Aspartame and Cancer in Rats vs. Humans

A friend of mine (who I swear sometimes suffers from hyperactive agency detection device) referred me here when he was telling me that aspartame (sometimes abbreviated as APM) is hazardous to human health.  Specifically, he was talking about this:

An animal study that fed 0, 4, 20, 100, 500, 2500, and 5000 mg per kilogram of body weight of aspartame to rats saw lymphoma/leukemia increase in female rats, starting from about twice the risk with 20 mg per kilogram of body weight (a person weighing 75 kilograms or 165 lbs, consuming 1500 mg aspartame, or about 8 cans of diet soda) compared with a control group that was not fed aspartame.

It's strange that he pointed me there when the rest of the article talks about how the most recent HUMAN study shows no association between aspartame consumption and cancer rates, but nevertheless, I'd like to deal with this issue.

Before I get into that, let me give a brief overview of the idea behind non-nutritive or "0 Calorie" sweeteners.  Sugar (such as sucrose or fructose -- there are many types of sugars) is perceived as sweet because it interacts with taste buds on our tongue.  These taste buds have receptors that temporarily interact with sucrose and other sugars, and when that happens our brain gets a signal that says "oooh, this tastes sweet."  Each of these sugars has a varying level of "sweetness" as perceived by the brain depending on how it interacts with these receptors.  Evolutionarily, this is an advantage in that sugars are used by our bodies for energy, so being able to detect sugar and have a pleasurable response to it makes sense.  But when we consume more Calories than we require and we become obese, this reward response can become counterproductive.  One weapon against this is to use compounds that activate our taste buds for "sweet" but without that compound being used for energy.  Instead, the compound passes through your digestive tract without being absorbed.  That way the food tastes good without making us fatter!

Dr. Paul Offit on NPR's Talk of the Nation

Dr. Paul Offit was a guest on Talk of the Nation last week to talk about vaccines.  He talked about his new book, Deadly Choices, which discusses the anti-vaccine movement.  I've already ordered it on my Kindle, but I haven't read it yet.  I'm hoping I can use it as a break from GRRM's A Song of Ice and Fire series soon (I'm ~65% through the 3rd book, A Storm of Swords). 

I had a chance to listen to the podcast while I was at the gym today, and it was enjoyable but immensely frustrating.  I think what people forget is that sometimes medicine doesn't make logical sense until you spend years studying the subject.  One of the callers refused to accept Offit's argument that having 5 vaccines in a single doctor's visit still isn't even a blip in the radar compared to what your immune system (or a child's) encounters every day.  When you see a child scream while getting stuck with a needle a few times, I can understand how it would seem that it's a bigger deal to your immune system, but factually it simply is not.

I could spend hours talking about vaccines and the anti-vaccine movement, but instead I'll have you check out the podcast yourself.  It's ~18 minutes long so you can listen to it while you're driving to class/work or while you're at the gym.  If you have a podcast application on your phone, you can subscribe to Talk of the Nation as well, which makes finding and listening to stuff like this much easier.  Hopefully I'll find some time to read Deadly Choices soon.  Based on what I heard on the podcast, I'm sure it'll be worth the time!

Cryolipolysis: What is it and does it work?

In the last couple weeks, I've realized that if I still lived back home, I'd probably be blogging a lot more often.  Talking to my family always gives me great ideas for new topics to cover on here!

This time, we have cryolipolysis (I think I've heard it called "cold lipo" as well).  This procedure involves exposing fat "problem areas" (like love handles) to intense cold.  It's non-invasive, and may seem like a nice alternative to people who are put off by the somewhat disturbing, violent procedure that is liposuction.  For people who are in good shape but still have some remaining problem areas they'd like to get rid of, it can be tempting.

The low temperature forces your adipocytes (fat cells) to undergo apoptosis (programmed cell death).  The idea is that killing these adipocytes will get rid of the fat they contain and thus reduce the amount of fat in the area.  A study from July 2009, entitled Clinical efficacy of noninvasive cryolipolysis and its effects on peripheral nerves looked at the procedure.  A search in PubMed for cryolipolysis didn't bring up any more recent studies for its efficacy in humans, which leads me to believe that this may have been something of a dead end (1.5 years and no larger trials to test the procedure?), but it's worth looking into. 

Before getting into the results of the study itself, let's consider what happens after an adipocyte undergoes apoptosis.  When an adipocyte dies, it releases its contents (fat) into the surrounding tissue.  From there, the fat can be taken up by the surrounding surviving adipocytes or picked up by the lymphatics and returned to the blood. From here, the fat has a few options:

1. Stay in the blood.  This would be bad.  What use is reducing your love handles if you give yourself high cholesterol instead?
2. Be "burned" for energy/calories.
3. Be transported throughout the body for storage, including back to the original site.
4. Excreted from the body.

Now it can get a little more complicated than that considering what else needs to happen to the released fat (lipids) before they can be stored or used for energy, etc., but that's enough for a general idea of what's going on.

Sloppy Research Regarding GM Crops

I've come to the conclusion that I'm too busy and far too easily distracted to post to Verbatio with any sort of regularity right now.  (That may change if/when SkepSIG starts up though).  I'll still post when something is on my mind, but in general, I won't beat myself up for not posting regularly.  So if I don't post for a few weeks at a time (like now), don't think that I've completely abandoned Verbatio.  Rather, it's likely that I've just been busy or haven't thought of something to post about lately.  But when something comes up, or when I feel like procrastinating instead of studying for an exam (like I'm doing now), I'll be sure to blog about it.

But I digress, onto the matter at hand: those evil genetically modified (GM) crops!  A classmate of mine linked this study, which compared the effects of 3 different GM maize/corn varieties on mice.  What caught my eye from the beginning is that the authors consistently use the term "toxic" or "toxicity" instead of simply "different."  A change in metabolite concentration in the serum or urine is a sign of hepatorenal toxicity rather than just being statistically different from the control.  Rather than state what their hypothesis was (that the GM crops would just be statistically different, or that certain concentrations would be decreased or elevated), they took any change from the control to be a sign of toxicity, rather than simply a difference.  Sloppy science.