Glycemic response to meals with a high glycemic index differs between morning and evening: a randomized cross-over controlled trial among students with early or late chronotype

PURPOSE

Glycemic response to the same meal depends on daytime and alignment of consumption with the inner clock, which has not been examined by individual chronotype yet. This study examined whether the 2-h postprandial and 24-h glycemic response to a meal with high glycemic index (GI) differ when consumed early or late in the day among students with early or late chronotype.

METHODS

From a screening of 327 students aged 18-25 years, those with early (n = 22) or late (n = 23) chronotype participated in a 7-day randomized controlled cross-over intervention study. After a 3-day observational phase, standardized meals were provided on run-in/washout (days 4 and 6) and intervention (days 5 and 7), on which participants received a high GI meal (GI = 72) in the morning (7 a.m.) or in the evening (8 p.m.). All other meals had a medium GI. Continuous glucose monitoring was used to measure 2-h postprandial and 24-h glycemic responses and their variability.

RESULTS

Among students with early chronotype 2-h postprandial glucose responses to the high GI meal were higher in the evening than in the morning (iAUC: 234 (± 92) vs. 195 (± 91) (mmol/L) × min, p = 0.042). Likewise, mean and lowest 2-h postprandial glucose values were higher when the high GI meal was consumed in the evening (p < 0.001; p = 0.017). 24-h glycemic responses were similar irrespective of meal time. Participants with late chronotype consuming a high GI meal in the morning or evening showed similar 2-h postprandial (iAUC: 211 (± 110) vs. 207 (± 95) (mmol/L) × min, p = 0.9) and 24-h glycemic responses at both daytimes.

CONCLUSIONS

Diurnal differences in response to a high GI meal are confined to those young adults with early chronotype, whilst those with a late chronotype seem vulnerable to both very early and late high GI meals. Registered at clinicaltrials.gov (NCT04298645; 22/01/2020).

Alignment between timing of 'highest caloric intake' and chronotype in relation to body composition during adolescence: the DONALD Study

PURPOSE

Our aim was to assess alignment in timing of 'highest caloric intake' with individual chronotype and its association with body composition in adolescents.

METHODS

We used repeatedly collected data from n = 196 adolescents (age 9-16 years, providing N = 401 yearly questionnaires) of the DONALD open cohort study. Chronotype was assessed by the Munich Chronotype Questionnaire from which midpoint of sleep (MSFsc) was derived. A sex- and age-specific diet-chrono-alignment score (DCAS) was calculated as the difference in hours between the chronotype-specific median timing of highest caloric intake of the studied population and the individual timing of 'highest caloric intake' or vice versa. Repeated-measures regression models were applied to study cross-sectional and longitudinal associations between the DCAS and body composition, e.g., Fat Mass Index (FMI) or Fat Free Mass Index (FFMI).

RESULTS

DCAS ranged from -6:42 h to + 8:01 h and was not associated with body composition. Among adolescents with a later chronotype (N = 201) a 1 h increase in DCAS (later consumption of 'highest caloric intake' in comparison to the median intake of that group), increased FFMI by 1.92 kg/m2 (95% CI: 0.15, 3.69, p value = 0.04) over a median follow-up of 0.94 year.

CONCLUSION

Alignment of energy intake with individual chronotype appears beneficial for FFMI among those with a late chronotype.

Associations of chronotype and social jetlag with eating jetlag and their changes among German students during the first COVID-19 lockdown. The Chronotype and Nutrition study

Due to their biologically later chronotype, young students are vulnerable to a discrepant sleeping pattern between work- and free days, coined social jetlag (SJL). This study examined whether a later chronotype and/or a larger SJL are related to an analogous discrepancy in meal timing defined as eating jetlag (EJL) and whether chronotype and/or changes in SJL during the first COVID-19 related lockdown in Germany associated with changes in EJL. Baseline data were collected from September 2019-January 2020 among 317 students (58% females) aged 18-25 years of which a total of 156 students (67% females) completed an online follow-up survey in June-July 2020 (1st lockdown). Data were collected on daily routines, timing of meals/snacks, and physical activity. Chronotype was determined using the Munich ChronoType Questionnaire; SJL and EJL correspond to the difference in the daily midpoint of sleep/eating duration between work- and free days. Multivariable linear regression revealed that students with a later chronotype or a larger SJL experienced a larger EJL (p_adjusted = 0.0124 and p_adjusted<0.0001). A later chronotype at baseline and reductions in SJL during lockdown associated with concurrent reductions in EJL (p_adjusted = 0.027 and p_adjusted<0.0001). In conclusion, students with a later chronotype exhibit a more erratic meal pattern, which associates with SJL. During lockdown, flexible daily schedules allowed students to align the meal timing with their inner clock.

