Extending the Overnight Fast: Sex Differences in Acute Metabolic Responses to Breakfast.

Fasting for over 24 h is associated with worsening glucose tolerance, but the effect of extending the overnight fast period (a form of time-restricted feeding) on acute metabolic responses and insulin sensitivity is unclear. The aim of this pilot study was to determine the acute impact of an increased fasting period on postprandial glycaemia, insulinemia, and acute insulin sensitivity responses to a standard meal. Twenty-four lean, young, healthy adults (12 males, 12 females) consumed a standard breakfast after an overnight fast of 12, 14, and 16 h. Each fast duration was repeated on three separate occasions (3 × 3) in random order. Postprandial glucose and insulin responses were measured at regular intervals over 2 h and quantified as incremental area under the curve (iAUC). Insulin sensitivity was determined by homeostatic modelling assessment (HOMA). After 2 h, ad libitum food intake at a buffet meal was recorded. In females, but not males, insulin sensitivity improved (HOMA%S +35%, p = 0.016, marginally significant) with longer fast duration (16 h vs. 12 h), but paradoxically, postprandial glycaemia was higher (glucose iAUC +37%, p = 0.002). Overall, males showed no differences in glucose or insulin homeostasis. Both sexes consumed more energy (+28%) at the subsequent meal (16 h vs. 12 h). Delaying the first meal of the day by 4 h by extending the fasting period may have adverse metabolic effects in young, healthy, adult females, but not males.

Effect of oral nutritional supplementation on growth and recurrent upper respiratory tract infections in picky eating children at nutritional risk: a randomized, controlled trial.

Objectives To evaluate the effect of oral nutritional supplementation (ONS) plus dietary counselling (DC) (intervention) versus DC alone (control) on growth and upper respiratory tract infection (URTI) in nutritionally at-risk, picky eating children in India. Methods We performed a 90-day, prospective, randomized, controlled trial. A total of 255 children aged 24-72 months with a weight-for-age z-score ≥-2 and <-1, picky eating behaviour, and acute URTI were randomized to the control (n = 128) or intervention group (n = 127). The outcomes included the change in weight-for-age z-score from days 1 to 90 and the URTI incidence. Results The mean age was 44.0 ± 14.3 months. The intervention group showed a significantly greater increase in mean weight-for-age and body mass index-for-age z-scores compared with the control group from day 10 onwards. Higher energy intake in the intervention group was observed at all follow-up visits, except for day 10. The incidence of URTI in the control group was 2.01 times higher than that in the intervention group, controlling for confounding factors. Conclusions ONS plus DC is effective for improving weight and reducing the incidence of URTI in nutritionally at-risk, picky eating children with an acute URTI episode.

Continuation of oral nutritional supplementation supports continued growth in nutritionally at-risk children with picky eating behaviour: A post-intervention, observational follow-up study.

Objectives To evaluate the 120-day post-intervention growth trajectory of picky-eating children aged 2 to 6 years who previously completed a 90-day, randomized, controlled trial of oral nutritional supplementation (ONS) plus dietary counselling (DC) (SDC, n = 98) compared with DC alone (n = 105). Methods A total of 203 children were included. Children were free to consume ONS during follow-up. Information on ONS consumption was collected. Weight-for-age percentile (WAP) and height-for-age percentile (HAP) were measured at Day 90 (beginning) and Day 210 (end point). Results Despite continued weight gain, there was a significant decline in WAP in both groups during the post-intervention period. However, children who took ONS voluntarily had a smaller loss in WAP compared with those who did not. Children in the SDC group showed no difference in a decline in HAP between those who took ONS during follow-up and those who did not. However, children in the DC group showed a marginally larger decline in HAP in those who did not take ONS during the follow-up compared with those who did. Conclusions Continued parental self-administration of ONS to their children slows down the loss of growth percentiles, supporting continued weight gain in picky-eating children at nutritional risk.

Differences in AMY1 Gene Copy Numbers Derived from Blood, Buccal Cells and Saliva Using Quantitative and Droplet Digital PCR Methods: Flagging the Pitfall.

INTRODUCTION: The human salivary (AMY1) gene, encoding salivary α-amylase, has variable copy number variants (CNVs) in the human genome. We aimed to determine if real-time quantitative polymerase chain reaction (qPCR) and the more recently available Droplet Digital PCR (ddPCR) can provide a precise quantification of the AMY1 gene copy number in blood, buccal cells and saliva samples derived from the same individual. METHODS: Seven participants were recruited and DNA was extracted from the blood, buccal cells and saliva samples provided by each participant. Taqman assay real-time qPCR and ddPCR were conducted to quantify AMY1 gene copy numbers. Statistical analysis was carried out to determine the difference in AMY1 gene copy number between the different biological specimens and different assay methods. RESULTS: We found significant within-individual difference (p<0.01) in AMY1 gene copy number between different biological samples as determined by qPCR. However, there was no significant within-individual difference in AMY1 gene copy number between different biological samples as determined by ddPCR. We also found that AMY1 gene copy number of blood samples were comparable between qPCR and ddPCR, while there is a significant difference (p<0.01) between AMY1 gene copy numbers measured by qPCR and ddPCR for both buccal swab and saliva samples. CONCLUSIONS: Despite buccal cells and saliva samples being possible sources of DNA, it is pertinent that ddPCR or a single biological sample, preferably blood sample, be used for determining highly polymorphic gene copy numbers like AMY1, due to the large within-individual variability between different biological samples if real time qPCR is employed.

