Oxalates are naturally-occurring substances found in plants, animals and in humans. It is the component that gives foods such as rhubarb, beet greens and spinach their bitter taste. In humans, they can be made by the body or ingested through food. They are considered to be an anti-nutrient because they can interfere with the absorption of nutrients by binding themselves to minerals in the gut which makes it more difficult for the body to break down and absorb. Oxalates can become a problem if they over accumulate in the body. They can impair digestion and cause kidney stones.

A kidney stone normally begins as a small crystal-like material and it gradually builds up into a larger, solid mass. Urine normally contains chemicals that inhibit the crystals from forming. Or, if crystals remain small enough they can travel through the urinary tract and pass out of the body without being noticed. However, when crystals combine together to form a kidney stone, it can stick to the lining of the kidney or settle in an area where urine cannot carry it out of the body.

Oxalates aren’t all bad news. They do play a supportive role in the metabolism of many plants and animals as well as in human metabolism.  They do not inhibit the absorption of calcium in other foods consumed at the same meal, and in terms of iron absorption, the body tends to absorb more iron from oxalic acid-rich foods when there is an iron-deficiency present. Oxalate foods also contain important antioxidants, fiber and other nutrients that are important for good health. They are not the sole cause of kidney stone formation. Our overall diet and lifestyle are the major contributors. A diet high in processed foods, animal proteins, trans fats and some saturated fats are major contributors of stone formation.

Certain individuals need to be careful about their intake of oxalic acid. Those who have existing and untreated kidney or gallbladder problems, a vulnerability to kidney disorders or stones, gout, rheumatoid arthritis, or certain forms of chronic vulvar pain. For others, the extent to which foods high in oxalic acid are a potential health problem varies from person to person.

The oxalic acid is lowered by boiling and steaming. A plant-based lower protein diet will prevent the formation of kidney stones. Being well hydrated and a daily dose of omega-3 fatty acids are also very effective in preventing oxalate deposition.

Oxalate containing foods: limit and rotate with low oxalate foods

  • Almonds
  • Beans
  • Beer
  • Beets and beet greens
  • Berries
  • Cashews
  • Chocolate
  • Coffee
  • Cranberries
  • Dark green vegetables, such as spinach
  • Oranges
  • Parsley
  • Rhubarb
  • Soda (cola)
  • Soy beans
  • Soy beverage
  • Spinach
  • Swiss Chard
  • Sweet potatoes
  • Tea (black)
  • Tofu
  • Wheat bran
  • Beef, pork, eggs, cheese
  • Too much vitamin C supplementation


Low oxalate foods:

Oxalic acid generally increases as foods mature, producing increasingly bitter vegetables. Young, fresh vegetables such as baby spinach are less likely to have oxalic acid.

  • Lettuce
  • Celery
  • Artichokes
  • Asparagus
  • Cucumber
  • Corn
  • Mushrooms
  • Onions
  • Peas
  • Peppers
  • Potatoes
  • Radishes
  • Zucchini
  • Watercress
  • Escarole
  • Asparagus
  • Dandelion
  • Cruciferous vegetables: kale, bok choy, broccoli, kale, cauliflower, cabbage and arugula.

Fruits:

  • Apples
  • Apricots
  • Avocado
  • Bananas
  • Cherries
  • Cranberries
  • Oranges and grapefruit,
  • Red or green grapes,
  • Lemon and lime juice
  • Melons,
  • Nectarines,
  • Papayas,
  • Peaches,
  • Pears,
  • Pineapples,
  • Strawberries


Lifestyle recommendations

  • Stay hydrated
  • Reduce the amount of sodium in your diet.
  • Support your digestion
  • Eat in a relaxed state, chew slowly, engage in conversation
  • Adequate exercise
  • Identify and reduce stressors