Saturday, December 20, 2014

Appetite Short News: Pavlovian Conditioning at Work in the Obese | Polydextrose as a Satiety Promoter | Parents, Just Like Their Kids, Fall for All the Tricks of the Food Industry

Too lean for Pavlovian Conditioning.
In today's "appetizing" installment of the short news, I have picked three of the latest publications from the scientific journal Appetite, of which I thought that they were newsworthy. In that, I cover the Pavlovian Conditioning of overweight individuals, the benefits of polydextrose on appetite control and the way product labels fool parents and children into buying unhealthy foods.

I have to admit: It's not all practically applicable, but who knows maybe you can use it to smart-ass during the holidays. Or maybe you bake some polydextrose enhanced super-satiating cookies for your family, ha?
More facts for your smart-ass sessions on the holidays ;-)

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  • Hedonic food cue conditioning in the obese: You know the story about Pavlov's dog starting to salivate, when the bell rang that would usually accompany his next feeding?

    Well, a recent study confirms that something very similar is at work in obese, but not lean subjects. While the former remain calm and cool to a visual cue that had previously been given alongside some tasty chocolate milk, the latter began to swallow, a reliable sign of increased salivation. As the scientists from the Allaint International University in San Diego say, these "
    are the first results to show differential acquisition of Pavlovian conditioned responding in overweight individuals compared to lean individuals" (Meyer. 2014)
    The fact that the conditioning worked was yet not the only significant finding, Meyer et al. made. They also observed that hedonic food stimuli were significantly more effective 'conditioners' in the obese than neutral stimuli.

    Practically speaking the observations the researchers from the Allaint International University in San Diego made, may partly explain the difficulties obese individuals who may have been conditioned / conditioned themselves to hedonic food stimuli for their whole lives have when it comes to controlling their energy intake.
  • Polydextrose as a satiety promoter: In their meta-analysis of the current literature on the effects of polydextrose on energy intake, researchers from the US and Finland found that...
    • polydextrose consumed with a mid-morning snack reduces energy intake (EI) at lunch time.
    • this reduction in EI at lunch time occurs in a dose-dependent manner.
    • but the energy intake during the rest of the day did not show any difference
    Now this probably wouldn't be newsworthy, then, if a a regression model had not been able to confirm a dose-dependent effect on the reduction of daily energy intake.
Added polydextrose reduces the insulin response to milk (Lummela. 2009)
What exactly is polydextrose? Polydextrose is a glucose polymer that is completely soluble in water. As a food additive it offers the texture of sucrose but provides only 25% of the equivalent energy, or 4 kJ/g. It has been approved for use in foods in over 60 nations and is recognized as a dietary fiber in more than 20 countries (FAO/WHO, 2009). Next to the reduced energy content it has another benefits of the fibrous substance is that its addition to foods like milk can reduce the insulinogenic response to this meals significantly - even in healthy individuals (Lummela. 2009).
  • More specifically, the meta-analysis was able to show that the dose of polydextrose consumed correlated significantly with the reduction of nergy intake at lunch (−0.67 Polydextrose (g/day) | 80% correlation; P < 0.01), due to which the energy intake was reduced by 1% per 2.86g of polydextrose per day.

    As Ibarra et al. point out, the sex-specific results are consistent with results for the whole group - the effect is thus similarly pronounced in both men and women. Accordingly, the meta-analysis "supports the notion that the consumption of polydextrose reduces voluntary energy intake at a subsequent meal" and that "this reduction in energy intake occurs in a dose-dependent manner" (Ibarra. 2014).
  • Parents of preschool children make (non-)sense of front-of-package visuals and claims on food - A recent study from the Colorado State University and the University of Illinois at Urbana-Champaign investigated what parents make of the colorful packaging of foods their kids like to buy and found that most of them tend to "accept misleading front-of-package claims when making quick food decisions" (Abrams. 2014).

    Parents fall for unwarranted claims, and misleading images children for cartoons.
    While playful visuals appeal to children, parents associate them with junk food. That does yet not mean that they would not fall for health claims, realistic graphics, and natural claims which make them classify the junkfoods that were investigated in the study at hand as healthier.

    Fruit graphics in particular were misunderstood to indicate that the respective foods actually contained fruit, when they were simply meant to communicate flavors, instead. Against that background it's not surprising that the unsettling result of this study in 28 women and 2 men revealed that "[parents may make unhealthy food choices as a result of front-of-package information" (Abrams. 2014).
Intensity is key to reduce the exercise induced increase in appetite | more
Bottom line: I understand very well that for most of you only news item #2 is of practical value. Item #1, on the other hand, is rather a description of the misery than a solution and #3 is something that you as a SuppVersity reader probably knew, already... that being said, simply adding more polydextrose to the foods dumb parents buy for their kids because there are fruits on the packaging is not going to help their kids becoming overweight adults who begin to salivate, whenever they see the right food cues. A long-term solution to the problem would thus have to start with the production of healthier foods by the food industry and the education of the public who would then no longer fall for the unwarranted health claims on the packaging of children and adult food products | Comment on Facebook!
  • Abrams, Katie M., Caitlin Evans, and Brittany RL Duff. "Ignorance is bliss: how parents of preschool children make sense of front-of-package visuals and claims on food." Appetite (2014).
  • Ibarra, Alvin, et al. "Effects of polydextrose on different levels of energy intake: a systematic review and meta-analysis." Appetite (2014).
  • Lummela, Netta, et al. "Effects of a fibre-enriched milk drink on insulin and glucose levels in healthy subjects." Nutrition journal 8.1 (2009): 45.
  • Meyer, Monica D., et al. "Pavlovian conditioning to hedonic food cues in overweight and lean individuals." Appetite (2014).