Kidney Disease—All Things Considered

Source: [36]

A national survey found that only 41% of Americans tested had normal kidney function, a drop from 52% about a decade earlier.^[1]

If your kidneys do not function property, metabolic waste products can accumulate in the blood and eventually lead to such symptoms as weakness, shortness of breath, confusion, and abnormal heart rhythms.  If your kidneys fail completely, you will either need a new one or have to go on dialysis. However, the average life expectancy of a person on dialysis is less than 3 years.^[3]

So, it's better to keep your kidneys healthy in the first place.

Video 1.  Treating Chronic Kidney Disease with Food (YouTube link)

Kidney Problems

Healthy kidneys work hard to retain protein and other vital nutrients, preferably filtering toxic or useless wastes out of the blood stream via your urine.  Patients with kidney problems can range from experiencing no symptoms to leaking protein into urine or to end-stage renal disease.

• Poor kidney function is not just a kidney disease
• Kidney malfunction can be so damaging to the rest of the body that most people don't live long enough to reach end-stage kidney failure.
• Poor kidney function is associated with diabetes, hypertension, and heart disease.
• For instance,  your kidneys are so critical to proper heart function that patients under age 45 with kidney failure can be 100 times more likely to die of heart disease than those with working kidneys.^[3]
• Each year, 64,000 Americans are diagnosed with kidney cancer, and about 14,000 die from it.^[29]
• Most kidney disease is characterized by a gradual loss of function over time.
• Common signs of kidney problems include frequent urination, problems urinating, and constant thirst
• Kidney Stones
• Read the companion article "Types of Kidney Stones "
• Approximately one in eleven Americans are affected today, compared with one in twenty less than two decades ago.^[20]

Video 2.  How Not to Die from Kidney Disease (YouTube link)

Renal Function Test

Creatinine is removed from the blood chiefly by the kidneys. Little or no tubular reabsorption of creatinine occurs. If the filtration in the kidney is deficient, creatinine blood levels rise. Therefore, creatinine levels in blood and urine may be used for kidney function tests.

• Creatinine Clearance
• A decreased creatinine clearance indicates poor renal function. Normal creatinine level is between 80 - 120 μmol/L. 
• Serum Creatinine
• Serum creatinine may be more useful clinically when dealing with patients with early kidney disease.
• Glomerular Filtration Rate (GFR)
• Blood creatinine levels may also be used alone to calculate the estimated GFR (eGFR).
• A normal eGFR for adults is greater than 90 mL/min/1.73m², according to the National Kidney Foundation. (Because the calculation works best for estimating reduced kidney function, actual numbers are only reported once values are less than 60 mL/min/1.73m²).

Reference Range for eGFR

What are the stages of chronic kidney disease (CKD)?

There are five stages of kidney disease.^[40] Your healthcare professional determines your stage of kidney disease based on the amount of kidney damage shown by your eGFR or mGFR.

• Over 90 mL/min/1.73m²: This indicates normal kidney function.
• 60-89 mL/min/1.73m²: Considered mild to moderate decrease in kidney function, also known as stage 2 chronic kidney disease (CKD).
• 30-59 mL/min/1.73m²: Indicates moderate to severe decrease in kidney function, corresponding to stage 3 CKD.
• 15-29 mL/min/1.73m²: Suggests severe decrease in kidney function, also known as stage 4 CKD.
• Below 15 mL/min/1.73m²: Indicates very severe decrease in kidney function, corresponding to stage 5 CKD or kidney failure.

What is a normal eGFR number?

The reference range for estimated Glomerular Filtration Rate (eGFR) varies depending on factors like age, sex, and ethnicity. In adults, the normal eGFR number is usually more than 90. eGFR declines with age, even in people without kidney disease. See chart below for average estimated eGFR based on age.

Source: kidney.org

Note that eGFR is a key tool for diagnosing and monitoring CKD, but it's not the only factor considered. Additional tests and assessments might be needed for a complete picture.

