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Several researchers have noted that the contemporary Western diet has increased in net acid load relative to diets of the ancestral pre-agricultural Homo sapiens.(TM) Quite possibly, this shift occurred because of the agricultural revolution and the ubiquity of processed grains and shelf-stable food products devoid of essential nutritional components. In addition to this underlying foundational change in diet, there is the overlay of various nutritional fads that have risen and fallen over the past few decades. Most recently, the latest diet trend has been an interest in high-protein foods accompanied by a compensatory decrease in the phytochemical load from fresh fruits and vegetables. Indeed, high-protein diets increase net dietary acid load and acidify the urine pH.25 Conversely, diets high in fruits and vegetables have been proposed to be associated with a greater degree of alkalinity.46 Remer and Manz calculated the potential renal acid loads of certain food groups and reported that alkaline-forming foods were primarily vegetable and fruits, whereas acid-forming foods were derived from cheese, meat, fish, and grain products (Table 1).4
Over time, ingestion of a high dietary acid load can progress to a chronic low-grade level of metabolic acidosis. The incidence of low-grade acidosis resulting from our modern diet has been well documented.1-3,6 A chronic acidic load can cause a number of health conditions such as osteoporosis, kidney disease, and muscle wasting.1,7 Sebastian et al articulates this cause and effect relationship eloquently: "Increasing evidence ... suggests that such persisting, albeit low-grade, acidosis, and the relentless operation of responding homeostatic mechanisms, result in numerous injurious effects on the body including dissolution to bone, muscle wasting, kidney stone formation, and damage to the kidney."1(p1308)
In order to maintain acid-alkaline balance throughout the various body systems, one system may be required to support another. For example, the bone matrix contains a substantial alkaline reserve such as calcium and magnesium cations that are released from the bone to balance an overly acidic dietary load in the event of inadequate buffering capacity in the blood. However, repeated borrowing of the body's alkaline reserve in response to a consistent increased (dietary) acid load can be potentially detrimental. In humans, hypercalciuria and negative calcium balance due to calcium efflux from bone may lead to metabolic bone disease and calcium nephrolithiasis.2,8,9...