Guar gum is a soluble fiber. I doubt its harmful for buns in the quantities wee discussing here. That something “has been linked to” doesnt necessarily mean there is any form of causality. In humans, a sudden intake of substantial amounts of guar gum (commonly used as a thickening agent in lots of foods like icecream) can have GI side effects such as gas and loose stools. Intake of guar gum with insuffient water intake can lead to constipation. But we wouldn’t suddenly let our buns pig out on treats, and if we did, theyd be likely to get GI upset pretty much regardless of type of treats. All new food items for buns should be introduced slowly, in small amounts.

I find a study from 1987 on PubMed

https://pubmed.ncbi.nlm.nih.gov/3820520/ that says guar gum caused a thickening of the “unstirred water layer” in the rabbit jejunum, which could in part explain why soluble fiber slows the uptake of certain nutrients. Guar gum became very popular as a functional food some 10-15 years ago beause it appears it can help lower blood cholesterol in humans.

This said, I’ll alert the other moderators to this. They might know more 🙂

I’ll do some more digging on this in the literature, but I tend to agree with Bam. You’ll notice on the ingredient list that guar gum is very low down, after natural flavors and just before the preservative. That means that it’s present in a very tiny amount!  Honestly I’d personally be more concerned about the flours and sugars than the guar gum. 😉

I looked up the paper that Bam linked, and the study was not done in live rabbits. They took rabbit intestinal tissue ( 🙁 ) and put it in different solutions of guar gum, then looked at permeability of the solution. So a very different type of situation than what would be occurring when a rabbit ate a treat with a tiny amount of guar gum.

I’ll keep digging for some more info though.

Did a bit more digging!

I also found this old thread with some great discussion about homemade treats, as well as the additives guar gum, xanthan gum, etc. https://binkybunny.com/forums/topic/ressurecting-bunny-cookies/

One study found that guar gum increased absorption and utilization of a medication in vivo (opposite of the in vitro study linked above): https://platform.almanhal.com/Files/2/39359

Another report, summarizing the effects for humans (which often involve animal studies), states:

“No acute toxicity was observed in studies in mouse, rat, rabbit and hamster at doses amounting up to 6,000–9,000 mg/kg bw per day (Stanford Research Inst., 1972; NTP, 1982; Sax, 1984).” and later on”repeated oral administration of guar gum caused some growth reduction in rats, mice and rabbits at high doses, but these effects can partially be attributed to the bulk properties of guar gum when in contact with water or intestinal juices and have not been considered as adverse effects. Increased caecum weight in animals fed high amounts (2–5% of the diet) of guar gum was also reported. ”  (this is a MUCH higher dose than would be in a treat)

It also seems there is more info on the internet (all in “grey” literature though, like blog posts) about guar gum being poorly tolerated in dogs and cats. In those cases, that makes more sense to me. Dogs and cats are obligate carnivores and cannot process fiber in their diet, and “bulking agents” like guar gum are often added to canned dog and cat food to cut costs. So that would mean these animals could be eating more of these substances daily, and lacking in what they actually need (protein).

Rabbits on the other hand, NEED fiber and process it much differently than carnivores. And an occasional treat is a very tiny part of a rabbit’s diet!

So this is a long winded way of saying, I don’t think you need to worry about these treats unless your bun has a SUPER sensitive digestive tract, and I would disagree with the instagram post that they should “thrown in the bin”. And in that case, he would prob do best without commercially made treats anyway.

I agree with Dana. I don’t think guar gum is anything to worry about. Especially not in the quantities we are talking. It’s a binder/bulking agent that’s essentially just fiber. It may not sit well with a carnivore, but a herbivore wouldn’t have the same problem.