Telomeres, Soda and Long Life?

The Washington Post picked up on a study linking consumption of sugared soda with DNA telomere length.    The study claims that this link implies a link between sugared soda consumption and aging. The most dramatic claim as described by the WP is the following:

According to the research, drinking a 20 ounce bubbly beverage every day is linked to 4.6 years of additional aging.  You get the same effect by smonking, said UCSF postdoctoral fellow Cindy Leung, lead author of the study.  About 21 percent of the sample said they drank at least that much soday per day.  However, researchers say, a link does not mean causation.

Many other outlets picked up the story.  Headlines included That Sweet Drink May Age You (CNN), Drinking Sugary Soda Makes Your Cells Age Faster, Study Suggests (Huffington Post), Perils of Drinking Sugary Soda: Weight Gain, Cavities, Shortened Lifespan and What? (Dallas News) and so on.

But are these claims justified.  Most of the media simply reported the claims of the researchers as described in a post on the web site home page of their institution (UC San Francisco).  In fact, the connection between telomere length and health is controversial as pointed out by Daniel Engbar at Slate in a piece headlined, Does Drinking Soda Really Age Your Cells?  His answer to the headline is given in a sub-heading: How the Science of Telomeres Turned into a Spurious Health Trend.  According to this Slate piece the basic science of telomeres is that they are strings of nucleic acid molecules at the ends of our genetic strands of DNA whose function is to keep the very long DNA strands from unraveling.  These telomeres get shorter every time the cell divides until they disappear and the cell line dies.That much is uncontroversial.  However, the connection between measured telomere lengths and any aspect of health or even aging is tenuous at best.  Engbar's position is:

The shallow write-ups and inveigling headlines are insulting, and possibly injurious. In this case, though, they’re less offensive than the underlying science. The newly published paper delivers a mishmash of suspect stats and overbroad conclusions, marshaled to advance a theory that’s both unsupported by the data and somewhat at odds with existing research in the field. Its authors are less concerned with the health effects of drinking soda than with their broader project to establish a still new and fuzzy concept—“cellular aging”—as a pole star for public health.

Engbar also points out that the study authors stand to gain from book sales, speaking fees and product endorsements if they can persuade the public to accept their assertions about telomere lengths and health.

This is a good example of the extent to which media reports of science need to be considered carefully.