Artificial Sweeteners – This is Your Brain on Drugs

colinchamp May 7, 2018 8 Comments

Back in the 80’s, I spent my days at school, playing in the yard and woods, fighting with my brother over baseball cards, and watching Thundercats and GI Joe. While doing the latter, every once in a while, the famous commercial – “this is your brain on drugs” – would air during a television break. During the commercial a man would show an egg and tell the audience “this is your brain.” He would crack the egg and drop the contents into a frying pan. As the whites of the egg sizzled, bouncing the yolk around, his voice would deepen as he cautioned the viewers, “this is your brain on drugs.” I first saw this when I was about 7 years old. I had no clue what it meant then. Now that I am 37, I still have no clue. In fact, it actually makes less sense to me now that I am a doctor.

If I told you that artificial sweeteners do the same thing to your brain, you would probably be just as confused. Yet, while combing through the scientific and medical literature on artificial sweeteners, that terribly executed commercial continued to pop into my head. I even rescripted it with a new saying:

“This is your brain on artificial sweeteners.”

 

Mankind’s Ancient Affair with Sweetness

Before diving too deep into the issues with artificial sweeteners, let’s take a step back and explore why we crave sweet foods. For the past millions of years, we nomadically roamed the Earth in search of food. Sweet ripe fruits contained a higher sugar content than unripe ones, which were more bitter. The ripe fruits also provided more energy, which our bodies desired. As processed foods and grocery stores did not exist, we ate food for its vitamin, nutrient, and energy content, and since the beginning of time, we always pushed for the biggest bang for our buck. Nutrient-empty foods like bread, pasta, and processed foods did not exist, yet, somewhere between then and now, the food pyramid popped up and we began to promote nutrient and calorie-sparse foods like skinless chicken breasts, grains, and other low-fat packaged foods.

Sugars are also quite effective at commanding our body to tightly grasp onto fat and store it. A scary thought in today’s climate of global obesity warming, for over 99% of our existence this signal would have been advantageous during times accompanied with little food security. Fructose, the sugar found in fruit and honey, for instance, has an exquisite ability to signal to our body to store fat. This effect has led to the controversial aim taken at fructose and high-fructose foods. Fructose is also extracted from sugar cane, sugar beets, and corn to make table sugar and high-fructose corn syrup (rocket fuel for weight gain).

At some point deep in our distant past, the survival benefits of eating sweet fruits became gradually embedded within our brain, leaving areas of it stimulated after the consumption of sweets. From an ancestral and evolutionary perspective, this made perfect sense – we craved safe fruits that helped us survive and continue as a species. Counter to the pleasant sweetness of a perfectly ripened mango, excessive sourness in foods or fruit would have indicated to our ancestors that the squishy, browned plantain may contain potentially harmful bacteria and was unsafe to eat. Bitterness would signify toxins, whereas sweet flavors and tastes effectively lit up the deeply embedded area of our brain, signaling that foods were safe from toxins and bacteria. Yet again, the attractiveness to sweetness signaled to the brain that the food source was safe, providing an evolutionary advantage for the generations of our great ancestors. As a result, we are left with an inherent craving for sweet tastes that has been deeply entrenched within our brain over the past several million years – a force to be reckoned with.

Fast-forwarding these million years, we have now isolated this brain stimulus, super-concentrated it, and packaged it for quick and easy consumption. Cans of soda can provide overwhelming amounts of sugar and sweet taste to stimulate our brains in a matter of seconds. During the decades of the anti-fat crusades, heavy carbohydrate and sugary foods filled our cupboards and dinner plates – we were even told this was healthy. In other words, we took the small sweet-craving flame smoldering within our brains and poured gasoline on it.

Enter Artificial Sweeteners and Hedonistic Sweeteners

After decades of a ballooning population and dozens of randomized studies revealing the superiority of a higher fat and lower carbohydrate diet,^1,2 the tide is turning. Nearly all sides of the current dietary minefield agree that the plethora of simple carbohydrates, sugary foods, and sweet beverages should be avoided in an effort to get our health back on track. Through artificial sweeteners, a massive experiment has been conducted to preserve the sweet brain-stimulating taste of these foods while removing the actual food. The main artificial sweeteners are listed in the graph below with their common marketing names.

