A reader wrote me today about a warning that he had seen from a well respected veterinarian: "Avoid feeding pets vegetables high in oxalic acid, a compound that interferes with calcium absorption. These include spinach, swiss chard and rhubarb."
Really, no spinach at all? Seems like a serious accusation that feeding any of these leafy greens will prevent calcium from being absorbed by your dog's body. I mean how can that be? Spinach and other leafy greens are touted as being being high in calcium. It's obviously time to dig a bit deeper.
The prosecution's evidence:
- Spinach and other leafy greens are loaded with oxalic acid, a compound that is responsible for the bitter taste, especially in older leaves.
- Oxalic acid is known to bind to calcium where it is then excreted in the urine.
If we stop there, it would probably be best if we all just left spinach in the occasional spinach dip.
The defense's evidence:
- The oxalic acid binds with 88% of the calcium in the spinach, as calculated from information from Dr. Andrew Weil. Dr. Weil states that it would take 16 cups of cooked spinach to equal the bioavailable calcium in 1 cup of yogurt when factoring in the effect of oxalic acid.
- Spinach and other green leafy vegetables provide a power house of fiber, vitamins A, B, K, calcium iron, magnesium and manganese, beta-carotene, zeaxanthin, lutein, carotenoids and glycolipids which are all beneficial compounds and worth having in the diet.
- There is no further evidence that demonstrates the oxalic acid in green leafy vegetables affect the remaining calcium in the diet.
The Verdict:
- Guilty of a misdemeanor. Sentenced to probation.
Probation Sentencing:
- Dogs with liver disease should not eat spinach, kale, beet greens and even carrots because of their high vitamin A levels that could cause complications since Vitamin A is stored in the liver.
- Dogs with kidney stones should not eat green leafy vegetables due to the fact that the oxalic acid and calcium bound together in the urine can lead to the formation of kidney stones.
- All dogs on homemade meals should have calcium supplemented in their diet whether or not green leafy vegetables are included in the meal.
- Spinach, kale, swiss chard, parsley and the rest of the gang can be incorporated into a dog's diet but like with all foods, it's wise to rotate through a variety of fruits and vegetables so that your dog receives a wide array of nutrients.
- For dogs and people, look elsewhere for sources of calcium
Feed Your Best Friend Better,
Rick
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