SummaryThere is evidence to support that mastication may contribute to the prevention of weight gain via reduction of appetite sensations and subsequent energy intake. However, the metabolic effect of mastication after consumption of a daily meal, composed of the staple food (rice), soup, main and side dishes, is limited. Therefore, the effect of thorough mastication on greater satiety and the thermic effect of a meal (TEM) was investigated in young women. In study 1, energy expenditure (EE) derived from masticatory muscle activity for 20 min was measured while chewing hard, tasteless, non-caloric gum in seven subjects. In study 2, ten subjects consumed a solid meal performing 30 chews per mouthful (30 CPM), or swallowed the same, pureed meal without chewing (0 CPM) on two separate days, and postprandial EE, substrate oxidation, subjective appetite ratings and autonomic nervous system (ANS) activity for 3 h were examined. Both test meals were iso-caloric (2,510 kJ) and -weighted (884 g), and consumed in 20 min. From study 1, the EE of mastication itself for the 20 min was estimated to be 3.760.8 kJ. From study 2, significantly higher TEM (134.2615.5 vs. 67.8613.8 kJ/3 h, p,0.001) as well as satiety (p50.005), and tendency toward greater fat oxidation (p50.090) and ANS activity (p50.069) were observed after consumption of the meal with 30 CPM compared to 0 CPM. In conclusion, thorough mastication before swallowing increased postprandial satiety and the TEM in young women, suggesting such eating behavior may be useful for preventing obesity.
BackgroundClock genes regulate circadian rhythm and are involved in various
physiological processes, including digestion. We therefore investigated the
association between the CLOCK 3111T/C single nucleotide
polymorphism and the Period3 (PER3)
variable-number tandem-repeat polymorphism (either 4 or 5 repeats 54 nt in
length) with morning gastric motility.MethodsLifestyle questionnaires and anthropometric measurements were performed with
173 female volunteers (mean age, 19.4 years). Gastric motility, evaluated by
electrogastrography (EGG), blood pressure, and heart rate levels were
measured at 8:30 a.m. after an overnight fast. For gastric motility, the
spectral powers (% normal power) and dominant frequency (DF, peak of the
power spectrum) of the EGG were evaluated. The CLOCK and
PER3 polymorphisms were determined by polymerase chain
reaction (PCR) restriction fragment length polymorphism analysis.ResultsSubjects with the CLOCK C allele (T/C or C/C genotypes: n =
59) showed a significantly lower DF (mean, 2.56 cpm) than those with the T/T
genotype (n = 114, 2.81 cpm, P < 0.05). Subjects
with the longer PER3 allele
(PER3
4/5 or
PER3
5/5 genotypes: n = 65) also showed a
significantly lower DF (2.55 cpm) than those with the shorter
PER3
4/4 genotype (n = 108, 2.83 cpm,
P < 0.05). Furthermore, subjects with both the
T/C or C/C and PER3
4/5 or
PER3
5/5 genotypes showed a significantly
lower DF (2.43 cpm, P < 0.05) than subjects with
other combinations of the alleles (T/T and
PER3
4/4 genotype, T/C or C/C and
PER3
4/4 genotypes, and T/T and
PER3
4/5 or
PER3
5/5 genotypes).ConclusionsThese results suggest that minor polymorphisms of the circadian rhythm genes
CLOCK and PER3 may be associated with
poor morning gastric motility, and may have a combinatorial effect. The
present findings may offer a new viewpoint on the role of circadian rhythm
genes on the peripheral circadian systems, including the time-keeping
function of the gut.
The 3111T/C single nucleotide polymorphism (SNP) of Circadian Locomotor Output Cycles Kaput (CLOCK) gene reportedly affects gastric motility before breakfast. It is of interest to know whether this SNP can affect the motility during the daytime. We investigated the association between the CLOCK 3111T/C SNP and several gastric motility parameters during the time period from 8:00 to 20:00 in 34 young women with scheduled meals. There were similar daytime fluctuations in gastric motility before and after the meals between the major (T/T) and minor (T/C) allele carriers. The CLOCK SNP may affect daytime gastric motility less than food stimulation.
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