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How Artificial Sweeteners Work
BY LEE ANN OBRINGER
If you're trying to lose weight, avoiding sugar is
one of the best ways to reduce your calorie intake.
Many dieters use artificial sweeteners and
artificially sweetened foods as a way to cut sugar without eliminating all
things sweet.
However, not all artificial sweeteners are calorie
free.
In fact, some have almost as many calories as sugar.
They're also somewhat controversial.
Although the manufacturers' Web sites and the Food
and Drug Administration (FDA) say that artificial sweeteners are
perfectly safe, some consumer groups and physicians disagree.
Even if you try to avoid artificial sweeteners, you
may still be consuming them in products you've never considered.
Did you know that artificial sweeteners are in your
toothpaste, mouthwash, chewable vitamins and cough drops?
In this article, we'll look at how artificial
sweeteners came about, how they're used and how they're approved.
We'll also examine the individual sweeteners and
learn about the controversies surrounding them.
Sweet Thing
Sweetness doesn't just come from sugar -- there are
hundreds of organic, synthetic, and inorganic compounds that taste sweet.
Many plants contain sugar derivatives known as glycosides.
Stevia, for example, is a plant high in glycosides that has been used for
centuries to sweeten foods and drinks.
The degree of sweetness we taste depends on how well
the receptors in our tongue interact with the molecules.
The stronger the interaction, the sweeter we perceive
the taste. (Check out this animation to learn more about how
taste buds work.)
Taste scientists at a company called Senomyx have
identified the taste bud receptor that is responsible for finding what we
consider "sweet."
Sugar and artificial sweeteners bind to this
receptor, creating the sweet sensation that we get when we eat them.
The receptors are found on the surfaces of cells all over the tongue and inside the
mouth. They send messages to the brain to tell it that we're eating something
sweet.
Artificial sweeteners are compounds that have been
found to elicit the same (or a similar) "sweet" flavor we get from
sugars.
Some are low-calorie because they so much sweeter
than sugar that only a tiny amount is needed.
Others are low-calorie (or no calorie) because our
bodies can't metabolize them. They simply pass through our digestive system
without being absorbed.
Next, we'll learn about the history and use of
artificial sweeteners.
STEVIA
is a natural sweetener. It is extracted from a plant
native to Brazil and Paraguay and has been used as a sweetener in other
countries for centuries. is roughly 300 times sweeter than sugar and is not
metabolized by our bodies, so it has no calories.
While advocates of quote studies that show no adverse
reactions or effects of the sweetener, other studies have shown that may lead
to lower production of sperm and fewer and smaller offspring.
The FDA has not approved for use in food, but it can
be sold as a supplement.
Artificial
Sweetener Basics
Saccharin, the first artificial sweetener, was discovered
in 1879 by a scientist who failed to wash his hands before dinner and noticed
that his fingers tasted sweet.
Other artificial sweeteners have also been discovered
simply because scientists licked their fingers while testing a new drug or
smoked a cigarette that was placed near a sweet-tasting compound.
Poor personal hygiene has been the dieting industry's
windfall.
These laboratory discoveries underscore the fact that
these sweeteners are artificial, regardless of how they're advertised.
Splenda®, the newest sweetener, has been
sued by the sugar industry for trying to make people think it is more natural
than it really is.
In a study by the Center for Science in the Public
Interest (CSPI), 57 percent of people thought Splenda was a natural product,
not an artificial sweetener.
Why are there so many different artificial
sweeteners? The answer is that there is no one sweetener that can be used in
every product that calls for sweetness.
Sucralose (Splenda), for example, is used in baked
goods because it can withstand heat.
Aspartame is found in "light" and
sugar-free dairy products like yogurt.
Sugar alcohols like xylitol and sorbitol are
routinely used in sugar-free ice cream.
The tricky part about sugar alcohols is that while
they don't affect blood sugar or promote tooth decay, they
have almost as many calories as sugar.
In addition to "light" and
"sugar-free" food products, you can find artificial sweeteners in
liquid and chewable medications (particularly children's medications), throat
lozenges, cough drops, chewable vitamins, toothpaste, mouthwash, and anything
else that could benefit from a little sweetness but shouldn't use sugar.
