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 whether or not an optimal preferred MSG concentration in several foods increases intake in elderly people.

Inclusion Criteria:
  • Elderly residents of a nursing home, "Dorpsveld," in Rotterdam, the Netherlands
  • The intake study included only elderly people from three nursing homes in Deventer, Gendringen and Rijssen, the Netherlands
  • Elderly subjects had to:
    • Be 65 years or older
    • Be able to participate in a sensory study
    • Have good eyesight
    • Have no allergy to MSG or the foods in this study
    • Not be on a sodium restricted diet
    • Have no disease in terminal phase
    • Have no use of antidepressants.
  • For young adults the inclusion criteria were 30 years of age or younger and not allergic to MSG or to the foods in this study
  • Everyone provided written informed consent.
Exclusion Criteria:

Not described.

Description of Study Protocol:

Recruitment

  • Young adults were recruited by advertisement in Wageningen University buildings
  • Elderly adults were recruited from three nursing homes in Deventer, Gendringen and Rijssen, the Netherlands.

Design

Single blind, randomized within-subjects crossover trial.

Blinding Used

Carried out single blind.

Intervention:

  • Pleasantness of foods was rated of foods each with zero, 0.5, 0.8, 1.3 and 2.0g of MSG per 100g
  • Intake was measured by weighing back leftovers of two meals with MSG (0.5% in mashed potatoes, 2% in spinach and ground meat) and without MSG.

Statistical Analysis

  • For the sensory study, a within-subjects repeated measures design (ANOVA) compared mean attribute ratings measured at five different MSG concentration levels
  • Age served as a between subject factor and concentration as a within subject factor
  • ANOVA compared pleasantness ratings measured at the five MSG levels between the low and normal group
  • The Wilcoxon Signed Rank Test compared differences in mean intake between the hot meals with and without MSG
  • The data of the intake study was not normally distributed and intake was measured within the same subject
  • A Pearson correlation coefficient determined if the change in energy intake was related to the ETOC score
  • All statistical analyses were performed with SPSS for Windows software, P<0.05 were considered significant.
Data Collection Summary:

Timing of Measurements

  • Sensory study started with a one-day pilot experiment to use in the main sensory study, which was divided over six test sessions
  • The intake study lasted four weeks.

Dependent Variables

  • Food intake by the elderly was measured by weighing the leftovers of each component (minced meat, spinach and mashed potatoes) together and separately. The data were converted into nutrients and energy using the Dutch Food composition table.
  • Knee-to-floor height (KFH) of the elderly participants was measured twice without shoes using a stadiometer in a sitting position from the anterior surface of the thigh to the floor with the ankle and the knee each flexed at a 90o angle against the metallic help
  • Body height was calculated as: Height (in cm)=3.16 KFH(cm)
  • Body weight was measured using a weighing scale
  • Taste intensity and pleasantness of the three foods with varied MSG concentrations were rated on a 10-point scale by the taste-and-swallow method
  • Malnutrition was identified in the elderly with the mini-nutritional assessment (MNA) tool
  • Olfactory sensitivity was identified by using the European test of Olfactory Capabilities (ETOC). The test contains 16 blocks of four vials and only one vial (15ml) contains an odor. The odors are vanilla, cloves, apple, eucalyptus, cinnamon, fuel-oil, pine, garlic, cut grass, anise, orange, fish, rose, thyme, lemon and mint.

Independent Variables

  • Foods each with zero, 0.5, 0.8, 1.3 and 2.0g of MSG per 100g
  • Two meals with MSG (0.5% in mashed potatoes, 2% in spinach and ground meat) and without MSG.
Description of Actual Data Sample:
  • Initial N: 127 total (39 elderly and 29 young adults in the sensory study and 59 elderly in the intake study)
  • Attrition (final N): 115 total [33 elderly (12 males, 21 females)] and [29 young (6 males, 23 females)] adults in the sensory study and 53 elderly (13 males, 40 females) in the intake study
  • Age: Mean age was 21.3 years for the young adults in the sensory study and 80.8 years for elderly in the sensory study. Mean age for elderly in the intake study was 85.8 years.
  • Ethnicity: Dutch
  • Anthropometrics: Mean BMI for young adults in the sensory study was 21.3kg/m2 and for elderly 27.4kg/m2. Mean BMI for elderly in the intake study was 26.5kg/m2.
  • Location: The Netherlands.
Summary of Results:

Key Findings

  • 0.5% MSG (P<0.05) was preferred in mashed potatoes but no optimal preferred concentration was found for spinach and ground beef, possibly because of their complex taste
  • Intake was not different between the foods with and without MSG or the total meal (all P>0.68).

 

 

Author Conclusion:

An optimal MSG concentration of 0.5% MSG in mashed potatoes and 2% in spinach and minced meat does not necessarily guarantee a higher intake of these foods. Factors such as denture wear, medicine use and the heterogeneity in olfactory functioning contribute as to why flavor enhancement cannot be used as a one-size fits all approach.  The chemosensory heterogeneity of the elderly population requires more individual flavor enhancement to improve the dietary intake and sensory experience.

Funding Source:
Government: European Commission Quality of Life and Management of Living Resources Fifth Framework Programme
Reviewer Comments:

The authors did note that it was not possible to perform both the sensory study and the intake study in the same population of elderly people. Even though both groups were institutionalized, they were heterogeneous and may have had a different sensory performance. Therefore, the optimal MSG concentration might have varied between the two groups.

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? 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? 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? 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? 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? N/A
  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)? ???
  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