Patients with chronic kidney disease are looking for a way to boost kidney function, and those with late-stage kidney disease hope to stave off the need for dialysis or a transplant. Even healthy individuals who wish to improve their kidneys look to herbal diuretics sold as detox products, to temporarily boost kidney output. Although various interventions can help improve the efficiency of the kidneys, one of the best and often overlooked strategies to help the kidneys is pushing detoxification through the skin.
If the kidneys work at all, the kidneys work hard. Damage to the kidneys is often not apparent until the patient is in an advanced state of disease. With approximately 1 million nephrons each, the kidneys can compensate for damage to the parenchymal tissue. The remaining functioning nephrons simply work harder to keep up with the demands of the body. This state of hyperfiltration can go on for years with no overt signs of kidney trouble. It is only when the kidneys reach a breaking point, where they cannot work any harder, that the creatinine starts to rise and the body becomes uremic. Patients often attribute a sudden shift in their lab work to causes from the recent past, but generally it is the day-to-day stress on the kidneys that occurs over the course of years that sets the stage for compromised function.
The uremic products most often considered are creatinine, BUN, and uric acid. However, currently 4054 metabolic waste products have been identified in urine. The Canadian government has sponsored the Human Urine Metabolome Database, which is yielding new insights into the chemical composition of urine as well as what urine compounds are associated with specific disease states.1
These uremic waste products also come through the skin. Skin lesions are often the first sign of systemic disease with renal involvement, such as amyloidosis and porphyria.2 Patients who suffer severe burns over large portions of the body often experience kidney failure. The waste products that were once eliminated through the skin now must be processed through the kidneys. This extra burden has the potential to overwhelm the kidneys. But it also shows the reciprocal relationship between the skin and the kidneys, and how these detox systems complement each other.3
If one encounters homeless people, one of the first qualities noticed is that these individuals often smell like urine. This is not necessarily the result of accidents or a weak bladder; a person who does not have access to daily showers cannot remove the uremic wastes that come through the skin every day. We also see the relationship of the skin to the kidneys with the phenomenon of uremic frost, a powdery discharge on the skin, which is typically seen when the BUN levels are around 200.4
This is in line with traditional medicines that emphasized skin detoxification. Many in Traditional Chinese Medicine refer to the skin as the third kidney. Pioneers in naturopathic medicine also knew the value of skin detoxification, with recommendations for extended baths and showers. Baths could be as long as 5 hours, at which time the bath water would be noted to be especially foul, making it difficult for the patient to continue. Showers could be as long as 8 hours, an outrageous proposition to many concerned with modern droughts.5
Modern research is yielding new insights into the value of skin detoxification for kidney patients. One German study evaluated the benefit of sweating for Stage 4 chronic kidney disease patients. Patients sweated into towels, and the towels were then chemically analyzed for content of uremic waste. Not only were uremic waste products found, but the researchers noted that the more often the patients experienced these sweating sessions, the more uremia came out in each session. The body learns to push this pathway through repeated stimulation.6 Another study found upregulation of urea transporters in the skin and sweat glands of uremic patients compared with normal subjects.7 In fact, urea concentrations may be up to 50 times greater in the sweat of uremic subjects when compared with serum concentrations.8
Some in mainstream nephrology have even suggested that skin detox can help bridge the gap if dialysis patients miss a session. Anuric patients on long-term dialysis have issues of fluid buildup between dialysis sessions. This necessitates fluid restriction, one of the most difficult aspects of life on dialysis. Although the fluid volume of sweat is small, the high salt concentration of sweat does much to help fluid balance. By utilizing the skin to eliminate water and salt, these patients may be able ease up on fluid restriction, which goes a long way to improving quality of life.9
On an ongoing basis, skin detoxification can be an adjunct therapy for those in renal failure. Some uremic waste products are easily eliminated with dialysis, such as BUN, and adequacy of dialysis can be measured with URR (urea reduction rate) by comparing the concentration of BUN before and after a session. But this is only one of thousands of uremic waste products. Other uremic wastes, particularly those of low molecular weight such as aluminum, can be hard to remove with dialysis, as these waste products may not be caught on the filter of the dialysis machine.10
Over time as uremic waste products build up in the body, many patients experience "uremic bronzing," a yellow-orange tone that occurs as wastes are deposited in the skin. Xerosis and pruritus are also noted with late-stage kidney disease.11 Pruritus is often the consequence of buildup of serum phosphate.12 In practice, the author works with many late-stage chronic kidney disease patients and dialysis patients on skin detox. Often in a short period of time, the uremic bronzing resolves and the symptomatic pruritus improves.
