The kidneys are two bean-shaped organs located on either side of the spine behind the abdomen. They are responsible for filtering waste and excess fluid from the blood to be excreted as urine. They also help maintain fluid and electrolyte balance in the body. When the kidneys are damaged or diseased, they cannot perform these vital functions properly. This is known as kidney disease.
There are many potential causes and risk factors that can put stress on the kidneys and increase the risk of developing kidney disease. Identifying and managing these factors is key to preventing damage and maintaining healthy kidney function. In this article, we will discuss the main lifestyle factors, medical conditions, and environmental exposures that can negatively impact kidney health over time.
Poor Diet and Nutrition
One of the most important modifiable risk factors for kidney disease is diet and nutrition. Making poor dietary choices that are unhealthy for the kidneys can increase risk. Key problem areas include:
– High sodium intake: Eating too much sodium from processed foods, restaurant meals, and salt added while cooking puts strain on the kidneys. The recommended limit is 1500-2300 mg per day for healthy individuals.
– High protein intake: Consuming excessive animal proteins stresses the kidneys as they must work harder to filter waste products from protein metabolism. Up to 10-35% of protein intake should come from high-quality plant sources.
– High phosphorus intake: Phosphorus is found in processed foods and colas. Excess phosphorus can deposit in the kidneys as mineral complexes. Phosphorus intake should be limited to 800-1200 mg daily.
– Low fluid intake: Not drinking enough water or hydrating fluids means the kidneys must work harder to filter and concentrate urine. Aim for at least six to eight 8-ounce glasses of fluids per day.
– Vitamin and mineral deficiencies: Being deficient in nutrients like calcium, potassium, magnesium, and B vitamins adds stress to kidney cells and function. A balanced, nutritious diet should provide sufficient amounts of these.
Making dietary improvements by eating more whole, unprocessed foods, limiting sodium, phosphorus, and animal protein, staying hydrated, and getting adequate nutrition supports healthy kidneys.
Obesity
Carrying excess body weight puts significant stress on the kidneys and raises the risk of chronic kidney disease. Obesity leads to increased filtration demands on the kidneys as well as metabolic changes like insulin resistance and inflammation that impair kidney function.
Studies show that the risk of developing chronic kidney disease is 2 to 7 times higher in obese individuals compared to normal weight individuals. The incidence of end-stage renal disease is also much higher in those who are obese.
Even being moderately overweight stresses the kidneys compared to being a normal weight. Losing weight if obese or overweight and maintaining a healthy body mass index protects the kidneys and reduces the risk of developing kidney disease.
Hypertension
Uncontrolled high blood pressure, also known as hypertension, is one of the leading causes of chronic kidney disease. Persistent hypertension forces the kidneys to work harder by increasing pressure in the blood vessels that filter waste. This damages the delicate filtration membranes over time.
Hypertension causes the kidneys to initially compensate by retaining more sodium and water to increase blood volume. This starts a vicious cycle as higher blood volume further strains the cardiovascular system. Damaged kidneys are also less efficient at excreting sodium, exacerbating hypertension.
Managing blood pressure through diet, exercise, medication, and a healthy lifestyle is crucial to prevent hypertension from injuring the kidneys. Regular screening and treatment of high blood pressure reduces the risk of developing chronic kidney disease significantly.
Diabetes
Diabetes mellitus, both type 1 and type 2, badly damage the kidneys over time in many patients and is the leading cause of chronic kidney disease. About 40% of people with diabetes will eventually develop diabetic nephropathy, kidney damage from diabetes.
Uncontrolled high blood sugar from diabetes injures and scars the blood vessels in the kidneys, reducing their ability to properly filter waste. High blood glucose also makes the kidneys work harder. Protein waste products cannot be adequately filtered and build up in the blood.
Good control and maintenance of healthy blood sugar levels, blood pressure, and cholesterol using medication, diet, exercise, and lifestyle changes helps prevent diabetes from harming the kidneys in the long run.
Heart Disease
Certain heart conditions like congestive heart failure and narrowed or blocked arteries impair kidney function. When the heart cannot pump strongly enough, blood backs up, and pressure in the veins going to the kidneys rises. This reduces kidney blood flow and filtration rate.
Atherosclerosis or plaque buildup in the arteries also decreases crucial blood flow to the kidneys. Kidney function deteriorates over time as the kidneys become damaged from the ischemia. Managing these cardiovascular conditions preserves kidney function.
Smoking
Smoking cigarettes or using tobacco is very toxic to kidney function. Tobacco use increases kidney cell injury and inflammation. It also damages the blood vessels of the kidneys directly and accelerates atherosclerosis.
Studies consistently show smokers are at 2-3 times greater risk of developing chronic kidney disease and experience faster deterioration of kidney function when injured. Quitting smoking and avoiding secondhand smoke is highly recommended to preserve kidney health.
Certain Medications
While many medications are processed and excreted by the kidneys, some drugs are directly toxic to the kidneys with regular long-term use. These include:
– Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen
– Certain antibiotics like aminoglycosides
– Antiviral drugs including tenofovir and acyclovir
– Some chemotherapy drugs like cisplatin
– Lithium
– Contrast dye agents used in some imaging tests
Use of potentially nephrotoxic medications should be carefully screened, dosed, and monitored by doctors to prevent harm, especially in those already at risk for kidney disease. Short-term or alternating use may also minimize kidney damage.
Autoimmune Diseases
Certain autoimmune conditions commonly impact the kidneys, causing immune cells to attack healthy kidney tissue. These include:
– Lupus
– IgA nephropathy (Berger’s disease)
– Glomerulonephritis
– Scleroderma
Treating the underlying autoimmune disorder and associated inflammation helps prevent progressive kidney damage. Immunosuppressant therapy may be warranted once kidney involvement occurs.
