Can L-sugars be used instead of artificial sweetners???

Depending upon how the sugar molecule is organized, it can be what is called, left or right handed. They will have exactly the same elements in exactly the same ratios, but be oriented differently. A levo or L-sugar is a left-handed version of the molecule. A Dextro or D-sugar is the right-handed version; Levo, from the Latin for Left and Dextro, from the Latin for Right. It refers to the properties of rotating plane polarized light. If the light rotates clockwise as it approaches an observer, this is known as dextrorotation, light with a rotation to the right. If the light rotates counterclockwise as it approaches the observer, then the light exhibits levorotation, rotation to the left.

Levo-sugar is a confusing chemical to the human body. To the tongue, it tastes just like regular sugar. But the body has never swallowed left- handed sugar and can't digest it.

e. g. L-Glucose does not occur naturally in higher living organisms, but can be synthesized in the laboratory. L-Glucose is indistinguishable in taste from D-glucose, but cannot be used by living organisms as source of energy because it cannot be phosphorylated by hexokinase, the first enzyme in the glycolysis pathway. 

One of the known exceptions is in Burkholderia caryophylli, the enzyme D-threo-aldose dehydrogenase is capable of oxidising L-glucose. L-Glucose was once proposed as a low-calorie sweetener and it is suitable for patients with diabetes mellitus, but it was never marketed due to excessive manufacturing costs.  The acetate derivative of L-glucose, L-glucose pentaacetate, was found to stimulate insulin release, and might therefore be of therapeutic value for type 2 diabetes. L-Glucose was also found to be a laxative, and has been proposed as a colon-cleansing agent which would not produce the disruption of fluid and electrolyte levels associated with the significant liquid quantities of bad-tasting osmotic laxatives conventionally used in preparation for colonoscopy.

So, in today’s world, after various side effects of artificial sweeteners in long term consumption, L-sugars can be again part of food scientist’s subject for discussion.