Which Herbal Teas Are High in Oxalates?

According to research, while most pure herbal teas contain relatively low levels of soluble oxalates compared to true teas, certain blends can be surprisingly high due to the addition of fruits, nuts, or specific herbs. Understanding which herbal teas are high in oxalates is vital for anyone managing their intake, particularly for individuals prone to kidney stones.

Quick Summary

Many herbal tea blends, especially those containing high-oxalate fruits or nuts, have higher oxalate concentrations. Prone individuals should monitor ingredients and choose low-oxalate herbal alternatives.

Key Points

• Check Ingredients: Many high-oxalate teas are blends that include berries, citrus peel, or nuts, which increase the overall oxalate content.

• Be Wary of Nettle: Older stinging nettle leaves and tea made from them can be particularly high in oxalates, posing a risk for individuals with kidney issues.

• Choose Low-Oxalate Herbs: Safest herbal teas include pure chamomile, peppermint, and rooibos, which are generally very low in oxalates.

• Stay Hydrated: Drinking ample water helps flush oxalates from the kidneys, reducing the risk of kidney stone formation.

• Add Calcium: Consuming calcium with high-oxalate foods or beverages can bind oxalates in the digestive tract and reduce absorption.

• Practice Moderation: Even low-oxalate teas should be consumed in moderation, especially if you are sensitive, as the cumulative effect can still contribute to your oxalate load.

• Consult a Doctor: Always seek medical advice if you are prone to kidney stones or have underlying kidney conditions before making significant dietary changes.

What are Oxalates?

Oxalates, or oxalic acid, are naturally occurring compounds found in many plants, including fruits, vegetables, nuts, and teas. When consumed, oxalates can bind to minerals like calcium in the gut, potentially reducing their absorption. In most healthy people, the body can process and excrete excess oxalates. However, for some sensitive individuals, particularly those with a history of kidney stones or certain gut disorders, high oxalate intake can be problematic. Calcium oxalate is the most common type of kidney stone, and dietary oxalate intake is a known risk factor for stone formation. For this reason, a low-oxalate diet is often recommended for susceptible people, making it important to scrutinize not only foods but also beverages like herbal teas.

Herbal Teas to Approach with Caution

While many popular herbal infusions are low in oxalates, the overall content can increase significantly when high-oxalate ingredients are included in the blend. The preparation method and the specific parts of the plant used also play a critical role. Below are some herbal teas and ingredients to be cautious of if you are on a low-oxalate diet.

Blends with High-Oxalate Fruits

Many commercially available herbal teas are flavored with dried fruits and berries, which can elevate the oxalate count. The following are common high-oxalate inclusions:

• Berries: Dried berries such as raspberries, blueberries, and strawberries are often used for flavor but are high in oxalates.
• Citrus Peels: Teas containing dried orange or lemon peels can contribute to the overall oxalate load.
• Ginger: This common tea ingredient is also known to contain moderate to high levels of oxalates.
• Black Currants: Similar to other berries, black currants are a high-oxalate fruit used in some herbal tea blends.

Specific High-Oxalate Herbs

Certain herbs used in standalone teas or blends also carry higher oxalate risks:

• Stinging Nettle (Urtica dioica): Older nettle leaves, especially after flowering, contain higher levels of calcium oxalate crystals that can irritate the kidneys. One study on stinging nettle found significantly higher oxalate levels compared to most other foods.
• Dandelion (Taraxacum officinale): While some sources suggest it's low in oxalates, a case study found high doses of dandelion tea caused hyperoxalemia (excess oxalate in the blood) in a patient with kidney disease. This suggests caution, especially with large amounts or for those with kidney issues.
• Purslane (Portulaca oleracea): This green, sometimes used in infusions, is extremely high in oxalates and should be avoided in teas by at-risk individuals.
• Chinese Medicinal Herbs: A study on Chinese herbs found some, like Houttuynia cordata and Nelumbo nucifera leaves, contained very high oxalate levels.

Comparison of Oxalate Content in Herbal Teas

Herbal Tea Type	Typical Soluble Oxalate (mg/cup)*	Notes
Rooibos	0.55 - 1.06	Naturally very low in oxalates. Good alternative.
Chamomile	0.4 - 0.67	Very low oxalate content, generally considered safe.
Peppermint	0.41	Very low oxalate content.
Hibiscus	0.27 (with Rosehip)	Relatively low, but content can vary between species.
Dandelion	Varies, caution with high dose	Oxalate content is variable and may be higher in certain preparations; use with caution.
Stinging Nettle	Potentially High	Older leaves and higher doses carry significant oxalate risk for sensitive individuals.
Fruit Blends	Potentially High	Depends heavily on ingredients like berries and citrus peel.

