A hot drink touted for its “anti-aging” virtues, supposed to smooth the skin and relieve joints by providing collagen, a long-simmered preparation has become part of well-being routines. What do the analyzes published by the Autonomous University of Nuevo León, the National Library of Medicine or Food and Nutrition Research really say about this? bone broth ?
The figures resulting from this work shake up the dream of a bowl that would “fill up” with collagen. They show a real intake of amino acids, but far from the doses used in studies on
collagen peptides. In other words, bone broth feels more like a comforting boost than a targeted cure for the skin or joints.
Bone broth and collagen: what the analyzes show
THE bone broth is prepared by simmering bones for 12 to 48 hours. The Autonomous University of Nuevo León, in Mexico, analyzed a beef femur broth in a study relayed by PubMed Central and the National Library of Medicine: 100 ml provided 232 mg of amino acids and approximately 248 mg of proteins, more than half of which were essential amino acids.
The Anses Ciqual tables give, for a pot-au-feu type broth, only 0.2 g of protein per 100 g, very far from the 0.83 g of protein per kilo of body weight recommended for adults.
By simmering bones, cartilage and sometimes pieces of meat for a long time, we extract collagen, as well as amino acids such as glycine, proline or glutamine. “There are also minerals (calcium, phosphorus), which are beneficial for joints, skin, tendons and the intestinal mucosa”
specifies Julie Boët, dietician-nutritionist.
Bone Broth, Collagen, and the Human Body: What You’re Really Getting
Long cooking turns the collagen in the bones into gelatin. Once drunk, it is broken down by digestion into peptides and then into key collagen amino acids such as glycine, proline or hydroxyproline, without arriving intact in the skin or cartilage. A 2018 study in the International Journal of Sport Nutrition and Exercise Metabolism showed that the levels of these amino acids in a standardized broth remained significantly lower than those provided by 20 g of collagen supplements.
The Inserm teams point out that the benefits of collagen peptides for the skin or joints remain modest and sometimes contradictory, even with well-quantified daily doses. For a simple bowl that provides less than one gram of protein, the effect can only be limited.
Bone broth: practical relevance, salt and heavy metals
Taken as a comfort food, bone broth hydrates, provides a little protein and flavors dishes, without replacing a major source of collagen. Be careful, industrial versions are often very salty, while INCA3 surveys already find intakes of around 7 g of salt per day for women and 9 g for men. A study published in 2017 in Food and Nutrition Research measured lead and cadmium levels of around a few micrograms per serving, with the risk considered minimal.