The association of chronotype and social jet lag with body composition in German students: The role of physical activity behaviour and the impact of the pandemic lockdown

Young adults with a later chronotype are vulnerable for a discrepancy in sleep rhythm between work- and free days, called social jet lag (SJL). This study analysed (i) chronotype/SJL association with visceral fat/skeletal muscle mass, (ii) the attribution to physical activity behaviour, and (iii) chronotype-specific changes in physical activity behaviour in young adults during the Covid-19 pandemic lockdown. Chronotype and SJL were derived from the Munich-Chrono-Type-Questionnaire in 320 German students (age 18-25 years) from September 2019 to January 2020, 156 of these participated in an online follow-up survey in June 2020. Body composition was assessed by bioimpedance analysis at baseline. Multivariable linear regression analyses were used to relate chronotype/SJL to body composition; the contribution of self-reported physical activity was tested by mediation analysis. At baseline, a later chronotype and a larger SJL were associated with a higher visceral fat mass (P<0.05), this relation was notably mediated by the attention to physical activity (P<0.05). Chronotype (P = 0.02) but not SJL (P = 0.87) was inversely associated with skeletal muscle mass. During the pandemic lockdown, chronotype hardly changed, but SJL was reduced. Timing and physical activity behaviour remained in most participants and changes were unrelated to chronotype (all P>0.07). A later chronotype/higher SJL may increase the risk of a higher visceral fat mass even in this relatively healthy sample, which may be partly due to their physical activity behaviour. Despite a reduction in SJL during the pandemic lockdown, later chronotypes did not change their physical activity behaviour more than earlier chronotypes.

Relative validity of a glycemic index extended food-frequency questionnaire

BACKGROUND AND AIMS

The dietary glycemic index (GI) and glycemic load (GL) are increasingly recognized as important for the prevention and management of diabetes mellitus. To extend the portfolio of assessment methods for large-scale epidemiological studies, we propose a GI-specific addition to an already established FFQ.

METHODS AND RESULTS

The German version of the EPIC-FFQ was extended by GI-specific questions for major carbohydrate sources varying notably in GI (breakfast cereals, bread, pasta, rice, potato etc.). We performed relative validation analyses comparing the GI-extended FFQ to three to four 3-day weighted dietary records (3-d WDR) in 100 middle-aged individuals with diabetes mellitus participating in the German Diabetes Study (GDS). Level of agreement between the two methods was assessed by correlation and cross-classification analyses as well as Bland-Altman-Plots, conducted separately for women and men. Spearman correlation analysis for female participants suggested good agreement between the GI-extended FFQ and 3-d WDRs for energy adjusted dietary GL (r = 0.52, p = 0.0004). For both women and men, agreement with the estimations of dietary GI, GL (for men) and carbohydrates from low and higher-GI food sources from the GI-extended FFQ was acceptable (r: 0.28-0.45). Classification of the dietary GI and GL in the opposite quartile was <10% comparing the GI-extended FFQ and 3-d WDR. Bland-Altman plots suggested a tendency for an overestimation of the dietary GI from the GI-extended FFQ in the lower GI-ranges, particularly for men.

CONCLUSION

Compared to the 3-d WDR, the GI-extended FFQ showed a moderate to good relative validity for parameters of carbohydrate quality.

Association between habitual coffee consumption and metabolic syndrome in type 1 diabetes

BACKGROUND AND AIMS

In the general population, habitual coffee consumption is inversely associated with the metabolic syndrome, a syndrome that is rather common also in patients with type 1 diabetes. However, whether coffee intake is beneficially related to the metabolic syndrome also in type 1 diabetes, is not known. We, therefore, studied the potential association between coffee consumption and the metabolic syndrome in a large population of individuals with type 1 diabetes. Furthermore, we investigated whether coffee consumption is associated with insulin resistance (estimated glucose disposal rate, eGDR), kidney function (estimated glomerular filtration rate, eGFR), and low-grade chronic inflammation (high-sensitivity C-reactive protein, hsCRP).

