1. Health article

Take care of your kidneys!

“The human body is not eternal. It contains flesh that can decay, and foul excreta. At the same time, present in this very same body are sacred feelings. It is for safeguarding this hidden treasure that you must take proper care of the body. Once the treasure is tapped and duly made use of, the body can be given up. This is the proper way to go through life.”…Sathya Sai Baba¹

1. System, structure, and function of kidneys

1.1 Kidneys are the most vital and primary organs of the urinary system, a prominent component of excretory system of our body to filter blood, balance electrolytes, and regulate blood volume and blood pressure.^2,3

1.2 Every person normally has two fist-sized, bean-shaped kidneys on either side of the spine in the lower back just below the rib cage, well protected; right kidney, slightly smaller than the left. Their weight depends on the height, weight, age, and body      mass index. Each kidney has more than a million filtering  units called nephrons to do the complicated process of producing urine. Ureters are muscular tubes that connect each kidney to the urinary bladder, a muscular sac-like organ that temporarily stores urine until it is excreted; every 10-15 seconds, urine is emptied into the bladder from the ureters in small amounts. A typically healthy adult bladder can retain about ½ litre of urine for 2 to 5 hours. Urethra is a tube that carries urine from the bladder out of the body. Two sphincter muscles like rubber bands around the opening of the bladder help keep urine from leaking. The nerves in the bladder alert a person when it is time to urinate. An adrenal gland on top of each kidney closely works with it in managing blood pressure and fluid balance, in addition to its independent role as an endocrine gland.^2-9

1.3 Three Core Processes of Kidney Function: As blood enters the kidneys through the renal arteries, it first undergoes filtration in the nephrons. Blood pressure forces water, urea, creatinine, acids, salts, and  glucose through tiny filters, while blood   cells and most proteins remain in the bloodstream. This is followed by reabsorption, during which essential substances such as glucose, amino acids, minerals, and most of the filtered water are returned to the blood. Finally, through secretion, additional wastes, excess acids, drugs, and toxins are actively transferred from the blood into the renal tubules. The remaining fluid becomes urine, which flows from the kidneys through the ureters to the bladder.^2-9

1.4 Amazing Kidneys! Although human body contains only about 5 litres of blood, kidneys receive about 1.2 litres of blood/min - nearly 1,700 litres/day. Since blood is about 55% plasma (+ 45% blood cells), almost 950 litres of plasma pass through the kidneys daily. Of this, about 180 litres are filtered and cleaned, yet less than 2 litres leave the body as urine. The remaining fluid is reabsorbed and reused. Despite weighing only about 300 g, the kidneys perform the work of a highly sophisticated chemical refinery, continuously filtering, balancing, and purifying the body's fluids.^2-9

Kidneys also control the acid-base (pH) balance of blood, make sugar when needed, and produce two hormones – calcitriol, a form of vitamin D to absorb calcium, and erythropoietin to make red blood cells. In essence, kidneys are a nonstop cleaning crew for our blood, the unsung tireless heroes!^2-9

 

 

2. Parameters for Kidney health

Kidney health is gauged using a combination of blood tests, urine evaluation, and physical markers.

2.1 Serum creatinine test: Creatinine is a natural chemical waste produced at a steady rate every day through normal muscle breakdown and daily physical activity. Its amount depends on the muscle mass, age, diet, and activity of a person; a body builder will naturally have a higher creatinine level. As it enters the blood stream, healthy kidneys filter nearly all of it, expelled through urine. A simple blood test determines the serum creatinine level, a powerful biomarker and a reliable indicator of filtration by kidney, the normal range being 0.5 to 1.1 mg/dL for women and 0.7 to 1.3 mg/dL for men. Elevated levels may mean kidneys are not filtering properly or could be due to dehydration, muscle disorders and injuries, high protein diet, intense exercise, health problems in pregnancy, or medications. If the level increases, usual symptoms are loss of appetite, nausea, vomiting, itchiness, anaemia, and in later stages, difficulty in breathing. Low levels are rare, mostly due to malnutrition, nerve disorder, muscle loss due to aging or prolonged illness.^2,9-13

2.2 eGFR (estimated Glomerular Filtration rate), a more accurate and best overall indicator of kidney function, tells us how many mL the kidney filters per minute. This is arrived at precisely using a mathematical formula combining the standard blood creatinine level with age, sex, and body size of the patient. An eGFR of 90mL/min/1.73m² or more is considered healthy and normal; a lower number signals reduced kidney function. eGFR helps to determine the stage of chronic kidney disease.^9-13