Urinary Tract Infections
Recurrent urinary tract infections from bacteria can form kidney infections or pyelonephritis. This occurs more frequently when urinary tract infections go untreated or unrecognized.
Kidney tissue becomes injured during the immune response to clear the bacteria. Repeated kidney infections create permanent scars on the kidney itself, impairing proper function. Prompt treatment of urinary tract infections prevents significant kidney injury.
Urinary Obstruction
Blockage anywhere in the urinary tract obstructs urine flow and pressure starts to build up behind the blockage. This back pressure damages the delicate kidney tubules and lowers kidney function over time.
Causes of urinary obstruction include:
– Kidney stones
– Benign prostatic hyperplasia (enlarged prostate)
– Tumors or cancers in the urinary tract
– Strictures
– Neurogenic bladder that does not empty properly
Relieving obstructions, treating bladder problems, and proper urinary catheter care preserves kidney health.
Kidney Infections
Bacterial and viral infections specifically affecting the kidney tissue, called pyelonephritis, are another common cause of kidney injury if they become chronic or recurrent. Certain viruses that can infect the kidneys include:
– Polyoma BK virus
– Hepatitis B and C viruses
– HIV
– Hantavirus
– Coxsackievirus
Bacterial kidney infections are often due to the bacteria E. coli, Klebsiella, Staphylococci, and Streptococci species travelling up to the kidneys from the bladder.
Kidney infections require prompt antibiotic treatment. Controlling any underlying medical conditions that increase susceptibility to kidney infections also helps prevent repeat infections that could lead to chronic kidney disease.
Exposure to Toxins
Exposure to environmental toxins and dangerous substances can directly damage the kidneys:
Heavy metals – Cadmium, lead, mercury, arsenic
Aristolochic acid – Found in some plants used in Chinese herbal medicine
Myotoxin in mushrooms – Some wild mushroom species
Chemicals – Ethylene glycol, dry cleaning chemicals, gasoline, ammonia, uranium
It is important to minimize exposure to nephrotoxins by taking safety precautions when handling hazardous substances. Getting prompt medical treatment after any toxic exposures can limit kidney damage. Certain medications like chelating agents help remove heavy metals from the body.
Genetic Kidney Diseases
There are also some inherited genetic mutations and conditions that cause a higher risk of developing chronic kidney disease and kidney failure. These include:
– Polycystic kidney disease
– Alport syndrome
– Fabry disease
– Sickle cell disease
Being aware of any potential genetic kidney conditions based on family history allows closer monitoring for early signs of disease. Limiting other kidney risk factors provides the best chance to slow further progression.
Aging
As we age, the kidneys naturally become less efficient. The number of functioning nephrons declines over time. Remaining nephrons also hypertrophy to adapt, losing some function.
Older adults produce less of the hormone erythropoietin, which signals the kidneys to make red blood cells. Renal blood flow is also reduced with aging kidneys.
Aging alone does not necessarily cause clinically significant kidney dysfunction. But the kidneys do lose some of their reserve capacity, making it important to be vigilant about controlling other CKD risk factors as we get older.
Dehydration
Not getting enough fluid intake leads to volume depletion and dehydration. This stresses all organs, including the kidneys. With dehydration, the kidneys conserve water by forming small, concentrated amounts of dark urine.
This concentrates waste in the urine and can lead to crystals or kidney stones developing. The kidneys may suffer subclinical injury each time dehydration occurs, increasing future CKD risk.
Certain groups like the elderly, athletes, outdoor workers, and kids are at higher risk for dehydration. Drinking adequate water and hydrating fluids throughout the day prevents volume depletion from recurring.
Risk Factors by Lifestyle
There are certain lifestyle factors and behaviors that negatively impact kidney health:
| Lifestyle Factor | Effects on Kidneys |
|---|---|
| Excessive NSAID use | Direct kidney injury, kidney scarring |
| Illicit drug use | Heavy metal toxicity, rhabdomyolysis |
| High protein supplements | Increased filtration demands |
| Chronic dehydration | Volume depletion, kidney stone risk |
| High-impact sports | Repeated kidney contusions |
| Heat stress | Ischemic kidney damage |
| Fad diets | Electrolyte imbalance, vitamin deficiencies |
Making positive lifestyle changes like staying well hydrated, limiting NSAIDs and protein supplements, and avoiding illicit drugs protects the kidneys from harm.
Preventing Kidney Disease
Many cases of chronic kidney disease can be prevented by prudently managing risk factors:
– Follow an overall healthy diet low in sodium, phosphorus, and animal proteins but high in fruits, vegetables, whole grains, and plant proteins. Stay well hydrated.
– Exercise and lose weight if obese or overweight. Reduce belly fat.
– Don’t smoke or use tobacco products. Avoid secondhand smoke.
– Control blood pressure and cholesterol with medication if prescribed.
– Manage blood glucose levels if diabetic. Get regular screenings.
– Restrict analgesics like NSAIDs if chronic use needed. Avoid illicit drugs.
– Drink fluids before, during, and after exercise or outdoor activities to avoid dehydration.
– Treat any infections promptly, especially recurrent UTIs. Practice safe sex.
– Avoid nephrotoxins like heavy metals and certain chemicals. Take precautions when handling.
– Get screened for kidney disease if at higher genetic risk.
Conclusion
Kidney disease develops slowly and silently over many years, often without symptoms until extensive damage has occurred. Several modifiable and non-modifiable risk factors contribute to the development and progression of chronic kidney disease.
Being aware of lifestyle habits, medical conditions, and environmental exposures that strain the kidneys allows steps to be taken early on to minimize damage and prevent impairment of function. With prudent risk factor management and lifestyle changes, kidney health can be preserved and improved.