Low-calorie sweeteners

Low-calorie sweeteners

November 19, 2019 14 By Ewald Bahringer


Most people love sweet foods. Originally, sweetness was nature’s way of
identifying energy-dense foods that were safe to eat. This was particularly important throughout
the long history of our species when food was scarce. But times have changed, and nowadays, sweetness
is mostly associated with the sugars added to foods and drinks. And unfortunately many people consume too
many calories from these sorts of added sugars. Over time, consuming more calories than the
body needs can contribute to the onset of chronic diseases like obesity, type 2 diabetes
mellitus, hypertension, or cardiovascular disease. Low-calorie sweeteners can satisfy our taste
buds while reducing the calories we eat from sugar. The good news is that randomized controlled
trials have shown that replacing full-calorie foods and beverages with low-calorie sweetened
versions can lead to modest weight loss, as long as the individual doesn’t over-indulge
on additional calories from other sources – say, by ordering dessert because they had
a diet soda with dinner. Low-calorie sweeteners don’t raise blood
glucose or insulin levels, so they can help people with diabetes control their blood sugar
and reduce the amount of total sugars they consume each day. Some low- and no-calorie sweeteners like stevia
and monk fruit extracts, come from plants, and others, like aspartame, sucralose, and
acesulfame potassium are man-made. It’s important to note that all of them
are sweeter than sugar, which means that only tiny amounts are needed to equal the sweetness
of sugar. As a result, low-calorie sweeteners are often
blended with carbohydrates like dextrose and maltodextrin or the sugar alcohol erythritol
when they’re found in table top packets. This makes the overall volume similar to a
packet of sugar, so that it’s easier to measure and pour. That’s why packets of low-calorie sweeteners
and sugar are about equal in size. Aspartame, which is about 200 times sweeter
than sugar, is composed of two amino acids, aspartic acid and phenylalanine, and a molecule
of methanol. When we consume aspartame, it’s rapidly
broken down in the small intestine into these three components, all of which are naturally
found in much higher quantities in other foods that we eat every day. Like sugar, aspartame contains 4 calories
per gram, but due to its sweetness, only a very tiny amount is needed to replace sugar. As a result, it doesn’t contribute a substantial
number of calories to our diet. Sucralose is about 600 times sweeter than
sugar and is made from the disaccharide sucrose, commonly known as table sugar, by replacing
three of its hydroxyl groups with chlorine atoms. This structure prevents digestive enzymes
from fully breaking it down, so only a small amount is metabolized and it doesn’t contribute
any calories. In fact, about 85 percent of the sucralose
we consume is not absorbed, and the small amount that is absorbed is rapidly excreted
in the urine. Acesulfame potassium, sometimes called ace-K,
is a potassium salt that’s 200 times sweeter than sugar. It’s usually added to foods and beverages
in combination with other low-calorie sweeteners. Ace-K is absorbed in the small intestine,
but it’s not broken down before being excreted in the urine, so it also doesn’t provide
any calories. Although it contains potassium, it contributes
very little of this nutrient to our diets, since only tiny amounts of ace-K are found
in foods and beverages. Stevia sweeteners are derived from the stevia
plant, which is native to South America, and are about 200 times sweeter than sugar. Stevia sweeteners are made by extracting sweet
compounds, called steviol glycosides, from the leaves of the stevia plant and purifying
them to remove some of the bitter compounds found in the crude extract. Some steviol glycosides are also made through
processes like fermentation, which allows sweeter and less bitter glycosides to be produced
on a larger scale. Glycosides are monosaccharides, like glucose,
which are bound to another molecule by a glycosidic bond. Steviol glycosides all have a common basic
backbone, called steviol. They include compounds like stevioside and
many different forms of rebaudiosides, the most common of which is rebaudioside A or
Reb A. Purified steviol glycosides remain intact through the upper gastrointestinal
tract and don’t get absorbed, which means that they do not contribute any calories to
our diet. When they get to the colon, our gut microbiota
cleave off the glucose molecules and use them as an energy source. The remaining steviol backbone is then absorbed
via the portal vein, metabolized by the liver, and excreted in urine. Monk fruit sweeteners come from the Siraitia
grosvenorii Swingle fruit, or monk fruit, a plant native to southern China, and they’re
about 250 times sweeter than sugar. Juice from monk fruit is extracted for its
mogrosides, the compounds that give the ripe fruit its sweetness. They’re a combination of a compound called
a mogrol, and glucose units or glycosides. Like steviol glycosides, monk fruit sweeteners
undergo only minimal systemic absorption, but the glycosidic attachments of the mogrosides
can be digested by the gut microbiota, leaving the basic mogrol backbone, which is then excreted. All of these low-calorie sweeteners have been
studied extensively to determine their safety and to establish levels of Acceptable Daily
Intake, also known as an ADI. The ADI represents the amount of a compound
in foods or beverages that could be ingested every day, over a lifetime, without health
risks. To calculate the ADI, the first step is to
study the effects of the compound in animals – like a rat or mouse. To be sure that the animal model testing is
relevant, scientists conduct human clinical trials to confirm there are no major differences
in metabolism between the animal models and people. Testing is then done in the appropriate animal
models and includes studies to ensure that there are no effects on pregnancy, growth,
or development or any indication of side effects, including with high intakes every day until
old age. From these results, a No Observed Adverse
Effect Level or NOAEL is determined. The NOAEL is then divided by 100 to arrive
at the ADI. In other words, the ADI is an extremely conservative
number to make sure that there’s no chance of harm. On average, the amount of low-calorie sweeteners
we consume each day is well below the ADI, even for people with a really sweet tooth. Okay – as a quick recap. Most people enjoy a sweet treat, but unfortunately,
many people eat more added sugar than is recommended, sometimes at the expense of nutrient-dense
foods they need. Low-calorie sweeteners can help reduce the
number of calories we eat from sugar without having to sacrifice sweet taste. Each low-calorie sweetener has a distinct
structure and metabolic pathway, and they all provide a unique level of sweetness as
compared to sugar. Extensive research has shown that they are
safe in the amounts expected to be consumed, can help with weight loss and weight maintenance,
and they can be an option for people trying to control their blood sugar.