Oxalic Acid is a hazy subject with lots of conjecture and not much actual fact. It has been challenging to find reliable information with sources listed. As in all food-related research, each individual must see how their individual body responds to particular foods.
I particularly like the following quote:
Before we even begin, let us emphasize that we are not physicians or trained medical persons; if you drink bleach and get sick, don’t say “but they said oxalic acid is no big deal.” – Oxalic Acid and Foods
This really sums up the common sense factor needed when reading anything, whether it is online or in a book.
It may also be important to note that many believe Oxalic acid is important for colon health. However, it is only available to the body in the raw form. Additionally when you cook greens, the Oxalic acid content seems to increase to many professionals recommend eating greens high in Oxalic acid either raw or only very lightly cooked. There is some research that even suggests that, when eaten in raw foods, oxalic acid is very beneficial and may be part of the reason many of these foods are also on lists of great anti-cancer foods.
Basically, the only plant with a high enough oxalic acid content to be toxic is rhubarb, and then only the leaves. All of the other greens that are high in Oxalic acid (each list is a little different) can be eaten and enjoyed as part of a diet of diverse healthy foods, and rich in greens. (So enjoy your green smoothies with spinach, chard and more!)
If you have a genetic predisposition to kidney stones then it would be wise to monitor your intake of oxalic acid. If this isn’t the case, then go ahead and enjoy your chard!
For those people who are prone to kidney stones, I would recommend that you have tests done on the stones to see exactly what is causing them, as there are several things that could be the culprit.
I’ve included URLs below from the sites I gleaned my information from. If you are prone to kidney problems, then I recommend cranberries to help with this. Fresh is best, however dried ones or tablets also help. The cranberries combat infections and stones.
Editor’s Note: I asked Veronica to research Oxalic acid because some of our readers were concerned when reading about the high Oxalic acid content in some of the wonderful greens they are now consuming when making green smoothies. As you can see it is a complicated research topic! If anyone has any information to add, please add it to the comments so we can together offer complete information to readers as they research the topic themselves.