Marilyn Harris 
> What I read about this ph stuff is that it is all nonsense. The body
> maintains and operates within, a very narrow range of acidity. Testing
> your
> pH from your urine proves nothing as this is an excretory product (and
> can
> show some variation). What's important is the pH of your blood.

While some, such as Gabe Mirkin, M.D.
(http://www.drmirkin.com/email/contact.asp) consider the acid/alkaline
theory of disease to be "nonsense," there is quite a bit of research backing
it up. I asked Dr. Mirkin for a comment on this research, but he didn't
reply. Vegetarians/vegans often use this research in their arguments, so the
initial reaction of Paleo diet advocates might be to discount it as bogus,
but Paleo diets that include fruits and vegetables actually have a favorable
acid/alkaline ratio, so the theory supports Paleo dieting as well, though it
does raise the question of whether an Inuit-type diet contributes to
osteoporosis, which some have indeed claimed.

Cordain says that urine pH can drop to 5 on an acidifying diet, and calcium
is leached to keep it at 5 when the pH drops further.


Are Higher Protein
Intakes Responsible for Excessive
Calcium Excretion? 
by Loren Cordain, Ph.D.
http://www.beyondveg.com/cordain-l/prot-calc/prot-calcium-loss-1a.shtml

"*Acid/alkaline dietary load.* Additionally, bone mass is also dependent
upon the relative acid/alkaline dietary load [Massey 1998; Barzel and Massey
1998]. Acid generated by the diet is excreted in the urine and can cause
calciuresis. Meat and fish have a high potential renal acid load (PRAL)
whereas fruits and vegetables have a negative PRAL, meaning they reduce acid
excretion. The human kidney cannot excrete urine with a pH lower than 5;
consequently the acids (mainly phosphate and sulfate) of acid-producing
foods such as meats, fish, and some cereals must be buffered partially by
calcium which is ultimately derived from the skeleton [Massey 1998; Barzel
and Massey 1998]."


Acid/Base Balance
by Loren Cordain, Ph.D.
http://www.thepaleodiet.com/acidbase.htm

"In the U.S. calcium intake is one of the highest in the world, yet
paradoxically we also have one of the highest rates of bone
de-mineralization (osteoporosis).  Bone mineral content is dependent not
just upon calcium intake but upon net calcium balance (calcium intake minus
calcium excretion).  Most nutritionists focus upon the calcium intake side
of the calcium balance equation, however few realize that the calcium
excretion side of the equation is just as important.

Bone health is substantially dependent on dietary acid/base balance.  All
foods upon digestion ultimately must report to the kidney as either acid or
base.  When the diet yields a net acid load (such as low-carb fad diets that
restrict consumption of fruits and vegetables), the acid must be buffered by
the alkaline stores of base in the body.  Calcium salts in the bones
represent the largest store of alkaline base in the body and are depleted
and eliminated in the urine when the diet produces a net acid load.  The
highest acid-producing foods are hard cheeses, cereal grains, salted foods,
meats, and legumes, whereas the only alkaline, base-producing foods are
fruits and vegetables.  Because the average American diet is overloaded with
grains, cheeses, salted processed foods, and fatty meats at the expense of
fruits and vegetables, it produces a net acid load and promotes bone
de-mineralization.  By replacing hard cheeses, cereal grains, and processed
foods with plenty of green vegetables and fruits, the body comes back into
acid/base balance which brings us also back into calcium balance.  The goal
is to avoid a net acid load on your kidneys.

The Paleo Diet recommends an appropriate balance of acidic and basic
(alkaline) foods (i.e., lean meats, fish and seafood, fruits, and
vegetables) and will not cause osteoporosis in otherwise healthy
individuals.  Indeed, The Paleo Diet promotes bone health.

In addition to promoting bone demineralization, a net acid-producing diet
also contributes to the following maladies and illnesses: calcium kidney
stones, age related muscle wasting, hypertension, stroke, asthma and
exercise induced asthma.

The following table lists the acid, base values for 114 common foods.
Base-producing foods are fruits and vegetables, whereas grains, meats, fish,
cheese and salted processed foods are acid-producing. ..."


Ray Audette, NeanderThin, p. 58:

"The milk of herbivores (cows, goats, etc.) is designed for an entirely
different sort of digestive system and often conflicts with that of humans.
Many people are lactose-intolerant ... or are intolerant to the acids
produced as a by-product of milk."


> Dr. Katherine Tucker led a study at Tufts University examining the bone
mineral status of a large group of elderly men and women. The study found
that the people who ate the most fruits and vegetables (alkaline foods) had
the greatest bone mineral densities and the strongest bones. (Tucker KL et
al. Bone mineral density and dietary patterns in olderadults: the Framingham
Osteoporosis Study. Am J Clin Nutr 2002;76:245-52.)

> Scientists at the Research Institute of Child Nutrition in Dortmund,
Germany found that plant-based diet appears to have a lower acid load,
whereas animal products increase acidity. (Remer, T. & Manz, F. Potential
renal acid load of foods and its influence on urine pH. J. Am. Diet. Assoc.
95:791-797.)

> A study in the New England Journal of Medicine by Dr. Anthony Sebastian
and his research group at the University of California at San Francisco
indicated that taking potassium bicarbonate (an alkaline base) neutralizes
the body's internal acid production, reduces urinary calcium losses, and
increases the rate of bone formation. (Frassetto L, Morris RC, Jr.,
Sebastian A. Long-term persistence of the urine calcium-lowering effect of
potassium bicarbonate in postmenopausal women. J Clin Endocrinol. Metab
2005;90:831-4.)

> Dr. Lawrence Appel at Johns Hopkins University reported in the Journal of
Nutrition that a low-salt DASH (Dietary Approaches to Stop Hypertension)
diet that is high in fruits and vegetables (alkaline foods), fiber,
potassium, calcium, and magnesium, and moderately high in protein, reduced
urinary calcium loss and bone turnover in 459 men and women, indicating it
may reduce the risk of osteoporosis. (Lawrence J. Appel et al. The DASH Diet
and Sodium Reduction Improve Markers of Bone Turnover and Calcium Metabolism
in Adults. J. Nutr. 133:3130-3136, October 2003.)

> Swiss researchers found that a high dietary acid load may have a negative
impact on bone density by increasing calcium excretion and bone resorption,
whereas alkalizing nutrients inhibit bone resorption. They called for
further research to determine whether reducing dietary acids is a preventive
measure against osteoporosis. (Buclin, T., Cosma, M., Appenzeller, M.,
Jacquet, A. F., Decosterd, L. A., Biollaz, J. & Burckhardt, P. 2001. Diet
acids and alkalis influence calcium retention in bone. Osteoporos. Int.
12:493-499.)