Rhubarb, a plant with a split personality, has been both a culinary delight and a source of concern for many. While its stalks grace our pies and jams, its leaves have a darker reputation. Let’s dig into the science behind rhubarb leaf toxicity and separate fact from fiction.
Caution: There are various strains of this plant found in different parts of the world, and the “toxicity research” mentioned in this article may not apply to all strains. Always exercise caution.
The Two Faces of Rhubarb
Rhubarb, known scientifically as Rheum species, is a member of the buckwheat family1. It’s a bit like that friend who’s great fun at parties but has a mysterious side you’re warned about.
The good: Rhubarb stalks are edible and widely used in cooking, especially in British cuisine2. They’re the star of many desserts and even find their way into refreshing drinks.
The bad: Rhubarb leaves have long been considered poisonous3. But just how dangerous are they?
The Culprit: Oxalic Acid
The main troublemaker in rhubarb leaves is oxalic acid4. It’s not unique to rhubarb – you’ll find it in other plants too, like spinach. But in rhubarb leaves, it’s present in higher concentrations.
What’s the big deal with oxalic acid?
Oxalic acid isn’t playing around. If consumed in large quantities, it can cause5:
- Nausea
- Reduced mineral absorption
- Potential kidney stones
It’s like that overly clingy friend who not only makes you feel bad but also prevents you from enjoying other good things in life.
Rhubarb Leaf Toxicity: How Worried Should We Be?
Now, before you start panicking and torching your rhubarb patch, let’s put things into perspective.
The toxicity of rhubarb leaves depends on several factors:
- Quantity consumed: You’d need to eat a lot of leaves to be in real danger. We’re talking kilograms, not a nibble or two6.
- Individual sensitivity: As with many things, some people might be more sensitive than others.
- Preparation method: Cooking can affect oxalic acid levels, but it doesn’t eliminate the risk entirely.
Here’s a fun fact to chew on: During World War I, when food was scarce, some folks tried eating rhubarb leaves as a vegetable. Spoiler alert: It didn’t end well. There were reports of acute poisoning, and sadly, even some deaths7.
Ehubarb Leaf Poisoning Symptoms
The edible part of rhubarb is its stalk, while its leaves contain oxalic acid. This compound is toxic to both animals and humans.
Common symptoms of poisoning include stomach pain, nausea, vomiting, diarrhea, weakness, difficulty breathing, and a burning sensation and pain in the throat and mouth8.
what happens if you eat a rhubarb leaf
The effects can vary from person to person, as individual tolerance to oxalic acid differs, but that’s not a reason to try consuming it.
The most severe consequences might include nausea, vomiting, difficulty breathing, and so on, while the mildest outcomes could be simple gastrointestinal discomfort9.
Nevertheless, do not eat the leaves of this plant.
When is rhubarb poisonous?
Once this plant has grown, its leaves become “toxic,” meaning that “oxalic acid” is present at all times. The more mature the plant is, the higher the potential concentration of oxalic acid may be.
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Beyond Oxalic Acid: The Plot Thickens
Just when you thought you had it figured out, rhubarb throws another curveball. Recent research suggests that oxalic acid might not be the only villain in this story.
Rhubarb leaves contain another toxic substance that hasn’t been fully identified yet. Some scientists suspect it might be a type of anthraquinone glycoside10. It’s like a mystery novel where we know whodunit, but we’re still figuring out the accomplice.
The Stalk: A Safer Bet
If all this leaf talk has you worried, here’s some good news: rhubarb stalks are much safer11. They contain only about 2-2.5% of the oxalic acid found in the leaves. So, you can keep enjoying your rhubarb pies and crumbles without losing sleep.
The Bottom Line: Better Safe Than Sorry
While you’d need to eat a substantial amount of rhubarb leaves to be in serious danger, it’s best to err on the side of caution. After all, with so many delicious and safe foods out there, why take the risk?
Here’s a simple rule of thumb: Stick to the stalks and leave the leaves alone. Your taste buds (and your kidneys) will thank you.
In conclusion, while rhubarb leaves are indeed toxic, you don’t need to live in fear of them. Just treat them with respect, like you would any potentially harmful substance. And remember, in the world of rhubarb, it’s the stalks that are the real stars of the show!
- Roggemans J, Boxus P. Rhubarb (Rheum rhaponticum L.)[M]//Crops II. Berlin, Heidelberg: Springer Berlin Heidelberg, 1988: 339-350. https://link.springer.com/chapter/10.1007/978-3-642-73520-2_16 ↩︎
- https://www.thelandconnection.org/il_specialty_crops/rhubarb/ ↩︎
- https://link.springer.com/article/10.1186/s13020-020-00370-6 ↩︎
- http://helios.hampshire.edu/~nlNS/mompdfs/oxalicacid.pdf ↩︎
- Stepanova N, Driianska V, Korol L, et al. Plasma oxalic acid and cardiovascular risk in end-stage renal disease patients: a prospective, observational cohort pilot study[J]. The Korean Journal of Internal Medicine, 2022, 37(1): 167. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8747923/ ↩︎
- https://www.bbc.com/ukchina/simp/50504851 ↩︎
- https://www.ag.ndsu.edu/news/columns/prairie-fare/prairie-fare-can-rhubarb-become-toxic ↩︎
- https://www.mountsinai.org/health-library/poison/oxalic-acid-poisoning ↩︎
- http://helios.hampshire.edu/~nlNS/mompdfs/oxalicacid.pdf ↩︎
- https://www.sciencedirect.com/science/article/pii/S0308814620312255 ↩︎
- https://extension.oregonstate.edu/ask-extension/featured/are-rhubarb-leaves-toxic ↩︎
