How the Kidney manages Protein
Your kidneys filter waste products from your blood allowing a clean and filtered supply to continue to flow through your body. Your kidneys ensure the blood re-entering your veins contains exactly what your body needs.
Specifically, the kidney maintains the balance of water, electrolytes and acid-base in addition to removing toxins, and producing various hormones that our bodies need.
The kidney deals with 2 basic types of Proteins: small proteins and large proteins.
Smaller proteins are absorbed as they pass through the kidney, broken down into amino acids and returned to the blood whereas large protein molecules, like Albumin, are retained in the blood due to their size.
An Albumin molecule is a flexible ellipsoid molecule about 3.6 nanometres in diameter and 15nm long. It encounters the kidney’s filter slit which is about 3.5nm wide. During blood filtration most albumin molecules do not pass through the kidney’s filter due to its physical properties, however, some will pass through due to their ellipsoid shape and their flexible nature somehow slipping through the filtration slit.
There are estimates that the kidney reabsorbs about 9.6 g per day of low weight protein molecules per day and filters and retains about 3.2g per day of Albumin per day.
Protein is important for the functioning of your body as it is in every cell in the body and is used to build and repair tissue, make enzymes, hormones, and other chemicals as well as being an important building block of bones, muscles, cartilage, skin, and blood.
What causes Protein in Urine?
As mentioned above, some protein will appear in your urine as part of the normal functioning of the body. There are healthy reasons why this base level of protein may increase, and unhealthy reasons which may indicate the presence of a condition that requires medical treatment.
Normal stresses such as exercise, dehydration, emotional stress, fever and pregnancy can lead to temporary increased protein excretion in the urine. This is not permanent and protein excretion will return to normal once the stress to the body has been removed.
If there is presence of protein in urine in the absence of the above stresses, and, or it appears over a longer period of time, this can be an important indicator of renal disease.
Kidney disease is insidious as it can develop undetected in the body until it is in a very late stage and it is too late to intervene to avoid serious health issues. Detecting Protein in Urine is important as it may be the first sign of a serious problem and may appear long before other clinical symptoms.
Before jumping to the most serious conclusions, it is important to understand some factors, temporary conditions or existing diagnosed diseases that can lead to increased protein in urine.
- Patients with a Urinary Tract Infection can experience a mild presence of protein in urine.
- Long term diabetes can lead to kidney damage. Patients with undiagnosed diabetes, or diabetic patients not treated well due to poor diet and/or drug management) can experience kidney damage revealed through the presence of protein in urine.
- High blood pressure and Hypertension over time often leads to Proteinuria caused by kidney damage. The high blood pressure literally forces the large protein molecules through the kidney’s physical filters permanently damaging them.
- Some drugs like nonsteroidal anti-inflammatory drugs such as Ibuprofen, can lead to protein in urine.
If you having any of the above conditions and have protein in urine, you are at high risk of developing further complications and should work with your Doctor to diagnose and manage any problems. Every time you protein appears in your urine it means protein has breached your kidney filters.
It’s, therefore, important to:
- Treat the cause (not only drugs but also diet),
- Investigate if your treatment is appropriate and accurate; and finally
- routinely monitor your urine and track any presence of protein in your urine.
Protein in Urine and Kidney Damage
- Chronic kidney Disease
- Kidney infection (pyelonephritis)
- Inflammation in the kidney cells that filter waste from blood (Glomerulonephritis)
- Focal segmental glomerulosclerosis
- Damage to small filtering blood vessels in the kidney (Nephrotic syndrome)
- Kidney inflammation resulting from a build-up of the antibody immunoglobulin A (Berger’s disease, IgA nephropathy)
- Acute tubular necrosis
What you can do
In any of the situations described in this article you can act proactively and better understand your condition by routinely checking, monitoring your urine, follow your disease evolution and share your results with your doctor.
The existence of low cost and widely available urine tests are a handy tool to help you do this. By testing Urine at home you can track the levels of protein in your urine, identify a potential urinary tract infection and other conditions and enable you to take action before the presence of other physical symptoms.
