Nasturtiums (Tropaeolum majus) are widely appreciated for their vibrant, peppery leaves and flowers, which are often used in salads and herbal remedies. However, like many herbal plants, they are not without potential downsides. The presence of glucosinolates, which produce mustard oil (benzyl isothiocyanate) when the plant is crushed or chewed, is the primary reason behind both its pungent flavor and its potential for causing side effects.
Gastrointestinal Discomfort
One of the most common side effects reported from ingesting large amounts of nasturtiums is gastrointestinal discomfort. The peppery compounds, specifically the mustard oils, can be irritant to the lining of the stomach and intestinal tract. This irritation is particularly pronounced with excessive consumption of the fresh leaves.
- Symptoms: Symptoms can range from mild indigestion to a more noticeable upset stomach. This can include stomach pain, nausea, and potentially vomiting or diarrhea, as the body attempts to expel the irritant.
- Severity: The severity of gastrointestinal upset is often dose-dependent. Small quantities used as a garnish are unlikely to cause issues for most healthy adults, but a large portion or daily intake over an extended period could lead to problems.
Skin Irritation and Allergic Reactions
For some individuals, especially those with sensitive skin, contact with nasturtium can lead to allergic contact dermatitis. This is due to the mustard oil contained within the plant.
- Dermatitis: The condition typically presents as a red, itchy rash on the skin, particularly on the hands of gardeners who handle the plant frequently.
- Precautions: Wearing gloves while harvesting or handling nasturtiums can prevent this reaction in sensitive individuals. Those with known allergies to mustard or other related plants should be particularly cautious.
Contraindications for Pre-existing Health Conditions
Certain pre-existing health conditions make nasturtium use unsafe, whether for culinary or medicinal purposes. Individuals with these issues should avoid nasturtiums entirely.
- Kidney Disease: High consumption of nasturtium can lead to kidney irritation and damage, and those with existing kidney disease should not consume it.
- Stomach and Intestinal Ulcers: The irritating nature of the mustard oils can aggravate ulcers and worsen the condition.
Special Considerations for Vulnerable Groups
Certain populations should exercise extreme caution or avoid nasturtiums completely due to insufficient safety information or known risks.
- Pregnancy and Breastfeeding: There is not enough reliable information regarding the safety of nasturtium during pregnancy and breastfeeding. Herbalists and doctors recommend avoiding its use during these periods to stay safe.
- Children: Nasturtium is considered unsafe for young children when taken orally. Their smaller body mass and less developed digestive systems make them more susceptible to its irritating effects.
Comparison of Nasturtium Side Effects
| Side Effect | Cause | Severity | Who Is at Risk? |
|---|---|---|---|
| Gastrointestinal Irritation | Mustard oil, overconsumption | Mild to Moderate | Individuals with a sensitive stomach, high consumption |
| Allergic Dermatitis | Allergic reaction to mustard oil | Mild to Moderate | Individuals with skin sensitivities or known allergies |
| Kidney Irritation | Mustard oil compounds, large amounts | Potentially Severe | Those with pre-existing kidney disease |
| Ulcer Aggravation | Irritating compounds in the plant | Potentially Severe | Those with stomach or intestinal ulcers |
Navigating Nasturtium Usage Safely
For most healthy adults, consuming nasturtiums in moderation as a garnish is unlikely to cause adverse effects. Here are some tips for safe usage:
- Start Small: If you've never had nasturtium before, start with a small amount to see how your body reacts. This is particularly important for raw consumption.
- Moderation is Key: Use nasturtiums as a complementary ingredient rather than a main component of a dish. Overconsumption is the primary driver of most side effects.
- Be Aware of Cross-Contamination: Always ensure your edible flowers are organic and have not been sprayed with pesticides or herbicides. Roadside flowers, in particular, can absorb pollutants.
- Consider Cooking: Cooking nasturtium leaves can help to break down some of the compounds responsible for irritation, making them potentially gentler on the digestive system. However, this may also diminish some of the flavor.
- Identify Correctly: Only consume plants you are 100% certain are nasturtiums. Misidentification can lead to severe and dangerous consequences.
Conclusion
While the vibrant nasturtium is a popular edible flower, understanding its potential side effects is vital for safe consumption. The main risks are gastrointestinal irritation from overconsumption and allergic skin reactions from handling, both linked to the plant's mustard oil content. Severe contraindications exist for those with kidney disease, ulcers, and for pregnant or breastfeeding women. By practicing moderation, proper identification, and consulting a healthcare provider if you have underlying conditions, you can minimize risk while still enjoying this peppery plant. For those seeking alternatives, other edible flowers like marigolds offer a different flavor profile with distinct safety considerations.
Outbound Link: For general guidance on identifying safe, edible flowers, a resource from a trusted horticultural society can be invaluable. The Royal Horticultural Society provides detailed information on edible flowers.
