Is Your High Protein Diet Causing Your Bones To Lose Calcium?

high protein diet is an acid ash diet

Following a high protein diet on your weight loss diet meal plan can make you lose calcium in your bones. The average American diet usually high in protein and low in fruits and vegetables generates large amounts of acid. This is totally not a welcome challenge to your kidneys. A diet high in acid ash proteins creates an excessive loss of calcium due to its acidogenic content. An excessive dietary protein from foods comes with a high renal acid load that adversely impacts the bone.


A high acid ash intake results from a diet rich in animal proteins, such as meat, poultry and fish. The acid load from the diet lowers urinary pH and citrate but increases urinary calcium, which increases the risk for the formation of uric acid and potential stone formation.


The acid ash load, often associated with an excessive intake of animal proteins, often results in a diminished citrate excretion and a reduced urinary pH, thus increasing the risk of calcium oxalate stone formation.


A high protein diet is associated with an increased excretion of calcium in the urine and an increased risk of osteoporosis. In fact if you raise your daily protein intake from 47 to 142 grams, it would double the excretion of calcium in the urine.


A diet high in salt or acid ash also causes calcium removal from the bones and increases calcium loss in the urine. Basically, experts recommend avoiding salt and eating an alkaline based diet such as the diets that focused on vegetables and fruits, nuts and legumes.



Acid as well as alkaline ash is produced in the body in varying amounts, largely depending on the foods consumed. Most of the acids generated by these protein rich foods is thought to arise from the oxidation of the sulfur containing amino acids.


Many factors influence the loss of your bone mass. However, protein has been considered as both detrimental and beneficial to bone health.


Protein makes up about 50% of the volume of the bone and about 1/3 of its mass. A protein intake can provide the structural matrix of the bone, optimizes the IGF-1 levels, increase the urinary calcium, and increase the intestinal calcium absorption.


The high protein content of the Western diet affects the calcium homeostasis and is often cited as a risk factor for osteoporosis and bone fractures. As the protein intake increases, the human body mostly develops negative calcium balance and an increase of the urinary calcium.


To give you an idea. A 50% increase in urinary calcium is caused by doubling protein intake, which is roughly 1 mg urinary calcium for every gram of dietary protein.


If the kidneys cannot excrete the excess acid load due to the absence of adequate fruit and vegetable intakes, the bone releases calcium, magnesium and carbonate as buffers where the buffering is thought to occur at the expense of the bone.


The animal protein based diets has been observed to have a greater effect on the skeletal health than the vegetable based diets. The anabolic effect of protein on the bone is further complicated by the potential negative effect on the overall dietary acid base balance.


The Western type diet has been reported associated with osteoporosis and urinary calcium loss. A low grade metabolic acidosis in the blood has been perceived generated by the ingestion of large amounts of high protein foods, including drinking soft drinks.


Eating the right amounts of fruits and vegetables should help buffer the acid. A high protein – high acid ash diet is highly associated with an increased risk of fracture when the calcium intake is low.


With very limited amounts of fruits and vegetables, the animal proteins and grain based items are central to the acid ash diet. The acid-ash concept states that where there are excess blood protons, the bone is eroded to provide an alkali to buffer the net acidity and maintain physiologic pH.


acid ash diet impacts calcium levels in bones


Can cola do you harm?

One good example of a product that yields high levels of acid is the cola drink. The pH of the cola ranges from 2.8 to 3.2. The human kidney is able to excrete urine with a pH no lower than 5. If you ingest and fully absorbs a beverage with a pH of 3, you need to dilute it to achieve a urinary pH of 5.


To buffer the acid of the soft drink, a liter of cola requires about 4 tablets of Tums. The urinary calcium nearly doubles in a higher protein diet.


The effect of dietary protein is higher as you age because the aging kidneys cannot generate as much ammonium ions and excrete hydrogen ions as young kidneys do.


Soft drinks contain phosphates or phosphoric acid known to lower the calcium levels and increase the phosphate levels in the blood. When phosphate levels are high and calcium levels are low, the calcium is pulled out of the bones, which is the main reason they linked to osteoporosis.



Refined sugar

Regular consumption of refined sugar increases the risk for loss of calcium from the blood. Calcium is pulled from the bones to maintain blood calcium levels that were excreted through the urine.


Refined sugar increases the loss of calcium from the bone. Know that about 90% of the calcium found in the human body is in the bones.




Barzel, U. S. & Massey, L. K. (1998). Excess dietary protein can adversely affect bone. American Society for Nutritional Services, 128(6), pp. 1051-1053.

Heaney, R. P. & Laman, D. K. (2008). Amount and type of protein influences bone health. American Society for Clinical Nutrition, 87(5), pp. 1576S-1570S.

Nicoll, R., & McLaren, Howard (2014). The acid-ash hypothesis revisited: A reassessment of the impact of dietary acidity on bone. J Bone Miner Metab, 32(5): 469-75.



The concept of the acid ash proteins suggests that an excessive acid load in your diet from a high protein intake may trigger the release of calcium from the skeleton to serve as buffer of its highly acidic environment, leading to osteoporosis. The average American diet, which is high in protein and low in fruits and vegetables, may generate a large amount of acid. Several studies found an increased potential renal acid load resulting from a high protein diet closely associated with the increased urinary calcium excretion.

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