MNT: Disorders of Lipid Metabolism (2015)

Citation:

Lim HJ, Choi YM, Choue R. Dietary intervention with emphasis on folate intake reduces serum lipids but not plasma homocysteine levels in hyperlipidemic patients. Nutr Res. 2008 Nov; 28(11): 767-774.

PubMed ID: 19083486
 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

What is the effect of MNT on blood levels of lipids, homocysteine and vitamins?

Inclusion Criteria:
  • Between 18 and 70 years
  • Total serum cholesterol higher than 200mg per dL
  • Triacylglycerol higher than 150mg per dL
  • No glycosuria
  • No use of lipid-lowering medications
  • No known coronary heart disease.
Exclusion Criteria:
  • Age less than 18 or more than 70 years
  • Presence of glycosuria
  • Use of lipid-lowering medications
  • Known CHD
  • Taking supplements of B vitamins.
Description of Study Protocol:

Design

Randomized controlled trial.

Blinding Used

  • Subjects and dietitians were not blinded
  • Data collectors were blinded as objective lab tests were used.

Intervention

MNT included five sessions of 30 to 40 minutes each. MNT included evaluation, assessment, intervention and communication. MNT session specifically stressed ideal body weight, avoiding foods high in saturated fat, simple sugars, alcohol or sodium. Dietary sources of folate were encouraged.

  • Week one:
    • Consent from subject
    • Baseline data collection
    • Introduction
    • 24-hour dietary recall and dietary assessment
    • General education about hyperlipidemia
  • Week zero:
    • Dietary therapy education (eat variety of foods including plenty of whole grains, vegetables, fruit, seaweed)
    • Educate about normal plasma levels
  • Week two:
    • Calculating energy, fat and sugar
    • Balancing food intake with physical activity
    • Food exchange table
    • Education about food exchange table and nutrient content of foods (especially folate, vitamins B6 and B12)
  • Week four:
    • Nutrition education about food choices according to dietary guidelines
    • Education about maintaining ideal body weight, physical activity and moderate alcohol consumption
  • Week eight:
    • Cholesterol and fat content of food (choosing diet low in fat, saturated fat and cholesterol)
    • Moderate salt consumption
    • Menu examples and tips for eating out.
  • Week 12: Reviewed all information and final data collection.

 Statistical Analysis 

  • Paired T-tests to assess changes in anthropometrics, blood values and dietary assessment between start and end (after 12 weeks) of trial
  • X2 test to verify significance between discontinuous variables
  • Significance set at P<0.05.
Data Collection Summary:

Timing of Measurements 

  • Baseline and at end of 12 weeks
  • Height, weight, body fat, lean body mass (Inbody 4.0 body composition analyzer)
  • Waist and hip circumference
  • Blood pressure
  • Blood tests for total homocysteine and vitamins.

Dependent Variables

  • BMI (change in kg/m2)
  • Body fat (change measured with Inbody 4.0 body composition analyzer)
  • Waist (measured in cm)
  • Hip (measured in cm)
  • Waist/Hip ratio (change in ratio)
  • Systolic BP
  • Diastolic BP
  • Average daily intake of intake before and after MNT (energy, carbohydrate/protein/fat ratio, fiber, cholesterol, folate, vitamin B6)
  • Blood values (total cholesterol, LDL-cholesterol, HDL-cholesterol), triacylglycerol, AI (total cholesterol – HDL-cholesterol)/HDL-cholesterol; tHcy; folate; vitamins B6 and B12.

Independent Variables 

Five sessions of MNT during a 12-week period using a protocol for hyperlipidemic subjects.

 

 

Description of Actual Data Sample:
  • Initial N: 40 (23 males and 17 females) divided into two groups of 20
  • Attrition: 40 (No attrition)
  • Age: Control 43.4±10.7 years; MNT group 46.7±6.5 (NS difference in age)
  • Ethnicity: Korean
  • Other relevant demographics: Subjects in control and MNT groups were similar in incidence of 30% to 40% were smokers; 70% to 80% drank moderately and 55% to 65% exercised; family history of CHD was low (10% to 20%).