Patients and practitioners often have questions on what is the best way to go about skin detoxification for kidney health. The extended bath or shower is often a difficult proposition. Busy patients worried about loss of time with a 3- to 4-hour dialysis session are not likely to agree to spending several hours in the bathtub each week. Of all of the recommendations that the author gives in protocols to kidney patients, skin detoxification unfortunately is usually the last piece they implement. However, once patients start with this, they do notice that they feel better, and continuing is self-reinforcing. For those already on dialysis, a 30-minute session on nondialysis days is associated with improvements across a wide range of clinical parameters.13
Another added benefit to sweating therapy is an improvement in potassium balance.14 As those in kidney failure cannot pass potassium out in the urine, serum potassium levels may rise to dangerous levels. The cardiac effects of hyperkalemia is the most immediate threat that dialysis patients face. The necessity of a low-potassium diet, however, eliminates a wide range of fruits and vegetables. Many end-stage renal disease patients believe that they have no choice but to eat processed foods of low nutritional value in order to control potassium. By improving potassium balance, these patients may be able to adopt more healthful eating habits.
While dry-brushing is convenient, and moving lymph is a good idea, there is far less transfer through air as through water. Some form of hydrotherapy is usually more effective. Traditional saunas and steam rooms are effective, but often too extreme for kidney patients. The sudden expansion of blood vessels with a very high temperature may lead to orthostatic hypotension with patients on hypertension medications.15 Footpads or ionic foot baths do not seem to give a substantial results, possibly due to not including enough surface area for significant skin detox.16
Infrared (IR) sauna, when available, is often a good option for kidney patients. These units typically use a lower temperature than traditional saunas and have a deeper penetration into the skin. A wide variety of IR saunas are available. Patients who invest in a home unit have the option of doing a 15-minute sauna daily. Frequency of sessions may be even more important than duration, as uremic wastes are generated 24/7. Some portable home IR saunas are more energy efficient than others, which can be a consideration over time. Also units with the heating element throughout are preferred over those that have discrete panels and only detoxify the area of skin directly in front of the panel. Some units also heat almost instantly, a big advantage over those that can take an hour to warm up. These convenience factors are a big consideration if one is to make IR sauna a part of the everyday routine.
The cardiovascular benefits of IR sauna should also be considered. The cause of mortality for most renal patients is not renal failure but secondary heart disease. Thermal therapy, which includes water immersion, traditional sauna, and IR sauna, was found to improve several parameters of cardiac health, including endothelial function, hemodynamics, cardiac geometry, neurohormonal markers, and quality of life.17
If IR sauna is not an option, detox baths may be the next best option. One cup of Epsom salt and 2 cups of apple cider vinegar in a standard bathtub can help create a draw in the bath water to pull out uremic toxins. (Bentonite clay is also useful, but one must consider that it can be hard on plumbing and difficult to drain.) The Epsom salt/apple cider vinegar combination has proved clinically useful, and the feedback from uremic patients has noted a significant improvement with uremic bronzing. Twenty minutes in the tub a few times a week is often all it takes. Patients would do well to scrub the skin and aim to maximize the surface area in the tub, submerging the upper body as much as possible. Some patients are concerned with the smell of apple cider vinegar staying with them after the detox bath. This is usually not a problem, but a quick shower after the bath will take care of any issue.
Another type of bath that can be helpful for kidney support is the salt bath. This uses two 1 lb. boxes of regular table salt. It makes the water especially salty, like seawater, and creates an osmotic gradient that can be helpful for skin detoxification. The salt bath is especially warming. Usually after a hot bath, a person feels chilled stepping out into the cooler air. A hot salt bath is deeply warming and closes the pores of the skin so that the heat stays with the person. TCM associates kidney chi with body heat, and many with kidney failure have a chronically low body temperature.18,19 For these patients, regular salt baths are especially helpful with cold and damp weather conditions.
Detox baths and salt baths can be used for patients at all stages of kidney disease. With diabetics, it is advisable to caution them to check the temperature of the water and make sure that it is not above 104 °F. Posttransplant patients should only have a warm bath and not a hot bath, as the high temperature acts like a fever, stimulating the immune response.20 Those with a transplanted kidney should also avoid IR sauna, as this is also too immune stimulating.
The benefits of skin detox happen over time with repeated sessions. Evidence from hair analysis indicates that it may take several months to clear aluminum and lead. Arsenic may clear even more slowly.21 Patients often report feeling better shortly after beginning a skin detox protocol, but they should be aware that this can be a long-term process.
In conclusion, skin detoxification is an especially useful approach for kidney patients or anyone interested in maintaining good kidney health. Rather than look to diuretics, which push the kidneys to work harder, skin detoxification helps reduce the stress on the kidneys. By reducing the workload, therapeutic baths and saunas offer support for chronically overworked kidneys.
Dr. Jenna Henderson is a graduate of the University of Bridgeport College of Naturopathic Medicine. Her practice, Holistic Kidney, addresses the unique needs of renal patients at all stages, including dialysis patients and transplant recipients. Her articles have been published in Natural Medicine Journal and Naturopathic Doctors News & Reviews. She has lectured across the US to both patient groups and professional groups. She has appeared on several radio shows and cohosted the program Improve Your Kidney Health. She is currently at work on a guidebook on natural medicine for transplant patients.