Alkaline Diet and Metabolic Acidosis: Practical Approaches to the Nutritional Management of Chronic Kidney Disease.
The kidneys play an extremely important role in maintaining the body acid–base balance by excreting nonvolatile acids and regenerating and reabsorbing bicarbonate in the kidney tubules. As the individual loses their kidney function, renal excretion of nonvolatile acid produced by metabolism of the diet is impaired, resulting in low-grade metabolic acidosis. With this in mind, it is relevant to better understand the dietary aspects related to the acid–base balance in chronic kidney disease metabolic acidosis and try to provide possible strategies for the nutritional management of these cases. The type of diet can deeply affect the body by providing acid or base precursors. Generally speaking, foods such as meat, eggs, cheese, and grains increase the production of acid in the organism, whereas fruit and vegetables are alkalizing. On the other hand, milk is considered neutral as well as fats and sugars, which have a small effect on acid–base balance. The modern Western-type diet is deficient in fruits and vegetables and contains excessive animal products. Thus metabolic acidosis may be exacerbated by a contemporary Western diet, which delivers a high nonvolatile acid load. The remaining acid is neutralized or stored within the body. Bone and muscle are lost to neutralize the acid and serum bicarbonate falls. Early studies suggest that lowering the dietary acid load with a reduced protein content and vegetable proteins replacements, associated with an increase in fruits and vegetables intake can improve the metabolic parameters of acidosis, preserve bone and muscle, and slow the glomerular filtration rate decline. More studies focusing on the effects of controlled dietary interventions among chronic kidney disease patients are needed to determining the optimal target for nutritional therapy.