"Protein Source: An Acid Test for Kidney Function"
Chronic kidney disease is a major public health problem
affecting about one in eight Americans,
increasing the risks of disease and death
even among those with only mild decreases in kidney function.
So low cost, low risk preventive strategies
that anyone can do are needed
to address the epidemic of kidney disease.
Diet plays a role in kidney function decline.
Specifically, diets higher in animal protein,
animal fat, and cholesterol,
may be associated with protein leakage into the urine
(a sign of kidney damage),
and generally, diets higher in fruits vegetables,
and whole grains, lower in meat and sweets,
may be protective against kidney function decline.
In comparison to the diet eaten by our ancestors,
not only are we eating more saturated fat, sugar, and salt
we're now eating an acid-producing diet,
as opposed to a base-producing or alkaline diet.
Ancestral human diets were largely plant-based,
and as such produced more base than acid.
Dietary acid load (DAL) is determined
by the balance of acid- inducing food,
which is rich in animal proteins
(such as meats, eggs,and cheese)
offset by base- inducing foods
such as fruits and vegetables.
And in this national survey of 12,000 American adults,
dietary acid load was associated with
kidney damage among U.S. adults.
Acid-inducing diets are believed to impact
the kidney via tubular toxicity,
damage to the tiny delicate urine-making tubes
in the kidney via increased ammonia production.
See, ammonia is a base, so the kidney creates ammonia
to buffer the acid from the food we eat.
This is beneficial in the short term
to get rid of the acid,
however, in the long term,
all that extra ammonia in our kidneys
day in and day out can exert toxic effects.
Our kidney function tends to decline progressively
after our 30’s, and by our 80’s
our kidney capacity may be down to half.
Perhaps this so-called age-related decline
in kidney function is a result of damage
induced by a lifetime of ammonia overproduction.
That’s just one theory, though.
The acidic pH may increase the production of free radicals
and damage the kidney that way, add to scarring.
Not only is protein derived from plant foods
accompanied by antioxidants to fight the free radicals,
plant protein is less acid forming in the first place,
because it tends to have less sulfur–containing amino acids.
One of the reasons plant foods tend to be less acid-forming
than animal foods is because acid is produced by the sulfur
in the protein, and there’s less in plant proteins.
So, the more important determinant of the effect
of dietary protein on kidney disease progression
is the QUALITY of the ingested protein
in other words, whether it induces acid-production
like most animal protein,
or base production like most fruit and vegetables
rather than the quantity of protein ingested.
Since American diets are largely acid-producing
because they are deficient in fruits and vegetables
and contain large amounts of animal products,
changing from a standard American diet to a vegan diet
may improve acidosis in patients with chronic kidney disease.
Under normal circumstances a vegetarian diet is alkalinizing
whereas a non-vegetarian diet leads to an acid load.
This is true even of vegetarians
that consume processed meat replacements like veggie burgers.
Plant-based diets have been prescribed for decades
for those with chronic kidney failure.
No animal fat, no cholesterol, less acid load,
and helps lower blood pressure.
And indeed if you compare the kidney function
of vegans to vegetarians to omnivores,
the most plant-based diet was associated
with improved parameters for the prevention
of degenerative kidney decline.