Artificial Sweeteners' Effects on the Kidneys

Are artificial sweeteners harming your health and kidney function?

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Stuart Miles/ FreeDigitalPhotos.net

Diet sodas, "sugar-free" desserts, ice creams...sugar substitutes are everywhere. Once considered a panacea for reducing the incidence of high-calorie hyper sweet food-related diseases (obesity, diabetes, dental caries), sugar substitutes are now increasingly coming under scrutiny and may or may not be as safe as previously thought.

I am using the term "sugar substitute" as an umbrella term to refer to both naturally sweet compounds other than sucrose (table sugar), and to artificially synthesized sweeteners.

Naturally sweet compounds include substances like sorbitol that is found in corn syrup and apples, lactose which is present in milk, and xylitol present in some fruits and vegetables. They are inherently sweet substances, who all have varying degrees of sweetness compared to sucrose. Not all of these substances are carbohydrates, like sucrose. For instance, brazzein is an extremely sweet protein, and not a carbohydrate.  

Most sugar substitutes that you are probably used to seeing are actually artificially synthesized compounds (with the notable exception of Stevia which is a natural substance obtained from the Stevia plant). These artificial sweeteners include aspartame (Equal), sucralose (Splenda), saccharin (Sweet N Low), etc. 

ARE SUGAR SUBSTITUTES HARMFUL?

We are all well aware of the dangerous effects of consuming high amounts of table sugar (sucrose). The current epidemic of obesity, hypertension, diabetes, heart disease, chronic kidney disease, gout, etc has a lot to do with the proliferation of easily available and cheap hyper sweet foods.

This has been also referred to as the so called cardiorenal epidemic, which implies the increasing incidence of heart and kidney diseases due to increased sugar consumption. Combine this with the difficulty in accessing healthy food worldwide and you have a perfect storm for seeing an increased incidence of the above mentioned diseases.

So having a sugar substitute without the empty calories that sucrose provides should be the perfect solution to solving the above health problem, right? Well, it is not that simple. Although it makes sense on paper, sugar substitutes do affect our physiology in more complicated ways that we are only beginning to understand. What we still don't know for sure is whether the potentially harmful effects of sugar substitutes outweigh the well understood harmful effects of sucrose. Hence, I guess a more complete question would be, are sugar substitutes more harmful than table sugar (sucrose)

As of this time, the US FDA considers sugar substitutes as food additives (except for Stevia owing to its natural origin and long history of use) and thus is able to regulate them. The FDA publishes what is known as the GRAS (Generally Recognized As Safe) database, as well as a Code of Federal Regulations which lists the currently approved sugar substitute additives. 

Let's briefly look at the health effects of some individual sugar substitutes:

ASPARTAME

One of the earliest mass produced sugar substitutes, aspartame (trade name Equal) has had an especially controversial past. Although there are concerns about aspartame's link with leukemia, lymphoma, and brain cancer, the official FDA and National Cancer Institute position is that the data is insufficient to make this conclusion in humans.  Conspiracy theorists still however continue to swear that the regulatory process itself is flawed and perhaps riddled with corruption!

SACCHARIN 

Saccharin (trade name Sweet N Low) was thought to be associated with bladder cancer in rats, but this association was never proven in humans. Consequently, it was banned in Canada in 1977. The US came close to doing the same but stopped short. What was done however was a requirement that saccharin carry a warning label. Even this requirement was lifted in 2001 after the so called Sweetness Act was passed.  

SUCRALOSE

The FDA conducted close to 100 studies before its sucralose (Splenda) approval in 1998. No specific health or cancer risk was found. 

STEVIA

No specific health risk is reported for Stevia which has been on the GRAS list since 2008.

IF THERE IS NO EVIDENCE OF HARM, WHAT'S THE FUSS ABOUT ?

The above list certainly does not conclusively report any proven side effects from sugar substitute use. Does that necessarily mean that we are in the clear? Maybe...maybe not. The potential for harm that is still unresolved is related not specifically to the chemical nature of any particular sweetener, but the human body's response to the sweet taste that they create.

There is some evidence that animals have evolved to use the sweet taste of foods to predict its caloric content. When you eat something sweet, it sets off a chain reaction of physiologic processes that include a spike in your insulin level. Insulin is an anabolic hormone that leads to weight increase by increasing the amount of fat content in the body (adiposity). Artificial sweeteners apparently mimic this process and fool your body into believing that you just consumed a load of sucrose or other metabolizable carbohydrates. Normally, the body's usual response to sucrose intake in such a situation is to reduce appetite, create a feeling of fullness, and reduce its caloric intake. This however apparently does not happen with artificial sweeteners, and you could potentially end up eating more 403! In other words, you get the insulin spike (which is bad), without the reduction in appetite (which would have been good). This phenomenon is also sometimes called "caloric compensation", and is thought to occur from this as well as other psychological (I didn't eat any real calories, so I have the liberty to eat more now!) reasons. This has been demonstrated in rats 403 who were made to consume artificial sweeteners and were shown to have increased intake and body weights. 

CONCLUSION

The American Heart Association and the American Diabetes Association came up with a scientific statement in July 2012, giving a guarded nod to artificial sweetener use.The bottom line of the statement was that "appropriate use" of these sweeteners could be a part of a multi-pronged dietary strategy. The statement warns against "calorie compensation" later by people who consume these sweeteners, and emphasizes that these are not "magic bullets" in the fight against obesity and diabetes. 

Use sugar substitutes if you will. Just remember they might not be as harmless as they appear and that we still might not know everything about how they affect our physiology. 

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