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For a quick rundown, aspartame, acesulfame, neotame, and saccharin are considered closer to manufactured chemicals when it comes to sweeteners. The sugar alcohols and sucralose are essentially sugars with a chemical added to hinder absorption or block the ability of our body to break down the sugar. They maintain their sweet taste but can pass through us untouched. Erythritol, for instance, gets absorbed into the blood stream from the intestines but leaves us intact through the kidneys with urine; 10% can get passed into the colon, which can cause a laxative effect. Along these lines, xylitol, maltitol, and some of the other unabsorbed sugar alcohols pass into the bowels undigested, causing potential issues. Stevia is the latest “natural” sweetener, as we will discuss below.

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The main reason we use artificial sweeteners is to supply our taste buds and brain with that sweet sensation without the insulin-stimulating and fat-promoting effect of excess sugars and carbohydrates. As described in the figure below, if carbohydrates turn to sugar in our blood and cause the release of insulin to combat this rise in blood glucose, simply removing the carbohydrates – but not the sweetness – will in theory eliminate this problem. In this sense, artificial sweeteners are basically viewed as empty calories; they are not a food, but rather a pleasure-inducing chemical.

 

 

The theory of using artificial sweeteners to avoid weight gain makes perfect sense on the surface. The science, unfortunately, paints an entirely different picture. In fact, data from studies in rats as far back as 1987, the same year that the war against drugs decided to fry an egg in their famous commercial, reveal that acelsulfame K – a common artificial sweetener – raises insulin in a dose-dependent manner very similar to glucose.³ As expected, this sweetener’s effect on blood glucose was less than sugar, likely due to its lack of sugar or carbohydrates. An increase in insulin unprovoked by a spike in blood glucose can actually lower blood sugar levels. A similar study revealed that while saccharin (Sweet N’ Low), sodium cyclamate (Canadian Sweet N’ Low), stevia, and acesulfame-K force the pancreas to release insulin, aspartame (NutraSweet) does not.⁴ Mouse studies further provide support that artificial sweeteners by themselves do not raise blood sugar levels, however, when food is consumed at a later time (often provoked by a sinking blood glucose level), blood sugar levels rise higher than would normally be expected.⁵

But do artificial sweeteners help us avoid the carbs and lose weight?

Epidemiologic data support the notion that artificial sweeteners do not aid in weight loss and, much like the foods they are trying to replace, may actually fuel weight gain.⁶ Studies, however, are mixed and may be biased by those individuals who turn to artificial sweeteners to try to help with their struggling diet – individuals who may be destined to gain more weight regardless of what actions they take. The difficulty with quantifying the exact cause of weight gain within these reports should also be noted; for instance, other studies have revealed weight loss with the usage of aspartame.⁷ Regardless, studies like this cast doubt on the effectiveness of artificial sweeteners to aid in weight loss.

Additional animal studies reveal the often-neglected psychological impact of artificial sweeteners: that repeated and chronic exposure to the sweet taste of saccharine conditions our brains to think that we are in fact eating sugary foods. As a result, our body secretes insulin to prepare for the “sugary” meal. When no sugar is present, the small amount of sugar in our blood, prompted by insulin, is shuttled into our cells. This evacuation leads to lower levels of blood sugar, and eventually hypoglycemia (low blood sugar).⁸ The calorically empty sweetness may have tricked us initially, but our body’s innate mechanisms are still activated, leaving us in an unwelcome physiological state. The corresponding dip in blood sugar can stimulate further hunger as the body strives to bring blood glucose levels back to normal, leaving us in an even worse position.⁹ Often, we may even end up eating more of the same foods we were trying to avoid.

 

Fueling the Brain’s Ancestral Addiction to Sweetness

Animal studies confirm that the signal to the sweetness-activated area of the brain suggests that a handful of calories are on the way. In other words, the brain predicts that number of calories expected to follow based on the sweetness of food, and providing it with “empty” sweeteners is ineffective at deceiving it.^10,11 In fact, while the hoax may work initially, the brain eventually realizes it was provided an empty briefcase and signals that it is time to pay up with interest. Following this “payback” period within the brain, we can often end up consuming even more food than we initially craved.¹² Once again, millions of years of ingrained behaviors leave a force to be reckoned with, and artificial sweeteners are hardly able to overcome it. When our brain uses sweetness to predict the number of calories we consume, a false signal will only serve to further ingratiate our appetite.

Whether this signal comes from a sugary Snickers bar or diet soda is less important – the sweetness leads to our delectable demise. As a result, the response may look more like:

Are the Health Effects of Artificial Sweeteners Concerning?

