Accumulating evidence suggests dietary fatty acids (FAs) may be sensed in the oral cavity. However, the effective cues have not been characterized. In particular, influences from other sensory cues have hampered identification of an independent gustatory contribution. Experiment 1 examined techniques to minimize the formation of FA oxidation products and improve the homogeneity of water/lipid emulsions to be used as stimuli in Experiment 2, a psychophysical study to determine FA detection thresholds in humans. Through sonication of chilled samples held in polypropylene labware and the addition of 0.01% ethylenediaminetetraacetic acid, calcium disodium salt, homogenous emulsions of unoxidized linoleic and oleic FAs were obtained. Spectrophotometric analysis revealed no oxidation product formation over a 24-h period. Coupled with these techniques, a masking approach was used to minimize other sensory cues imparted from linoleic, oleic, and stearic FAs. Concentration ranges from 0.00028% to 5% (w/v) were prepared in mixtures with 5% mineral oil (w/v) and 5% gum acacia (w/v) to mask lubricity and viscosity effects, respectively. Testing was conducted under red light with nares blocked to eliminate visual and olfactory cues. Oral rinses with 20 ppm capsaicin were administered to desensitize participants to selected irritation effects prior to remeasuring linoleic acid detection thresholds. To determine if the effective stimulus was an oxidation product, oxidized linoleic acid was included among the test stimuli. Detection thresholds were obtained using a 3-alternative, forced-choice ascending-concentration presentation procedure. The mean detection threshold for linoleic acid pre-desensitization was 0.034 +/- 0.008%, for linoleic acid post-desensitization was 0.032 +/- 0.007%, for oleic 0.022 +/- 0.003%, for stearic 0.032 +/- 0.005%, and oxidized linoleic 0.025 +/- 0.005%. The results suggest that linoleic, oleic, stearic, and oxidized linoleic acids are detectable in the oral cavity of humans with minimal input from the olfactory, capsaicin, and viscosity-assessing tactile systems.
Selected free fatty acids (FFAs) are documented effective somatosensory and olfactory stimuli whereas gustatory effects are less well established. This study examined orthonasal olfactory, retronasal olfactory, nasal irritancy, oral irritancy, gustatory, and multimodal threshold sensitivity to linoleic, oleic, and stearic acids. Sensitivity to oxidized linoleic acid was also determined. Detection thresholds were obtained using a three-alternative, forced-choice, ascending concentration presentation procedure. Participants included 22 healthy, physically fit adults sensitive to 6- n-propylthiouracil. Measurable thresholds were obtained for all FFAs tested and in 96% of the trials. Ceiling effects were observed in the remaining trials. Greater sensitivity was observed for multimodal stimulation and lower sensitivity for retronasal stimulation. There were no statistically significant correlations for linoleic acid thresholds between different modalities, suggesting that each route of stimulation contributes independently to fat perception. In summary, 18-carbon FFAs of varying saturation are detected by multiple sensory systems in humans.
OBJECTIVES-To determine if participation in usual moderate-intensity or more vigorous physical activity (MVPA) is associated with physical function performance and to identify sociodemographic, psychosocial and disease-related covariates that may also compromise physical function performance. DESIGN-Cross-sectional analysis of baseline variables of randomized controlled intervention trial. ACR -analysis and interpretation of data, and preparation of manuscript. JMG -concept and design, acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. MPW, MEM -concept and design, analysis and interpretation of data, and review and editing of manuscript. WJR -acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. JAK -acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. ACK -concept and design, acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. NWG -acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. SNB -concept and design, acquisition of subjects and/or data, analysis and interpretation of data, and review and editing of manuscript. RAF -concept and design, analysis and interpretation of data, and review and editing of manuscript. RESULTS-The SPPB summary score was associated with minutes of MVPA (ρ = 0.16, P = 0.001). In multiple regression analyses, age, minutes of MVPA, number of medications and depressive symptoms were associated with performance on the composite SPPB (P < 0.05). There was an association between 400 m walk time and minutes of MVPA (ρ = −0.18; P = 0.0002). In multiple regression analyses, age, gender, minutes of MVPA, BMI and number of medications were associated with performance on the 400 m walk test (P < 0.05). SETTING-Four NIH Public AccessCONCLUSION-Minutes of MVPA, gender, BMI, depressive symptoms, age, and number of medications are associated with physical function performance and all should be taken into consideration in the prevention of mobility-disability.
24% higher in Y SA and O SA compared with CON ( p = .009). Eukaryotic initiation factor 2B e phosphorylation was 33% and 9% higher in Y SA and O SA compared with CON ( p = .04). Translational signaling in young adult and aged plantaris muscle is equally responsive to chronic overload.
This review focuses on the importance of aerobic and resistance modes of physical activity for healthy aging as supported by newly discovered and previously documented health-related benefi ts that were reported in 2007. Overall, the studies support the prevailing view that both modes have measurable but often different health benefi ts. They reassert that the relative contribution of aerobic activity is associated with improvements in symptoms related to pain and depression as well as attenuation in age-related weight gain and that the benefi ts associated with resistance training are associated with increased functional autonomy and favorable neural adaptations. Both modes are associated with a reduction in chronic disease risk. Data continue to accumulate that a synergistic effect on health outcomes exists when both modes are combined. As such, the preferred exercise paradigm would incorporate both forms of physical activity.
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