EAL

NNNS: Nutrient Quality (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To present two experiments investigating the time course of the effects of pre-loads on children's subsequent ad libitum consumption by employing three intervals between pre-loads and ad libitum consumption: No delay, 30 minutes and 60 minutes.

Inclusion Criteria:

None.

Exclusion Criteria:

None.

Description of Study Protocol:

Recruitment: Pre-schoolers
Design: Two experiments; two- to five-year old children's responsiveness to caloric density cues were examined
Blinding used: N/A for food preferences
Intervention: In the pre-loading protocol consumption of fixed volumes of drinks (205ml in Experiment One and 150ml in Experiment Two), sweetened with sucrose, aspartame, aspartame plus low glucose maltodextrin or a water control, followed by ad libitum consumption from a variety of foods
Statistical analysis: ANOVA.

Data Collection Summary:

Timing of Measurements

Experiment One

Children were randomly assigned to one of three groups (N=8), differing in the delay interval between pre-load consumption and consumption of the ad libitum portion of the snack.
Delay intervals were zero, 30 minutes or 60 minutes. The snack was 20 minutes long. Children in the no-delay group could eat for 20 minutes, following consumption of the pre-load and in the 30-minute and 60-minute delays, children ate from 30 to 50 minutes and from 60 to 80 minutes, following the pre-load. Each child participated in two mid-morning snacks per week. All pre-loads were the same volume and included plain water, drink mix with sucrose (0.44kcal/ml), drink mix with aspartame and drink mix with aspartame plus soluble low-glucose maltodextrin isocaloric to the sucrose pre-load.
Children were presented with relatively large quantities of a set of snack foods, including both sweet and savory items, and given 20 minutes in which to consume as much as they liked.

Dependent Variables

Total calories consumed and amounts in kcal of each of the seven snack foods. Caloric content (kcal/g) was calculated for each item, based on available nutrition information. Individual weights and caloric intake were determined.
Preference data for the food consumed, based on pre-experimental preference assessments, seven snack foods (raisins, cookies, sugar wafers, potato chips, butter thin crackers, beef franks and american cheese) were presented in the ad libitum snack session.

Experiment Two

Pre-load preparations were identical to Experiment One. However, because children were 19 months younger, they were given smaller pre-loads (150ml), making the difference between the high- and low-calorie pre-loads about 60 kcal. Five of the seven foods and smaller amounts were also given because the young children were less capable of making choices.
Procedure was about the same as in Experiment One, except each child was seen in all time delays and pre-load conditions. Two presentation orders were generated where half of the children were assigned to each. In each order, the pre-loads were within the same time delays. The order was the same as in Experiment One. Time delays were zero, 30 minutes and 60 minutes for half of the children and 60 minutes, 30 minutes and no delay for the other half. Complete preference data was not obtained due to scheduling and language level.

Description of Actual Data Sample:

Experiment One

Initial N: 24 pre-school children, 10 males and 14 females
Attrition: N/A
Age: 45 months to 66 months
Other relevant demographics: Classroom.

Experiment Two

Initial N: 20 pre-school children, seven males and 13 females
Attrition: N/A
Age: 26 months to 49 months
Other relevant demographics: Classroom.

Summary of Results:

Other Findings: Experiment One

Food inake was influenced by the type of preload.
Consumption data summed over delay intervals: Over three delay intervals, showed the aspartame pre-load reduced ad libitum consumption relative to the water pre-load, but was mariginally significant and data was mainly due to the effect in the 30-minute data.
Sucrose and LGM+ASP pre-loads produced highly significant reductions in consumption relative to water (P<0.001). Sucrose and LGM+ASP pre-loads suppressed consumption significantly relative to aspartame (P<0.001). The table below shows data by each time interval.

For No-Delay

Overall pre-load approached significance
The contrast between water and aspartame did not approach significance
Sucrose and LGM+ASP both suppressed consumption relative to aspartme (P<0.05)
Neither of the caloric pre-loads produced compensation that differed significantly from perfect compensation.

