Are Low-Acid Foods the Next Miracle Diet for Kidneys?

Acid producing diets could worsen your kidney function to the point of dialysis!

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Courtesy pallavi_damera; Flickr; Creative Commons 2.0 License

Acid in the blood is a normal waste product of metabolism. All living organisms require a tight balance between acid and alkali levels for normal life processes to work.The kidneys play an important role in regulating the level of acid in your blood.  Patients with kidney disease can see higher acid levels in the blood as compared to normal people.  

There is also recent evidence that high acid level in the blood might accelerate the decline in kidney function and increase the risk of death.

 It is because of these data that supplementing alkali to neutralize or "buffer" the excess acid is now an integral part of treatment of the chronic kidney disease patient.

Recently we have seen a lot of interest in understanding the role of diet in influencing acid levels in the blood.  For the holistic minded, it is an attractive approach because it could mean that reducing acid load in the diet (without resorting to medications) might slow down kidney disease progression.

THE ROLE OF DIET

The major source of acid in the blood is the food we eat.  Specifically protein.  Proteins are made of building blocks called "amino acids".  Some of these are amino acids are rich in sulfur. Therefore, normal metabolism leads to production of sulfuric acid which is one of the major circulating acids in the blood. Typical western diets are rich in acid or acid producing because of being high in animal-product content, while being low in foods and vegetables.

 

Why am I talking about this? Well, if acid is bad for your kidneys and mainly comes from diet, then perhaps dietary modification could help your kidneys? 

IS THERE ANY EVIDENCE TO SUPPORT THIS HYPOTHESIS

The science is there. Absolutely.

We do have evidence that diet can affect the acid alkali balance in our bodies.

We also know that this acid retention can lead to progressive decline in kidney function. But here is the most interesting part. Apparently this decline in kidney function can be slowed down by an alkaline diet! In a study, rats with kidney disease who were fed alkali as part of their diet (usually with sodium bicarbonate, aka baking soda), saw lesser decline in their kidney function than those who were not lucky enough to feast on baking soda.

Significantly, we might not even need to take questionable tasting substances like baking soda to see this benefit. Another influential study published in the Clinical Journal of the American Society of Nephrology in 2013 showed that a diet that was rich in alkali producing fruits and vegetables was as good as supplementation with sodium bicarbonate when it came to producing beneficial effects on the kidneys. 

Finally, another recent study published in the Journal of American Society of Nephrology has further confirmed these findings. What it showed was that in people with known chronic kidney disease, eating a diet that is high in acid producing foods is likely to accelerate decline towards complete kidney failure, or end-stage renal disease requiring dialysis or transplantation.

SHOULD WE ALL BE MODIFYING OUR DIETS?

These new data are compelling. In the field of nephrology, it might just be the final nail in the coffin of the typical, high-acid, high salt, high meat- content western diets that we have been used to for the last many decades.  In all honesty, these data seem to be consistent with guidelines put forth by the National Institutes of Health in the form of DASH diet or the recent data about the benefits of the Mediterranean diet.  All these diets essentially have one thing in common.  There are rich in fruits and vegetables, and they're low in sodium and fat.

However in kidney disease patient specifically, there is one small thing that one needs to be cautious about.  And that is the potassium content in foods and vegetables. Patients with advanced kidney disease who eat these diets could be susceptible to high potassium levels in the blood which come with its own set of risks.  Hence although high fruit and vegetable diets should be beneficial, they need to be taken under proper supervision of a physician who can monitor your blood potassium levels.

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