Some products that could use sugar use artificial
sweeteners simply because they're less expensive.
A recent report from the Food
Commission (UK) found that some orange sodas that were not
marketed as "diet" were using blends of artificial sweeteners.
Aspartame costs only two cents per liter of beverage,
compared with six cents per liter for sugar.
If you don't want to ingest artificial sweeteners,
you'll have to check ingredient labels and make sure you know the
"real" names as opposed to the product names.
Next, we'll look at some of the controversy
surrounding artificial sweeteners.
SWEET FUTURE
Scientists at Senomyx are trying to find chemicals
that enhance the efficiency of the sweetness receptor.
They have a lab full of tiny manufactured taste buds
that glow green when in contact with sugars.
By testing different chemicals for sweetness by using
the "taste buds," they hope to find the one that will taste like
sugar but without the aftertaste -- and hopefully without side effects.
Artificial
Sweetener Controversy
Fear of artificial sweeteners rose shortly after the
first sweeteners were introduced in the food market.
When public health trends, such as an increase in
certain types of cancer, show up, scientists look to
newly-introduced substances.
Saccharin and cyclamate have been around the longest,
and both were eventually linked to cancer in laboratory mice and rats.
Studies associating saccharin with bladder cancer may
have spurred the long-term perception that all artificial sweeteners could
cause cancer.
The press is often blamed for reporting on possible
carcinogenic effects without having the scientific evidence to back it up.
In addition to cancer, thousands of Web sites and
forums have information on other dangers and side effects associated with
aspartame, sucralose, and other artificial sweeteners.
Multiple sclerosis, Alzheimer's disease, brain
tumors, nervous disorders and other health problems have been blamed on them.
Aspartame is getting most of the criticism, but
sucralose is also under scrutiny.
The FDA stands behind the products that it has
approved. A question and answer page on the FDA Web site includes the
following:
All consumer complaints related to the sweetener
[aspartame] have been investigated as thoroughly as possible by federal
authorities for more than five years, in part under FDA's Adverse Reaction
Monitoring System.
In addition, scientific studies conducted during
aspartame's pre-approval phase failed to show that it causes any adverse
reactions in adults or children.
Individuals who have concerns about possible adverse
reactions to aspartame or other substances should contact their physicians.
Medical groups such as the American Heart
Association and the American Diabetes Association also
approve of the use of artificial sweeteners by diabetics and for weight control.
If diet soft drinks and sugar-free foods are
readily available, why are so many people still overweight?
A recent study by researchers at Purdue University
found that drinking diet soft drinks might actually be part of the problem.
Professors in the Department of Psychological
Sciences found that artificial sweeteners may interfere with the body's natural
ability to "count" calories.
Our bodies' ability to match how many calories we
need with how many calories we take in is partially based on how sweet a food
is.
The sweeter and denser it is, the higher it is in
calories. Our bodies use this as a gauge to tell us when to stop eating.
Artificial sweeteners, however, throw a wrench into
this process.
By eating and drinking foods and beverages that use
artificial sweeteners (and therefore have lower calories), we may be retraining
our bodies to no longer associate sweetness with higher calories.
That means that when we eat or drink foods sweetened
with real sugar, our bodies miscalculate the true calories associated with that
food. As a result, we consume more calories.
In the Purdue study, rats that had been given both
artificially-sweetened liquids and sugar-sweetened liquids for 10 days
proceeded to eat more of a sugar-sweetened (high-calorie) chocolate snack than
rats that had been given only the sugar-sweetened liquids for 10 days.
The rats that experienced the inconsistent
relationship between sweet taste and calories had lost some of their ability to
compensate for the calories in the food.
The National Soft Drink Association argued
that the study was flawed and that many other studies showed that the use of
low-calorie sweeteners does promote weight loss.
In the next section, we'll discuss how artificial sweeteners
make it in the food chain.
From Lab to
Kitchen
The Delaney Clause in the Food
Additives Amendment of 1958 states that no food additive can be considered safe if
it is found to induce cancer when ingested by humans or
animals.
