How a High-Oxalate Diet Changes Gut Bacteria and Affects the Body
Recent research shows that eating a lot of oxalates—compounds found in foods like spinach, beets, and almonds—can change the types of bacteria in your gut. These changes can affect important body processes like how we handle inflammation, cholesterol, blood pressure, and even how we clear waste like oxalates from our system.
Two gut bacteria are especially affected: Ruminococcaceae_UCG-014 and Parasutterella. Normally, Ruminococcaceae_UCG-014 helps prevent oxalate buildup, while Parasutterella can contribute to problems if it grows too much. A high-oxalate diet lowers Ruminococcaceae_UCG-014 and increases Parasutterella.
This imbalance can lead to hyperoxaluria, a condition where too much oxalate builds up in the urine, which can cause kidney stones and other health problems. But the good news is that a fecal matter transplant (FMT)—a procedure that replaces bad gut bacteria with good ones—can reverse this. Interestingly, the FMT doesn’t work by increasing bacteria that break down oxalates. Instead, it strengthens the gut lining and improves transport proteins in the gut that help remove oxalate from the body.
What Else Changes?
In just 15 days of eating a high-oxalate diet, mice showed signs of leaky gut and metabolic problems. Their intestines became inflamed and damaged. They also had less of a substance called 2-hydroxycinnamic acid, which helps the body make salicylates—natural anti-inflammatory compounds. This could explain why some people develop salicylate sensitivity while eating a high-oxalate or carnivore diet.
People on a carnivore diet should note that hydroxyproline (a protein building block found in collagen-rich animal foods) also increased oxalate levels in this study. That might explain ongoing oxalate issues some carnivores face.
Sulfur and L-Cysteine Handling
Parasutterella loves to consume L-cysteine, a sulfur-containing amino acid. L-cysteine is essential for managing blood sugar, reducing inflammation, and making glutathione, the body’s main detox chemical. If Parasutterella grows too much, it might lower L-cysteine levels, which could contribute to diabetes, weight gain, and even sulfur sensitivities. However, some balance is needed because L-cysteine can also help prevent calcium oxalate buildup.
Oxalate Transport and Blood Pressure
The gut uses special transport proteins (called SLC transporters) to get rid of oxalate. After FMT, more oxalate left through the feces instead of urine, showing that transporter activity had improved. Parasutterella makes a compound called succinate, which can affect how these transporters work. Succinate helps balance oxalate and citrate, a chemical that helps prevent kidney stones. Too much succinate, however, may increase blood pressure by interfering with how transporters work.
Cholesterol and Bile Acids
Parasutterella also influences cholesterol and bile acid levels. Some studies show it helps lower LDL (bad) cholesterol, especially when people eat resistant starches like cooked and cooled potatoes. It also helps regulate bile acids, which are needed to digest fats and remove cholesterol from the body. Parasutterella seems to reduce harmful bile acids while encouraging the body to make more of the helpful ones. This balance helps the liver stay healthy and may reduce the risk of fatty liver disease or liver damage.
Aromatic Amino Acids
Parasutterella also plays a role in handling aromatic amino acids like tyrosine and tryptophan. These amino acids are important for making brain chemicals like dopamine and serotonin. In the study, more Parasutterella was linked to less of a harmful byproduct called p-cresol, and more of helpful compounds like N-hydroxy-L-tyrosine (a dopamine precursor) and ethylphenol (which may fight fungal infections).
The Bottom Line
This study shows that eating a lot of oxalates changes the gut in major ways—lowering good bacteria like Ruminococcaceae_UCG-014 and increasing bacteria like Parasutterella. These shifts affect much more than oxalate levels. They influence inflammation, gut health, blood pressure, cholesterol, and even mental well-being. A low-oxalate diet might help restore balance, especially in people struggling with oxalate-related health problems.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11776474/
https://pmc.ncbi.nlm.nih.gov/articles/PMC9037427/
https://pmc.ncbi.nlm.nih.gov/articles/PMC6776049/