Calorie Restriction Extends Lifespan of Normal Cells and Inhibits Atypical Cells
Posted Dec 22 2009 12:00am
I have always been intrigued by the well-documented observation in lab animals that caloric restriction increases longevity, at least in lab rats. It would be interesting to isolate the physiologic basis for this observation that could lead to other less rigorous dietary interventions to produce this same effect. A recent article provides some hints about progress in this direction with a bonus about a possible mechanism to suppress the proliferation of atypical cells (see: Calorie Intake Linked To Cell Lifespan, Cancer Development). Below is an excerpt from it:
Researchers from the University of Alabama at Birmingham...have discovered that restricting consumption of glucose, the most common dietary sugar, can extend the life of healthy human-lung cells and speed the death of precancerous human-lung cells, reducing cancer's spread and growth rate....The UAB team conducted its tests by growing both healthy human-lung cells and precancerous human-lung cells in laboratory flasks. The flasks were provided either normal levels of glucose or significantly reduced amounts of the sugar compound, and the cells then were allowed to grow for a period of weeks....In particular, the researchers found that two key genes were affected in the cellular response to decreased glucose consumption. The first gene, telomerase, encodes an important enzyme that allows cells to divide indefinitely. The second gene, p16, encodes a well known anti-cancer protein. "Opposite effects were found for these genes in healthy cells versus precancerous cells. The healthy cells saw their telomerase rise and p16 decrease, which would explain the boost in healthy cell growth," [one of the researchers] said. "The gene reactions flipped in the precancerous cells with telomerase decreasing and the anti-cancer protein p16 increasing, which would explain why these cancer-forming cells died off in large numbers." The UAB research into the links between calorie intake, aging and the onset of diseases related to aging is thought to be a first of its kind given that it used the unique approach of testing human cells versus laboratory animals.
So, in a preliminary way, it now appears that restricting
the consumption of dietary sugar extends the life of cultured lung cells
and inhibits the growth of atypical (i.e., precancerous) cells. In a
previous note, I commented about the "toxicity"
of four chemicals/foods that we common are exposed to: sugar,
fat, nicotine/tar from cigarettes, and ethyl alcohol (see: Federal Tax on Soda Pop Proposed: Can This Be Justified?).
There are a number of good reasons to shun these substances. However, I was under the impression when I wrote this note that the ill
effects of sugar ingestion, for example, was the result of obesity and altered circulating enzyme levels rather than any
effects of the sugar on genes.
It's also interesting that, at least in this study, the observed effects of the sugar were mediated by telomerase and P16 that code for an enzyme and protein associated with aging and cell growth. The anti-aging movement will be a major driver for the clinical lab industry (see: Anti-Aging Medicine as a Major Driver of Complex Lab Testing) so it's important for lab professionals to pay attention to any research that is published in this area. I have also commented in the past about how leukocyte telomere length has been used as a measure of physical activity (see: Leukocyte Telomere Length as a Measure of Physical Activity).