The Physiological Answer to a Therapeutic Mystery
The medical findings on urine and urine constituents are overwhelming, and yet it’s difficult for most people to understand why our bodies excrete elements that are so obviously valuable to human health and well-being.
The commonly-asked question, “If your urine is so good for you, why does your body excrete it?” is best answered by looking into how our kidneys function. As your blood moves through the circulatory system, it flows through the kidneys at a rate of about 1200 ml of blood per minute. Inside the kidneys, the blood is continuously filtered through a huge system of minute tubules called nephron which sift out excess water, vitamins, minerals, enzymes, salts, and hundreds of other elements including vital antibodies, urea and uric acid.
A large portion of these key physiological elements are reabsorbed into the bloodstream, but a certain amount of critical blood constituents are pooled by the kidney into a liquid which doctors refer to as a “plasma ultrafiltrate” (we call it urine). Much of this sterile, nutrient filled ultrafiltrate, or urine, is reabsorbed and some remains in the kidney for a period of time and is eventually released into a tube called the urethra which empties the urine into the bladder where it is finally excreted. Now you’re probably wondering why the body excretes valuable nutrients, water, hormones, enzymes, etc. that are critical to body functioning. Doesn’t it make more sense to retain these elements? If urine is a collection of such life-sustaining elements, why does the body get rid of it?
The answer is that the kidneys excrete a portion of urine as a way of removing certain key elements in your blood that are simply not needed at a specific point in time. For instance, you’ve just been out jogging. You come home and have one or two big glasses of water to drink. Now at this point you’ve probably taken in more water than your body actually needs. But not to worry — your kidneys will balance the amount of water delivered into your bloodstream by your copious water drinking and through the urine will excrete whatever amount of water from the blood that isn’t needed at the time.
Now water is certainly a life-sustaining element the body cannot do without. So why is it excreted from the body? The answer is obvious. There are times when there’s too much water in your system and it needs to be excreted.
It’s a physiological fact that in order for us to function normally, the amounts or concentrations of every element in our blood must be carefully and strictly controlled and this is done by the kidneys. Too much water in the blood is fatal. Too much salt in the blood is deadly. As wonderful a nutrient as vitamin C is, too high a concentration of it or any nutrient could kill you. This is why the kidneys excrete valuable elements from the body — too much of any good thing isn’t good for your health.
The same is true of urea. People who have heard of uremic poisoning are surprised when they read the medical research showing urea to be a widely-used, FDA-approved medicine. But just like any other element in the blood, urea only becomes dangerous to the body when the kidneys are damaged or diseased and can’t properly balance the amount of urea (and all other substances) in the bloodstream.
Your kidneys aren’t doing damage to your body by getting rid of particular excess nutrients, they’re just simply excreting the precise amount not presently needed by your body at a given time. And the same goes for practically every nutrient, enzyme, hormone, antibody, etc. that are critical to your survival — the kidneys keep what your body needs at a certain time, and excretes what it isn’t momentarily using into your urine. And as medical scientists and doctors have discovered, these urinary ingredients extracted from the blood can be therapeutic magic bullets.