The above gives us a primer on artificial sweeteners, which at the end of the day are often a well-intentioned attempt to make the unpalatable palatable. However, we should pause and ask ourselves what we are trying to accomplish with artificial sweeteners. Are we making something that would otherwise be intolerable able to be consumed (like protein powders, supplements, or medicine) or are we simply trying to feed the pleasure and addictive areas of our brain? Mary Poppins may have had it right decades ago, but things have gone out of control lately.

As you can read below, artificial sweeteners affect several distinct elements of our health. More effects exist, but we simply have not studied them sufficiently to expose all of the issues. At the end of the day, it is clear that artificial sweeteners are more than just empty calories when considering our body’s metabolic response, and viewing them as such is an unfortunate  leftover from the days of counting calories and viewing them all as the same. Artificial sweeteners directly affect insulin secretion, subsequent blood sugar levels, and other unknown metabolic effects likely exist as well. Below are several of the key areas where studies expose a concerning link between sweeteners and our health.

Artificially Sweetening our Bowel Bacteria

Stealing a line from the movie Zoolander, bowel bacteria and our microbiome are “so hot right now.” It seems as though this is the focus of everyone in the health arena and blogosphere. As is the case with any food we eat, our bowel bacteria get the first and last shot at it. The effect of artificial sweeteners on bowel bacteria was not even considered initially, but scientists have recently taken this interaction more seriously.

Many artificial sweeteners, like the sugar alcohol xylitol, are toxic to oral bacteria, helping to reduce cavities. While a potential benefit of artificial sweeteners, what happens when these same antibacterial effects are applied to our healthy bowel bacteria? Splenda, for instance, significantly alters the amount of normal bowel bacteria in mice, decreases fecal pH, and limits the ability of normal bowel bacteria to metabolize and breakdown potentially harmful chemicals in our food, a vital process of detoxification to reduce our risk of cancer.¹³ Damage to the watchmen of our gastrointestinal tract should be a major concern with sweeteners.

Other data reveal that our gut bacteria metabolize saccharine into proprionate, a bacterial end product that affects insulin secretion and can lead to elevated blood sugar levels.¹⁴ The data is mixed but the fact that these sweeteners affect our physiology is clear. These effects also support the notion that we are not what we eat, but rather we are what we eat after our gut bacteria eats it.

Artificially Feeding Our Addiction

Both sweet foods and addictive drugs stimulate the ventral striatum of our brain via dopamine signaling. This pathway involves both the processing of rewards and learning. Our brain can actually change when we consume pleasurable and addictive substances. For instance, rats that drink a sweet sucrose cocktail for just three weeks experience changes in neuronal activity in the emotion and pleasure center of the brain, known as the limbic area.¹⁵

Further supporting the connection between the addictive areas our brains and the sweet taste of sugar are studies revealing opioid-like dependence and withdrawal in mice forced to abstain from sugar.¹⁶ These mice even experienced a Chapelle Show Tyrone Biggums-like teeth chattering, forepaw tremor, and head shakes. Severe withdrawal is experienced by mice provided sweet glucose and then the drug naloxone – the same drug given in the emergency room after heroin overdoses. The similarities to a withdrawing heroin addict are uncanny, interesting, and most of all, frightening.

Perhaps the most alarming study was one where scientists tested the effect of saccharine on morphine tolerance in mice. As a person takes more and more narcotic pain medications, their tolerance generally increases, requiring higher doses for the narcotic to be effective at fighting pain; the body adjusts to opioids. When mice were given a daily saccharin solution for 28 consecutive days, morphine no longer resulted in any amount of the typical analgesia.¹⁷ In other words, the tolerance of opioids in the mice was increased from the sweet taste of saccharine, necessitating larger doses of opioid drugs to achieve similar analgesic effects. The scientists suggested that chronically elevated saccharin intake may cause the release of opioids within our body, resulting in raised tolerance to external morphine. In other words, saccharin may elicit similar physiologic effects as heroine.

Artificial Sweeteners: The Methadone of the Diet World

The addictive, drug-like effects of sweet tastes are so powerful that some have suggested “unsweetening the world’s diet may be the key to reversing the obesity epidemic.”¹⁸ Methadone, a drug used to detox opioid and heroin addicts, is much easier to wean off of than typical street opioids. A nicotine patch or gum is similar, as a tobacco addict uses it to abstain from cigarettes, then is eventually weaned off of the nicotine supplement.

