A couple of weeks ago, a joint
statement came out from the American Heart Association and the American
Diabetes Association that while
non-caloric sweeteners may be useful for limiting carbohydrates and added
sugars in the diet, the evidence is inconclusive as to whether it works in the
long run to cut calories, reduce sugar, and lose weight. The statement in itself was a bit
curious since it states that the non-caloric sweeteners may be useful for
limiting added sugars in the diet, but the evidence is inclusive that it
reduces sugar in the diet.
On the contrary, data from a number of epidemiologic
studies found that the evidence seems more in favor of the sweeteners
increasing sugar and calorie intake and weight gain. Why is this? Here
are two proposed reasons:
1. They cause us to
overcompensate. Because the
taste of sweet is normally followed by calories, as is the case with
real/natural sugars, consuming artificial sweeteners may lead to overeating to
compensate for the lack of calories. Studies in adults showed that while consuming sucrose
before a meal helped to lower the number of calories consumed at a subsequent
meal, artificial sweeteners like aspartame did not. This was also demonstrated in rats that were fed either
water with sucrose/glucose or an artificial sweetener before a meal. The rats fed artificially sweetened
water ate more and gained more weight than the rats that drank sugar water, suggesting
that a mechanism for energy balance is in play.
2. They leave us wanting
more. There are two branches
of the food reward pathway that target different regions of the brain. The first involves the
hypothalamus. Functional MRI
studies have shown that glucose and sucralose act differently on the
hypothalamus. In addition,
aspartame binds to sweet taste receptors differently than sugar and activates
the second branch of the pathway (that involves the insula, orbitofrontal
cortex, and amygdala regions of the brain) to a lesser extent than sugar. This all suggests
we don't derive the same pleasure from artificial sweeteners as we do from
natural sugars.
On the topic of whether
artificial sweeteners are safe to consume, I mentioned last week that the data
is inconclusive but there is plenty of human experiences to suggest that they cause
problems for many people. If you
read this Citizen’s
Petition against aspartame on the FDA site, you will get a glimpse into
some of the findings about aspartame during it’s development and testing. A search
on their site also turns up a number of complaints submitted to the FDA.
In addition, while there has been
some concern about aspartame and a risk of cancer, in one study, rats that
developed higher numbers of lymphomas and leukemias that were fed aspartame,
were given doses equivalent to 8 - 2,083 cans of diet soda per day. Anything in excessive doses can be
toxic, even water.
Would I recommend using artificial
sweeteners on a regular basis? Not
unless you can tolerate them and you can truly reduce your sugar/simple carb
intake with them. For many people,
I don’t think an occasional diet soda is harmful unless you know for sure that
you experience specific reactions to artificial sweeteners. For example, people
with PKU who cannot metabolize the amino acid phenylalanine should avoid
aspartame entirely. In addition, while
many people do not react to sucralose with a rash, knowing what it can do, I choose not to take the risk.
In my mind, the real issue here
is not whether or not we should be consuming artificial sweeteners, but rather,
why do we need so much “sweet” in the first place? Yes, we have sweet receptors and there are lots of natural
foods that can activate them, like fruits and sweet vegetables. Why isn’t this enough for us and why is
our food supply swimming in both calorie-containing and non-caloric
sweeteners? If we were sweetening
our lives in other ways, perhaps our need for sweet taste would dissipate.
Image courtesy of Audfriday13