What Makes Artificial Sweeteners Sweet?

QUESTION: What makes artificial sweeteners sweet? And after all the
discussion in recent years about cyclamates and saccharin, can we be sure
they're safe to use?
------------------------------------------------------------------------------
ANSWER: A variety of synthetic and natural substances are used to sweeten
foods, and are classified as nutritive or nonnutritive, depending on whether
they add calories to the diet or not.
Sugars are the most common sweeteners, and are found widely in nature,
including glucose, fructose (which together compromise sucrose--in granular
form, the stuff you and I put on our corn flakes), lactose (present in milk),
maltose, honey and maple syrup.
Aspartame (well known by its NutraSweet trade name) is a nutritive
(caloric) sugar made from two amino acids. While the equal of sucrose in
calories, it is over 200 times sweeter; the tiny amount needed to sweeten any
food is calorically insignificant.
Saccharin, the most widely known nonnutritive sweetener, has been around
since 1879, and is 300 times sweeter than sucrose. While a 1977 study that
fed megadoses of the substance to laboratory rats prompted health warnings on
saccharin-bearing products, to date no proof has been found that a normal
level of saccharin consumption is dangerous.
Possibly because of those health warnings (and because of a lack of any
aftertaste), aspartame has replaced saccharin in a wide variety of sweetening
applications. However, aspartame contains a chemical called phenylalanine,
dangerous to individuals with the inherited disease phenylketonuria.
Cyclamate sweeteners were not as lucky. Popular in the 1960's,
cyclamates were removed from the market in 1969 after one test showed a
possible cancer link. This link has never been confirmed, and cyclamates may
one day return to the market in the U.S., joining the 40 countries around the
world that approve their use.