Risk Factors of Kidney Diseases

• Animal Products^[4]
• Researchers at Harvard University found three specific dietary components associated with declining kidney function:  animal protein, animal fat, and cholesterol.
• And they found no association between kidney function decline and the intake of protein or fat from plant sources.
• Kidney Stones
• Read the companion article "Risk Factors of Kidney Stones"
• When urine is more alkaline, stones are less likely to form and vice versa.
• A high intake of zinc was associated with a higher risk.^[21]
• Lipid Nephrotoxicity
• Fat and cholesterol in the blood stream could be toxic to the kidneys.^[5,6]
• "Meat-Sweet" Diet^[7]
• Excess table sugar and high-fructose corn syrup consumption is associated with increased blood pressure and uric acid levels, both of which can damage the kidney.
• The saturated fat, trans fat, and cholesterol found in animal products and junk food are associated with impaired kidney function, and meat protein increases the acid load in the kidneys, boosting ammonia production and potentially damaging our sensitive kidney cells.^[8,14]
• Excess Phosphorus Intake
• Having too much phosphorus in the blood may increase the risk of kidney failure, heart failure, heart attacks, and premature death.^[24]
• Phosphate (in animal foods) vs Phytate (in plant foods)^[26]
• Phosphorus in meat is present within the cells as organic phosphates, which is easily hydrolyzed and absorbed. 
• Because mammals lack the degrading enzyme phytase, bioavailability of phosphorus from plant-derived foods is relatively low, despite their high phosphorus content.
• Inorganic phosphate vs organic phosphate^[26,27,28]
• Inorganic phosphate from additives is readily absorbable and the worst offenders.
• Inheritance
• Approximately 4% of kidney cancer are hereditary.^[30]
• Tobacco Use (hint: nitrosamines)^[30]
• Similar to tobacco carcinogens, you can find both nitrosamines and nitrosamides in processed meats
• Nitrites themselves are not carcinogenic.  However, if they turn into nitrosamines and nitrosamides, then they are.
• With amines and amides, which are abundant in animal products, nitrites can be transformed to carcinogen.
• In the case of plant foods, the vitamin C and other antioxidants that are found naturally in them block the formation of these carcinogens in your body.^[31]
• Medications
• Long-term use of blood pressure drugs may cause kidney damage, one study suggests.^[38]
• Dietary Acid Load^[8,14]
• Dietary acid load is determined by the balance of acid-inducing foods (such as meats, eggs, and cheese) and base-inducing foods (such as fruits and vegetables).
• A higher dietary acid load was associated with significantly higher risk of protein leakage into the urine, an indicator of kidney damage.^[14]

Video 3.  How to Treat Kidney Stones with Diet (YouTube link)

How Not to Die from Kidney Disease^[12]

• Protein restricting diet
• A renal diet is a diet that becomes increasingly more restrictive as your kidney function declines. 
• It starts out with having you limit your salt and the amount of protein you eat.^[9,39]
• Eating plant-based diets
• People eating a plant-based diets appear to have better kidney function.
• Originally thought to be due to their lower overall protein intake^[10]
• However, we now know that it's more likely due to the fact that the kidneys appear to handle plant protein very differently from animal protein.^[11]
• Half a dozen clinical trials have shown that plant protein replacement can reduce hyperfiltration and/or protein leakage.^[12]
• Why does animal protein cause the overload reaction while plant protein doesn't? Because of the inflammation animal products can cause.^[13]
• Uric acid stones—the 2nd most common type of kidney stones—can apparently be dissolved away completely with a combination of eating more fruits and vegetables, restricting animal protein and salt intake, and drinking at least ten glasses of fluid a day.^[23]
• While nitrite from animal sources was associated with an increased risk of kidney cancer, some of the highest nitrate-containing vegetables, such as arugula, kale, and collards, are associated with significantly reduced risk for kidney cancer.^[32]
• Avoid meat-rich diet
• The chronic, low-grade, metabolic acidosis attributed to a meat-rich diet helps explain that:
• Why people eating plant-based diets appear to have superior kidney function.^[15]
• Why various plant-based diets have been so successful in treating chronic kidney failure.^[16-19]
• Oxford University researchers found that subjects who didn't eat meat all all had a significantly lower risk of being hospitalized for kidney stones, and for those who did eat meat, the more they ate, the higher their associated risk.^[21]
• Phosphate (in animal foods) vs Phytate (in plant foods)
• Most Americans consume about twice as much phosphorus as they need.^[25]
• Phosphate is absorbed into the bloodstream more readily than phytate.^[26]
• Avoid Phosphate additives in cola drinks and meat (for enhancing color)
• Phosphate additives have been described as "a real and insidious danger" for kidney patients, since they have diminished capacity to excrete it.^[27]
• A supermarket survey found more than 90% of chicken products contained phosphate additives.^[28]