 

 

2.3 Blood Urea Nitrogen (BUN) test: While digesting proteins, the liver produces a waste, urea, carried through the blood as nitrogen and filtered by the kidneys. BUN test measures the amount of urea nitrogen that remains in the blood, which varies with age and gender. Normal range for adult females is 6-21mg/dL and for males 8-24 mg/dL. Elevated BUN levels may be caused by dehydration, a high-protein diet, or reduced kidney function. However, when both BUN and creatinine levels are elevated, it strongly suggests kidney dysfunction.^13,14

2.4 Urine tests: uACR (Urine Albumin-to-Creatinine Ratio):  It is used as a screening tool to detect the earliest sign of kidney damage, if albumin, a kind of protein, in the urine is beyond the normal range of 30mg/g. Consistent dense foam or bubbles in urine is also an indicator of excess protein in urine. Urinalysis, a quick screening tool, would show presence of red or white blood cells, infections, or leakage of some protein in the urine. Urine culture test can identify the bacteria or fungi that cause urinary tract infection (UTI) and help manage it promptly to prevent it from spreading to kidneys.^2,9,13-15

2.5 Other indicators of kidney disorder are imbalanced level of electrolytes like sodium, potassium, calcium, and phosphorous in the body, uncontrolled blood pressure, and urine colour changes. Urine colour and smell are helpful initial clues to check kidney and bladder health and flag potential problems like dehydration, infection, and strain on the kidneys. Normal healthy urine will be clear, pale straw or transparent yellow. Darker yellow or honey coloured urine means you need more water. A darker, brownish colour may indicate a liver problem or severe dehydration; dark brown like tea or cola is a sign of kidney disease or failure. Such changes are more frequent in women, older adults, and those with family history of kidney or bladder stones; when they last for more than a few days and are not tied to food or medication, one should seek medical advice.^16,17

 

 

 

 

3. Kidney disorders

3.1 Urinary Tract Infection (UTI): Urinary tract includes the bladder, urethra, and kidneys. UTI refers to inflammation due to a bacterial infection often in the lower urinary tract, with symptoms of pain or burning  during urination; also, urine may be red tinged, greenish, or cloudy or murky; very common in females due to shorter urethra closer to the rectum. Foul or   pungent smell can indicate a bacterial infection in the urethra (urethritis), bladder (cystitis, most common) or kidneys (pyelonephritis, less common but more serious). Other symptoms are frequent urination, feeling the need to urinate even on empty bladder, bloody urine or pressure or cramping in groin or lower abdomen; also, fever, chills, severe pain in lower or side of back, and nausea or vomiting when serious.^18-22

3.2 Kidney stones (renal calculi/nephrolithiasis), more common in men, happen when crystals formed in the urine join together to become stones in the bladder, kidney, or ureter obstructing the urine flow. Symptoms are as in UTI, most common being pain in lower or side back or belly, and urinary urgency or frequency. Small stones like a grain of sand can pass through urine though painful sometimes, larger ones can get trapped in ureter or urethra. High oxalate, sodium, or sugary or low calcium foods, vitamin C and Ca supplements, and inadequate intake of water are the major causes; animal proteins can cause uric acid stones. Strangury is a warning sign of an underlying issue of stones or tumour with symptoms of severe, urgent, and continuous desire to urinate, accompanied by painful cramping spasms in the lower abdomen, releasing only few drops of urine at a time by straining.^23,24

3.3 Bedwetting (nocturnal enuresis) is accidental release of urine during sleep and can affect children, teenagers, and adults too. Most children stop doing it on their own as they grow and have better bladder control. It will be a concern if your child is over age 12 and continues to wet the bed twice a week for at least three months in a row. Though not serious, it can be stressful. It could be genetic or an underlying health condition. Key causes are slow bladder maturation, deep sleep patterns or a nerve related issue, low levels of vasopressin - the anti-diuretic hormone (ADH), or underlying health issue like constipation, UTI, diabetes, or sleep apnoea. Such people should avoid drinking water at least two hours before bedtime.²⁵

3.4 Haematuria is presence of red blood cells in urine characterised by pinkish red urine, a warning sign to be addressed; when not visible, only a lab test can detect. Causes could be UTI, cysts, vigorous exercise or injury to urinary system, enlarged prostate in men, endometriosis in women, sickle cell disease that affects red blood cells, kidney diseases, or cancer.²⁶

