Frieda Wallace writes:

PA>What evidence actually exists that high-protein diets cause acidosis?  In
PA>what groups has this ever actually been observed?  The Inuit eat remarkable
PA>amounts of meat and don't seem to have trouble with acidosis.  Do they have
PA>some kind of special buffering that other humans do not?

            By high-protein diets we need to delineate them as either ketogenic or anti-ketogenic.  On a ketogenic diet, irrespective of the levels of the two main macronutrients (fat and protein) ketoacidosis by definition CAN NOT occcur in normal healthy human beings on this type of diet for the following reasons:
            1. Ketoacidosis envelops due to a total lack of insulin
            on a ketogenic diet, insulin's levels are indeed low, but the sensitivity of tissues to insulin's anti-ketogenic nature is vastly increased, i.e. less insulin but greater sensitivity to it.  Contrast this to a type I diabetic (IDDM) in which they are insulin deficient and are also ketoacidosis-prone. Type II diabetics are NOT ketoacidosis prone due to higher systemic insulin, but less tissue sensitivity, thus insulin's antiketogenic effect is in place.
            2. Ketoacidosis occurs due to a competition between fuels.
            Ketoacidosis only occurs in IDDM and alcoholics.  In IDDM ketosis occurs with hyperglycemia (high blood glucose levels).  Since the body is accostomed to using carbohydrates are a fuel (especially the brain) the ketones are not used and accumulate in the bloodstream, bring down pH, and a coma will shortly ensue.
            3. Ketones are self-regulating.
            The most amazing thing about ketosis as on a low-carb diet is the ability of ketone bodies to limit their production so as to never cross the maximal threshold.  They accomplish this mighty task by feedback regulation which includes the secretion of insulin to limit overproduction.  In IDDM with the lack of insulin this negative feedback inhibition is no longer present, and insulin is unable to reprise it's role in limiting over production.  In fact hyperketonemia, and the uncontrolled production of ketone bodies is accepted amoung the other above statements as one the central reasons this will occur in IDDM.

            There are other factors, but they require a working knowledge of interconversion rates between AcAc (acetoacetate) and BHB (beta-hydroxybutyrate), and the normal ratios of these two substrates in the body in normal vs. IDDM subjects.

            Don't be fooled by anyone though.  A ketogenic diet will lower pH some, but that only reflects the dietary intake of a ketogenic diet, the products of metabolism, and the compensatory mechansims at work like bi-carb reabsorption, ammonia to gluatmine, and the like.  If you are refering to non-ketogenic diet, that I highly doubt there would be any acidosis, and even then the protein intake would have to be substantial and far above any reasonable and prudent intake, i.e. excessive.

            JPK