Is Houttuynia cordata poisonous? Will it harm the kidneys?

Houttuynia cordata, commonly known as fish mint or chameleon plant, has been a subject of debate in recent years due to concerns about its potential toxicity. This article delves into the scientific evidence surrounding this plant and its effects on human health, particularly focusing on kidney function.

What is Houttuynia cordata?

Before we dive into the potential risks, let’s briefly introduce our subject. Houttuynia cordata is an herb native to Southeast Asia, often used in traditional medicine and as a culinary ingredient. Its distinctive fishy odor gives it the nickname “fish mint.”

Warning: For those who want to try it, the taste of this herb can be disastrous for some people.

The controversy: Is Houttuynia cordata poisonous?

The short answer is: yes, Houttuynia cordata can be potentially harmful, particularly to the kidneys. But as with many things in life, the devil is in the details.

The culprit: Aristolochic acid and aristolactam

The main concern with Houttuynia cordata stems from its content of aristolochic acid and its derivative, aristolactam¹. These compounds have been linked to serious health issues, including:

1. Kidney damage
2. Urinary tract cancer

It’s worth noting that the toxicity of these compounds is not a matter of immediate poisoning, but rather a slow, cumulative effect over time²³.

The dose makes the poison… or does it?

You might have heard the phrase “the dose makes the poison.” While this is generally true for many substances, aristolochic acid and aristolactam are particularly tricky customers.

No safe dose

Here’s the kicker: there’s no known safe dose for aristolochic acid. Why? Two main reasons:

1. Accumulation: The body doesn’t have an effective way to metabolize and excrete these compounds. They tend to build up over time, forming stable DNA adducts in the kidneys.
2. Irreversible damage: The kidney damage caused by these compounds, particularly interstitial fibrosis, is virtually irreversible⁴.

A hidden threat

Kidneys are remarkable organs with a significant reserve capacity. This means that damage can accumulate silently for years before symptoms become apparent. By the time kidney problems are noticeable, it’s often too late for conventional treatments to be effective⁵.

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How much is too much?

While we can’t pinpoint a “safe” dose, studies have shown concerning levels of these compounds in Houttuynia cordata. Dry weight samples have been found to contain about 16 mg/kg of aristolactam.

To put this in perspective, let’s look at a related case:

A 17-year-old male developed proximal renal tubular damage after taking just three packages of a traditional medicine containing 3-14 mg of aristolochic acid per package.

While this isn’t a controlled study, it gives us a ballpark idea of how little it might take to cause harm.

Beyond kidney damage: Cancer risk

As if kidney damage wasn’t concerning enough, aristolochic acid is classified as a Group 1 carcinogen by the International Agency for Research on Cancer⁶. This means it’s known to cause cancer in humans.

Patients with kidney disease related to aristolochic acid exposure have an unusually high rate of urinary tract cancer. This adds another layer of risk to long-term consumption of plants containing these compounds.

What about other medicines with side effects?

Some might argue that many pharmaceuticals have side effects, so why single out Houttuynia cordata? The key difference lies in transparency and informed consent.

Reputable medications come with clear warnings about potential side effects, allowing patients and healthcare providers to make informed decisions. The problem arises when natural remedies are marketed as “pure and side-effect free” without acknowledging known risks.

The bottom line

While Houttuynia cordata has a long history of use in traditional medicine and cuisine, modern research has unveiled potential risks that can’t be ignored. The presence of aristolochic acid and aristolactam raises serious concerns about long-term kidney health and cancer risk.

This doesn’t mean we need to panic or call for an outright ban. However, it does underscore the importance of:

1. Being aware of the potential risks
2. Using caution with long-term or high-dose consumption
3. Considering regular kidney function checks if you’re a frequent consumer

Remember, natural doesn’t always mean safe. When it comes to your health, it’s always best to stay informed and consult with healthcare professionals.

1. Yu X, Gao Y, Xu Y, et al. Study of the contents of analogues of aristolochic acid in Houttuynia cordata by ultra-high performance liquid chromatography tandem mass spectrometry[J]. Foods, 2022, 11(3): 302. https://www.mdpi.com/2304-8158/11/3/302 ↩︎
2. 马兜铃酸I和马兜铃内酰胺I对大鼠肾小管损伤机制及其对肾脏水通道蛋白1表达的影响 https://www.cnki.com.cn/Article/CJFDTotal-ZYXY201104002.htm ↩︎
3. 服用含马兜铃酸成分药物对尿毒症透析患者伴发尿路移行细胞癌的影响 https://www.cnki.com.cn/Article/CJFDTOTAL-ZHYX200535016.htm ↩︎
4. Han J, Xian Z, Zhang Y, Liu J, Liang A. Systematic Overview of Aristolochic Acids: Nephrotoxicity, Carcinogenicity, and Underlying Mechanisms. Front Pharmacol. 2019 Jun 11;10:648. doi: 10.3389/fphar.2019.00648. PMID: 31244661; PMCID: PMC6580798. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6580798/ ↩︎
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10695617/ ↩︎
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8284306/ ↩︎