 

 

 

 

 

 

 

 

 

 

3.5 Serious Kidney diseases: Kidney disease is often called a ‘silent killer’ because the kidneys can continue to function effectively despite significant damage. As a result, symptoms may not appear until up to 60% of   kidney function has already been lost. Chronic kidney disease (CKD)     and nephropathy, usually caused by chronic high BP and unmanageable diabetes, develop over months or years, and are usually permanent. There is a dangerous two-way relationship between blood pressure and kidneys. High BP damages them, but diseased kidneys also cause high BP forcing the body to retain salt and water, creating a vicious cycle. CKD progresses in five stages, from mild to kidney failure stage. Only during stage 3, symptoms may be noticeable –  frequent urination, fatigue, loss of appetite, shortness of breath, swelling of hands, ankles, feet and puffy eyes, foamy or bubbly urine, dry itchy skin, darkening of skin, numbness, muscle cramps, high BP, nausea or vomiting, trouble concentrating and sleeping. In addition to these symptoms, nephropathy will have persistent protein in the urine. In polycystic kidney disease (PKD), cysts  are formed due to genetic condition leading to high BP and kidney failure.^2,27,28

3.6 Disorders that can affect kidneys are acidosis - excess acid which kidneys can’t get rid of, so ends up in blood stream; acute nephritis due to inflamed kidneys: azotaemia where nitrogen waste build up in the blood:

   hydronephrosis where the urinary system gets blocked; proteinuria due to high level of protein in urine – a sign of kidney damage; uraemia when toxins are not cleared by kidneys. People with diabetes and high blood pressure are at a high risk of kidney disorder; accidents and trauma can also harm the kidneys.²

 

 

3.7 Kidney failure can happen suddenly due to an acute kidney injury (AKI, often reversible if treated promptly), due to severe dehydration, toxins or a sudden drop in blood flow. In the last stage of a kidney disease when the kidney fails, the only options are dialysis or kidney transplant.⁹

3.7.1 Dialysis cannot replace all renal functions for blood and bone synthesis. So, patients can develop anaemia or bone metabolism disorders, high BP, or reduced physical fitness.⁹

  

 

 

 

3.7.2 Kidney transplant is the ultimate option provided a donor is available. After transplant, one has to take immunosuppressants for life otherwise the body is likely to reject the donor’s kidney.⁹

 

 

 

 

 

 

4. Life with one kidney!

Kidney is one of the reserve organs in our body. It is in pairs like many other vital organs primarily to maintain bilateral symmetry and provide a back-up in case of illness or injury to one of them. Most people can live well with one kidney. If someone is born with a single kidney, their overall kidney function is often normal. One can donate a kidney to someone in need, the other one can rapidly take over the function of the pair, often up to 70% of their original efficiency. Single kidney has to work harder, is more vulnerable to injury, needs lifelong regular checkups for blood pressure and creatinine. Transplanted kidney is less protected than a normal one as it is usually placed into the pelvis. Those with one functioning kidney should avoid sports like boxing, wrestling, martial arts, field or ice hockey, and football. One should take care, maintaining diet and hydration according to medical advice. Kidney from a living donor functions for an average of 15 to 20 years, as against 10 to 15 years in case of a deceased donor. After that, one can get another kidney transplant.^29-32

1. Tips for Kidney health^2,11,33-37
2. Stay well hydrated - vital as a natural cleanse, normal adult should drink 2-3 litres of plain water daily - kidney’s best friend!
3. Follow a kidney friendly diet - enjoy nutritious fibre-rich diet, healthy fats, moderate amount of high quality plant-based protein; include herbs and spices like tulsi (basil), ginger, garlic, parsley, oregano, rosemary, and pepper, instead of excess salt to; choose fruits like berries especially cranberries, cherries, citrus fruits, pineapples, and apples; No added sugar!
4. Adjust your diet if you have advanced kidney disease. Those with significant kidney impairment or on dialysis may need to restrict fluid intake and limit foods high in potassium like banana, mango, tomato, potato, and phosphorous eg, dairy and dark colas.
5. Avoid unnecessary strain on kidneys. Limit processed and high-sodium foods, sugary drinks, alcohol, and tobacco. Use over-the-counter painkillers such as aspirin and ibuprofen only when necessary and under medical guidance. Avoid unnecessary supplements, especially high doses of calcium and vitamin C.
6. Monitor your kidney health regularly. Annual kidney function tests are particularly important for those with high blood pressure, diabetes, heart disease, obesity, family history of kidney disease, recurrent infections, or on regular medications.

