Chronic Constipation - Insoluble vs. Soluble Fiber

Poppy has chronic constipation. I am trying to manage it, and have some questions about insoluble vs. soluble fiber.

Poppy’s main problem is not being regular. Now that she's getting Miralax, her poop is soft, but doesn’t come out in a regular or timely manner. The vet has said soft poop is more important than the timing, but recently Poppy had to have an enema even though she had soft poop.

I’ve been giving her pumpkin and more recently Benefiber (in place of the pumpkin—she started rejecting pumpkin), which I understand are sources high in soluble fiber. I’ve also read that you shouldn’t give high amounts of insoluble fiber to treat constipated cats.

But here’s what I don’t understand – insoluble fiber is supposed to make food pass faster and in a more regular manner. Soluble fiber slows down the passage of food but adds water to the waste. So could it be that Poppy is lacking enough insoluble fiber? Or perhaps that there’s too much soluble fiber compared to insoluble fiber? I’ve been thinking I should cut out the pumpkin/Benefiber.

Would insoluble fiber also help with hairballs? Poppy is long hair.

Hi.  Years ago I had a cat (Isaac) that had chronic constipation which lead to megacolon.  No matter what I tried nothing really helped.  We had to give him enemas.

More recently I had another cat (Ernie) who also got chronic constipation.  Once again nothing the vet suggested helped.

I finally learned (I think on this board) about miralax.  Once I started Ernie on that he was never constipated again (over 2 years).  Once in a while he'd get a bit of loose stool but never constipated.  Before that the enemas were very stressful on him and I think the miralax prolonged his life.

Miralax is great as far as I'm concerned.  Note that there may be a health reason for the constipation (hypothyroid for example)

I hope this was helpful.    -James

The problem with insoluble fiber for cats is that it bulks up the stool, which I don't think you want with a constipated cat. Insoluble fiber is also vegetable matter-based so again not appropriate for cats. When you say she's not pooping on a regular or timely basis, what do you mean? How often she poops is going to depend on her diet. And my cat definitely does not poop at the same time of day. I would agree with your vet that as long as she's not straining or in pain the soft poop is ok as long as it's not runny like diarrhea. Hopefully with the enema clearing her out, the other things you're doing to treat her will help with the constipation. I'm just not sure how adding insoluble fiber would help.

Poppy does not poop at the same time, even though her daily routine is VERY regular. She also does not poop daily. Although the vet said it was OK, before she started having problems, she would poop at the same time and daily. It was like clockwork. And her diet hasn't changed significantly.

I'm thinking that since Poppy is long haired, perhaps the regular, quick passage of poop is necessary to prevent clogs. Slow poop, and the hairballs build up. I do groom her almost every day, and I'm giving her egg yolk lecithin.