The influence of oral lubrication on food intake: A proof-of-concept study

Abstract

As overeating, overweight and obesity remain public health concerns, it is crucial to design satiety-enhancing foods that suppress appetite and lower snack intake. Existing research identifies oro-sensory targets to promote satiation and satiety, yet it remains unclear as to whether it is 'chewing' or 'oral lubrication' that might amplify satiation signals. In this study, techniques from experimental psychology, food material science and mechanical engineering have been combined to develop model foods to investigate the role of chewing and oral lubrication on food intake. Novel model gels, similar in pleasantness, were given as a preload then their effects on subjective appetite and intake of a salty snack were measured in a between-subjects design. Three mint flavoured hydrogels were engineered to vary in their texture (fracture stress) and lubrication (inverse of coefficient of friction), and a control group received mint tea. Results showed that snack intake was suppressed by 32% after eating the low chewing/high lubricating preload compared to the high chewing/low lubricating preload (p < 0.05). Hunger ratings decreased from t 1 to t 3 (p < 0.05), however differences between conditions were subtle and not significant. Thus, this proof-of-concept study demonstrates that manipulating oral lubrication is a promising new construct to reduce snack intake that merits future research in the oro-sensory satiety domain.

Food texture influences on satiety: systematic review and meta-analysis

“…Many included studies adopted a within-subject design, with the exception of three which used a between-subject design 29 , 50 , 51 .…”

“…hydrocolloid based gels with various inclusions to create different levels of textural complexity or in other words higher degree of heterogeneity and assess the relationships between the gels and satiety. Besides classical rheological measurements, McCrickerd et al (2014) 28 and Krop et al (2019) 29 measured the lubricity of foods without or with simulated saliva (food boli i.e. food and simulated saliva mixture), respectively, using a Mini Traction Machine tribometer.…”

“…food and simulated saliva mixture), respectively, using a Mini Traction Machine tribometer. Such differentiation in the lubricity of hydrogels was used for the first time by Krop et al (2019) 29 to see their effects on snack intake.

Figure 1 Key milestones in research timeline of food textural manipulations for achieving satiety and the quantitative techniques used to measure food texture.

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Microgels as viscosity modifiers influence lubrication performance of continuum

“…For instance, recent studies have demonstrated correlation between the tribological performance of edible hydrogels in soft silicon contacts with oral perception attributes, such as pastiness and slipperiness 8 and effects of such unique lubrication on satiety responses. 9 Aqueous lubrication has been recognized as one of the main mechanisms for bio-lubrication due to the abundance of water in complex living organisms. 10 Aqueous lubrication is attributed to the capacity of biopolymers to electrostatically bind water molecules while being tethered to the bio-surfaces.…”

Design principles of food gels

“…Indeed, food gels increasingly come with performance comparable to, and in some cases greater than, synthetic polymer gels owing to specific structuring and processing mechanisms typical of these systems [13][14][15][16] . Food gels also play a critical role in modern food design, such as in structuring foods with desired sensorial textures 17 , preserving metastable food structures and increasing shelf-life 18,19 , replacing fats 20 , enhancing satiety by reducing food intake [21][22][23] and in the design of complex food shapes via three-dimensional (3D) printing 24 . The appropriate design of food gels can not only improve food quality, but also improve nutrition and bioavailability features of foods [25][26][27] .…”