Healthy Kidney Function (Maintaining a good GFR)
Kidneys filter your blood, a total of about 200 quarts per day as it moves throughout your body. They remove waste products, excess water and chemicals that would be harmful to your health if they weren’t removed. Your kidneys have tiny filtering tubes called glomeruli that strain out poisonous substances. Ideally, they filter waste from your blood at the rate of 90 milliliters (mL) or more per minute. This is called the glomeruli filtration rate (GFR). Although these glomeruli are remarkably adaptable to your body’s changes, there are things you can do to help them and your kidneys maximize their effectiveness at doing their job to help keep you healthy.
Kidney Enemy #1: Excess Creatinine
A principal measure of kidney health is the blood level of a substance called creatinine. The creatinine level is used to calculate the GFR. Although the ideal GFR is 90, you can reach a reduced kidney function with a level as low as 50, be stable and never slide down to the next stage of kidney disfunction. However, if you are experiencing some of the symptoms that appear in the next paragraph, it is recommended that you have a lab test to check your GFR because, according to Dr. Melanie Hoenig, an assistant professor of medicine at Harvard-affiliated Joslin Diabetes Center, “Most people don’t start feeling really ill until kidney function is under 10%”.1 After age 30, attention to your GFR is vital because “GFR declines 1% per year for every year of life after the third decade”.2
How High Blood Pressure Damages Your Kidneys
High blood pressure can cause the arteries that feed blood to the kidneys to become narrow. When this happens the body produces a hormone called renin, which makes the arteries even narrower. Narrowing the arteries in this way makes for even higher blood pressure, causing more kidney damage and eventually destroying the nephrons, the tiny filtering units inside your kidneys. 3
Symptoms of Kidney Disease
Signs and symptoms of chronic kidney disease develop over time if kidney damage progresses slowly. Signs and symptoms of kidney disease may include:
- Loss of appetite
- Fatigue and weakness
- Sleep problems
- Changes in how much you urinate
- Decreased mental sharpness
- Muscle twitches and cramps
- Swelling of feet and ankles
- Persistent itching
- Chest pain, if fluid builds up around the lining of the heart
- Shortness of breath, if fluid builds up in the lungs
- High blood pressure (hypertension) that’s difficult to control
Signs and symptoms of kidney disease are often nonspecific, meaning they can also be caused by other illnesses. Because your kidneys are highly adaptable and able to compensate for lost function, signs and symptoms may not appear until irreversible damage has occurred.
Causes of Kidney Disease
Chronic kidney disease occurs when a disease or condition impairs kidney function, causing kidney damage to worsen over several months or years.
Diseases and conditions that cause chronic kidney disease include:
- Type 1 or type 2 diabetes
- High blood pressure
- Glomerulonephritis, an inflammation of the kidney’s filtering units (glomeruli)
- Interstitial nephritis, an inflammation of the kidney’s tubules and surrounding structures
- Polycystic kidney disease
- Prolonged obstruction of the urinary tract, from conditions such as enlarged prostate, kidney stones and some cancers
- Vesicoureteral reflux, a condition that causes urine to back up into your kidneys
- Recurrent kidney infection, also called pyelonephritis
Factors that may increase your risk of chronic kidney disease include:
- High blood pressure
- Heart and blood vessel (cardiovascular) disease
- Being African-American, Native American or Asian-American
- Family history of kidney disease
- Abnormal kidney structure
- Older age
Chronic kidney disease can affect almost every part of your body. Potential complications may include:
- Fluid retention, which could lead to swelling in your arms and legs, high blood pressure, or fluid in your lungs (pulmonary edema)
- A sudden rise in potassium levels in your blood (hyperkalemia), which could impair your heart’s ability to function and may be life-threatening
- Heart and blood vessel (cardiovascular) disease
- Weak bones and an increased risk of bone fractures
- Decreased sex drive, erectile dysfunction or reduced fertility
- Damage to your central nervous system, which can cause difficulty concentrating, personality changes or seizures
- Decreased immune response, which makes you more vulnerable to infection
- Pericarditis, an inflammation of the saclike membrane that envelops your heart (pericardium)
- Pregnancy complications that carry risks for the mother and the developing fetus
- Irreversible damage to your kidneys (end-stage kidney disease), eventually requiring either dialysis or a kidney transplant for survival 4
Protecting Your Kidneys
Keep your blood pressure and blood sugar within norms. This will help slow the decline in kidney function. Especially, keep blood pressure below 130/80.
Lower your cholesterol. Taking a statin medication to lower “bad” LDL cholesterol may help to protect the kidneys. Also, individuals with reduced kidney function are at greater risk for cardiovascular disease, so reducing cardiac risk factors is important.
Limit protein intake. Eating too much protein can strain weak kidneys. Limit your protein intake every day to no more than 1 gram per kilogram (2.2 pounds) of body weight. Consulting with a dietitian can help you plan meals that are safe for weak kidneys.
Use NSAIDs with caution. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (e.g., Advil and Motrin) and naproxen (e.g., Aleve), interfere with kidney function. Taking them when you are also depleted of fluids can lead to kidney shutdown and possibly hospitalization. Drink plenty of water if you must take NSAIDs. As kidney function declines, doses of other medication may need to be reduced to prevent kidney damage, including antibiotics, diabetes drugs, and some heart medications. Consult your primary care practitioner if you are taking any of these and have concerns about how they may adversely affect your kidneys’ health and function.
Consider medication. Certain prescription medications can protect the kidneys. The two that physicians often use for this purpose are ACE inhibitors (also commonly prescribed for high blood pressure) and angiotensin-receptor blockers (ARBs). These or other drugs can lower pressure in the kidney filters and limit further damage.5
Non-prescription Herbal Remedies to Maintain Kidney Health
Many turn to herbs and supplements containing herbs to avoid the higher cost of prescription medicines. Some assume that because they are natural, they are not potentially harmful. However, because they are not subject to testing and approval by the Federal Drug Administration (FDA), they carry no warnings of adverse reactions and potential interactions with other medicines and supplements. It is best to get the opinion of a health care professional before using them.
To get more information about drug-free and dialysis-free treatment of kidney disease and the learn how to avoid developing kidney problems in the first place, click on the banner below.
1 Weak kidneys? Pay attention but don’t worry excessively, published May, 2013 by the Harvard Medical School, https://www.health.harvard.edu/diseases-and-conditions/weak-kidneys-pay-attention-but-dont-worry-excessively
2 Diagnosis and Management of Chronic Kidney Disease, John W. Graves, M.D., September, 2008 Mayo Clinic Proceedings, http://www.mayoclinicproceedings.org/article/S0025-6196(11)60609-5/fulltext
3 Weak kidneys? Pay attention but don’t worry excessively, published May, 2013 by the Harvard Medical School, https://www.health.harvard.edu/diseases-and-conditions/weak-kidneys-pay-attention-but-dont-worry-excessively
5 Weak kidneys? Pay attention but don’t worry excessively, published May, 2013 by the Harvard Medical School, https://www.health.harvard.edu/diseases-and-conditions/weak-kidneys-pay-attention-but-dont-worry-excessively