fracture. Strong bones are about 50% minerals and 28% collagen.
Dr. Milan Adam (Institute of Rheumatism Research in Prague) studied 120 osteoporosis patients for three years. Half of the patients took a calcium supplement, the other half collagen hydrolysate. Loss of collagen and bone mass were much lower in the collagen group. Bone fractures were also significantly lower in the collagen group.
Homemade bone broth and collagen rich foods are the traditional way to get collagen in the diet. Today, you can also take a collagen supplement like collagen hydrolysate/peptides.
For more information on collagen and homemade broth:
Nourishing Broth: An Old-Fashioned Remedy for the Modern World
by Sally Fallon Morell and Kaayla T. Daniel