METHODS AND RESULTS

Data from 1040 participants in the Finnish Diabetic Nephropathy Study were included in these cross-sectional analyses. Metabolic syndrome was assumed if at least 3 of the following cardiovascular risk factors were present: central obesity, high blood pressure, low HDL-cholesterol concentration, high triglyceride concentration, and hyperglycaemia. Subjects were categorized based on self-reported daily coffee intake: non-consumers (<1 cup/d), low (≥1 cups/d < 3), moderate (≥3 cups/d < 5), and high coffee consumption (≥5 cups/d). In multivariable logistic regression analysis, moderate and high coffee consumption was associated with increased odds of the metabolic syndrome. Moreover, any level of coffee consumption was associated with increased risk of the blood pressure-component. An increasing trend was observed in the eGFR with increasing coffee consumption.

CONCLUSIONS

In type 1 diabetes, high coffee intake is associated with the metabolic syndrome, and especially its blood pressure-component.

Correlation between symptoms developed after the oral ingestion of 50 g lactose and results of hydrogen breath testing for lactose intolerance

BACKGROUND

Lactase deficiency is a common condition responsible for various abdominal symptoms. Lactose hydrogen breath test is currently the gold standard in diagnosing lactose intolerance.

AIM

To assess sensitivity and specificity of symptoms developed after oral lactose challenge.

METHODS

Intensity of nausea, abdominal pain, borborygmi, bloating and diarrhoea was recorded every 15 min up to 3 h after ingestion of 50 g lactose in patients with positive (i.e. breath H2-concentration > or =20 p.p.m. above baseline) and negative lactose hydrogen breath test.

RESULTS

Between July 1999 and December 2005, 1127 patients (72% females) underwent lactose hydrogen breath test. A positive result was found in 376 (33%). Sensitivity of individual symptoms ranged from 39% (diarrhoea) to 70% (bloating) while specificity ranged from 69% (bloating) to 90% (diarrhoea). A positive lactose hydrogen breath test was found in 21% of patients with one symptom, 40% of patients with two symptoms, 44% of patients with three symptoms, 67% of patients with four symptoms and 82% of patients with five symptoms. Symptom intensity was significantly higher for each symptom in the positive group.

CONCLUSION

Evaluating symptoms developed after ingestion of 50 g lactose can be used as a simple screening test to select patients who need to be referred for lactose intolerance testing.

Clinical trial: effects of tegaserod on gastric motor and sensory function in patients with functional dyspepsia

BACKGROUND Tegaserod, a serotonin receptor type-4 partial agonist, stimulates gastrointestinal motility and has been shown to increase gastric volumes before and after a meal in healthy volunteers. Its effect on gastric motor and sensory function in patients with functional dyspepsia is unclear. AIM To evaluate the effects of tegaserod on gastric compliance, accommodation and gastric sensory function in patients with functional dyspepsia and healthy volunteers. METHODS Sixteen patients with functional dyspepsia and 12 healthy volunteers were studied on two occasions, each after a 7-day treatment with either placebo or tegaserod 6 mg b.d. using a double-blind, randomized, crossover design. After each treatment period a gastric barostat study was performed fasting and during intraduodenal lipid infusion. RESULTS Tegaserod increased postprandial gastric compliance in functional dyspepsia patients (P = 0.04). Healthy volunteers showed enhanced postprandial gastric compliance after placebo (P = 0.03). Between-treatment analysis of gastric accommodation revealed a significant increase in intrabag volumes after tegaserod in healthy volunteer (P = 0.04); no difference could be seen in functional dyspepsia patients. Tegaserod had no effect on gastric sensation. CONCLUSIONS Tegaserod enhances postprandial gastric compliance in functional dyspepsia patients and gastric accommodation in healthy volunteers. The improvement of proximal gastric motor function suggests a beneficial role of tegaserod in patients with functional dyspepsia.

The effects of tegaserod on oesophageal function and bolus transport in healthy volunteers: studies using concurrent high-resolution manometry and videofluoroscopy

BACKGROUND

Tegaserod is a partial 5-hydroxytryptamine 4 receptor agonist with prokinetic effects on the gastrointestinal tract, its effects on oesophageal function are unknown.