This is tested by feeding large dosages of the
additive (in this case artificial sweeteners) to small numbers of rats and
mice.
Large dosages are used to compensate for the fact
that a relatively small number of animals are used -- perhaps a few hundred.
The large dosages also compensate for the possibility
that rodents may be less sensitive to the chemical than people might be.
Although it may seem that only a large dose of any
chemical can cause cancer, small doses can too -- just less often.
Companies that want to market a new sweetener (or any
food additive) must petition the FDA for approval, unless the new sweetener is
made up of components generally recognized as safe (GRAS).
The FDA usually requires strong evidence, including
animal studies, to show that the sweetener will not cause harmful effects if
humans consume unexpected quantities of it.
Companies may also submit studies of the additive's
affect on humans.
When deciding whether an additive should be approved,
the FDA considers its composition and properties.
For instance, does the sweetener break down into
harmful by-products? What is the amount likely to be consumed, and what are the
probable long-term effects?
Because they can't determine absolute safety, the FDA
has to decide if the sweetener is safe based on the best scientific knowledge
available.
If a sweetener is approved, the FDA determines the
types of foods in which it can be used, the maximum amounts to be used, and how
it should be identified on food labels. It is then said to be GRAS.
They FDA continually monitors consumption as well as
any new research on the sweetener's safety to assure that its use continues to
be within safe limits.
The Adverse Reaction Monitoring System (ARMS)
serves as an ongoing safety check for all food additives.
The system monitors and investigates all complaints
that are believed to be related to specific food additives.
If reported adverse reactions represent a real public
health hazard, the FDA will take action.
Next, we'll take an in-depth look at some artificial
sweeteners, starting with saccharin.
WHAT'S LEGAL?
There are four legal categories under the 1958 Food
Additives Amendment to the Federal Food, Drug, and Cosmetic Act (FD&C Act)
for substances added to foods:
· Food additives: Substances with no proven safety track record have
to be reviewed and approved by the FDA before they can be used in any food
product
· Generally
recognized as safe (GRAS):
Substances that do have a proven track in foods based on a history of use
before 1958 or on published scientific evidence do not need to be approved by
the FDA prior to use
· Prior-sanctioned: Substances that were assumed to be safe by
either the FDA or the U.S. Department of Agriculture before 1958, to be used in
a specific food
· Color
additives: Dyes
that are used in foods, drugs, cosmetics, and medical devices must be approved
by the FDA before they can be used
Saccharin
Tab is
one of the few products on the market to contain saccharin.
Basics
Saccharin (the Latin word for sugar) is a synthetic
chemical that was discovered in 1879 and was the first artificial sweetener.
Two
chemists at Johns Hopkins University discovered saccharine when a vessel boiled
over in the lab where they were creating new chemical dyes from coal tar
derivatives.
One
of the chemists forgot to wash his hands before eating and noticed that his
fingers tasted sweet.
Saccharin
is 300 times sweeter than sugar and not metabolized by the body, so it has no calories.
Use
There are very few products that contain saccharin
these days.
Fountain
Diet Coke® and Pepsi® use a blend of saccharin and
aspartame, as does Tab®. It's also
still available as Sweet 'N Low®, a
tabletop sweetener in the familiar pink packet.
Controversy
Saccharin has had a very controversial past. The FDA
tried to ban it in 1977 because some animal studies showed that it caused cancer (mainly bladder cancer, but also
uterine, ovarian, skin, and others).
Saccharin
stayed on the market because of pressure from the diet food industry (and the
dieters themselves).
However,
it carried a warning label that stated it had been shown to cause cancer in
laboratory animals until the late 1990s.
The Calorie Control
Council argued that people don't develop bladder cancer in the
same way that rats do, so the warning label should be removed.
In 2000, the National Cancer Institute (NCI) stated
that people who used saccharin had no greater risk of bladder cancer than the
population as a whole.
