The last time I took our ol' princess, Belle in for her dental, I asked my vet about what causes FORLs. She said there has not been a real determination on what causes it. I asked specifically about genetics or calcium deficiencies, and she said nope, that all those things have been studied to death and not proven to be factors. I said I thought that was pretty bizarre, which made her laugh in agreement.
She explained that FORLs are essentially an immune trigger/reaction that rejects/absorbs the teeth. It's the same trigger that happens when the body gets rid of baby teeth. Only, for some unknown reason, it is triggered in some cats after they've grown in their adult teeth. Once the reaction is triggered, it will not stop until all the teeth have been lost, which is why FORLs can go on for years. I asked if the process would continue to the bones when the teeth were gone. She said no, the process is specific to the teeth, and once it's done with teeth, the immune system goes back to "normal". So weird.
So, I'm not sure if adding the extra calcium into the diet is really going to change the long term outcome. But it might slow down the process a bit, so kitty can keep their teeth just a little bit longer.
I would think hormones, specifically growth hormones, trigger baby teeth to fall out, as part of the aging/growing process (pre-puberty). And maybe I'm being obsessive about this, but nutrition has a large impact on hormones.
Even if I'm way off base about the tooth resorption, that explanation (baby teeth) doesn't explain why his jaw is soft. The vet specifically mentioned that to me, which is why I started thinking that this is a form of osteoporosis, in that his body isn't getting enough minerals and is pulling those minerals from his bones to make sure there's enough in the blood. Humans have to have a certain level of calcium in their blood at all times to live, and I suspect that's true for all mammals.
I did contact Susan Thixton, who had written one of the articles that Dee posted a link to, and she replied back but didn't think you could give too much broth and didn't know how much she gives her pets because she mixes it in their food. So I can't explain how that person developed hypercalcemia other than perhaps the broth he was drinking wasn't balanced or he was taking supplements in addition to the broth and it wasn't mentioned in the article.
But since I certainly don't want to make things worse, I'm going to err on the side of caution.
So here's my thinking, and if I'm way off, please correct me, because math was never my strong suit: Raw feeders usually go by the rule of 80% meat/10% bone/10% organ (including liver). So, if I use the 5.5 oz can (per day) as my 80% meat (I'll round down to 5 oz to make it easier, esp. since I'll need to cut back on his food anyway to help him lose some weight), then 10% bone would be .5 oz. Solid weights are different from liquid weights, so I would need to convert that .5 oz from a solid to liquid (broth). I found one place that stated that 2.1 tablespoons = 1 solid ounce. I want to confirm that, but if it's true, then .5 oz bone (solid) would be just over 1 tablespoon of broth.
5 oz can = 80% meat
5 x 10% = .5 oz bone (solid)
.5 oz solid bone = 1 tablespoon "liquid bone" broth (conversion to be confirmed)
I realize it still doesn't make for a balanced diet, but I think it would be an improvement. Does my math work (other than the conversion of solid to liquid) or am I totally messing it up? I was trying to keep it simple but I may have oversimplified.