I haven’t posted about hunger/weight loss for awhile, but in honor of my tenth month of weight loss maintenance, I thought I’d share two new articles that crossed my desk today.
The first, by Kaveh Ashfrafi and his colleagues at UC San Francisco, looked at the effects of serotonin on appetite and fat storage in…..worms, C. elegans to be exact [1]. Okay, I’m a psychologist, not a biologist, but I didn’t even know that worms could get obese. What does a fat worm look like? Is this a fit one? A fat one? Who knows….
Back to appetite and fat…the UCSF team report that serotonin has two coordinated, but independent pathways for regulating feeding and fat metabolism. In an interview posted by the UCSF PR people, Ashrafi points out that drugs targeting serotonin’s effects on feeding have been disappointing, and the discovery of a separate fat storage mechanism might stimulate the development of more effective weight loss drugs. I must confess, my favorite part of the UCSF press release says that C. Elegans “shares half its genes with humans and is often a predictor of human traits.” As I mentioned in an earlier post, human beings share 98% of their genes with chimpanzees, 92% of their genes with mice, 44% with fruit flies, 26% with yeast, and 18% with thale cress (that’s a weed, in case you’ve never heard of it).This sharing genes thing can be a bit overdone, in my personal view.
Next up, we have a study that says that people with a particular version of the GLUT 2 gene eat more sugar (20-30 grams, or about the amount of sugar in a regular cola) than other people [2]. Well, at least we’re talking about people now, not worms. GLUT 2 is expressed not only in the pancreas, but also in the brain, leading the researchers to wonder if it participates in appetite as well. The GLUT 2 difference was very specific to sugar–people with the sugar version of the gene did not eat more protein, more fat, or more non-sugar carbs than people with other versions. These people probably shouldn’t work at this Louisiana sugar processing plant:
I’m wondering what kind of GLUT 2 gene I might have. I do like sweets, but much less so than I did as a child.
It’s hard to tell if studies like these will eventually lead to practical advice for those who want to lose weight, but hopefully, the answer will be yes. I do worry a bit about the “gene for sweet tooth” approach, because so many people believe that genetic factors cannot be modified by experience and environment, which of course, they can. All of us have successful ancestors who did a very nice job of surviving famine, but that doesn’t mean we are doomed to obesity.
1. Srinivasan, S., Sadegh, L., Elle, I.C., Christensen, A.G.L., Faergeman, N.J., & Ashrafi, K. (2008). Serotonin regulates C. elegans fat and feeding through independent molecular mechanisms. Cell Metabolism, 7, 533-544.
2. Eny, K. M., Wolever, T. M. S., Fontaine-Bisson, B., & El-Sohemy, A. (2008). Genetic variant in the glucose transporter type 2 is associated with higher intakes of sugars in two distinct populations. Physiological Genomics, 33(3), 355-360.
2 Comments
svallier · June 6, 2008 at 10:42 am
When imagining what scientific advances will be made in the future, I question if there is even a possibility of what I imagine becoming a possibility considering how fast everything in the world is evolving and changing. After reading your last article on how certain genes do affect sugar intake, I began thinking about whether genes will be genetically altered to loose weight. Is it even possible, and if it is how would it effect man kind. I do worry that the facts of the side effects, as well as the ethics will be much slower behind the up and coming technology of such an interesting topic. Interesting that scientists can uses facts like “we share half our genes” when they probably know exactly what you know about this, we also share 44% with fruit flies…an important reminder of how easily the facts are skewed if you aren’t well read on the subject. Thus I do want to keep an ear out for studies like these taking their research to the next level – actual human studies.
l.ogden · June 6, 2008 at 8:53 pm
At this point I would consider that worms can get fat as a simple fun fact. The anatomy and mechanisms of a worm don’t seem extremely relevant. Maybe it will inspire more research in humans or significantly closely related species, but for now I’m surprised there is an article on it. To me, it just shows the desperation to find any way to a skinnier life. I find the information about the GLUT 2 gene more interesting. I honestly wouldn’t be surprised if I had such a disposition (i crave sugar more than virtually anyone i know), but know i cannot use this as an excuse and let my appetite run wild. Urges are controllable and I think that as long as the public remains informed of this, further research will be interesting and beneficial.
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