You can have your cake and eat it too. The widespread use of artificial sweeteners in products ranging from syrup to soft drinks embodies the mantra that food should possess the taste of sugar, while avoiding its higher calorie content. Commonly used artificial sweeteners such as aspartame, saccharin, sucralose, acesulfame K, and stevia leaf, impart a strong taste without adding calories because they are either non digestible or have a miniscule amount of energy. Renewed interest in healthier consumption habits, combined with improved formulation of artificial sweeteners, has put Diet Coke sales ahead of regular Pepsi (Sicher 2011) while masculinzed artificially sweetened soft drinks, such as Coke Zero and Dr. Pepper Ten, have been successful in removing the stigma of “diet” and increasing consumption among men. Yet anybody who has tried diabetic candy or added artificial sweetener to their morning joe can tell you the difference between the original and substitute can be a world apart.
The key to improving the taste of artificial sweeteners lies within our ability to understand and manipulate taste receptors in our mouth, particularly our sweet taste receptors. Current models of the sweet taste receptor indicate that sweet taste originates not merely from stimulation of the sweet taste receptor, but from the binding of sweeteners to multiple sites (Cui and others 2008). If we imagine our sweet taste receptor as a musical instrument, it acts much more like a piano which requires the precise strokes of a musician and much less like a bell which requires only crude pounding. Table sugar, or sucrose, is able to create a palatable melody with our taste receptors by hitting the right notes for the ideal amount of time. Artificial sweeteners bind to sweet taste receptors in a different manner and at different binding sites, giving them the tune of sugar's imperfect cover band. Researchers contribute the metallic and bitter aftertaste of artificial sweeteners to the interaction with and activation of bitter taste receptors (Riera and others 2007). Thus while artificial sweeteners such as saccharin and acesulfame-K can operate the sweet piano, they are also blowing into an irritating vuvuzela. Current approaches to mask these harsh “noises” include using blends or duets of artificial sweeteners that bind to different regions of our sweet taste receptors to complement each other's sweet side and drown out the bitter background noise. Although moderately successful mixtures, such as saccharin and cyclamate, have reduced bitterness, they have not succeeded in matching the pleasant taste of sugar.
The future success of improving sweet taste perception may not rely on making artificial sweeteners better musicians, but on either amplifying the tune that natural sugars have perfected or silencing the off sounds of artificial sweeteners. Current investigations have uncovered sweet taste modulators that have no taste by themselves, but are effective in increasing the binding strength between natural sugars, such as sucrose, and sweet taste receptors. This amplification effect allows for 33% reductions in sugar content while maintaining its strong and familiar taste (Servant and others 2010). While foods and drinks sweetened with sugar and the amplifier molecule would contain some calories, bitter aftertastes would be eliminated. Furthermore future discoveries of stronger amplifier molecules could mean even fewer calorie counts while retaining equivalent taste. A promising calorie free solution can be found in recently synthesized bitter blocking molecules, which effectively plug the artificial sweetener vuvuzela by inhibiting the activation of bitter taste receptors. These bitter blockers were successful in reducing the aftertaste of common artificial sweeteners to a merely recognizable note (Slack and others 2010). As food and beverage companies investigate new ways to amplify sweetness and inhibit bitterness, it is important that consumers use artificial sweeteners in a healthy and responsible manner.
Artificial sweeteners offer a healthy alternative to high calorie sugars and can be a key tool in maintaining a healthy weight and fighting obesity. Yet some studies have suggested a relationship between the consumption of reduced calorie sweeteners and weight gain (Fowler and others 2008). It is important to note that this relationship is correlational, not causational. No biochemical pathway linking weight gain to artificial sweeteners has been discovered (Mattes and other 2009) and it is reasonable to conclude that consumers increase diet beverage consumption when they perceive weight gain or wish to avoid it. It is important to understand that artificial sweeteners give the option to have a slice of cake and eat that slice too. But justifying a second slice of cheesecake, because it is sweetened with an artificial sweetener, can result in a higher calorie intake than if a single slice of sugar-sweetened cheesecake were enjoyed.
Our relationship with artificial sweeteners has been bitter sweet. They offer the promise of calorie free beverages and reduced calorie desserts, yet lag behind sugar in terms of sensory satisfaction. Innovations, such as bitter blockers, amplifiers, and smart substitution, could bring the artificial sweetener cover band to the same stadium as its sugar counterpart. Let's hope for sweet surprises in lieu of bitter disappointments.