I found a website that mentions some foods to avoid and why:
* "Empty" food like lettuce and celery. They provide very little useful nutrition or fiber. Only use it to entertain a turtle that is already well fed.
* Food high in oxalic acid like spinach, chard and rhubarb. Oxalic acid blocks the absorption of calcium. These foods cause the turtle to become calcium deficient even if a good source of calcium is provided.
* High purine foods which include peas, beans, mushrooms should be used sparingly because they can contribute to gout if overused.
* Also avoid cabbage, brussel sprouts, broccoli, bok-choi, and kohlrabi (brassica family). In excessive amounts of these plants contribute to kidney disease and goiter. Turnips, soybeans, radishes, rapeseed, and mustard also contain goitrogens. These should be used rarely. However, the addition of kelp to the diet may reverse the goitrogenic effect of the brassicas.
2 RES Zeke 9 years on 2/1 7 & 1/2"
Rudy 4 years old 4 &/1/2"
5 Cats: DeeJay, Mini Dee, Munchie, Mercedes & Tigglet
3 Dogs: Zoey, Shellie & Ziva