CC / Originally posted in How to Prevent Kidney Stones with Diet
You mention oxalates in other videos. But a vegan friend of mine has found that many of the veggies that are great sources of calcium are also high in oxalates. I understand they can affect kidney stones and the gall bladder. Any other effects? Possible subject: “How should vegans get enough calcium while avoiding oxalates”. Can they affect uric acid? Generally, “what are the hazards of oxalic acid/oxalates?” At least add both “oxalic acid” and “oxalates” to your list of topics….Thanks for whatever attention you can bring to this.
Answer:
*Update: I have become concerned enough about kidney stone risk that anyone who eats cups a day (as they should!) of dark green leafy vegetables should probably stick to low-oxalate greens (i.e. basically any greens other than spinach, swiss chard, and beet greens). Video forthcoming, but just wanted to give everyone a heads up.*
If someone already has kidney problems they should really watch their intake of turmeric (See: Who Shouldn’t Consume Curcumin or Turmeric?). Even though turmeric and cinnamon contain about the same amount of oxalates, 90% of the oxalates in turmeric are soluble (readily absorbed), which is why those with kidney problems or prone to stone formation should limit turmeric to like 1 teaspoon per day. Cinnamon isn’t a real concern oxalate-wise (but raises concerns about coumarin).
The oxalates do bind up calcium in vegetables, though, so spinach and beet greens are therefore not good sources of calcium (though wonderful foods in their own right!) Healthy sources of calcium include: kale, broccoli, collards, beans, tofu, dried figs, fortified plant-milks, and even blackstrap molasses – one of the healthiest sweeteners you can use! Calcium needs for adults 19-50 years old is 1,000 mg per day. Adults older than 50 need 1,200 mg of calcium per day, but calcium recommendations vary greatly by country. It’s like 700 mg in the U.K., which is odd , right? This huge discrepancy gives Dr. Greger the hibigeebies, meaning he questions the government panels issuing these recommendations. What does the science say? Stay tuned for clarifications in his new videos: “Are Calcium Supplements Safe?” and “Are Calcium Supplements Effective?” If you cannot wait ’till November they are available as a video download as part of his new Latest in Clinical Nutrition volume 27 (of course, all proceeds go to charity). It can also be ordered as a physical DVD. Lastly, a great cheat sheet on meeting calcium needs on a plant-based diet can be found here.
For more on diet and kidney failure watch Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet (both summarized Dr. Greger’s blog post: Preventing and Treating Kidney Failure With Diet).
Image Credit Keith Hall / flickr
