General Safety Profile of Ashitaba
Based on current research, the toxicity of ashitaba, also known as Angelica keiskei, is generally considered low, especially at doses typical for dietary supplements. The plant's long history of use as both a vegetable and traditional medicine in Japan and other Asian countries supports its overall safety when consumed in moderation. The primary bioactive compounds, including flavonoid chalcones like xanthoangelol and 4-hydroxyderricin, have been the focus of modern toxicological studies.
In a 2017 review, an acute oral toxicity study in rats showed no adverse clinical signs after a single high dose of 2000 mg/kg. Furthermore, genotoxicity studies using bacterial reverse mutation and chromosome aberration assays found no evidence of genetic damage, though some cytotoxicity was observed at very high concentrations in laboratory settings. These findings suggest that ashitaba is not inherently harmful from a genotoxic perspective.
The European Food Safety Authority (EFSA) also conducted a safety assessment on ashitaba sap powder for use in food supplements. Their panel determined a safe dose of 137 mg per day for adults, based on a No-Observed-Adverse-Effect Level (NOAEL) found in a 90-day rat study. This assessment reinforces the safety of regulated ashitaba products at appropriate doses.
Potential Toxicological Effects from Animal Studies
While ashitaba has a low toxicity profile, animal studies have identified some potential dose-dependent effects, primarily at very high intake levels far exceeding standard human consumption:
- Nephropathy: A dose-related alpha 2-urinary globulin nephropathy was observed in male rats during a 90-day study, though it was considered a male-specific rodent pathology and not a major toxicological concern for humans.
- Jejunal Lymphangiectasia: High-dose (1000 mg/kg/day) rats in the same 90-day study showed dilated lacteals in the jejunum, a minor finding in both sexes.
- Hematological and Lipid Changes: Elevated doses also led to decreased platelet counts and increased coagulation indices (PT and APTT) in male and female rats. This is an expected pharmacological effect due to the antithrombotic properties of ashitaba's chalcones. Increases in serum alkaline phosphatase, cholesterol, and triglycerides were also observed at the highest doses.
Contraindications and Significant Interactions
Several precautions and potential interactions should be considered before using ashitaba, especially in supplement form.
Contraindicated Populations
- Pregnancy and Breastfeeding: There is insufficient data to determine the safety of ashitaba for pregnant or breastfeeding women. It is strongly advised to avoid its use during these periods.
- Hypersensitivity: Individuals with known allergies to ashitaba or other plants in the Angelica family should avoid it.
- Children: There is a lack of data on the use and dosing of ashitaba for children, so it is not recommended for this population.
Drug Interaction Risks
- Blood Thinners: Ashitaba chalcones have demonstrated anti-platelet and antithrombotic properties. This increases the risk of bleeding in individuals taking blood-thinning medications like warfarin, aspirin, or clopidogrel.
- Diabetes Medications: Due to its potential to affect blood sugar and improve insulin sensitivity, ashitaba could cause hypoglycemia (low blood sugar) when combined with diabetes drugs.
- Liver-Metabolized Drugs: Ashitaba may interfere with the liver's cytochrome P450 enzyme system, which is responsible for metabolizing many medications. This could alter drug levels in the body, increasing the effects and side effects of other medications.
Side Effects and Considerations
While generally well-tolerated, some individuals may experience side effects, particularly with higher doses or extended use. These can include:
- Gastrointestinal Discomfort: Some users report stomach upset or other digestive issues.
- Hypoglycemia: As noted under drug interactions, ashitaba's blood sugar-lowering effects can be a side effect, especially for those with low blood sugar levels or taking diabetes medication.
- Photosensitivity: As with other members of the Angelica genus, ashitaba contains furanocoumarins, which can increase photosensitivity in some people, leading to skin reactions upon sun exposure.
Comparison of Ashitaba Safety Considerations
| Parameter | Normal Dietary Use | Therapeutic Supplement Use | High/Excessive Doses (Animal Studies) |
|---|---|---|---|
| Genotoxicity | Not genotoxic | Not genotoxic | Minor cytotoxicity at highest lab concentrations |
| Overall Toxicity | Low | Considered possibly safe short-term | Potential dose-related effects |
| Coagulation | Expected pharmacological effect | Increases bleeding risk with blood thinners | Decreased platelet counts |
| Metabolic Effects | Generally safe | Potential for hypoglycemia | Altered lipid metabolism |
| Gastrointestinal | Well-tolerated | Possible discomfort | Jejunal lymphangiectasia observed |
| Liver Effects | No adverse effects reported | Possible interactions with liver-metabolized drugs | Altered enzymes and lipid vacuolation observed |
Conclusion
Ashitaba has a long history of use as a food and traditional medicine with a favorable safety profile at normal dietary intake levels. However, its use as a concentrated supplement warrants caution, as potential side effects like hypoglycemia and gastrointestinal discomfort can occur. The most significant safety concerns arise from its interactions with conventional medications, particularly blood thinners and drugs metabolized by the liver. Due to insufficient data, pregnant and breastfeeding women, along with children, should avoid its use. As with any supplement, consulting a healthcare provider before use is recommended to ensure it is appropriate for your individual health circumstances. For more in-depth scientific data on ashitaba's chalcone toxicity, refer to this toxicological assessment.
