naturestee
Well-Known Member
Some of you may have noticed warnings about oxalates in rabbit vegetables, particularly from the House Rabbit Society safe veggie list:
http://www.rabbit.org/care/veggies.html
Supposedly they are toxic if fed too often or too much. Because of this, many people choose not to feed, or to feed very little of, high-oxalate veggies such as kale. This comes up in the email list Etherbun every once in a while, and one person recently linked back to this older post from 2003. It shows that oxalates from veggies generally aren't absorbed into the body at all, and so would not be toxic.
Dana is Dana Krempels, Ph.D, who owns the Etherbun list and is quite the rabbit expert herself. She gave me permission to post this on RO. Susan Smith, Ph.D., is an expert in rabbit nutrition who also works a lot with the Wisconsin House Rabbit Society (now if only I could drive that far to see her speak!). Many of you have probably already read health articles from both of them, as they tend to be staples for rabbit care.
Anyway, on to the email!
___________________________________________________________________
Mary Cotter remembered something about dietary calcium oxalates not being
biologically available, and mostly excreted via the stool. I didn't
remember this, so thought to ask our favorite professional nutritionist,
Susan Smith, Ph.D. (University of Wisconsin) about this. Her answer,
which she has given me permission to forward to EB appears below.
I think a lot of kale-loving bunnies are going to be very happy about
this!
Dana
---------- Forwarded message ----------
Date: Tue, 25 Feb 2003 16:23:23 -0600
From: Susan M. Smith
To: Dana Krempels <dana@...>
Subject: Re: [hrsed] Calcium oxalates?
>A post recently appeared on EB asking about oxalates, and someone
>responded by saying that brassicaceous vegetables (i.e., broccoli,
>cabbage, cauliflower, etc.) should be avoided because they're all high in
>calcium oxalates.
Not true. Oxalate values in brassicas are quite low.
>I wrote back to mention that the concentration of calcium salts (including
>oxalates) in plant tissues varies with cultivar and with growing
>conditions (soil composition, etc.). But Mary then reminded me that she'd
>heard somewhere that in the form of calcium oxalate salts, oxalate isn't
>even biologically available, and might not even pass out of the intestine
>and be a problem for the kidneys.
True. And true. Most plants bearing oxalates also contain lots of calcium
and magnesium, and these tie up the oxalate and block its absorption into
the body. It's largely a non-issue.
Most of the oxalate reaching the kidney is from metabolism of vitamin C
(esp if one takes those whopping supplements) and metabolism of
the nonessential amino acid glycine. Indeed, about 1/3 of the oxalate
in normal kidney comes from metabolism of vitamin C.
Susan S.
WI - HRS, sorry to be back in frigid Wisconsin
http://www.rabbit.org/care/veggies.html
Supposedly they are toxic if fed too often or too much. Because of this, many people choose not to feed, or to feed very little of, high-oxalate veggies such as kale. This comes up in the email list Etherbun every once in a while, and one person recently linked back to this older post from 2003. It shows that oxalates from veggies generally aren't absorbed into the body at all, and so would not be toxic.
Dana is Dana Krempels, Ph.D, who owns the Etherbun list and is quite the rabbit expert herself. She gave me permission to post this on RO. Susan Smith, Ph.D., is an expert in rabbit nutrition who also works a lot with the Wisconsin House Rabbit Society (now if only I could drive that far to see her speak!). Many of you have probably already read health articles from both of them, as they tend to be staples for rabbit care.
Anyway, on to the email!
___________________________________________________________________
Mary Cotter remembered something about dietary calcium oxalates not being
biologically available, and mostly excreted via the stool. I didn't
remember this, so thought to ask our favorite professional nutritionist,
Susan Smith, Ph.D. (University of Wisconsin) about this. Her answer,
which she has given me permission to forward to EB appears below.
I think a lot of kale-loving bunnies are going to be very happy about
this!
Dana
---------- Forwarded message ----------
Date: Tue, 25 Feb 2003 16:23:23 -0600
From: Susan M. Smith
To: Dana Krempels <dana@...>
Subject: Re: [hrsed] Calcium oxalates?
>A post recently appeared on EB asking about oxalates, and someone
>responded by saying that brassicaceous vegetables (i.e., broccoli,
>cabbage, cauliflower, etc.) should be avoided because they're all high in
>calcium oxalates.
Not true. Oxalate values in brassicas are quite low.
>I wrote back to mention that the concentration of calcium salts (including
>oxalates) in plant tissues varies with cultivar and with growing
>conditions (soil composition, etc.). But Mary then reminded me that she'd
>heard somewhere that in the form of calcium oxalate salts, oxalate isn't
>even biologically available, and might not even pass out of the intestine
>and be a problem for the kidneys.
True. And true. Most plants bearing oxalates also contain lots of calcium
and magnesium, and these tie up the oxalate and block its absorption into
the body. It's largely a non-issue.
Most of the oxalate reaching the kidney is from metabolism of vitamin C
(esp if one takes those whopping supplements) and metabolism of
the nonessential amino acid glycine. Indeed, about 1/3 of the oxalate
in normal kidney comes from metabolism of vitamin C.
Susan S.
WI - HRS, sorry to be back in frigid Wisconsin