People
who were heavy saccharin users (six or more servings of saccharin or two or
more 8-ounce servings of diet drink daily) had "some evidence of an
increased risk of bladder cancer, particularly for those who heavily ingested the
sweetener as a tabletop sweetener or through diet sodas."
Because
of this study and other research with laboratory animals, it was decided that
saccharin was not a major risk factor for bladder cancer in humans.
Saccharin
was removed from the NIH's list of carcinogens and Congress agreed to
remove the warning requirement from products containing it.
Next, we'll learn about aspartame, another
controversial sweetener.
CYCLAMATE
was accidentally discovered in 1937 by a graduate
student at the University of Illinois. It is 30 to 50 times sweeter than sugar.
The
FDA banned cyclamate in 1970 after reports that it caused cancer in animals,
but there is currently a petition for re-approval.
It is still used in over 50 countries, including
Canada (where it is the sweetener in Sweet n' Low). Ironically, saccharin is
banned in Canada except for use by diabetics.
Aspartame
Basics
Aspartame (sold under the brand names Equal®, NutraSweet®,
and NatraTaste®)
is derived from a combination of two amino acids: aspartic acid and
phenylalanine.
It
was discovered in 1965 by chemist Jim Schlatter of the pharmaceutical company
G. D. Searle & Co. (now a part of Pfizer).
Schlatter
licked his finger to pick up a piece of paper while testing a new anti-ulcer
drug.
Aspartame is 180 to 200 times sweeter than sugar, so
only very tiny amounts are necessary to sweeten a food or beverage.
When
digested, aspartame breaks down into three components: aspartic acid,
phenylalanine, and methanol (wood alcohol).
People with the rare genetic disorder phenylketonuria (PKU) should avoid
aspartame because their bodies are deficient in the enzyme that breaks down
phenylalanine.
If
they consume foods or beverages containing significant amounts of
phenylalanine, it can build up in their bodies and can cause mental impairment
and possibly brain damage. Newborns are routinely checked for PKU.
Use
Because aspartame breaks down in heat, it is not
generally used in baked or heated foods.
According
to the official aspartame Web site, it can be found in "more than
6,000 products including carbonated soft drinks, powdered soft drinks, chewing
gum, confections, gelatins, dessert mixes, puddings and fillings, frozen
desserts, yogurt, tabletop sweeteners, and some pharmaceuticals such as
vitamins and sugar-free cough drops." Aspartame was approved as a food
additive by the FDA in 1981.
Controversy
There appears to be more controversy over the safety
of aspartame than any other artificial sweetener.
Since
its approval, 75 percent of all complaints reported to ARMS have been about
aspartame. Only about one percent of people who experience a problem actually
report it.
While no officially recognized studies have shown
problems with aspartame, many consumer groups and individuals are speaking out
against it.
Aspartame
is blamed for a number of health problems, including headaches, seizures,
chronic fatigue syndrome, memory loss, and dizziness.
It
has also been associated with an increase in multiple sclerosis, Alzheimer's
disease, and cancer.
Critics of aspartame claim that although aspartame's
two amino acids are a natural part of our diets, when they are consumed
normally in food they appear with many other amino acids that cancel out any
negative affects.
When
these amino acids are on their own, as they are in aspartame, the concern is
that they enter the central nervous system in abnormally high concentrations.
A similar problem allegedly occurs with the methanol
(wood alcohol) that aspartame breaks down into when digested.
When
it occurs naturally in fruit juices and alcoholic beverages, methanol is always
accompanied by higher amounts of ethanol, which acts as an antidote for methanol
toxicity.
Ten
percent of aspartame is absorbed into the bloodstream as methanol.
The Environmental
Protection Agency set a recommended limit of only 7.8
milligrams per day of methanol, while a one-liter aspartame-sweetened beverage
contains about 56 milligrams, or eight times the recommended amount.
In 2005 the European Journal of Oncology published an
article about a study of aspartame that showed that it caused lymphomas and
leukemia in female rats.
The
lowest level of aspartame that was still found to increase these risks in
adults was equal to about eight cans of aspartame-containing soda a day (two
for children).
Brain
tumors were also found in 12 of 1500 animals that received aspartame, while the
animals that received no aspartame had no brain tumors.
