Milk thistle is a plant native to Europe. It was introduced to North America by early settlers. Like chamomile and echinacea, it belongs to the Asteraceae family. Milk thistle is also known as silymarin, the active ingredient and powerful antioxidant found in its seeds and sap. Regarding its medicinal properties, milk thistle may notably protect the liver (see Gamma Force Liver Formula and ATP Lab's Hepatik Defense) against certain diseases and the harmful effects of alcohol. It is also said to potentially improve blood sugar control in people with diabetes. Let’s explore what research suggests about the effects of this dietary supplement on health.
Milk thistle and the liver
A systematic review with meta-analysis published in 2017 evaluated the effect of silymarin on various biochemical markers in individuals with liver diseases. Different liver problems (e.g., cirrhosis) can increase blood levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (γGT), the three biochemical markers used in this study. The meta-analysis results indicate a significant but clinically irrelevant reduction in ALT and AST levels after silymarin use. In contrast, the results show no significant change in γGT levels. Subgroup analyses show no significant difference based on the type of intervention, duration of intervention (≥ 6 months or < 6 months), or whether silymarin was isolated or combined with other nutrients. Moreover, the evaluated studies present a high degree of heterogeneity and low methodological quality. In conclusion, the results of this meta-analysis suggest that silymarin minimally reduces, but without clinical relevance, ALT and AST levels in individuals with non-alcoholic fatty liver disease, a liver condition that can cause cirrhosis at an advanced stage. However, studies with higher methodological quality are needed to confirm these observations.
Milk thistle and type 2 diabetes
A systematic review and meta-analysis published in 2018 evaluated the effects of silymarin supplementation in individuals with type 2 diabetes. Seven studies including a total of 370 participants were included in the meta-analysis. The meta-analysis results show that silymarin supplementation can decrease fasting blood glucose, hemoglobin A1C, insulin, and LDL cholesterol (the “bad” cholesterol) and increase HDL cholesterol (the “good” cholesterol). However, the results show no significant effect of silymarin on total cholesterol or triglycerides. In conclusion, the data from this study suggest that silymarin supplements have beneficial effects in patients with type 2 diabetes. However, current evidence is insufficient, and more studies are needed to confirm silymarin’s effectiveness.
Possible side effects of milk thistle
No serious adverse effects have been reported. Digestive side effects have sometimes been reported. Finally, consumption of the aerial parts (above ground) of milk thistle is not recommended for women with hormone-related diseases, such as breast cancer and endometriosis.
Possible interactions of milk thistle with medications
Milk thistle may interact with medications used to lower blood sugar levels and those used to treat HIV.
References
- https://www.merckmanuals.com/fr-ca/professional/sujets-sp%C3%A9ciaux/compl%C3%A9ments-alimentaires/chardon-marie
- https://www.merckmanuals.com/fr-ca/accueil/sujets-particuliers/compl%C3%A9ments-alimentaires/chardon- marie?query=Chardon%20Marie
- https://www.nccih.nih.gov/health/milk-thistle
- https://www.groupeproxim.ca/fr/article/laboratoires/aspartate-aminotransferase-ast
- https://www.groupeproxim.ca/fr/article/laboratoires/alanine-aminotransferase-alt
- https://labtestsonline.org/tests/gamma-glutamyl-transferase-ggt
- https://www.merckmanuals.com/fr-ca/professional/troubles-h%C3%A9patiques-et-biliaires/prise-en-charge-du-patient-pr%C3%A9sentant-une- h%C3%A9patopathie/st%C3%A9atose-h%C3%A9patique-non-alcoolique
- Hadi, A., Pourmasoumi, M., Mohammadi, H., Symonds, M., & Miraghajani, M. (2018). The effects of silymarin supplementation on metabolic status and oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta- analysis of clinical trials. Complementary therapies in medicine, 41, 311–319. https://doi.org/10.1016/j.ctim.2018.08.010
- de Avelar, C. R., Pereira, E. M., de Farias Costa, P. R., de Jesus, R. P., & de Oliveira, L. (2017). Effect of silymarin on biochemical indicators in patients with liver disease: Systematic review with meta-analysis.World journal of gastroenterology, 23(27), 5004–5017. https://doi.org/10.3748/wjg.v23.i27.5004