NRSC 4132 Blog

Raw sugar. Where did it go? I don't remember the last time I actually saw one-hundred percent, real, authentic sugar on the table the last time I was seated at a restaurant. Whether it's an iced tea, coffee or whatever I'm ordering that doesn't arrive at the table sweet enough to my liking, the only quick option I have is to choose one, or many, of those artificial sweetener packets located within arms reach. One might view one of those many companies who put so much time and money into making these packets so readily available at nearly every restaurant, a small additive solution to America's obesity issue that I discussed last week. Do you want sweet and low? Equal? How about Splenda? Or maybe even Truvia. Regardless, they're all fake. And for the most part, they all satisfy our need to make not only beverages, but confections and whatever else, taste more sweet.

The molecular mechanisms involved with sweet taste and the impact of artificial sweeteners are still not completely mapped out. Before I get into some of the interesting findings in the July 11' edition of The Journal of Neuroscience, let me give you a piece of advice: next time you reach for that white ceramic square containing all those fun colors of artificial sweeteners, stop yourself before you do and ask for some real sugar--it's in your best interest.

Taste qualities can be broken down into five major categories; sweet, bitter, sour, salty, and umami. Thus far, it has clearly been identified that the family C G-protein coupled receptor Tas1R2 and Tas1R3 heterodimer mediates the primary sensory transmission process of sweet taste perception. This receptor can be stimulated by many of these diverse natural or synthetic sweet ligands and proteins.

In Bo Liu et al.'s research involving artificial sweeteners, he and his team heterogeneously expressed and functionally assessed these receptors from a squirrel monkey which belongs to the genus Samimiri of New World monkeys. Using receptor chimeras between humans and squirrel monkeys, species-dependent sweet taste differences were determined by a combination of a few specific interaction sites on the Tas1R2 and Tas1R3 receptors. Using two primary ingredients to some (aspartame and neotame), but not all, artificial sweeteners, they found that Old World monkeys but not New World monkeys are able to taste the sweet sensation of such products. In their analysis of such results it was noted that specific residues, are required to taste something sweet and that the extracellular domain of the human Tas1R2 receptor is a critical site and contains important molecular determinants for activation by aspartame and neotame. Old World monkeys (and rats) had a hydrophobic binding site on these receptors which no longer exists on the New World species.

Though Liu et al. did not go on to mention any further experimentation or draw parallels for the human population, considering their BLAST search between the primates and human samples used was a strong 89% correlation some inferences can be made. To what extent evolution of New World monkeys and rats plays a part in this de-sensitization remains unknown, however, what happened to those specific species that hasn't happened to Homo sapiens yet? Regardless of whether or not we're going to potentially lose the ability to percept aspartame and neotame in the future, artificial sweeteners are already known to be bad for human homeostasis. Even though products such as Splenda (Sucralose) and Truvia claim to be all natural and aren't involved in this research, in large quantities, artificial sweeteners can be carcinogenic and in some studies have shown to actually cause weight gain. Considering the vast research boycotting the use of such products, I think it's best to say that we should just stick to the old fashioned way of making our drinks sweeter--with pure sugar cane. Whether you like it raw or not, your sugar cane that is, it just seems to be the smarter option.