One of the things I've been doing regularly for the past year or so is making carcass broths and bone broths and making stews and soups with it. I make the distinction of carcass v. bone because I mostly make two versions: (1) pork from pork shoulder bones my amazing pork guy provides me free by the bagful (so I don't have to save up bones in the freezer which is a huge bonus!) and (2) chicken from the whole carcass from chickens or everything from the parts -- e.g. a fair amount of skin and cartilage and "stuff".
There was a question about pork rinds and satiety the other day on PaleoHacks that reminded me of a few things. One was that whenever I would hear of the health bennies of gelatin protein, I always remembered reading that it was not a good major protein source because it is not a complete protein. Well, the protein from such broths may not be complete, but it is special indeed. I'm not one for anecdotes but my less-than-perfect-diet hubby is prone to getting bronchitis or worse at least a couple of times every winter and he's had issues with prolonged bouts that turn into one long episode. Last winter? One short cold! I tend to think that's no coinky dink.
Turns out bone/carcass broths are rich in, among other things, the amino acid glycine. From more general info sources on bone broth in general with some specific references to glycine:
A Google scholar search (these will fluctuate, but I only present to give you an idea of number of seemingly quality cites): glycine immunity.
From a supplement hawk: Amino Acid Glycine
And then there's this study:
Glycine intake decreases plasma free fatty acids, adipose cell size, and blood pressure in sucrose-fed rats
The study investigated the mechanism by which glycine protects against increased circulating nonesterified fatty acids (NEFA), fat cell size, intra-abdominal fat accumulation, and blood pressure (BP) induced in male Wistar rats by sucrose ingestion. The addition of 1% glycine to the drinking water containing 30% sucrose, for 4 wk, markedly reduced high BP in sucrose-fed rats (SFR) (122.3 ± 5.6 vs. 147.6 ± 5.4 mmHg in SFR without glycine, P < 0.001). Decreases in plasma triglyceride (TG) levels (0.9 ± 0.3 vs. 1.4 ± 0.3 mM, P < 0.001), intra-abdominal fat (6.8 ± 2.16 vs. 14.8 ± 4.0 g, P < 0.01), and adipose cell size were observed in SFR treated with glycine compared with SFR without treatment. Total NEFA concentration in the plasma of SFR was significantly decreased by glycine intake (0.64 ± 0.08 vs. 1.11 ± 0.09 mM in SFR without glycine, P < 0.001). In control animals, glycine decreased glucose, TGs, and total NEFA but without reaching significance. In SFR treated with glycine, mitochondrial respiration, as an indicator of the rate of fat oxidation, showed an increase in the state IV oxidation rate of the ß -oxidation substrates octanoic acid and palmitoyl carnitine. This suggests an enhancement of hepatic fatty acid metabolism, i.e., in their transport, activation, or ß -oxidation. These findings imply that the protection by glycine against elevated BP might be attributed to its effect in increasing fatty acid oxidation, reducing intra-abdominal fat accumulation and circulating NEFA, which have been proposed as links between obesity and hypertension.
There's lots in this paper that I'm too bogged down in other things to go off on yet another tangent here. But since I had it on the mind I wanted to at least throw this up here for your perusal. Meantime, a bennie of it getting colder is that it's soup season. I've got a big ass jar (probably from somewhere like Costco) in the fridge that I'll spoon out (yep it gets that set up) for cups of hot broth, and I've got chicken soup to be made! When I first started reading about broths I was not convinced. How could it taste that much different? Well, once you cook with bone broths instead of water you'll know what everyone's raving about!