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.