Can he really eat nothing but boiled bones?

March 3, 2012 2:43 AM

Can vegetarian "gelatine" be eaten before a colonoscopy?

My husband has to have a colonoscopy next month. The instructions he got from the hospital say that for about 18 hours before the procedure, he isn't allowed to eat anything except "jelly." I assume that by "jelly" they mean traditional, animal-based gelatine. As vegetarians, we don't eat this; if I made jelly, it would be with agar agar. Would it be OK for him to eat this, or does it contain stuff he shouldn't have before the colonoscopy?

Bonus question: The letter specifically says he can have any colour of jelly except red. Why would this be?

Thanks so much!

posted by Perodicticus potto to Health & Fitness (8 answers total)

The red dye in the jelly will end up in his intestines, and it will confuse a search for bleeding by the gastroenterologist doing the colonoscopy.

I can't answer the agar question, but from my bench work days pouring plates (Petri dishes of agar and nutrients), I remember agar to be light brown, which might not affect the procedure.

Just call their office and ask a nurse or assistant. They'll know for sure.
posted by Blazecock Pileon at 3:03 AM on March 3, 2012 [2 favorites]

Yeah, just agreeing that the "no red" thing is because it will be hard for the gastroenterologist to distinguish between bleeding tissue and bits of lodged red jelly. I recently had an endoscopy and I was also instructed to avoid red foods and drinks.
posted by Cygnet at 3:35 AM on March 3, 2012

2nding call the office and ask.
posted by Ochre,Hugh at 5:20 AM on March 3, 2012

Best answer: I had a colonoscopy 3 weeks ago. I was allowed (instructed) to drink water (at least 2 litres), sports drinks (like Gatorade), jello, and broth. They suggested chicken broth, but any clear liquid was fine, maybe you should also ask about vegetable broth?
posted by BozoBurgerBonanza at 6:21 AM on March 3, 2012

In addition to the red, you also don't want any solids interfering with the field of vision--docs get grumpy when they're having to navigate the camera around masses of digested food, unable to see the colonic surfaces. Obviously do ask the doc, but any clearish non-solid should be fine.
posted by mittens at 6:48 AM on March 3, 2012 [1 favorite]

Best answer: Animal-based gelatin is digested into individual amino acids, which are water soluble. In contrast, agar is not digestible at all by humans, and passes through the gut as indigestible fiber. It seems like a bad idea to eat anything indigestible before a colonoscopy.
posted by Ery at 10:25 AM on March 3, 2012 [2 favorites]

Response by poster: Thanks, Ery, that is just the sort of information I was looking for. Checking the letter again, I see it says he can also have clear soups, so it looks like it will be lots of vegetable broth for him.
posted by Perodicticus potto at 11:06 AM on March 3, 2012

I drank lots of black coffee, had a few clear soups and generally went hungry. Was all fine according to my doctor.

My brother was given a prep solution that he had to drink liters of, I was given a different one that was just several 500ml glasses of it during the day - I highly recommend comparing the instructions on the various preps to find one that's not awful.

Also, I recommend he get some games on his mobile phone, and put a charger near the porcelain throne.
posted by Jerub at 4:27 PM on March 3, 2012