[Stones] Oxalate Content of Peppers and Tomatoes

Lynx lynxletter@hotmail.com
Sun, 16 Mar 2003 12:50:33 -0500


Amy writes: "I realize there is some variation from list to list, but I have
several such lists, including the book "Oxalate Content of Selected Foods"
from UC San Diego Medical Center, and all of them list green (but not red)
peppers as high and fresh tomato as moderately high."

Well, I guess someone's  information may be off.  The  oxalate data
mentioned comes from a referenced USDA website.  Of course these are just
averages,  hopefully representative of the  food you feed.  Unless you test
a particular vegetable, you don't know what the nutritional/oxalic acid
content is.  In my experience, plants high in oxalic acid are markedly
bitter and become increasingly bitter as the oxalic acid content increases.
Since most  green peppers and no tomatoes I've ever eaten are  bitter, I am
guessing the information I have may be somewhat more accurate.

Here's another source of oxalate information based on dry weight:
http://www.ars-grin.gov/duke/highchem.html

Doing a search on 'oxalic acid' turns up "Black Pepper, Pepper, White
Pepper" as pretty darn high at 34,000 ppm (parts per million -- this is on a
dry weigh basis).  Perhaps this is where you got the idea peppers were high
in oxalic acid? This not green pepper which is listed as "Bell Pepper,
Cherry Pepper, Cone Pepper, Green Pepper, Paprika, Sweet Pepper" and has
1,171 ppm (a fraction of the above type pepper).  Additionally, tomato is
listed as having 263 ppm.

To put this into better perspective,
Lambsquarter -- 300,000ppm
Purslane, Verdolaga --16,790 ppm
Rhubarb --13,360 ppm
Spinach -- 6,580 ppm
Mustard Greens -- 1,287 ppm
Green pepper -- 1,171 ppm
Tomato -- 263 ppm

This would seem to indicate also that both green pepper and tomato aren't
all that bad.  So with two separate sources, I'm going to figure that they
are okay as far as oxalic acid goes.