American Journal of Clinical Nutrition 2012; 96:1419-28.
Last month, a very interesting
article was published examining diet soda consumption and risk of certain
cancers. The results were a bit
surprising and a bit disturbing. I
thought I’d use this post to explain the ramifications of this investigation.
Summary Of Findings
The objective of this
study was to examine the association between diet soda consumption and risk of
3 cancers: non-Hodgkin’s lymphoma, multiple myeloma, and leukemia. The study included 47,810 men from the
Health Professional Follow-up Study and 77,218 women from the Nurses’ Health Study. Participants were followed for 22 years. Here are the main findings:
-When the 2 cohorts were
combined, there was no significant association between diet soda consumption
and risk of these cancers.
-Men consuming the most
diet soda had a 31% increased risk of non-Hodgkin’s lymphoma and a 102%
increased risk of multiple myeloma.
-This association was not
seen in women.
-Men consuming the most
regular soda (not diet) had a 66% increased risk of non-Hodgkin’s lymphoma.
Why You Should Be Concerned
1) This is a very well
designed study. Harvard’s Nurses’ Health
Study and Health Professional Follow-up Study are two of the best cohort
studies in the whole world.
2) A recent very large study
in rats saw increases in risk of these cancers with a high consumption of
aspartame, which is the sweetener used in diet soda.
3) This association is
biologically plausible. Aspartame in
liquid breaks down to its 3 ingredients; methanol, aspartic acid, and
phenylalanine. Formaldehyde is
metabolized from methanol and is a documented carcinogen.
Why You Should Not Freak Out Entirely
1) There is a lot of
previous research on the health effects of aspartame, I mean a lot. It is arguably the most tested food substance
in the history of the world. The results
of this research in both humans and animals is that it is safe.
2) When the cohorts were
combined, there was no association between diet soda and these cancers. Also when women were analyzed separately,
there was no association between diet soda and these cancers.
3) The men showing an
increased risk of cancer were drinking a lot of diet soda, an average of 11
servings per week. A serving is
considered 12 ounces. Men with lower
consumption, even up to 6 servings per week, saw no increased risk of these
cancers.
4) It may not even have
been the aspartame that caused the problem.
Because there was an increased risk in non-Hodgkin’s lymphoma in men
drinking a lot of regular soda, the researchers theorized that it may be
something else in soda in general, perhaps another ingredient common to both
diet and regular soda (such as the caramel coloring) or a substance used in the
packaging.
5) There is really no
reason that there should be a sex difference in risk of cancer with this exposure. The sex difference in risk combined with the
fact that risk was elevated in regular soda drinkers as well means the results
could have been due to chance. In fact,
the researchers mention as much in their own conclusions.
Recommendations
As the first study to show
harm with high levels of diet soda consumption, this will no doubt spur new
research in this field. We should all
keep our eye on it.
My clients and readers of
my books know that I advocate 100% sugar avoidance and, instead, occasional
non-nutritive sweetener use twice a week on splurge meals. It is my opinion that this level of
consumption is safe, even after reading this study. Two or three diet cokes a week have never been
shown to cause any problem, including in this investigation. If you are drinking tons of diet soda every
day, is this study enough to make you stop?
It probably would be for me.
However, my clients and
readers of my books already know that daily consumption of diet soda is a bad
idea for a number of reasons. But that
is a whole other story and this post is long enough already!
Although this study is the
first to suggest a potential negative health effect of diet soda, keep in mind
that lots of research has found an association between regular soda and risk of
obesity, diabetes, and even heart disease.
Artificial sweeteners, although far from perfect, when consumed in
moderation, are still the lesser of two evils.
Before I read this study,
I had aspartame in the “occasional use” category. In other words, I looked at it as I did red
meat. Now and again consumption is not
likely to cause a problem, but daily consumption may. After reading this article and considering
all previous literature, I still look at it this way.
One last note: both this
study, and the study in rats focused on aspartame, also known as Equal. Sucralose, also known as Splenda, has not
been shown to have any negative health effects.
Therefore, when you do occasionally use an artificial sweetener, it may be a good idea to go for products made with Splenda instead of Equal just to be on the safe side.
