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 confirm the effect of monosodium glutamate (MSG) on the food intake of older people.

Inclusion Criteria:

Mental and physical fitness
Ability to feed oneself
Ambulatory condition
Negative history of significant illness
Negative major surgical operation
Negative gastrointestinal bleeding
Negative cardiovascular disease
Negative low-salt diet as advised by a physician
Negative food allergy.

Exclusion Criteria:

Not meeting the inclusion criteria.

Description of Study Protocol:

Recruitment

Candidates at three different cottages (facilities for the aged) were reviewed and recruited based on inclusion criteria.

Design

Non-randomized, cross-over study.

Blinding Used

Double blind.

Intervention

MSG (Monosodium glutamate)
Iodized salt.

Statistical Analysis

Descriptive statistics
Paired T-tests.

Data Collection Summary:

Timing of Measurements

Baseline:
- Anthropometrics
- Blood pressure
- Serum sodium.
Trial 1: A 24-hour food intake for two months (three weekdays and one weekend per week)
One-week washout period was observed after Trial 1 for another baseline measure
Trial 2 (crossover): A 24-hour food intake for two months (three weekdays and one weekend per week).

Dependent Variables

Dietary intake
Weight
Blood pressure
Serum sodium levels.

Independent Variables

MSG

Control Variables

Iodized salt.

Description of Actual Data Sample:

Initial N: 67 (36 male, 31 female)
Attrition (final N): 60 (31 males, 29 females)
Age: Mean 73 years of age (72 years of age for males and 75 years of age for females)
Ethnicity: Philippine descent
Other relevant demographics:
- Majority were single (58.3% male, 41.9% female)
- Majority reached elementary level (44.4% male, 64.5 female)
Location: Philippines.

Summary of Results:

Key Findings

**Mean Weight, Serum Sodium of Male and Female Elderly Across Intervention Periods**
Gender/Data	Baseline	MSG	Mean Difference (CI)	Baseline	Iodized Salt	Mean Difference (CI)
Male weight (kg)	50.9±6.8	52.6±6.8	-1.71** (-2.66 to -0.76)	53.1±7.6	52.6±7.6	0.46 (0.33 to 0.20)
Male serum Na (mmol per L)	142.3±3.26	139.5±1.86	3.05** (1.86 to 4.25)	142.3±3.26	139.6±2.60	2.68** (1.7 to 3.66)
Female weight (kg)	42.7±9.7	43.9±9.3	-1.25** (-2.14 to -0.36)	43.6±11.4	44.0±11.0	-0.32 (-1.40 to 0.75)
Female serum Na	144.2±2.52	138.7±2.12	5.28** (4.49 to 6.64)	144.2±2.52	139.0±2.62	5.56** (4.47 to 6.10)

** Significant at less than 0.01.

**Mean Blood Pressure (mm Hg) of Male and Female Elderly During Intervention Period**
	MSG				Iodized Salt
Gender	Baseline		Endpoint		Baseline		Endpoint
	SP	DP	SP	DP	SP	DP	SP	DP
Male MBP	120	76	128**	74	127	76	130**	74
Female MBP	122	72	133**	77	133	75	129*	75

** Significant at less than 0.01.
* Significant at less than 0.05.

Other Findings

Males had significantly increased intake for energy and nutrients such as fat and carbohydrate; food intake with added salt also has significantly increased for energy and carbohydrate
Among male participants there was a significant increase in protein during MSG intervention while there was a higher carbohydrate intake with iodized salt
Female participants had significantly increased intake of energy and nutrients such as fat and carbohydrate when given iodized salt as well as MSG.

Author Conclusion:

The use of flavor enhancers increased food intake and was found to be well tolerated by older persons. Weight increased for both males and females after MSG but not after iodized salt. No difference in blood pressure and serum sodium was noted in both MSG and iodized salt intake.

Funding Source:

Government:

Food and Nutrition Research Institute, Philippines

Reviewer Comments:

Additional treatments and therapies such as medications and daily activities were not described or statistically accounted for
Statistical differences between groups were not compared to determine impact of differences in both primary and secondary outcomes
History of illness was not considered or mentioned as a part of screening patients, nor was the impact of historical exposure to both MSG and sodium described or screened.

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?		???
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	???
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	???
	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?	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?	No
	6.6.	Were extra or unplanned treatments described?	No
	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?	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?	???
	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?	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