Is this true? Can drinking soda cause kidney stones? Are dark sodas worse than others? Read on to learn everything you need to know about soda and kidney stones. And, what you should drink to prevent kidney stones.
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Nutrition in Soda
First, lets take a look at what is actually in soda.
Of course, nutrition varies between types of soda. Generally regular soda contains a lot of sugar (usually in the form of fructose). Cola (regular or diet) contains phosphoric acid. Diet sodas are sweetened with a variety of artificial sweeteners such as aspartame, acesulfame k, Splenda or Stevia.
Does Soda Cause Kidney Stones?
In short, yes. Soda can cause kidney stones. People who drink at least one sugar-sweetened soda per day have a 23-33% increased risk of kidney stones. (1)
Let’s dive into why that might be.
Sugar in Soda
Most sodas are sweetened with fructose, a type of sugar. Time and time again, fructose has been associated with kidney stones. Fructose can increase urinary calcium, oxalate and uric acid. High levels of these substances in urine can cause kidney stones. (2)
It is important to know that fructose in fruit does not cause kidney stones. In fact, people who eat more fruit (and veggies!) are much less likely to have kidney stones. (4) (5) The amount of fructose in fruit is significantly less than in soda. And, fruit has many other beneficial components such as fiber, potassium and other vitamins and minerals.
Phosphoric Acid in Soda
Cola, specifically, has a lot of phosphoric acid in it. Other kinds of sodas usually do not have phosphoric acid.
In addition to sugar, phosphoric acid may be why soda can cause kidney stones.
Some articles have suggested that phosphoric acid dissolves kidney stones. This is not true. No food or supplement can dissolve kidney stones. However, nutrition can play an big role in prevention!
Bottom Line: Because phosphoric acid is harmful for people with kidney disease, this indicates it generally is not good for kidneys. I would steer clear of dark sodas for kidney stone prevention.
Does Diet Soda Cause Kidney Stones?
Although diet cola doesn’t have sugar in it, it does have phosphoric acid. Diet cola is not a good choice for kidney stone prevention.
Diet Non-Cola Sodas
Diet sodas, other than cola, usually do not have phosphoric acid in them.
Examples of diet non-cola sodas:
- Diet 7-Up
- Diet Squirt
- Diet Sunkist Orange
- Sierra Mist Zero
- Diet Canada Dry
Diet non-cola soda is usually sweetened with ingredients that contain citrate, such as potassium citrate. They also often contain citric acid itself. Dark sodas like Coke, Pepsi, root beer or Dr. Pepper have much less citrate in them. (9)
Despite relatively high citrate, research has not consistently shown a reduced risk of kidney stones with non-cola diet soda. (1) This may be because the amount of citrate in non-cola diet soda is not enough to make a difference for kidney stone prevention.
However, non-cola diet sodas do not increase kidney stone risk like regular soda.
What To Drink To Prevent Kidney Stones
Drinking (a lot!) of fluid is key to preventing kidney stones. It is the #1 thing you can do for kidney stone prevention. The American Urological Association recommends drinking enough to make at least 2 1/2 liters of urine every day. (11) I recommend aiming for 3 liters of fluid per day for most people.
So, what should you drink?
Unsurprisingly, plain old water is the best choice for kidney stone prevention. Most of your fluid should come from water.
Getting in this much water is no easy task! Many of my patients love using a smart water bottle, such as the Hidrate Spark*. This water bottle tracks how much water you drink, and even reminds you to drink if you fall behind!
Unsweetened Carbonated Water
These drinks have zero sugar and are a wonderful way to mix up your fluids and make water a little less mundane.
Getting enough calcium is very important for people who have calcium kidney stones. Milk is a wonderful calcium source, and counts toward your fluid goal!
Coffee & Tea
Despite concerns over oxalate, people who drink coffee and tea are less likely to have kidney stones. (1)
If you have very high urine oxalate, limiting black tea may be necessary.
Crystal Light Lemonade
Crystal Light Lemonade* contains a very high amount of citrate. Much more than diet sodas.
If you have low urine citrate, Crystal Light Lemonade* may help increase it to the normal range. Eating more fruits and vegetables can also increase urine citrate.
Small Amounts of Non-Cola Diet Soda
Drinking non-cola diet soda is a great way to mix it up and help meet your fluid goals!
I usually recommend no more than 1 can of non-cola diet soda per day. There is some research that diet soda, in large amounts, is associated with disease.
Does Soda Cause Kidney Stones? The Verdict
Any kind of sugar sweetened drink, including soda, can cause kidney stones. Diet cola may also cause kidney stones.
However, non-cola diet sodas may have some beneficial ingredients for kidney stones. These sodas can be consumed in moderation for people who have kidney stones. As always, most of your fluid should be water.