Broth is an ancient food. It’s been around as long as people have boiling food in water. Long-simmered stocks made from vegetables, meats and bones have a history of recognition for not only their culinary value, but also their nutritive merits. Humans have a long tradition of strengthening weak constitutions with broth, from its use by early nutritionists as an inexpensive protein-sparing diet staple for the malnourished, to everyone’s favorite cold remedy – chicken soup.
The primary protein extracted in broths made from animal bones is collagen (a large protein which breaks down into smaller peptide subunits of gelatin, formed from amino acid building blocks with a high proportion of glycine and proline residues). In early years of modern nutrition science, when research focused on identifying which components of foods were essential to growth and survival, gelatin was concluded to be a “poor quality” protein due to its deficiency in several essential amino acids. Man cannot live on broth alone. But a growing body of research supports a positive nutritional role for collagen-derived proteins as a food/supplement.
- Recommended Reading:
- Bone and vegetable broth – by nutrition science pioneers McCance & Widdowson in 1934
- A weak link in metabolism: the metabolic capacity for glycine biosynthesis does not satisfy the need for collagen synthesis.
- Dietary Glycine Is Rate-Limiting for Glutathione Synthesis and May Have Broad Potential for Health Protection
- Collagen hydrolysate for the treatment of osteoarthritis and other joint disorders: a review of the literature.
- Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study
- Orally administered collagen peptide protects against UVB-induced skin aging through the absorption of dipeptide forms, Gly-Pro and Pro-Hyp.
- Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women—A Randomized Controlled Study
Reports like these have fueled renewed attention and reverence for bone broth in popular nutrition culture. In typical fashion, public commentary ranges from earnest enthusiasm, to rabid sensationalism, to bitter skepticism. On the latter end of the spectrum, a common thread among mainstream health professional critiques seems to be a dismissal of claims that dietary collagen proteins can directly impact tissues, citing as common knowledge an understanding that proteins are broken down into their amino acid building blocks before they are absorbed in the intestine. This would support an argument that dietary collagen/gelatin would have no inherent benefit over a general balanced diet adequate in essential amino acids. But this common assumption about protein digestion and absorption seems to be untrue, I’ve learned, thanks to Dr. Rhonda Patrick for sharing a study involving radio-labeled gelatin hydrolysate supplements, which revealed preferential accumulation of the labeled proteins in subjects’ cartilage tissues – indicating absorption and assimilation of the gelatin in high molecular form: Oral Administration of 14C Labeled Gelatin Hydrolysate Leads to an Accumulation of Radioactivity in Cartilage of Mice (C57/BL)
Making the effort to craft a batch of home-made stock is high on my list of Noble Kitchen Pursuits. It does take some effort, but thankfully, I’ve found one thing that makes the job a little easier: pressure cooking in my trusty Instant Pot. When I make broth, my priority is getting the most complete/efficient extraction I can, and higher pressure/temperature in a pressure cooker helps break down your ingredients in less time. The enclosed cooking vessel also preserves volatile compounds from escaping (like they would for hours on an uncovered simmer), resulting in more flavor.
I opt for two rounds of pressure cooking, first two hours for just the bones (with added vinegar), followed by another two hours after adding whatever vegetables I have handy, along with a piece of kombu seaweed for even more minerals and savory umami flavor. After straining, I usually get about 3 quarts of rich, golden broth, which keeps well in the freezer. Stock up!
[Instant Pot] Insta-Broth! Pressure Cooker Bone Broth
- about 2 lbs chicken or beef bones
- 3 quarts water
- 2 tablespoons vinegar
- vegetables of choice; the pictured batch (a typical one for me) contains 1 quartered onion, 1 large sweet potato sliced into wedges, 2 halved carrots, one bundle of swiss chard stems, and a handful each of fresh parsley and chives
- a credit card-sized piece of dried kombu seaweed
- salt to taste
- In a pressure cooker, add the bones, and top with water and vinegar. Cover the cooker with its lid, ensuring that the valve is in sealed position. Cook under high pressure for 2 hours (with Instant Pot, press ‘Manual’ mode, and adjust time to 120 minutes).
- When the cooking time is complete, allow the pot to de-pressurize naturally. Open the lid, and place the vegetables into the broth. Cover the cooker again with its lid set to sealing position, and cook again under high pressure for 2 hours.
- Again, when the cooking time is complete, allow the pot to de-pressurize naturally before opening the lid. Carefully strain the hot stock and chill promptly.