Stevia: Not All Artificial Sweeteners are Bad for You

The non-nutritive sweeteners (provide sweet taste but have zero calories and do not raise blood glucose levels) that contain extracts from the Stevia rebaudiana plant are gaining in popularity after originally being banned for sale in the US by the FDA in 1991 but then specific glycoside extracts from the plant were FDA approved as sweeteners in 2008. Common trade names for sweeteners containing Stevia extracts sold in the US are Truvia and PureVia. The major sweet tasting compound in extracts from the Stevia rebaudian plant is called rebaudioside A which is a steviol glycoside (steviol to which carbohydrates have been attached). Steviol is a diterpene synthesized in plants via a pathway that resembles a portion of the cholesterol biosynthesis pathway in humans. Steviol glycosides, specifically rebaudioside A, contain four glucose residues (and only glucose, never any other sugar) attached in various linkages. When placed in the mouth rebaudioside A activates sweet receptors but at a level up to 250-300 times as intensely as that for sucrose which is the natural sugar in sugar beets and sugar cane. Athough rebaudioside A contains glucose attached to steviol, clinical studies have demonstrated that the consumption of the compound does not alter blood glucose homeostasis.

A recent study published in the Journal of Nutrition found that there may be significant clinical benefits to the consumption of rebaudioside A as it was shown to not only enhance the synthesis and release of the gut hormone GLP-1 (glucagon-like peptide 1) but that it also increased the number of intestinal cells that make and release GLP-1.

The Noncaloric Sweetener Rebaudioside A Stimulates Glucagon-Like Peptide 1 Release
and Increases Enteroendocrine Cell Numbers in 2-Dimensional Mouse Organoids Derived from Different Locations of the Intestine

First let's review briefly what exactly is GLP-1 and what would be the significance of enhancing its production. Greater detail can be found in the Gut-Brain Interrelationships page of my website:

The gut hormone GLP-1 is produced by a specific subset of cells found in the small intestines (specifically enteroendocrine L cells of the ileum) and it is released in response to food intake. Release of GLP-1 from these cells is into the blood. From the blood GLP-1 exerts effects within the gastrointestinal system and it is transported to the pancreas and to the brain. GLP-1 binds to specific receptor proteins on target cells in these organs and induces specific responses. Within the gut the actions of GLP-1 are primarily to reduce the rate of gastric emptying so that one feels fuller longer, and thus, less likely to continue eating. Within the pancreas GLP-1 activates the synthesis and release of insulin and inhibits the release of glucagon. Hormones that enhance food intake-mediated release of insulin are called incretins. These concerted effects result in enhanced removal of glucose from the blood and prevention of the liver from producing more glucose. Within the brain GLP-1 acts upon the hypothalamus which is a structure in the brain that is the major regulator of feeding behavior. GLP-1 effects in the hypothalamus are to reduce the desire for food. All of these effects of GLP-1 suggest it is a viable drug target in the treatment of obesity and type 2 diabetes. Indeed, numerous drugs are currently being used in the treatment of type 2 diabetes that mimic the actions of GLP-1 or prolong its life time in the blood. Examples include Victoza and Onglyza.

The TAKE HOME from this study is two-fold. First, not all non-nutritive sweeteners result in disturbances in the normal processes of feeding behavior that are activated in response to food intake (see my recent blog post concerning sucralose (one of the many commercial products is named Splenda). Second, and MOST significant is that the consumption of rebaudioside A (for example as Truvia or PureVia) may in fact lead to reduced feeding behavior, improved glycemic control in type 2 diabetics, and possibly, secondarily, reduction in weight.

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