When it comes to bone nutrition, the situation with protein is somewhat of a paradox — similar to that with fats. While some protein is essential, too much is detrimental. Protein is beneficial for intestinal absorption of calcium, and protein is a major building block for bone. By weight, roughly one-third to one-half of our bone is living organic protein matrix! Protein malnutrition debilitates bone, and can be a significant problem among the elderly in Western countries.
Yet over-consumption of dietary protein (think Atkins diet) — again, if not adequately balanced with alkalizing compounds of minerals like calcium, magnesium, potassium — can likewise lead to bone loss. In this case the loss results from an increased acid load which our bodies must buffer daily by drawing calcium and other alkalizing mineral compounds from the bones.
While adequate protein intake is certainly necessary, the average person in the US consumes far too much protein in the form of meat and dairy products. Not that either of these foodstuffs are bad per se — we just need to remember to balance them with plenty of alkalizing fruits and vegetables, including some high-carb but nutrient-dense veggies like sweet potatoes and carrots. This excess animal protein intake leads to a state known as chronic low-grade metabolic acidosis (CLGMA), which actually washes calcium out of the body.
For more information on chronic low-grade metabolic acidosis, see my article on acid-alkaline balance.