Anthropometrics

  • Participants were of healthy body weight at beginning of the study
  • BMI: Control group males 24.8±2.3 and females 23.2±1.8; MNT group BMI males 25.4±1.9 and females 24.0±3.3kg/m2.

Location

Seoul, Korea.

 

 
Summary of Results:

The control subjects had no significant changes in any end points.

Dependent Variable

Change Week Zero to Week 12

Control

(N=20)

MNT

(N=20)

P-value

BMI males
NS
25.4±1.9 to
23.9 ±1.7
P<0.001
BMI females
NS
24.7±3.3 to
23.3±3.3
P<0.001
Body fat percentage, males
NS
24.8±3.5 to
22.3±3.4
P<0.5
Body fat percentage, females
NS
32.1±6.9 to
28.4±6.8
P<0.001
Waist (cm), males
NS
90.8±6.8 to
86.5±5.2
P<0.05
Waist (cm), females
NS
82.8±10.7 to
73.5±22.6
P<0.01
Hips (cm), males
NS
97.4±4.5 to
94.2±3.6
P<0.01
Hips (cm), females
NS
95.3±5.7 to
94.0±4.8
NS
Waist/hip ratio, males
NS
0.93±0.4 to
0.92±0.04
NS
Waist/Hip ratio, females
NS
0.87±0.07 to
0.78±0.23
P<0.01
Systolic BP, males
NS
124.6±11.9 to 121.3±10.3
NS
Systolic BP, females
NS
120.2±20.0 to
110.4±14.0
P<0.05
Diastolic BP, males
NS
88.4±9.5 to
83.8±9.1
NS
Diastolic BP, females
NS
78.1±12.7 to
72.4±9.4
P<0.05
TG (mg per dL), all
NS
174.6±28.8 to
108.3±34.5
P<0.001
Total cholesterol, (mg per dL)
NS
229.2±158 to
181.3±16.3
P<0.001
LDL-cholesterol (mg per dL)
NS
149.3±23.6 to
127.6±23.7
P<0.001
HDL-cholesterol (mg per dL)
NS
44.6±9.6 to
46.0±11.9
NS
LDL/HDL ratio
NS
3.5±0.9 to
2.9±0.9
P<0.001
A1 (total cholesterol - HDL/HDL)
NS
4.4±1.1 to
3.1±0.9
P<0.001
Homocysteine
NS
8.9±2.7 to
8.5±2.5
NS
Folate (ng per ml)
NS
6.6±1.7 to
90.0±3.6
P<0.01
B6 (nmol per L)
NS
66.5±43.5 to
102.3±50.3
P<0.01
B12 (pg per L)
NS
633.9±151.0 to
730.1±207.2
P<0.05

Although increased after MNT, homocysteine and vitamin levels remained within normal reference limits.

Dependent Variable
Change Week Zero to Week 12
Control
(N=20)
MNT
(N=20)
P-value
Dietary energy (KJ)
NS
9221.7± to
6241.1±625.7
P<0.001
C/P/F percent ratio
NS
NS change
NS
Fiber (mg)
NS
NS change
NS
Cholesterol (mg), males
NS
345.1±119 to 202.4±69.5
P<0.05
Cholesterol (mg), females
NS
286.1±108.6 to
205.4±92.0
P<0.05
Folate (mcg), males
NS
240.4±49.4 to
306.8±130.6
P<0.05
Folate (mcg), females
NS
264.0±482.6 to
300.8±127.7
P<0.05
Vitamin B6
NS
NS change
NS

 

Author Conclusion:

MNT is effective at reducing blood lipid levels and increasing blood levels of folate and vitamins B6 and B12 in Korean hyperlipidemic patents.

Funding Source:
Government: Government: Brain Korea 21 project
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) ???
  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? 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? 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? N/A
  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)? No
  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? 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