EAL

UM: Role of Umami in the Regulation of Healthy Food Choices (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine if adding monosodium glutamate (MSG) to certain foods affects food selection.

Inclusion Criteria:

Hospitalized diabetic patients.

Exclusion Criteria:

Not reported.

Description of Study Protocol:

Recruitment

Patients were selected as they arrived at the hospital. Recruitment methods were not otherwise described.

Design

Randomized controlled trial
Pairs of patients were matched for type and duration of diabetes, age, sex and body mass index
In each matched pair, one patient was randomly ascribed to the experimental group and the other patient to the control group
Lunch intake was monitored over four consecutive days.

Blinding Used

Patients were blinded to intervention and measurements.

Intervention

0.6% MSG was added to the vegetable and starch dish of the lunch meal for four consecutive days.

Statistical Analysis

Computerized one-tail T-tests for correlated samples were used to compare the amount of foods ingested by both groups
Two-tailed T-tests for correlated samples were used to compare differences in nutrient intake between groups and differences in subjects' characteristics.

Data Collection Summary:

Timing of Measurements

Lunch intake was measured by weighing amounts served and leftovers.

Dependent Variables

Food intake: Foods were weighed before and after meals on scientific scales:

Appetizer
Meat
Vegetables
Starch
Cheese
Bread
Butter
Lemon juice
Yogurt
Fruit and fruit pie.

Independent Variables

0.6% MSG was added to the vegetable and starch dish of the lunch meal.

Control Variables

All foods were prepared and supplied by the Eurest Company, in charge of the hospital kitchens and cafeteria. Patients ate lunch meals in the ward's dining room.

Description of Actual Data Sample:

Initial N

62 (28 males, 34 females).

Attrition (final N)

62.

Age (years)

	Experimental		Control
	Mean	SD	Mean	SD
Insulin-dependent diabetes
Male	48.0	12.0	49.0	16.0
Female	42.0	13.0	44.0	15.0
Non-insulin-dependent diabetes
Male	53.0	8.4	53.0	6.6
Female	60.0	8.2	58.0	10.0

Anthropometrics

No statistically significant differences between groups for height, weight and BMI.

Location

Paris, France.

Summary of Results:

Key Findings

Intake of starch foods was significantly higher in the experiment group
Intakes of lemon juice and yogurt were significantly lower in the experiment group
Intake of vegetables was higher in the experiment group, but the difference was not statistically significant
There was no statistically significant between-group differences in nutrient intake, including energy intake.

Food Intake (Grams)
	Experimental Group		Control Group		T(30)	P
	Means	SEM	Means	SEM	T(30)	P
Starch	139.81	5.45	124.83	5.79	1.910	<0.05
Lemon juice	2.56	0.82	5.50	1.60	-1.752	<0.05
Yogurt	55.84	9.56	69.83	9.05	-1.780	<0.05

Author Conclusion:

The presence of MSG seems capable of enhancing the intake of some target foods.

Funding Source:

Industry:

Umami Manufacturers Association

Food Company:

Reviewer Comments:

The dose of 0.6% MSG may have been excessive for some patients and may have affected intake
An earlier study showed that eating the same MSG-containing food repeatedly enhanced the acceptability and intake of this food. There were fewer different starch foods than vegetables presented on the lunch menus. This may help to explain why the between-group differences for starch intake were significant while the differences for vegetables were not significant.
Small sample size (62) and inclusion and exclusion criteria and recruitment methods were not well described
Short duration (four days)
Patients were hospitalized so they could attend dietary and diabetes management classes. It is not clear how this affected their intake.

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?		???
	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?	???
3.	Were study groups comparable?		N/A
	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?	Yes
	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?	No
	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?		???
	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?	???
	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?	Yes
	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?		???
	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?	???
	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?	???
	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?	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?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes