Kidney Disease 99were 40 to 60 percent less likely to have a recurrence of kidney stones
than the group with increased fl uids only.
The problem with large quantities of meat in the diet is that urea,
the by-product of protein breakdown, causes too much urine to be
excreted. This has the effect of throwing out the baby with the bath-
water, because alkaline-forming mineral molecules are excreted along
with the urea when urine output is excessive. Without enough alka-
linizing minerals to neutralize acid waste in the blood, the urine
becomes highly acidic. The greater number of acidic particles in the
urine the more likely they are to stick together. When enough of these
particles adhere to each other, they form a stone.
Kidney stones are usually composed of calcium and oxalic acid.
What most people with kidney stones don’t know is that oxalic acid,
like calcium, performs a vital function. Ninety-eight percent of the
oxalic acid in the body is produced internally and is used for moving
food through the digestive tract by peristalsis (the contraction and
relaxation of muscles). Oxalic acid also aids in the absorption of calcium
into the cells.
Leftover oxalic acid, along with excess calcium, is removed from the
blood by the kidneys and passes into the urine. Calcium oxalate perme-
ates the urine generally, but only in those people whose urine is over-
loaded with acid waste does it form stones.
It would seem that the way to prevent kidney stones would be to
alkalinize the urine. But urologists, unaware apparently that the pH
factor in the urine determines whether or not stones are formed, rec-
ommend reducing the levels of calcium and oxalic acid in the diet. Kid-
ney stone patients are instructed not to eat any green vegetables,
especially broccoli, which is high in calcium, and spinach, beet greens,
and chard because of their high oxalic acid content. By doing so, doc-
tors are depriving their patients of valuable nutrients, one of which,
calcium, actually helps prevent kidney stones by alkalinizing the
urine.
It’s probably a good idea for anyone who has a tendency to form
stones to go easy on cooked spinach, beet greens, and rhubarb, the only
foods that are extremely high in oxalates (although oxalates from these
foods constitute only 2 percent of the oxalates in the body, hardly
enough to be considered responsible for creating stones). These greens,
however, can be eaten in generous amounts if they are raw.