EAL

UM: Role of Umami in the Regulation of Energy Intake (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the impact of MSG on motivational ratings (MR) of hunger and fullness and on energy intakes at a subsequent test meal for female participants.

Inclusion Criteria:

Healthy women 18 to 25 years of age
BMI of 18.5kg/m² to 24.9kg/m²
Non-smoking
No prescribed medications except for oral contraceptive if using for more than three months.

Exclusion Criteria:

Food allergy or food restriction
Stable weight in the prior three months (no change of more than 4kg to 5kg)
Diet restrained as assessed by Three Factor Eating Questionnaire and Eating Disorders Inventory.

Description of Study Protocol:

Recruitment

Advertisements on Web sites and flyers.

Design

Repeated-measures (within-subjects) crossover design, with each subject serving as their own control.

Blinding Used

Test broths were blinded to both subjects and investigators serving the broth.

Intervention

Broths containing MSG and nucleotides were compared with two control conditions, one being an equal energy control (base broth) and the other being a higher-energy broth with added fat (BAF).

Statistical Analysis

Repeated measures ANOVA with the pre-load broth (four pre-load types) and time (12 ratings from 09:15 a.m. to noon) as the within-subject factors. A second analysis of the effect of the first and second pre-loads alone on MR, using the nine ratings before the second delivery of the pre-load (P1, 09:15 a.m. to 11:30 a.m.) for one analysis using a repeated-measures ANOVA and the four ratings from 11:15 a.m. to noon (P2) for another repeated-measures ANOVA were also conducted. Analysis of lunch intakes were done using repeated-measures ANOVA with the four pre-load broths as the repeated measures. Pair-wise comparisons were made with ANOVA was significant. Differences in palatability and sensory scores were also analyzed by repeated-measures ANOVA with the pre-load broth as the within-subject factor.

Data Collection Summary:

Timing of Measurements

At each of four visits, the women completed the MR at 9:00 a.m., then immediately consumed 240ml of broth and a slice of plain white toasted bread within 10 minutes. Questionnaire were completed every 15 minutes. The second serving of broth was served alone at 11:15 a.m. Hedonic and sensory characteristics were rated following that. At noon they ate an ad libitum lunch and at 12:30 p.m. they completed the final MR.

Dependent Variables

Hedonic, appetite and sensory ratings: Computerized visual analog scale (VAS). Each participant positioned a cursor along the 100mm bar anchored at each extreme with labels "not al all" and "extremely." Appetite ratings included hunger, desire to snack, desire to eat, fullness and thirst. Hedonic value was defined by ratings of liking and pleasantness. Sensory ratings included savory, salty, creamy, bitter, sour and sweet.
Motivational scales: One scale per person on computer monitor.
Intake:
- Energy intake (kJ)
- Energy from protein (%)
- Energy from carbohydrate (%)
- Energy from fat (%).

Independent Variables

Four broths:
- Base chicken broth (base broth)
- Chicken broth with 1.19g MSG and 0.03g nucleotides (MSG+)
- Chicken broth with 1.22g MSG (MSG)
- Chicken broth with added fat (BAF).
Base broth was fat-free reduced sodium (420mg Na per 240ml and 63kJ. 600mg Na was added to each broth. BAF (681kJ) had unsalted butter containing 11g fat (7g SFA) added.
The broths were served in two doses for a total of 2.44g MSG
Ad libitum lunch consisting of choices of:
- Two grains (crackers and pita bread)
- Two fruits (apples and bananas)
- Two vegetables (snap peas and carrots)
- Two cheeses (havarti and cheddar)
- Two meats (ham and turkey)
- Two sweets (rice treat and chocolate candies)
- One yogurt
- One ice cream cup
- Hummus
- Potato chips
- Still water (591ml) chilled in an opaques cup with lid and straw.

Control Variables

Fasting except for water after 10:00 p.m.the night before testing.
No alcohol for 24 hours
Exercise as normal as possible before each session
Subjects remained quiet during the study session.

Description of Actual Data Sample:

Initial N: 39 females
Attrition (final N): 35 females
Age: 24.6 years (SEM, four to six years)
Anthropometrics: BMI 21.6kg/m² (SEM, 1.8kg/m²)
Location: Seattle, WA.

Summary of Results:

Findings

The addition of MSG to chicken broth did not increase energy intakes at lunch or affect motivational ratings over the entire testing session. Both hunger and desire to snack between the second pre-load exposure and the test meal were significantly reduced in the MSG condition relative to the base broth condition (both, P=0.03). Only the BAF significantly suppressed energy intakes at lunch compared with the base broth control condition.

Author Conclusion:

Supplementing chicken broth with MSG can lead to some stronger feeling of satiety but does not alter energy intake at the next meal relative to an equal energy broth without added MSG.

Funding Source:

Industry:

Ajinomoto, Ic.

Food Company:

Reviewer Comments:

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?	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?	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?	N/A
	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?	N/A
	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?	Yes
	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)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	N/A
	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