References

1. Coresh J, Selvin E, Stevens LA, et al.  Prevalence of chronic kidney disease in the United States.  JAMA, 2007;298(17):2038-47.
2. Stokes JB.  Consequences of frequent hemodialysis: comparison to conventional hemodialysis and transplantation.  Trans Am Clin Climatol Assoc.  2011;122:124-36. 
3. Kumar S, Bogle R. Banerjee D. Why do young people with chronic kidney disease die early?  World J Nephrol. 2014;3(4):143-155.
4. Lin J, Hu FB, Curhan GC.  Associations of diet with albuminuria and kidney function decline.  Clin J Am Soc Nephrol. 2010;5(5):836-43.
5. Moorheaqd JF, Chan MK, El-Nahas M, Varghese Z. Lipid nephrotoxicity in chronic progressive glomerular and tubulo-interstitial disease.  Lancet.  1982;2(8311):1309-11.
6. Hartroft WS.  Fat emboli in glomerular capillaries of choline-deficient rats and of patients with diabetic glomerulosclerosis, Am J Pathol.  1955;31(3):381-97.
7. Odermatt A.  The Western-style diet: a major risk factor for impaired kidney function and chronic kidney disease.  Am J Physiol Renal Physiol, 2011; 301(5):F919-31.
8. van den Berg E, Hospers FA, Navis G, et al.  Dietary acid load and rapid progression to end-stage renal disease of diabetic nephropathy in Westernized South Asian people.  J Nephrol. 2011; 24(1):11-7.
9. Piccoli GB, Vigotti FN, Leone F, et al.  Low-protein diets in CKD: how can we achieve them? A narrative, pragmatic review.  Clin Kidney J. 3015;8(1):61-70.
10. Wiseman MJ, Hunt R, Goodwin A, Gross JL, Keen H, Viberti GC.  Dietary composition and renal function in healthy subjects.  Nephron.  1987;46(1):37-42.
11. Nakamura H, Takasawa M, Kashara S, et al.  Effects of acute protein loads of different sources on renal function of patients with diabetic nephropathy.  Tohoku J Exp Med. 1989;159(2):153-62.
12. How Not to Die (Dr. Michael Greger), Chap 10;Ref 24-30.
13. Fioretto P, Trevisan R, Valerio A, et al.  Impaired renal response to a meat meal in insulin-dependent diabetes:  role of glucagon and prostaglandins.  Am J Physiol, 1990;258(3 Pt 2):F675-83.
14. Banerjee T, Crews DC, Wesson DE, et al.  Dietary acid load and chronic kidney disease among adults in the United States.  BMC Nephrol. 2014 Aug 24;15:137.
15. Wiseman MJ, Hunt R, Goodwin A, Gross JL, Ken H, Viberti GC. Dietary composition and renal function in healthy subjects.  Nephron. 1987;46(1):37-42.
16. Kempner W. Treatment of heart and kidney disease and of hypertensive and arteiosclerotic vascular disease with the rice diet.  Ann Intern Med. 1949;31(5):821-56.
17. Barsotti G, Morelli E, Cupisti A, Meola M, Dani I., Giovannetti S.  A low-nitrogen low-phosphorus vegan diet for patients with chronic renal failure.  Nephron.  1996;74(2):390-4.
18. Goraya N, Simoni J, Jo C, Wesson DE. Dietary acid reduction with fruits and vegetables or bicarbonate attenuates kidney injury in patients with a moderately reduced glomerular filtration rate due to hypertensive nephropathy.  Kidney Int. 2012;81(1):86-93.
19. Uribarri J, Oh MS.  The key to halting progression of CKD might be in the produce market, not in the pharmacy.  Kidney Int. 2012;81(1):7
20. Scales CD Jr, Smith AC, Hanley JM, Saigal CS; Urologic Diseases in America Project, Prevalence of kidney stones in the United States.  Eur Urol. 2012;62(1):160-5.
