"Since we don't absorb collagen whole, the idea that eating collagen somehow promotes bone growth is just wishful thinking," Percy [associate professor at the University of South Dakota's Sanford School of Medicine] says. Instead, he says, the digestive system will break down the collagen into amino acids, and the body will use these building blocks wherever they're needed.
Kantha Shelke has a different take. She's a food scientist and spokesperson for the Institute of Food Technologists, and a principal with the food science and research firm Corvus Blue LLC.
She says that if you want to build collagen, you need more than bone broth.
"Eating a diet rich in leafy green vegetables is ideal," she says. "Plants offer richer sources in collagen building blocks and, in addition, provide nutrients not found in sufficient quantities in meats or broth."
What's more, bone broth may provide vitamins and enzymes, but they get denatured from heat as the broth cooks, rendering them less useful to the body, according to Shelke.