30-Minute Delay

Overall pre-load was significant (P<0.01)
Ad libitum consumption following aspartame was signifiantly reduced relative to water (P<0.05) and consumption following sucrose was signifcantly reduced realtive to water (P<0.01), as was consumption following LGM+ASP (P<0.001)
The contrast between aspartame alone and LGM+ASP was significant (P<0.05). Neither of the caloric pre-loads produced compensation that differed significantly from perfect compensation.

60-Minute Delay

The main effect of pre-load was significant, as well as the differences between water and sucrose (P<0.01) and between water and LGM+ASP (P<0.01)
The difference between water and aspartame did not approach significance
Neither of the caloric pre-loads produced compensation that differed significantly from perfect compensation.

Experment One: Mean Intake Following Pre-Loads at Zero, 30 and 60 Minutes


Time Delay	Water	ASP	Sucrose	LGM+ASP
None	454*	451*	397^T	373^T
30 minutes	521*	458^T	459^T	394^V
60 minutes	421*	378*	388*	293^T
Overall delays	466*	429^T	381^V	353^V

Columns with differing superscripts are significantly different.

Other Findings: Experiment Two

There was no higher order interactions or main effects of sex, presentation order or flavor pre-load pairing nor pre-load or time delay
Overall analysis revealed only a main effect of pre-load (P<0.0001), providing evidence that ad libitum food intake was influenced by the type of pre-load
As in Experiment One, neither the main effect of time delay nor the pre-load X time delay interaction approached significance
Aspartame pre-load reduced consumption significantly, relative to water (P<0.05).

No delay

Overall effect of pre-load was significant (P<0.001)
Aspartame did not suppress consumption relative to water, but sucrose suppressed consumption significantly, relative to water (P<0.001), as did the LGM+ASP pre-load (P<0.001).

At 30 Minutes

Overall pre-load was significant (P<0.001)
Asparatame again suppressed consumption relative to water (P<0.05). Both sucrose and the LGM+ASP pre-loads (P<0.001) suppressed consumption relative to the water
The contrast between consumption following aspartame and sucrose was significant (P<0.05), as was the contrast between aspartame and the LGM+ASP pre-load (P<0.01).

At 60 Minutes

Effect of pre-load was significant (P<0.01)
There was no suppression of intake relative to water following the aspartame pre-load
Both the sucrose and LGM+ASP pre-loads suppressed consumption relative to water (P<0.01) respectively
Although consumption following sucrose was less than following aspartame, the contrast was not signifcant
However, the contrast between consumption following aspartame and LGM+ASP pre-loads showed a significant effect of LGM (P<0.05).

Mean Intake Following Pre-Loads at Zero-, 30- and 60-Minute Delays


Time Delay	Water	ASP	Sucrose	LGM+ASP
No delay	371*	350*	290^T	253^T
30 minutes	391*	353^T	300^T	288^V
60 minutes	367*	346^T	317*	303^V
Overall delays	376*	350^T	302^V	281^V

Columns with difffering superscripts are significantly different.

Author Conclusion:

The results revealed evidence of caloric compensation, but none of the pre-load X time delay interaction. In both experiments, aspartame produced a significant suppression of intake relative to water, mainly due to the pattern at 30 minutes following the pre-load. Across conditions, the suppression following aspartame was usually significantly less than that produced by caloric sweet drinks, providing evidence for post-ingestion effects. In Experiment One, suppression of intake was related to the children's preferences for the foods.

Calories from drinks replaced those from food and there was evidence that consumption of non-preferred foods was most affected by the pre-loads. The results suggest that children's ability to respond to caloric density cues, when combined with the presentation of sweetened drinks as long as one hour prior to eating, suppressed food intake and this common feeding practice may also reduce quality dietary variety.

Additional research is needed to investigate the time course effects beyond the first hour and over longer periods of time that include several meals or snacks.

Limitations

The procedure was not as sensitive to time delay effects as it might have been if children were allowed 20 minutes ad libitum consumption periods.

Funding Source:

Industry:

Quaker Oats Company

Food Company:

University/Hospital:

Pennsylvania State Unviersity

Reviewer Comments:

These findings are important for nutritionists in promoting dietary variety in children's diets.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	No
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	Yes
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	No
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	No
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	No
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes