NNNS: Behavior Changes, Cognitive Function and Moods (2006)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To determine if consumption of sugar (glucose and sucrose) vs. non-nutritive sweetners (aspartame and saccharin) have negative effects on aggressive behavior.
Inclusion Criteria:
- Sugar-responsive
- Parents report history of behavioral changes following ingestion of sugar or improvement in behavior following restriction of sugar
- Onset of behavior changes occur within 75 minutes of ingesting sugar.
- Boys
- Two to six years of age
- Familiar playmate of the sugar-responsive child.
Exclusion Criteria:
- Girls
- Seizure disorder
- Diabetes
- PKU
- Any other medical disorder.
Description of Study Protocol:
Recruitment
- Local newspaper advertisements and local schools.
Design
- Lab component of the study: Randomized double-blind
- Home testing: Randomized double-blind.
Blinding Used
- All treatments were provided in a lemon-flavored carbonated drink
- Trained individuals videotaped the boy's behavior following each treatment (laboratory-based). The videotape operators were blind to the treatment provided to the children.
Intervention
- 1.75g glucose per kg of body weight
- 1.75g sucrose per kg of body weight.
Statistical Analysis
- Sugar responders vs. playmates were compared on all baseline measures by T-test for independent variables
- Two-way ANOVA with repeated measures, using sugar responsiveness as a grouping factor for all four substances (glucose, sucrose, aspartame, saccharin), was performed on all measures
- Significant main effects were tested with Bonferroni correction for multiple comparisons
- Pearson product-moment correlations were calculated between mean daily sucrose consumption, total sugar consumption, carbohydrate-to-protein ratio and behavioral measures for the responders and for the group as a whole.
Data Collection Summary:
Timing of Measurements
- Eight total challenges occurred
- Four separate challenge days in the laboratory
- One challenge day per substance (glucose, sucrose, aspartame, saccharin)
- Five- to seven-day washout period between challenges in the laboratory
- Ninety minutes of free play, including 11 minutes of staged arguments and friendly conversations by trained research assistant
- Fifteen minutes of story time
- Fifteen minutes of each individual being placed in a standard object-conflict situation.
- Four separate challenge days at home
- One challenge day per substance (glucose, sucrose, aspartame, saccharin)
- Home challenges occurred within two to four days of the laboratory challenge
- Parents evaluated destructiveness and aggression hourly for five hours following the ingestion of the "sweetened beverage"
- Parents guessed as to the contents of the beverage.
- Four separate challenge days in the laboratory
- Sugar-responsive children and playmates were tested in pairs
- Sweetened beverage was given at the beginning of a two-hour play session.
Dependent Variables
- Conners 48-item scale completed at baseline by parent to assess behavior
- Seven-day food diaries to evaluate habitual dietary intake
- Mean daily sucrose consumption
- Total sugar consumption
- Carbohydrate-to-protein ratio.
- Conners 10-item scale to rate impulsive, restless and inattentive behaviors
- In a laboratory setting, the "teacher" scored the child during the play
- A parent scored the child for five hours after the visit to the lab to detect delayed effects.
- Conners 12-item scale, which is the same as the 10-item test plus two additional items to assess destrutiveness and aggression
- Home setting: Parents completed for the five hours after the child drank the beverage.
- Motor activity measured via an acceleromotor worn around the child's waist for the two hours after ingestion of the sweetened drink
- Total duration of interpersonal aggression assessed via videotaping
- Total duration of aggression against property assessed via videotaping.
Independent Variables
- Sucrose (primary variable of interest)
- Glucose.
Control Variables
- Two controls were used (saccharin and aspartame). What follows is the justification provided by the authors for the use of these two controls
- Saccharin (amount not provided): Used as a control since saccharin has not been shown to affect behavior, but is not a good taste match
- 30mg of aspartame per kg of body weight: A better taste match, but "is currently under investigation for its possible behavioral effects."
Description of Actual Data Sample:
Initial N
- Fourteen sugar-responsive boys
- Fourteen familiar playmates recruited without regard to responder status
- Two additional boys were recruited (one "sugar-responsive," the other his playmate).
Attrition (Final N)
- Eighteen sugar-responsive boys
- Four of the playmates were determined to be "sugar-responsive" and were taken out of the playmate group
- Twelve playmates
- The two additonal boys recruited above were both non-sugar-responsive and were placed in the playmate group.
- Sugar-responders: 51.4±13.6 months (mean±SD)
- Playmates: 51.3±14.6 (mean±SD).
Ethnicity:
- Information not provided.
Other Relevant Demographics
- Each child was evaluated by two child psychiatrists
- Among the sugar-responders, diagnosis included (eight of the children had no diagnosis):
- Attention deficit disorder with hyperactivity (N=4)
- Oppositional disorder (N=2)
- Conduct disoder (N=2)
- Adjustment disorder with disturbance of conduct (N=1)
- Separation anxiety disorder (N=1).
- Among the playmates:
- Eleven had no diagnosis
- One had borderline intellectual functioning.
Anthropometrics
- No significant differences between groups for body weight or socio-economic status
- Body weight:
- Sugar responders: 18.3±3.4kg (mean±SD)
- Playmates: 17.5±3.5kg (mean±SD)
- Socio-economic status (information on how this is determined was not provided)
- Sugar responders: 1.7 ± 1.7 (mean ± SD)
- Playmates: 1.1±0.3 (mean±SD).
Location
- Laboratory of Developmental Psychology at the National Institutes for Mental Health.
Summary of Results:
|
Variables |
Conners 10-Item Scale (Playroom "Teacher") |
Conners 10-Item Scale (Parent for Rest of Day) Mean±SD |
Actometer |
Interpersonal Aggression (Log-Corrected Seconds) |
Total Duration of Aggression (Log Corrected Seconds) |
12-Item Scale (Five-Hour Challenge at Home) Mean±SD |
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Glucose |
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| Sucose Responders Playmates |
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| Saccharin Responders Playmates |
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| Aspartame Responders Playmates |
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Other Findings
- Baseline measures revealed that "sugar-responsive" children were more behaviorally disturbed, as indicated by psychiatric diagnosis, higher hyperactivity ratings by teachers and parents and higher behavior screening questionnaire scores
- Conners 10-item scale (parents for the rest of the day)
- Significant main effect of group, P=0.001.
- Actometer
- Significant main effect of substance, P=0.006
- Significantly less activity following ingestion of aspartame than glucose or sucrose.
- Total duration of interpersonal aggression: Not different between groups or substances
- Total duration of aggression against property: Not different between groups or substances
- Parent ratings of activity and aggression: Failed to show differences between substances for either group
- No parent correctly identified the beverages
- Only two of 51 correlations for diet were significant
- Carbohydrate-to-protein ratio and sucrose consumption did not differ between groups
- Sugar consumption (mean daily sucrose intake and as total daily sugar) correlated with duration of aggression against property for the responders, regardless of treatment (R=0.60, P=0.03)
Author Conclusion:
- Study attempted to elicit the effects of sugar on behavior by specifically recruiting alleged sugar responders
- Acute sugar loading did not increase aggression or activity in pre-school children
- Behavioral effects of aspartame were either extremely subtle or absent.
Funding Source:
| Government: | NIMH |
Reviewer Comments:
- The primary focus of this study was to evaluate the effects of sugar intake on behavior. Aspartame was used as a control.
- The specific total amount of aspartame provided to the children was not stated. Children received 30mg per kg of body weight of aspartame. Using the average weight of the children in each group, the following amounts were provided:
- Sugar-responsive group: 549mg aspartame (18.3kg x 30mg per kg of body weight)
- Playmates: 525mg aspartame (17.5 x 30mg per kg of body weight).
- This study only studied each treatment two times; once in the laboratory and once at home.
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Quality Criteria Checklist: Primary Research
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| 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? | Yes | |
| 2.2. | Were criteria applied equally to all study groups? | Yes | |
| 2.3. | Were health, demographics, and other characteristics of subjects described? | Yes | |
| 2.4. | Were the subjects/patients a representative sample of the relevant population? | No | |
| 3. | Were study groups comparable? | No | |
| 3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | No | |
| 3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | No | |
| 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")? | Yes | |
| 4. | Was method of handling withdrawals described? | Yes | |
| 4.1. | Were follow-up methods described and the same for all groups? | N/A | |
| 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? | Yes | |
| 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? | Yes | |
| 6. | Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? | No | |
| 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? | No | |
| 6.4. | Was the amount of exposure and, if relevant, subject/patient compliance measured? | No | |
| 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? | N/A | |
| 6.8. | In diagnostic study, were details of test administration and replication sufficient? | No | |
| 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? | Yes | |
| 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)? | No | |
| 8.6. | Was clinical significance as well as statistical significance reported? | Yes | |
| 8.7. | If negative findings, was a power calculation reported to address type 2 error? | No | |
| 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? | No | |
| 10.2. | Was the study free from apparent conflict of interest? | Yes | |