Note: Oxalate levels can vary based on brewing time, plant part, and other factors.

Managing Oxalate Intake from Tea

If you are sensitive to oxalates but still want to enjoy herbal tea, a few strategies can help mitigate the risk:

• Check the Ingredients: Always read the ingredients list on commercially prepared tea blends to identify high-oxalate additives like berries, nuts, or citrus peel.
• Choose Wisely: Opt for known low-oxalate herbal teas such as rooibos, chamomile, peppermint, and ginger, but be aware that ginger itself can have moderate levels. Rooibos and honeybush are particularly safe options.
• Shorten Steeping Time: The longer you steep a tea, the more oxalates are extracted into the water. Shorter infusion times can reduce the oxalate concentration in your cup.
• Add Calcium: Consuming a source of calcium, such as adding milk or a calcium-rich food to your meal, can help bind oxalates in the digestive tract, preventing their absorption.
• Stay Hydrated: Drinking plenty of water is essential for flushing oxalates from your kidneys and reducing the risk of stone formation, regardless of your tea choice.
• Moderate Consumption: Even with low-oxalate options, excessive consumption could potentially accumulate enough oxalates to cause issues for susceptible individuals. Practice moderation.

Conclusion

While the vast majority of pure herbal teas are considered low in oxalates and safe for most people, some specific herbs and many commercially prepared blends contain significant levels. Individuals with a history of kidney stones or other oxalate sensitivities should exercise caution with teas containing ingredients like berries, citrus peel, nuts, or mature nettle and dandelion leaves. By understanding the oxalate content of your favorite herbal infusions and adopting smart consumption habits, you can continue to enjoy the health benefits of tea while effectively managing your dietary oxalate intake. For personalized advice, particularly concerning underlying health conditions like hyperoxaluria, consulting a healthcare professional is always recommended.

Important

For more information on hyperoxaluria and its management, you can refer to the resources provided by the Cleveland Clinic.

A Note on Matcha

Matcha, a green tea powder, is a noteworthy exception. Because you consume the entire ground tea leaf, matcha has a higher oxalate content than brewed green tea. Those avoiding oxalates should limit or avoid matcha.

The Broader Picture

It's important to remember that herbal teas are just one small part of a person's overall dietary oxalate load. Many common vegetables like spinach and rhubarb contain far higher concentrations. A balanced and varied diet, along with good hydration, is the best strategy for managing oxalate intake.

Choosing High-Quality Tea

Selecting high-quality, pure herbal teas and avoiding excessive use of blended products can significantly lower your oxalate risk. Single-ingredient teas from known low-oxalate herbs are the safest bet.

Boiling May Help

Some research suggests that boiling and then discarding the water can reduce the oxalate content of certain high-oxalate vegetables. While this is less practical for steeping tea, it highlights the solubility of oxalates and why shorter steeping times can reduce content.

Oxalate-Busting Gut Bacteria

The presence of certain gut bacteria, like Oxalobacter formigenes, can help break down oxalates in the digestive system. Maintaining a healthy gut microbiome through diet may therefore play a role in managing oxalate levels.

Frequently Asked Questions

Is hibiscus tea high in oxalates?

Hibiscus tea is relatively low in oxalates compared to true teas, though its content can vary by species. Some studies even suggest it may help decrease oxalate retention in the body, but moderation is advised for those with kidney issues.

Which herbal tea is lowest in oxalates?

Herbal teas like peppermint, chamomile, and rooibos are known to be very low in oxalates. Ginseng tea has also been reported to have undetectable levels of oxalates.

Can drinking herbal tea cause kidney stones?

While most pure herbal teas are not a concern, drinking large quantities of high-oxalate teas can contribute to kidney stone formation in susceptible individuals. Dietary hyperoxaluria, caused by eating foods high in oxalates, is a recognized risk.

Does steeping time affect the oxalate content in tea?

Yes, longer steeping times generally lead to a greater extraction of soluble oxalates into the water. Using shorter steeping times can help minimize the oxalate content in your cup.

How can I reduce the oxalate content of my tea?

To reduce oxalate content, choose low-oxalate teas like rooibos or chamomile, steep for a shorter duration, and consider adding milk or a calcium supplement to bind the oxalates.

Is dandelion tea safe for people with kidney problems?

Dandelion tea's safety depends on the individual's condition and dosage. A case report linked high-dose dandelion tea to hyperoxalemia in a patient with end-stage renal disease. Individuals with kidney issues should consult a doctor before consuming dandelion tea.

Are all herbal teas low in oxalates?

No, not all herbal teas are low in oxalates. The content varies widely depending on the ingredients. While pure herb infusions like peppermint are low, blends with high-oxalate fruits like berries or citrus peel can be much higher.