Does Milk Thistle Help the Kidneys?

Milk thistle, a member of the daisy family, is native to parts of Europe, Africa and the Middle East. Documented use of milk thistle as a remedy for liver ailments goes back to the first century, according to the website Herbal Legacy. Recent research has proven beneficial health effects of milk thistle for the kidneys, as well as for the liver. Consult with a qualified medical professional before using milk thistle.

Damaging effects of drugs on kidney cells are lessened or avoided with the help of milk thistle, according to a German study published in the September 1999 "Journal of Pharmacology and Experimental Therapeutics." In the study, silibinin, an extract of milk thistle was added to kidney cells of primates before or after exposing the cells to three different drugs known for their kidney toxicity and results showed both protective and restorative benefits of the milk thistle extract.

Milk thistle protected against diabetic nephropathy -- a complication of diabetes in which the filtering ability of the kidneys is impaired -- in laboratory rats in an Iranian study, published in the July 2010 "Renal Failure." The study reported that milk thistle increased activity levels of the enzymes catalase and glutathione peroxidase, which protect kidney cells.

In addition to its well known liver-protective effects, milk thistle was found to have anticancer and cancer preventive effects on the the kidneys, according to a Czech Republic study published in the 2007 "Current Medicinal Chemistry." The ability of milk thistle to scavenge free radicals is well established, however, new information on the activities of silybin -- an active constituent of milk thistle -- has emerged that show the compound manipulates cells. For example, silybin activates receptors on the surfaces of cancer cells that induce apoptosis -- programmed cell death -- in those cells.

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Milk thistle protected mice from kidney cancer in an Indian study published in the October 2010 "Investigational New Drugs." Diets containing 0.5 percent and 1 percent silymarin provided significant protection against oxidative stress and inflammation induced by a potent kidney toxin and carcinogen, ferric nitrilotriacetate. Silymarin also restored antioxidant status that was depleted by the toxin and suppressed precancerous activity in kidney cells.

Kidney damage from the chemotherapy drug cisplatin is decreased when the drug is used in combination with milk thistle, according to an Iranian study on rats published in the September 2005 "Evidence Based Complementary and Alternative Medicine." Supplementation with milk thistle extract prior to administration of cisplatin effectively prevented kidney damage, according to the study. When milk thistle extract was administered 2 hours after cisplatin therapy mild to moderate damage to kidney cells occurred and blood markers of kidney function showed better levels of kidney function in the milk thistle group than in the group that received only cisplatin.

Interaction of milk thistle with the drug warfarin in a U.S. study led researchers to caution against the use of milk thistle by patients who take the blood thinning drug. The study, published in the March 2010 "Journal of Pharmacology and Experimental Therapeutics," found that two components of milk thistle, silymarin and silibinin, inhibited warfarin. The researchers noted that the effect occurred at realistically achievable doses.