Artificial sweeteners are often used much like these reverse gateway drugs to get off of the drug-like addictive sweet taste of sugar. While these sweeteners do provide the sweet taste of sugar, they are generally – perhaps incorrectly – felt to provide less of an effect on insulin and weight gain. The above studies would argue that artificial sweeteners may lead to more addiction, fully defeating this purpose. We often neglect the fact that our food can resemble addictive drugs, and artificial sweeteners may be the worst culprits.

Perhaps most astonishing are the changes seen in the human brain from different eating patterns. Imaging of the brains of obese individuals reveals changes that mimic those visualized in cocaine and drug addicts.^19,20 Addictive eating can lead to obesity, sweet taste appears to fuel this addiction, and sweeteners elicit similar responses as heroin and cocaine within the brain. The difference, of course, is that one of these is found in many foods and all supermarkets while the others are considered illegal drugs. Yet another even scarier difference has been shown in a mouse study – the addictive reward from sweetness actually surpasses that of cocaine.²¹ You read that correctly – mice prefer drinking a sweet cocktail over cocaine.

 

When all Else Fails

But, we are human and have our moments. If you absolutely need an artificial sweetener, Stevia may be the best option. It is made from the Stevia rebaudiana plant. The extract from its leaves is about 150 times sweeter than sugar, though it does have a pinch of a black licorice taste. Stevia has been used for almost 2,000 years in South America to sweeten medicinal compounds. It apparently has a small or even insignificant effect on our blood sugar. It is the most natural – if an artificial sweetener can be natural – of the sweeteners and this provides some mental, albeit not necessarily scientific, comfort.

Like all of the artificial sweeteners, there were some initial concerns of whether stevia could contribute to cancer. Since, these fears have lessened and Stevia seems to be the poster child for artificial sweeteners.

Will this fame be short-lived? It is difficult to tell, and frankly, there is not a lot of data on the safety of stevia. More studies will surely question its safety over the next several years. At the end of the day, stevia currently seems like the best bet – that is, after avoiding sweeteners, of course.

Just Eat Real Food and Turn to Positives for Pleasure

Sweet taste, sugar, and insulin-spiking carbohydrates all have their issues. To minimize one without the other does not circumvent any of these issues. Furthermore, how we deal with food is a symbiotic interaction between our body, brain, and the bacteria that reside within our gut. Artificial foods and chemicals may have unwanted effects on this interaction and can negatively influence our health.

If we are turning to sweetened beverages and foods for pleasure, satisfaction, or to deal with stressful and difficult situations, this may signify deeper issues in our lives that need addressed. We may want to turn towards more healthful behaviors for reward, and especially those that provide longstanding gratification. The next time you turn to a can of Diet Coke for fulfillment, take a walk or hike, or engage in some resistance or weight training instead. Exercise stimulates the same reward areas of the brain as these addictive and sweet drugs, so why not use it to channel reward instead?²² Remember that feeling you get after a tough weight session at the gym? It is much more rewarding than a sweet treat.

If you think a sweet treat will turn a bad work day good, you are mistaken. Like the answer to most issues within the diet and nutrition world, just eat real food and ditch the artificial sweeteners. Leave the chemicals to science experiments and feed your body the foods that we thrived on for millions of years.

 

Moving Forward – Recalibrating Your Sweet Tooth

Artificial sweeteners are bad for your body’s glucose control – the main reason most people use them instead of sugar – defeating the rationale of using them in the first place. The damage they impart to our bowel bacteria adds fuel to the unhealthy fire of these little packets of chemicals. Acting on our brain much like cocaine or heroin is perhaps the most concerning of all and leaving us craving more sweets afterwards once again defeats the purpose of artificial sweeteners.

As always, I am a fan of recalibrating my sweet tooth to no longer crave sweet foods and instead be content with more rich or even bitter foods. When I eat artificially sweetened foods, I find myself craving more sweets and immediately fear a return to my past where one bite of ice cream turned into emptying the entire carton. It is as though I can feel the addictive flame in my brain being ignited by these sweet foods that I have avoided for so long. This feeling is an uncomfortable one that I would much rather avoid. Instead, I turn towards lasting rewards, and hit the gym.

 

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Artificial Sweetener References:

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21. Lenoir, M., Serre, F., Cantin, L. & Ahmed, S. H. Intense Sweetness Surpasses Cocaine Reward. PLoS One 2, e698 (2007).
22. De Chiara, V. et al. Voluntary exercise and sucrose consumption enhance cannabinoid CB1 receptor sensitivity in the striatum. Neuropsychopharmacology 35, 374–87 (2010).

 

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