Oxalates are phytonutrients that exist in certain vegetables, fruits, nuts and grains in nature for their protection. It prevents most bugs and invasive natural enemies to such produce from eating them by hurting their teeth or means of taking in the product. It is nature's way of protecting such foods and allowing them to grown and exist.

Usually, if there is any discomfort or issue with the gut in intestinal tract, foods that are high in oxalates would be hard to process and handle for the system--thus the need for them to be either avoided or eaten in smaller amounts (depending on your particular case and need). If you are experiencing health issues in such areas it is best to avoid foods with oxalates in general. Other than that, usually, the body can handle and process certain amounts of oxalates.

VERY HIGH OXALATE (over 50mg per serving)

These foods, in general, could contain very large amounts of oxalate that would be in the range of 50 to 520 mg of oxalate per serving. Of course, any natural produce and it's ingredients or nutrients would largely depend on how it is grown, it's soil and environment. These are pretty accurate estimates though.

The following foods may contain very large amounts of oxalate in the range of
50 - 520mg oxalate per serving size listed.

Vegetables

• Beetroot - boiled or pickled ¼ cup (50g)
• Beet greens
• Leeks ½ cup (62g)
• Okra ½ cup (100g)
• Poke weed 1 oz (30g)
• Spinach 1 oz (30g)
• Sweet potatoes ½ cup (120g)
• Swiss chard (boiled) 1 oz (30g)
• Swiss chard (raw) ¼ cup (9g)

Soy Products and Soybeans (1 oz or equivalent)

• Soy milk ( 1/2 cup)
• Soy Protein
• Textured vegetable (which is soy protein in most case)
• Soy nuts
• Soy yogurt
• Tofu ( 3 oz )
• Soy flour
• Any soy made product in general

Fruits

• Elderberry, raw 3.5 oz (100g)
• Figs, dried 3.5 oz (100g)
• Green gooseberries ½ cup (75g)
• Rhubarb, raw, canned or stewed ¼ cup (120g)
• Star fruit (Carambola) 1 oz (30g)
• Black berries ½ cup (72g)
• Black currents ½ cup (56g)
• Black raspberries ½ cup (60g)
• Blueberries ½ cup (73g)
• Currants, red ½ cup (56g)
• Dewberries ½ cup (72g)
• Figs, raw (3.5 oz) 100g
• Gooseberry, red (3.5 oz) 100g
• Grapes, concord ½ cup (80g)
• Kiwi, raw 1 med (76g)
• Raspberries, red ½ cup (62g)

Grains and Starches

• Amaranth* 1 oz (30g)
• Buckwheat, dry 2 oz (60g)
• Wheat bran, dry 1 oz (30g)

*The oxalate content of Amaranth is unclear. Due to the fact that it is considered to be related to spinach family, it may contain high levels of oxalates as well.

Legumes, Nuts and Seeds

• Almonds
• Hazelnuts
• Peanuts
• Peanut butter
• Pecans
• Pistachio
• Sesame seeds
• Tahini
• Refried beans (cooked)

HIGH OXALATE (10-50mg per serving)

The following foods may contain large amounts of oxalate in the range of 10 - 50mg
oxalate per serving.

Vegetables

• Baked beans in tomato sauce 1 cup (120g)
• Beans, green ½ cup (68g)
• Beans, kidney ½ cup (120g)
• Celery (raw) ½ cup (60g)
• Chicory, raw ½ cup (90g) Collard (boiled) ½ cup (64g)
• Dandelion greens (raw) 1 cup (55g)
• Dandelion greens (boiled) 1 cup (105g)
• Mustard greens, raw ½ cup (90g)
• Olives, green, canned 1 oz ( 7-8 small)
• Peppers, chilies, raw ½ cup (75g)
• Peppers, green, raw ½ cup (113g)
• Potatoes, raw 5 oz (150g)
• Potatoes , boiled 5 oz (150g)
• Potatoes , baked 5 oz (150g)
• Potato, chips (small bag) 1 oz (30g)
• Potatoes, French fries 5 oz (150g)

Grains and Starches

• Wheat germ 1 Tbsp (7g)
• Whole-wheat flour ½ cup (60g)
• Most breakfast cereals (especially the ones that would contain high fiber, gluten, wheat, rye, wheat germ)
• Grits (from white corn)
• Rye or Wheat bread
Miscellaneous
• Chocolate (Hershey bar) 1 oz (30g)
• Chocolate (dark) 1 oz (30g)
• Cocoa, dry powder 1 Tbsp (5.4g) Three Musketeers Bar 1 oz (30g)
• Butterfingers Bar 1 item (45 gram)
• Vegetable soup 1 cup (240g)

Beverages

• Beer: dark, robust 12 fl oz (356g)
• Chocolate ( M & Ms) 1 oz
• Coffee (30g), instant 1 tsp (1.8g)
• Ovaltine, 1 tsp (2.67g)
• Black tea, 1 cup (240g)
• Tea - rosehip, 1 cup (240g)