The role of digestive factors in determining glycemic response in a multiethnic Asian population.

PURPOSE: There are wide inter-individual differences in glycemic response (GR). We aimed to examine key digestive parameters that influence inter-individual and ethnic differences in GR in healthy Asian individuals. METHODS: Seventy-five healthy male subjects (25 Chinese, 25 Malays, and 25 Asian-Indians) were served equivalent available carbohydrate amounts (50 g) of jasmine rice (JR) and basmati rice (BR) on separate occasions. Postprandial blood glucose concentrations were measured at fasting (-5 and 0 min) and at 15- to 30-min interval over 180 min. Mastication parameters (number of chews per mouth and chewing time per mouthful), saliva α-amylase activity, AMY1 gene copy numbers and gastric emptying rate were measured to investigate their relationships with GR. RESULTS: The GR for jasmine rice was significantly higher than for basmati rice (P < 0.001). The median number of AMY1 gene copies was 6, with a range of 2-15. There was a significant positive relationship between AMY1 copy number and α-amylase activity (P = 0.002). There were no significant ethnic differences in GR. For both rice varieties, the number of chews per mouthful was positively associated with the GR (JR, P = 0.011; BR, P = 0.005), while chewing time per mouthful showed a negative association (JR, P = 0.039; BR, P = 0.016). Ethnicity, salivary α-amylase activity, particle size distribution, gastric emptying rate and AMY1 gene copy numbers were not significant contributors to GR (P > 0.05). CONCLUSION: Mastication parameters contribute significantly to GR. Eating slowly and having larger food boluses before swallowing (less chewing), both potentially modifiable, may be beneficial in glycemic control.

Flavonoids from fruit and vegetables: a focus on cardiovascular risk factors.

Epidemiological studies suggest that high intakes of dietary flavonoids are associated with decreased cardiovascular disease mortality and risk factors. Less is known about the cardioprotective effects of flavonoids from fruit and vegetables. This review summarizes data from studies which examine the effects of commonly consumed fruit and vegetables on cardiovascular disease risk biomarkers in healthy volunteers or at-risk individuals. Although flavonoids from apples, berries, and onions appear to impact positively on blood pressure, vascular function, and serum lipid levels, further research is required to find out the optimal quantity and food matrix for conferring substantial clinical benefit. The benefits from citrus flavonoids are still inconclusive. Further robust, longer-term dietary intervention studies, with the inclusion of placebo or control arms, are required to improve the credibility of the findings and confirm current observations. An improved understanding of the impact of flavonoids from fruit and vegetables can help one make discerning food choices for optimal cardiovascular health.

Dietary disinhibition modulates neural valuation of food in the fed and fasted states.

BACKGROUND: Dietary disinhibition is a behavioral trait associated with weight gain and obesity. Because food choices are made according to the relative value assigned to each option, examination of valuation signals through functional magnetic resonance imaging (fMRI) may elucidate the neural basis for the association between dietary disinhibition and weight gain. OBJECTIVE: We examined how food valuation signals differ in the fed and fasted states between persons with high dietary disinhibition (HD) and low dietary disinhibition (LD). DESIGN: Sixteen men with HD and 14 with LD underwent fMRI once while fasted and once after being fed in a counterbalanced order. In-scanner preference to consume a test food relative to a neutral-tasting, neutral-health reference food was examined. The slope of magnetic resonance signal change corresponding to these food preferences constituted the food valuation signal that was compared across disinhibition group and satiety state. RESULTS: Both the HD and LD participants reported being less hungry (F(1,28) = 113.11, P < 0.001) after being fed than when fasted. However, food valuation signals in the ventromedial prefrontal cortex (vmPFC) differed between the groups (F(1,28) = 21.34, P < 0.001). Although LD participants showed attenuated vmPFC activity after being fed (t(13) = 4.11, P < 0.001), HD participants showed greater vmPFC activity in the fed than in the fasted state (t(15) = -2.56, P < 0.05). CONCLUSIONS: Despite reporting normal decreases in hunger ratings after being fed, persons with HD have an altered neural valuation of food. This may be a mechanism underlying their propensity to overeat and gain weight. This trial was registered at clinicaltrials.gov as NCT00988819.