The RenalTracker Team
October 28, 2021

I hope you enjoy reading this blog post. It has been written and vetted by RenalTracker's team of kidney experts and researchers. The same team was awarded the KidneyX Prize organized by the American Society of Nephrology and HHS for pre-dialysis solution in Washington DC in 2019.   

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The average American drinks bout 45 gallons of soda each year. Sodas are a main source of calories and added sugar in the United States diet. While carbonated drinks quench thirst, soda consumption is linked to chronic diseases such as obesity, type II diabetes, kidney disease, cirrhosis, and cardiovascular disease.

Soda drinks is something you should limit or steer clear of if you have chronic kidney disease, as even sugar-free sodas can further strain your kidneys.

soda and CKD

Can Soda Harm the Kidneys?

Soda consumption has been associated with risk factors such as diabetes, hypertension, and obesity that lead to other chronic diseases. More so, drinking soda not only strains the kidneys but could and also lead to stroke, heart disease, and premature death. Besides its high sugar content, carbonated drinks, especially dark soda, contains Phosphoric Acid that can exacerbate your kidney condition. High amounts of phosphoric acid can lead to kidney damage and eventually kidney failure. 

obesity soda

A study was conducted to examine the connection between carbonated beverages (including cola) and chronic kidney disease. Drinking 2 or more colas each day was linked to an increased risk of CKD compared to non-cola carbonated drinks. These initial results suggest that soda drink consumption may raise the risk of CKD. Drinking soda among CKD patients is dangerous as certain sodas, especially dark ones, contain phosphorus additives or inorganic phosphates.

dark soda

What is Phosphoric Acid?

Phosphoric Acid (H3PO4) is a colorless, odorless, and corrosive crystalline liquid that gives carbonated drinks its tangy flavor and prevents mold and bacteria growth. According to British pharmacist Niraj Naik, the intense sweetness of Coca-Cola should make a person throw up as soon as it enters the body, but the phosphoric acid dulls the sweetness, allowing people to keep the drink down. Colas are acidified by phosphoric acid, unlike other carbonated soda drinks that use citric acid. Phosphoric acid is made from the mineral phosphorus that is naturally found in the body.

carbonated drinks

It works with calcium to support bone health, kidney function, and the body’s ability to store and use energy. Phosphorus is responsible for all cellular processes and plays an essential role in using B vitamins, delivering oxygen to tissues, and growing connective tissue.

As phosphorus is found naturally in many foods, it is more common for people to have too much phosphorus in the body. People with healthy kidney function remove excess phosphorus naturally. However, people with CKD cannot remove phosphorus efficiently, increasing their risk of developing hyperphosphatemia.

Hyperphosphatemia refers to abnormally elevated serum phosphate levels as a result of decreased phosphate excretion or increased phosphate intake. Most people with hyperphosphatemia don’t manifest symptoms. For people with CKD, elevated phosphate levels trigger calcium levels in the body to drop.

decline of kidney function

Symptoms of low calcium are muscle cramps or spasms, bone and joint pain, rash, numbness, and tingling around the mouth. Ultimately, this may lead to elevated parathyroid hormone secretion, further decline of kidney function, increased risk of cardiovascular disease, and higher mortality rate. Which is one of the reasons why soda drinks and CKD is not a good match.

Elevated serum phosphorus levels are a constant challenge for dialysis patients and the clinical team. Although dialysis removes excess phosphorus from the blood, it can still build up in the body during between sessions. Renal patients need to manage their serum phosphorus and, in many cases, remember to take their phosphate binders.

Role of Sugary Soda Drinks in CKD

Sugary Soda Drinks in CKD

The direct correlation between chronic kidney disease and sugar-sweetened beverages has not been definitely established. However, increasing consumption of sugar-sweetened soda drinks has been shown to increase the risk factors for CKD. Consuming foods and drinks that are loaded with sugar can cause unwanted weight gain which could eventually lead to obesity, diabetes, hypertension, hyperuricemia (elevated uric acid levels), and nephrolithiasis (kidney stones).

Even though the direct connection between soda drinks and CKD isn’t clear, it is advisable to limit sugar intake to manage the detrimental effects on CKD risk factors. The American Heart Association (AHA) suggests that Americans cut back on added sugar to prevent obesity and heart disease. AHA recommends an added sugar limit of no more than six teaspoons or 24 grams of sugar or 100 calories a day for most women. Men shouldn’t exceed more than nine teaspoons/36 grams/ or 150 calories of added sugar.

diabetes and CKD

Phosphorus Additives

According to the guidelines set by the International Society of Nephrology in 2017, people with CKD not yet on dialysis are recommended to maintain serum phosphate in the normal range. Most resources suggest that you should maintain a range of 2.5 to 4.5 milligrams of phosphorus for every deciliter of blood (2.5 - 4.5 mg/dL). However, it’s always recommended to check in with your nephrologist to determine your phosphorus intake.

Keeping a healthy Phosphorus level in your blood can be challenging, as your kidney can no longer filter excessive nutrients effectively. As mentioned, soda drinks are loaded with phosphoric acid, which can worsen your kidney function. The amount of phosphorus from food additives is much higher compared to natural food sources such as animal and plant-based proteins, this is according to Kalantar-Zadeh and colleagues. Besides phosphorus, soda drinks also contains sodium and potassium.

Phosphorus Additives

Phosphorus salts are added into processed foods to prolong shelf life, improve flavor, maintain moisture and enhance the color of the food. Phosphorus additives on food labels are hard to determine due to the complex names of the ingredients.

The U.S. Food and Drug Administration doesn’t require manufacturers to list the quantity of phosphorus per serving on food labels. It becomes hard to determine the distinction between natural phosphorus and inorganic phosphate used as additives.

Soda drinks consumption

The Bottomline

Soda drinks consumption has been linked to the risk factors of CKD such as obesity, diabetes, hypertension, and cardiovascular diseases. Although there is no direct correlation between sugar-sweetened beverages such as soda and CKD, it is advised to limit added sugar intake as sugar can contribute to these risk factors.

Furthermore, carbonated drinks, especially soda drinks, are loaded with phosphoric acid that can cause Hyperphosphatemia. You can go easy on your kidneys by slowing down on soda consumption or avoiding it altogether. Consequently, you can check in with your renal dietitian for soda alternatives that are gentle on your kidneys.