Diplomate, Board Certification of Emergency Medicine
Chairman, Department of Emergency Medicine Ma'ayenei Hayeshua
Hospital
Processed food is full of chemicals. Even unprocessed food
contains many substances that the body can't use and may be
harmful. Bacteria are swallowed with all food, as are
insecticides, and occasionally soil products, insect eggs and
cleaning agents. How does the body deal with this?
Indigestible products are the easiest. They leave through the
stool, untouched, usually. Chemicals and poisonous by-
products are generally cleared by the liver, and we will
speak about them in the near future. Bacteria rarely leave
the stomach alive, as the area is so acidic that few species
can live there.
This article and the next will deal with soluble poisons,
that is, by-products that the body can dissolve in water.
This is the kidney's job and it is an amazing one.
One by-product of cell metabolism is urea, which comes from
the breakdown of proteins and creatinine. Often sodium,
water, potassium, calcium, magnesium and other salts must be
removed from the body due to excesses. Acids and bases can be
buffered to make them less dangerous and then removed via
this pathway as can medications and substances that are
dissolvable in water. The end product is urine and the study
of urine through a urinalysis can often reveal to us exactly
what is going on in the body.
A major artery brings the blood to the kidney, where it is
filtered by millions of units called glomeruli. Afterwards
this fluid goes down a loop which exposes it to many small
blood vessels where fine-tuning is done, and much of the
filtrate is reabsorbed. When there is too little water in the
blood stream, such as in dehydration, much of the fluid is
reabsorbed to conserve fluid, and the urine is very
concentrated (this may appear as dark urine and less need to
urinate). Too much water? Well a very dilute urine will
result, light in color, and a person will need to use the
bathroom soon after imbibing too much fluid.
Too much salt in your food? The kidneys will get rid of that
too, but salt requires water to travel with it, so the
kidneys will tell the body to drink more. The result will be
thirst and water retention until the kidneys can catch up.
Potassium excess works the same way. It follows that giving
too much water can dilute the sodium in a person's body,
which can be dangerous, but normal kidneys can deal with this
just fine.
Sugars and proteins are generally not filtered through,
unless there has been an excess of either or the kidneys are
not working well.
Before we speak about pathology, let us just deal with some
common signs. Excess urination is usually a result of excess
fluid in the body, but can be a sign of diabetes or
infection. Smelly urine can be from infection or overeating
proteins -- this is an ammonia smell. Orange and blue urine
are from medications, burgundy colored urine can be bleeding
or from eating beets. Generally urine is sterile when it
leaves the body and is neutral in pH. If urine burns when it
comes out, this is a sign of infection. Write me in care of
the Yated.
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