Common Varieties of Clover and Their Risks
Not all clover is the same, and the risks associated with drinking it vary by species. Red clover (Trifolium pratense) is the most commonly used variety for herbal preparations, but other types, like sweet clover (Melilotus spp.) and alsike clover (Trifolium hybridum), carry unique dangers.
Red Clover (Trifolium pratense)
Red clover is widely recognized for its high concentration of isoflavones, a type of phytoestrogen.
- Hormonal Effects: The estrogen-like compounds in red clover can cause hormonal fluctuations. For some, this may result in vaginal spotting, prolonged menstrual periods, or breast tenderness.
- Digestive Issues: Some users have reported experiencing nausea, upset stomach, or bloating after consuming red clover tea or supplements.
- Headaches and Skin Irritation: Headaches and skin rashes are other potential side effects, although they are considered rare.
Sweet Clover (Melilotus spp.)
Sweet clover is primarily a concern when it becomes moldy. Under damp conditions, a substance called coumarin converts into dicoumarol, a potent anticoagulant.
- Increased Bleeding Risk: Dicoumarol is a blood-thinning agent that can lead to severe internal bleeding. While this is a well-documented risk in livestock, particularly from moldy hay, it underscores the importance of sourcing herbal products from trusted, safe suppliers.
- Unsafe for Humans: Because of this toxicity risk, spoiled sweet clover is not safe for human consumption in tea or other forms.
Alsike Clover (Trifolium hybridum)
Alsike clover is primarily a known toxin for animals, especially horses.
- Liver Damage: Long-term consumption of Alsike clover has been linked to liver damage and liver failure in livestock.
- Photosensitivity: It can also cause photosensitization, a condition where the skin becomes highly sensitive to sunlight, leading to inflammation and lesions.
Who Should Avoid Drinking Clover?
Due to its various active compounds and potential side effects, certain individuals should avoid or be extremely cautious when consuming clover.
- Pregnant and Breastfeeding Women: Because red clover contains phytoestrogens that can affect hormone levels, it is not recommended during pregnancy or breastfeeding.
- Individuals with Hormone-Sensitive Conditions: People with conditions like breast cancer, ovarian cancer, uterine cancer, endometriosis, or uterine fibroids should not use red clover, as its estrogenic effects could worsen these issues.
- Those on Blood-Thinning Medication: Red clover has mild blood-thinning properties and can increase the risk of bleeding, especially when combined with anticoagulant drugs like warfarin.
- Individuals Awaiting Surgery: To prevent excessive bleeding, it is advised to stop taking red clover at least two weeks before any scheduled surgery.
- People with Liver Issues: While primarily a risk in animals from alsike clover, anyone with pre-existing liver conditions should consult a doctor before consuming any type of clover.
Comparison of Clover Varieties
| Feature | Red Clover (Trifolium pratense) | Sweet Clover (Melilotus spp.) | Alsike Clover (Trifolium hybridum) |
|---|---|---|---|
| Primary Active Compounds | Isoflavones (Phytoestrogens) | Coumarin (Converts to dicoumarol in moldy hay) | Unknown toxins (Likely from fungal contamination) |
| Main Health Concern | Hormonal effects, mild side effects | Severe bleeding risk from dicoumarol | Liver damage and photosensitivity (primarily in livestock) |
| Common Side Effects | Nausea, headaches, vaginal spotting | Internal bleeding, hemorrhaging | Skin photosensitivity, liver failure |
| Main Caution | Hormone-sensitive conditions, pregnancy, medications | Ingesting moldy hay; not for human use | Highly toxic to horses; avoid consumption |
Potential Drug Interactions
Beyond specific pre-existing conditions, drinking clover can pose risks through interactions with various medications. The phytoestrogens in red clover can affect how the liver processes certain drugs, while its blood-thinning properties require extra caution with other medications.
- Tamoxifen: Red clover may interfere with this breast cancer medication, potentially decreasing its effectiveness.
- Methotrexate: There have been reports of methotrexate toxicity in patients also taking red clover.
- Hormonal Birth Control and HRT: The estrogen-like effects of red clover can interfere with hormonal contraception and hormone replacement therapy.
- Liver-Metabolized Drugs: Red clover can alter the rate at which the liver breaks down various medications, changing their effects and potential side effects.
The Risks of Foraging for Wild Clover
Foraging for wild clover to make tea or other remedies carries additional risks. Besides the potential for misidentification of toxic species, wild plants can be contaminated with harmful substances.
- Pesticide Contamination: Clover growing in urban or treated areas, such as lawns and parks, may contain pesticides and herbicides that are dangerous if ingested.
- Incorrect Species: Mistaking one species of clover for another can be dangerous. Sweet clover, for example, is toxic when moldy, and alsike clover is a known hepatotoxin for animals.
Conclusion
While clover is celebrated in some traditional medicine circles, it is crucial to approach its consumption with caution due to the notable side effects and risks, particularly from red clover's phytoestrogen content and the toxic potential of other varieties. Common side effects range from mild digestive upset to more serious issues like hormonal interference and increased bleeding risk. Furthermore, certain populations, including pregnant women and individuals with hormone-sensitive cancers, should avoid it entirely. Before considering drinking clover, consult with a healthcare professional, especially if you are taking other medications or have pre-existing health conditions, to ensure your safety.
