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Volume 87 Issue 13 | p. 64 | Newscripts
Issue Date: March 30, 2009

Let them eat sweets, Squid snacks

Department: Newscripts
Can I, Ma?:
Growing bones might signal a need for sweets.
Credit: Shutterstock
8713ns_lolipop
 
Can I, Ma?:
Growing bones might signal a need for sweets.
Credit: Shutterstock

Don't let your kids read the latest issue of the journal Physiology & Behavior (2009, 96, 574)—unless you're willing to surrender parental leverage over how many sweets they eat.

A team of physiological psychologists from the University of Washington, Seattle, and the Philadelphia-based Monell Chemical Senses Center set out to uncover biological factors that explain why children adopt as a major goal in life maximizing the SUGARY CONSUMABLES they ingest but then lose that drive as they finish growing.

Using advertisements on Seattle city buses, the researchers recruited 143 participants, ages 11–15, and their parents for the study. With a series of increasingly sweeter sugar solutions, the investigators measured the children's preferences for either high- or low-intensity sweetness. A battery of surveys, interviews, and other information-gathering tools added data about perceptual, physiological, and eating differences between participants who couldn't get enough sugar and those who could.

But the data most suggestive of the biological basis for kids' differing sweetness cravings, Monell researcher Danielle R. Reed says, were from a urine test for bone resorption markers designated NTx, which is short for type I collagen cross-linked N-telopeptides. The higher the NTx concentration, the greater the kids' growth rate. Reed and her colleagues found that the high-NTx kids generally were the same ones who would, given the chance, lick sugar off of a discarded shoe. Participants who were done growing or had lower NTx levels were satisfied with lower sweetness solutions.

The crux of it, Reed argues, is that growing kids crave sugar because it packs the energy their bodies need. It's a drive that in the world's richer contexts might contribute to obesity rates, she notes. As if to spoon-feed children with parent-baiting ammunition, however, the researchers write in their paper that the sugar cravings of growing kids bring "into question the assumption that this propensity is invariably unhealthy and undesirable among this age group."

Depthy Data:
Giant squid beaks bear records of habitat and diet.
Credit: Mike Johnson/Flickr
8713ns_beak
 
Depthy Data:
Giant squid beaks bear records of habitat and diet.
Credit: Mike Johnson/Flickr

It's no revelation that kids love candy, but just what giant squid, octopods, and other deep-sea cephalopods like to STUFF IN THEIR BEAKS isn't obvious. In the whale-eat-cephalopod ocean depths, the only thing that remains of these spineless prey in whales' stomachs are chitinized beaks, but that was enough for a French research team eager for clues.

With a cache of beaks from nearly 20 cephalopod species retrieved from the stomachs of three sperm whales that had become stranded in the Bay of Biscay in 2001, the researchers from the National Center for Scientific Research (CNRS) and the University of La Rochelle, used a high-end mass spectrometer to measure the stable isotopes 13C and 15N—indicators, they say, of where the animals spend their time and what they eat.

In Biology Letters (DOI: 10.1098/rsbl.2009.0024), the researchers report that all the measured 13C values were depleted compared with values for shallow-water cohorts such as cuttlefish, indicating that the squids and octopods that became whale meals had themselves foraged in oceanic waters, not along the continental shelf. The more depleted the beak 13C values, the deeper living the former beak-owner. The protein-indicating 15N values presented a wider range, indicating to the researchers that the species spanned 1.5 trophic levels, similar to the range of common ocean mammals such as dolphins.

The data bolster claims that the giant squid species Taningia danae is a top predator like the sperm whale and is, in the researchers' words, "an aggressive and tenacious predator rather than a sluggish, inactive squid as previously thought." The data also indicate that the giant octopus Haliphron atlanticus dwells higher in the water column and is more apt than his gigantic squid cousin to become someone else's meal.

 

Ivan Amato wrote this week's column. Please send comments and suggestions to newscripts@acs.org.

 
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