The kidneys, part of the body's urinary system, are important eliminatory organs---they help clean the body of wastes and toxins. They also regulate the amount of body fluids, which has an effect on blood pressure and heart health. Problems involving the kidneys include stones, infection and cancer.
Herbs are a natural way to improve kidney function and keep the kidneys in optimal health. Herbs' actions may be tonic, antiseptic or antilithic. It is important to consult a health care professional before starting herbal therapy for kidney function and to follow recommended doses.
Bearberry
Bearberry, or Arctostaphylos uva-ursi, is an evergreen shrub with glossy leaves and red berries. Traditional healers used the leaves as an antiseptic to treat diseases of the bladder and kidneys. It was also used as a tonic to strengthen the whole urinary system, and some commercial products include it in teas for kidney and bladder health. The active ingredient is a glycoside called arbutin, which converts to hydroquinone in the body and has an antibacterial, antifungal and astringent effect. Herbalist David Hoffmann states that bearberry soothes and strengthens the tissues of the urinary system, and he recommends it for kidney stones or ulceration. Studies are needed to support the traditional use of bearberry as a kidney-specific herb.
Nasturtium and Watercress
Nasturtium, or Tropaeolum majus, is a perennial climber native to Peru with deep yellow or orange trumpet-shaped flowers. Watercress, or Nasturtium officinale, is a perennial with tiny white flowers. The leaves of both plants are used as salad food and in herbal medicine to treat urinary tract, respiratory and fungal infections. In their 2009 book, "Medicinal Plants of the World," Ben-Erik van Wyk and Michael Wink state that folk healers use watercress as a diuretic and spring tonic.
A research study conducted in Turkey by Dr. Tevfik Ozen and published in the March 2009 issue of "Acta Poloniae Pharmaceutica" tested extracts of watercress leaf for their antioxidant effects on kidney, brain and liver cells. The study found that the extract significantly inhibited free-radical damage in all cells, but the highest inhibition rate was in kidney cells: 71.80 to 97.06 percent. This action was most likely due to the plant's phenolic compounds. Further studies are needed to confirm these results and determine the efficacy of nasturtium and watercress on humans.
Cranberry
Cranberry, or Vaccinium oxycoccos, is a creeping evergreen found in bogs throughout northern climates. The fruit is a traditional remedy for urinary tract and kidney disorders. It also prevents infection, according to Ben-Erik van Wyk and Michael Wink. This is supported by a study conducted by C. H. Han and colleagues in Korea and published in the November 2007 issue of "BJU International," which found that the juice had an anti-inflammatory effect and may prevent kidney damage from bacterial infection. Cranberries may also prevent the formation of kidney stones, according to a study conducted by T. McHarg, et al, from South Africa and published in the November 2003 issue of "BJU International." In this random clinical trial, 20 South African students drank a mixture of cranberry juice and water for two weeks, and a control group drank just water. The study found significant changes in the urinary analysis of the treated group. Cranberry juice decreased the amount of oxalate the kidneys excreted into the urine, thereby reducing the amount of calcium oxalate crystals, one of the major causes of kidney stones. The researchers concluded that cranberry can prevent kidney stones, but since this was a small study, more research is needed to confirm these findings.
References
- "Medical Herbalism: The Science and Practice of Herbal Medicine"; David Hoffmann; 2003
- "Acta Poloniae Pharmaceutica"; Investigation of Antioxidant Properties of Nasturtium Officinale (Watercress) Leaf Extracts; Ozen Tevfki; March 2009
- "BJU International"; Protective Effects of Cranberries on Infection-induced Oxidative Renal Damage in a Rabbit Model of Vesico-ureteric Reflux; CH Han, SH Kim, SH Kang, OR Shin, HK Lee, HJ Kim, YH Cho; November 2007
- "BJU International"; Influence of Cranberry Juice on the Urinary Risk Factors for Calcium Oxalate Kidney Stone Formation; T McHarg, A Rodgers, K Charlton; November 2003