References and Links

1. Sathya Sai Speaks, Summer Course, 17 May 2000, Brindavan: https://saispeaks.sathyasai.org/discourse/human-body-and-its-importance
2. Structure and functions of kidneys: https://my.clevelandclinic.org/health/body/21824-kidney
3. https://www.hopkinsmedicine.org/health/wellness-and-prevention/anatomy-of-the-urinary-system
4. Function of kidneys video: https://www.youtube.com/watch?v=CShAIAD-ask
5. https://byjus.com/biology/human-excretory-system/
6. https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work
7. https://www.urologyhealth.org/healthy-living/urologyhealth-extra/magazine-archives/winter-2023-kidney-lumps-n-bumps/insights-what-do-the-kidneys-do-and-why-do-we-have-two
8. https://www.nuhospitals.com/blog/know-your-kidneys/
9. https://www.era-online.org/publications/understanding-kidneys/
10. Parameters of kidney health: https://medlineplus.gov/lab-tests/creatinine-test/
11. Understanding creatinine levels: https://www.apollo247.com/diagnostic-health-topics/creatinine-serum/your-kidney-health-monitor-understanding-and-managing-creatinine-levels
12. Ideal Creatinine level: https://www.youtube.com/watch?v=hoCmv7ZpxAg
13. Kidney function tests: https://my.clevelandclinic.org/health/diagnostics/21659-kidney-function-tests
14. BUN blood test: https://my.clevelandclinic.org/health/diagnostics/17684-blood-urea-nitrogen-bun-test
15. Urine tests: https://www.healthline.com/health/normal-urine-test-results-chart
16. Urine changes: https://my.clevelandclinic.org/health/diseases/15357-urine-changes
17. Colour of urine: https://www.kidney.org/kidney-topics/what-color-your-urine-means
18. UTI basics: https://www.cdc.gov/uti/about/index.html
19. UTI: https://my.clevelandclinic.org/health/diseases/9135-urinary-tract-infections
20. https://my.clevelandclinic.org/health/diseases/22858-urethritis
21. https://my.clevelandclinic.org/health/diseases/21203-bladder-inflammation-cystitis
22. Kidney infection: https://my.clevelandclinic.org/health/diseases/15456-kidney-infection-pyelonephritis
23. Kidney stones: https://jsshospital.in/early-signs-of-kidney-stones/
24. https://my.clevelandclinic.org/health/diseases/15604-kidney-stones
25. Bedwetting: https://my.clevelandclinic.org/health/diseases/15075-bedwetting
26. Haematuria/Blood in urine: https://my.clevelandclinic.org/health/diseases/15234-hematuria
27. CKD: https://my.clevelandclinic.org/health/diseases/15096-chronic-kidney-disease
28. Diabetic nephropathy: https://www.hopkinsmedicine.org/health/conditions-and-diseases/diabetes/diabetic-nephropathy-kidney-disease
29. Organs in pairs: https://www.health.harvard.edu/blog/kidneys-eyes-ears-and-more-why-do-we-have-a-spare-202310202984
30. https://www.kidney.org/kidney-topics/children-born-one-kidney#
31. https://www.kidneyresearchuk.org/kidney-health-information/about-kidney-disease/living-with-one-kidney/
32. https://www.health.harvard.edu/diseases-and-conditions/weak-kidneys-pay-attention-but-dont-worry-excessively
33. Kidney friendly diet plan: https://www.kidneyfund.org/living-kidney-disease/healthy-eating-activity/kidney-friendly-eating-plan
34. https://www.kidney.org/news-stories/spice-your-diet-7-kidney-friendly-seasonings
35. https://www.healthline.com/health/kidney-cleanse#takeaway
36. Kidney friendly fruits: https://www.medicinenet.com/what_fruit_is_good_for_kidneys/article.htm
37. https://www.freseniuskidneycare.com/thrive-central/fruits-for-kidney-disease

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2. Workshop & Seminars 

4. Anecdote

From the Diary of Dr Jit Aggarwal - Padukas in the Suitcase: Silent Sentinels at the Border