AIM

A randomized, placebo controlled, double-blind trial assessed the effect of tegaserod on the oesophagus in healthy, asymptomatic subjects.

METHOD

A 7-day course of tegaserod 6 mg b.d. vs. placebo was prescribed (n = 17/21 completed both phases of study). High-resolution manometry and pH measurements were performed before and after a test meal. Bolus transport of liquids and solids was studied by high-resolution manometry and videofluoroscopy.

RESULTS

Tegaserod had no effect on lower oesophageal sphincter pressure compared with placebo, peristaltic velocity increased (P < 0.001) and distal contractile pressure decreased slightly (P < 0.05). Transient lower oesophageal sphincter relaxations and reflux were infrequent regardless of treatment. During the studies of bolus transport, high-resolution manometry revealed that tegaserod promoted mid-oesophageal contractility (P < 0.02) and shortened the 'proximal transition zone' (P < 0.05), the level where bolus escape occurred most frequently. These effects had no effect on liquid bolus transport; however a non-significant trend to improved solid bolus transport was observed (66% vs. 31%;P = 0.07).

CONCLUSION

Tegaserod did not alter lower oesophageal sphincter pressure, but had significant effects on peristaltic function. High-resolution manometry promoted mid-oesophageal contractility during bolus transport. This effect was associated with a non-significant trend to improved solid bolus transit.

The pathophysiology of faecal spotting in obese subjects during treatment with orlistat

BACKGROUND

The intermittent loss of oil or liquid faeces ('spotting') is an adverse effect that occurs in obese patients during treatment with the lipase inhibitor orlistat; the pathophysiology is unknown.

AIM

To investigate the effects of orlistat on anorectal sensorimotor function and continence.

METHODS

Obese subjects susceptible to spotting were identified by an unblind trial of orlistat. Obese spotters (n = 15) and non-spotters (n = 16) completed a randomized, double-blind, cross-over trial of orlistat and placebo. Anorectal function was assessed by rectal barostat and anal manometry, together with a novel stool substitute retention test, a quantitative measurement of faecal continence.

RESULTS

Orlistat increased stool volume and raised faecal fat and water. Treatment had no effect on anorectal motor function, but rectal sensation was reduced; on retention testing, the volume retained was increased. Subjects susceptible to spotting had lower rectal compliance, heightened rectal sensitivity and weaker resting sphincter pressure than non-spotters. On retention testing, gross continence was maintained; however, spotters lost small volumes of rectal contents during rectal filling.

CONCLUSION

Treatment with orlistat has no direct adverse effects on anorectal function or continence. Spotting occurs during treatment with orlistat when patients with sub-clinical anorectal dysfunction are exposed to increased stool volume and altered stool composition.

[Successful treatment of anemia in hemolysis patients using recombinant human erythropoietin. Maintenance dosage and serum concentration]

Recombinant human erythropoietin (r-huEpo) was administered i.v. to eight anemic patients on hemodialysis in increasing doses 3 times a week. 7 out of 8 patients showed an increase in hemoglobin level by 2 g/dl over the baseline of 7.9 +/- 0.8 g/dl after a mean period of 8 +/- 2 weeks. During treatment a cumulative dose of 692 +/- 358 IU/kgBW erythropoietin was given. Before the rise in hemoglobin, reticulocytes increased from 1.6 +/- 0.7% initially to 5 +/- 1.6%. The serum ferritin concentration decreased from 426 (range 19-1223) to 250 (5-707) micrograms/l. No side effects were observed. Mean blood pressure before dialysis increased slightly from 125 mmHg to 137 mmHg systolic, and diastolic pressure from 75 to 80 mmHg. Maintenance doses to maintain hemoglobin values between 10 und 12 g/dl varied from 2 X 72 IU/kgBW to 3 X 168 IU/kgBW per week. Measurement of serum levels of erythropoietin by radioimmunoassay showed deficiency of the hormone in the patients with chronic renal failure: before treatment mean serum values were 4 +/- 6.4 mU/ml and during maintenance doses with r-huEpo 33.7 +/- 8.1 mU/ml, which is within normal ranges related to hematocrit. These data show erythropoietin to be effective in ameliorating anemia during hemodialysis treatment.