A friend directed me to a comment on another bird site that revealed some serious misinformation regarding oxalic acid. One of the posters listed off all of the vegetables she discovered that contained oxalic acid and recommended that they be discontinued in the diets of everyone’s birds based on concerns that have been circulating for years now. Oxalic acid is a term that is on the lips of many parrot owners and it appears to be only slightly less concerning to them than battery acid. So, let’s get our facts together.
What is oxalic acid?
Oxalic acid is a naturally occurring compound that is found in many of the leafy greens like chard, collard or spinach, and is present in lesser amounts in beets, bell peppers, sweet potatoes, and cabbage to name a few other vegetables. It can be found in some nuts, seeds, grains, fruits and legumes as well.
The concern about oxalic acid is that it inhibits calcium absorption. This is true. Calcium is important to our birds, and especially so seasonally when eggs might be produced. But to put the message out there in such simplistic terms causes people to over-react. What most people don’t understand is that oxalic acid does not randomly obliterate the calcium content of a meal. That is a lot of where people’s fears originate.
The fact is that oxalic acid will only suppress the absorption of calcium from food that contains oxalic acid. For instance, spinach contains both calcium and oxalic acid. The oxalic acid in the spinach binds with its calcium and will block its absorption into the blood stream. However, it does not affect the calcium in other foods even when eaten in the same meal.
Since calcium can come from multiple sources, your bird will derive the necessary amounts from the other foods it eats. Most of the foods with oxalic acid have so many other great nutritional attributes that they must be kept in the diet, regardless of the calcium issues.
Are there REAL concerns?
When you stop and reason it out, there are so many common foods that contain varying levels of oxalic acid that our birds (and ourselves) would be starved for calcium if the fears circulating were justified.
However, if spinach is ALL your bird ever eats (and I am not picking on spinach for any reason other than continuity in this article), then your bird will wind up with a calcium deficiency because the oxalic acid will cancel out the bird’s only source of calcium. There would likely be other deficiencies as well if your bird only ate that one food.
If your bird’s diet is varied and well rounded, you don’t really need to give oxalic acid any further consideration because your bird will have its calcium needs met through other foods.
DO NOT eliminate known healthy foods from your bird’s diet based on the fearful words of others. It is true what they say about the relationship between oxalic acid and calcium. But it is the same relationship that has always been and will always be. If we scratched every food with what appears to be a downside off our shopping list, neither we, nor the birds would have anything left to eat. Nature has it all worked out as usual, so don’t worry needlessly.
For a complete guide to parrot diet and nutrition click here: Natural Feeding.
NOTE: The foods that are commonly listed as safe for parrots might contain oxalic acid in amounts that are safe for consumption. However, rhubarb leaves contain a toxic amount of oxalic acid and should not be eaten by humans or fed to the birds at any time.
Patty Jourgensen specializes in avian health, behavior and nutrition and has been working with and caring for rescue birds since 1987.
4 comments
This was an interesting tale but I’m not sure it’s correct. I’m a human with oxalate toxicity and in relation to humans, it is understood that oxalate binds to (and makes biounavailable) any minerals in the food containing oxalate and any other food eaten with it. So spinach has such a high amount of oxalate that not only does the oxalate bind to all the iron in the spinach, but also binds to some of the iron (and other minerals) in the foods eaten as part of the same meal, making that also unavailable to the body. I don’t know of any reason why this would be any different with birds. The mineral-depleting effects of oxalate apply to all minerals, not just calcium, though there’s some variation in how much it binds to different minerals. The very highest oxalate foods in the world are rhubarb, spinach, sweet potato, almonds, beetroot and dark chocolate (not for birds!)
I agree with you on everything you wrote above. However, I have a 25 yo Jardine’s parrot who first his first hypocalcemia-related seizure in 2016. Exposure to sun and avian lamp resolved the issue up until October 2020, when he was administered an antibiotic after the removal of rhinoliths (truth be told until then I fed him almost exclusively pellets, and a bean mix and 1/2 walnut a day). After the course of the antibiotic he had a seizure again (the antibiotic he was given is known to interact with calcium absorption). The issue here is that where I live (Athens, Greece), there are no knowledgeable and experienced avian vets, other than for wild bird sanctuaries. He was then given a supplement to promote liver function, because his blood work showed an AST of 380. After 5 days into the supplement, he had seizures again. Since then I’ve been feeding him raw organic vegetables (including okra and artichokes), germinated seeds (including oats, which are high in calcium), and herbs (including dried dandelion, high in oxalates). After having been feed a chop of artichokes, okra, broccoli, carrots, beets, dried dandelion, among other things, for four days, he had another seizure today (a month from the last one), albeit not as severe. My point being, the okra, artichokes, and dandelion are the only thing that changed in his diet. Exposure to avian lamp and sun continues. And all this, despite being given a calcium supplement into his water three times a week. I’m trying to find a balance here, and oxalates have to factor in somehow, but I don’t want to exclude veggies solely on the basis of oxalic acid content. Maybe quantities play a role.
I purchased the cookbooks. I was hoping for a list of what items a parrot can have and ways it should be prepared for giving. I wanted a list to turn to just to offer. Do you know of a reliable list I can follow I see many contradictions on certain foods. Thank you so much.
Could you tell me why the little feathers on my conure are sticking up like she is mad? Is she missing something in her diet or getting ready to molt??? Thank you
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