Both black tea and spinach are high in oxalates, and he destroyed his kidneys as if he were drinking ethylene glycol (anti-freeze) which metabolizes into oxalic acid, and crystallizes in the kidneys.
I'll take a stab and postulate that the China man was drinking lots of black tea, too.
From google:
Vegetables that contain high levels of oxalate include rhubarb, okra, leeks, spinach, beets, and Swiss chard. To reduce how much oxalate you get, avoid almonds, cashews, and peanuts, as well as any soy products. Grains such as Bran Flakes, Fiber One, wheat germ, and quinoa are also higher oxalate foods.
Foods that contain oxalates
The following are some examples of the most common sources of oxalates, arranged by food group. It is important to note that the leaves of a plant almost always contain higher oxalate levels than the roots, stems, and stalks.
Fruits:
blackberries, blueberries, raspberries, strawberries, currants, kiwifruit, concord (purple) grapes, figs, tangerines, and plums
Vegetables (see Table 1 for additional information):
spinach, Swiss chard, beets (root part), beet greens (leaf part), collards, okra, parsley, leeks and quinoa are among the most oxalate-dense vegetables
celery, green beans, rutabagas, and summer squash would be considered moderately dense in oxalates
Nuts and seeds:
almonds, cashews, and peanuts
Legumes:
soybeans, tofu and other soy products
Grains:
wheat bran, wheat germ, quinoa (a vegetable often used like a grain)
Other:
cocoa, chocolate, and black tea
http://www.whfoods.com/genpage.php?tname=george&dbid=48