21. Turney BW, Appleby PN, Reynard JM, Nobel JG, Key TJ, Allen NE.  Diet and risk of kidney stones in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).  Eur J Epidemiol. 2014;29(5):363-9.
22. Siener R, Hesse A.  The effect of a vegetarian and different omnivorous diets on urinary risk factors for uric acid stone formation.  Eur J Nutr. 2003;42(6):332-7.
• Removing all meat from a standard Western diet appears to reduce the risk of uric acid crystallization—the 2nd most common type of kidney stones—by more than 90% within as few as five days.
23. Kim JW, et al. Increased fluid intake and adequate dietary modification may be enough for the successful treatment of uric acid stone.  Urolithiasis. 2013;41(2):179-82.
24. Ritz E, Hahn K, Ketteler M, Kuhlmann MK, Mann J. Phosphate additives in food—a health risk.  Dtsch Arztebl Int. 2012;109(4):49-55.
25. Calvo MS, Uribarri J. Public health impact of dietary phosphorus excess on bone and cardiovascular health in the general population.  Am J Clin Nutr. 2013;98(1):6-15.
26. Fukagawa M, Komaba H, Miyamoto K. Source matters: from phosphorus load to bio-availability. Clin J Am Soc Nephrol. 2011;6(2):239-40. 
27. Benini O, D'Alessandro C, Gianfaldoni D, Cupisti A.  Extra-phosphate load from food additives in commonly eaten foods: a real and insidious danger for renal patients.  J Ren Nutr. 2011;21(4):303-8.
28. Sullivan CM, Leon JB, Sehgal AR.  Phosphorus-containing food additives and the accuracy of nutrient databases: implications for renal patients.  J Ren Nutr. 2007;17(5):350-4.
29. American Cancer Society.  Cancer Facts & Figures 2014.  Atlanta: American Cancer Society; 2014.
30. Kirkali A, Cal C. Renal Cell Carcinoma: Overview. In Nargund VH, Raghavan D, Sandler HM, eds.  Urological Oncology. London, UK: Springer; 2008:263-80.
31. Bartsch H, Ohshima H, Pignatelli B. Inhibitors of endogenous nitrosation.  Mechanisms and implications in human cancer prevention.  Mutat Res. 1988;202(2):307-24.
• Such inhibitors of nitrosation include vitamins C and E, phenolic compounds, and complex mixtures such as fruit and vegetable juices or other plant extracts. 
32. Liu B, Mar Q, Wang X, et al.  Cruciferous vegetables consumption and risk of renal cell carcinoma: a meta-analysis.  Nutr Cancer.  2013;65(5):668-76
• Our findings supported that cruciferous vegetables consumption was related to the decreased risk of renal cell carcinoma.
33. How to Prevent and Treat Kidney Problems With Food (Dr. Mercola) 
34. 7 Secrets to Keeping Your Kidneys Healthy
35. How Not to Die from Kidney Disease
36. Current insights toward kidney injury: Decrypting the dual role and mechanism involved of herbal drugs in inducing kidney injury and its treatment
37. Proton pump inhibitors associated acute kidney injury and chronic kidney disease: data mining of US FDA adverse event reporting system
• The present study identified six PPIs-associated AKI (acute kidney injury) and CKD (chronic kidney disease) signals based on the FAERS data.
38. Long-term use of blood pressure drugs may cause kidney damage, study suggests
39. What Are the Best Foods for Kidney Health?
40. Estimated Glomerular Filtration Rate (eGFR)