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 determine the prevalence of and associated factors for overweight, especially to determine the relationship between the intake of monosodium glutamate (MSG) as a seasoning and overweight in Vietnam.

Inclusion Criteria:

Households in which all members usually ate their meals at home and had at least one member 20 years old or older.

Exclusion Criteria:

Malformation
Chronic or acute disease
Pregnancy and lactating
Special diet for:
- Weight loss
- Weight gain
- Vegetarianism
- Salt reduction
- Diabetes mellitus
- Other dietary reasons.

Description of Study Protocol:

Recruitment

Multi-stage sampling method:

In each selected province or city, one commune in a rural area and one ward in an urban area was selected randomly from all communes and wards
Lists of all household in selected communes or wards were established and family codes created
First families were selected by randomly picking a family code
Other families were approached using a "random walking" method to obtain 255 adults (about 80 households) for each commune or ward.

Design

Cross-sectional survey.

Statistical Analysis

A student's T-test was applied to examine differences in age, BMI, waist-to-hip ratio, energy intake and MSG intake between participants according to region of residence (rural vs. urban). A chi square was used to examine difference in prevalence of physical activity level, education level and lifelong occupation of heavy workers. Multiple logistic regression analysis was used to test several models for associations between overweight and other variables.

Data Collection Summary:

Timing of Measurements

Over three consecutive days in 2008.

Dependent Variables

BMI: Standing height on stable plane and weight in light clothing and no shoes
Waist-to-hip ratio: Minimum circumference between the umbilicus and iliac crest and hip at the widest circumference around the buttocks.

Independent Variables

MSG intake: Difference between the weight of seasoning bottles before and after a meal for all family members. MSG content in seasonings was calculated from food labels combined with analysis. Individual intake was calculated according to the MSG intake of all family members multiplied by the proportion of actual food intake of the individual using an average of three days.
Dietary intake: 24-hour recall for three consecutive days at participant's home, conducted by trained researchers before and after each meal.

Control Variables

All meals were prepared and eaten at home during the survey.

Description of Actual Data Sample:

Initial N: 1,530
Attrition (final N): 1,528 (706 males, 822 females)
Age: 45.6±15.6 years
Ethnicity: Asian
Anthropometrics: No significant difference in age and BMI between rural and urban areas
Location: Vietnam.

Summary of Results:

Findings

Waist-to-hip ratio and energy intake in rural areas were significantly lower than in urban areas (P<0.05). Prevalence of participants with the lowest education level was higher in rural areas than urban (P<0.01).
All took their meals at home during the survey, of whom 81.0% were MSG users. Average MSG intake was 2.2±1.8g per day. Average animal and plant protein intakes were 31.0±19.0g per day and 41.4±15.2g per day, respectively. Thus, GLU from food was estimated to be equal to 14.7±6.7g per day. There were no differences between rural and urban areas in MSG intake.
There was no significant difference between males and females in prevalence of overweight. The prevalence in rural areas (21.4%) was significantly lower than in urban areas (31.8%, P<0.05).
There was no significant association between overweight and the intake of MSG.

Author Conclusion:

Although MSG intake was relatively high, a relationship between MSG intake and overweight was not found.

Funding Source:

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)	N/A

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)	N/A
	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.)	N/A
	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?	Yes
	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?		N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	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.)	N/A
	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?	N/A
	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?	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)?	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?	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