On the other hand, many groups have also performed
studies that show aspartame is safe and causes no health problems.
Next we'll explore acesulfame, a lesser-known
sweetener.
NEOTAME
is similar to aspartame in that it is derived
combination of aspartic acid and phenylalanine. is more stable, however,
because the bond between the amino acids is harder to break down.
It
was developed over 20 years and is 8,000 times sweeter than sugar.
According
to the neotame Web site,
only six milligrams are needed to sweeten a 12-ounce beverage.
Because neotame doesn't break down into phenylalanine
like aspartame does, it is safe for people with PKU. Products containing
neotame will also be able to be cooked or baked.
was approved by the FDA in 2002 for use in beverages,
frozen deserts, yogurt, ice cream, chewing gum, candy, baked goods, toppings,
fruit spreads, breakfast cereals and more.
Because
it's still new, there aren't many products that use neotame yet.
Acesulfame
Basics
 |
| This meal replacement powder uses acesulfame as a sweetener. |
It
was discovered in 1967 by Hoechst AG, a German life-sciences company that is
now part of Aventis.
Our
bodies can't metabolize it, which is why it's considered low calorie.
Acesulfame
is made from a process involving acetoacetic acid and its combination with
potassium.
Use
The FDA approved acesulfame in 1988 and it is found
in more than 4,000 products around the world.
In
the United States, acesulfame potassium has been approved for use in candies,
tabletop sweeteners, chewing gums, beverages, dessert and dairy product mixes,
baked goods, alcoholic beverages,
syrups, refrigerated and frozen desserts, and sweet sauces and toppings.
It
can be found under the brand names Sweet
One® and Sunett®.
Acesulfame
is often blended with other artificial sweeteners to produce a more sugar-like
taste.
Controversy
In August of 1988, the Center for Science in the
Public Interest formally asked for a stay of acesulfame's approval by the FDA
because of "significant doubt" about its safety.
CSPI
claimed that the studies were flawed and did not sufficiently prove that
acesulfame did not cause cancer.
According
to the CSPI Web site, "...acetoacetamide, a breakdown product of
acesulfame, has been shown to affect the thyroid in rats, rabbits, and dogs.
Administration of 1 percent and 5 percent acetoacetamide in the diet for three
months caused benign thyroid tumors in rats. The rapid appearance of tumors
raises serious questions about the chemical's carcinogenic potency".
Next, we'll learn about one of the newest artificial
sweeteners: sucralose.
Sucralose
Basics
To create sucralose, three of the hydrogen (H) and
oxygen (O) groups in a sugar molecule are replaced with three chlorine (Cl)
atoms.
At that point it is no longer sugar -- it is an
artificial sweetener that is 600 times sweeter than sugar.
Sucralose isn't metabolized by the body, so it has
virtually no calories.
The chlorine that prevents it from being absorbed by
the body also gives it the ability to withstand enough heat to be used in
baking.
(Other sweeteners lose their sweetness if you try to
bake with them.) It was approved by the FDA for use in foods and
beverages in 1998.
Use
Sucralose, marketed as Splenda®, is the
fastest growing artificial sweetener on the market.
It can be found in everything from frozen desserts,
to sodas, to cookies, gum, and candies.
Sucralose is sold in bulk for baking and is available
in a small yellow packet for sweetening your coffee or tea.
Controversy
Sucralose isn't as controversial as aspartame.
However, the Food and Drug Administration's 1998
report that gave approval for sucralose also stated that it is "weakly
mutagenic in a mouse lymphoma mutation assay."
This means it caused minor genetic damages in mouse
cells.
In addition, it stated that one of the substances
sucralose breaks down into when digested is also "weakly mutagenic in the
Ames test."
The Ames test is the standard method used to detect
possible carcinogens.
The other controversy is over the way Sucralose is
marketed as Splenda.
Because of their tagline, "Splenda is made from
sugar, so it tastes like sugar," many people believe that Splenda is a
natural sweetener and therefore healthier, which isn't the case.
Because there have been no long-term studies, no one
really knows if sucralose is healthier than other artificial sweeteners.
Next, we'll discuss tagatose, another new artificial
sweetener.
Tagatose
Basics
Tagatose (or Natrulose®) is a new
artificial sweetener manufactured from lactulose, or milk sugar.
In one step, lactose is hydrolyzed (broken
down into smaller molecules by using water)
to glucose and galactose.
In the second step, galactose is isomerized (changed
to a molecule with the same chemical formula but a different atom arrangement)
to D-tagatose by adding calcium hydroxide.
Tagatose was discovered when Gilbert Levin, founder
of Spherix, wanted to find a new sweetener and thought a
"left-handed" sugar might be the answer.
In chemistry, a molecule can be chiral ("left-handed"
or "right-handed") if it cannot be superimposed on its mirror image.
For example, our hands are mirror images of one
another and cannot be superimposed.
Levin was accidentally sent D-tagatose, a
"right-handed" molecule that structurally similar to L-fructose. It
turned out to be just what he was looking for.
Tagatose has about 1.5 calories per
gram, and does not significantly impact blood glucose or insulin levels.
It can't be digested, so it passes through the body
unabsorbed.
It is equal in bulk and sweetness to sugar and can be
combined with other artificial sweeteners to improve flavor and texture.
The FDA accepted a Generally Recognized As Safe
(GRAS) declaration submitted by the manufacturer of tagatose in 2001.
Use
Because it's so new, tagatose is not used in many products
yet.
Currently it is used in Diet Pepsi Slurpees®sold
at 7-Eleven®, and Florida Gold®'s new Light and Tangy
frozen juice beverage concentrate.
It can be used in breakfast cereals, diet soft
drinks, health bars, frozen yogurt/nonfat ice cream,
soft confectionaries, hard confectionaries, frosting, and chewing gum.
Controversy
Again, the newness of tagatose means that there isn't
much controversy about it yet.
It isn't absorbed well and can cause GI distress if
consumed in large quantities.
Next, we'll discuss sugar alcohols.
THE NEWEST SWEETENERS
Dihydrochalcones (DHCs) are noncaloric sweeteners
derived from bioflavonoids of citrus fruits, and glycyrrhizin is a noncaloric
extract of licorice root, 50 to 100 times sweeter than sugar.
Both of these sweeteners are already approved for use
as flavors and flavor enhancers.
Alitame (brand name Aclame®), is reported
to be 2,000 times sweeter than sugar. A petition for its use has been filed
with the FDA.
Sugar Alcohols
Basics
Sugar alcohols are made
from adding hydrogen atoms to sugars. They don't contain ethanol, so they're
not related to alcoholic beverages.
 |
| This sugarless gum uses sorbitol, a sugar alcohol, as a sweetener. |
Sugar alcohols have about one-half to one-third fewer
calories than regular sugar, because they convert to glucose more slowly.
They don't usually cause sudden increases in blood
sugar, so can be used in moderation by diabetics.
Some people with Type I diabetes have
found that their blood sugars will rise if they consume sugar alcohols in large
amounts.
The caloric content varies by specific sugar alcohol.
Erythritol, for example, is not absorbed as easily as
others, so it essentially has no calories.
Some of the other sugar alcohols can have almost as
many calories as sugar, so they're not necessarily used in "diet"
foods, but in sugar-free gum.
Use
Sugar alcohols are found in many sugar-free processed
foods, such as hard candies, cookies, chewing gums, soft drinks, throat
lozenges, toothpaste, and mouthwash.
Look on product labels for mannitol, sorbitol,
xylitol, lactitol, isomalt, erythritol, maltitol, and hydrogenated starch
hydrolysates (HSH).
Controversy
The FDA requires products that contain what would
equate to a daily dose of 50 grams or sorbitol or 20 grams of mannitol to be
labeled with a "laxative effect" warning.
This is because higher levels of sugar alcohols
unabsorbed in the intestines can cause bloating, gas, and diarrhea.
According to the Center for Science in the Public
Interest, only 10 grams of sorbitol can cause GI distress.
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