DLM: Plant Stanols and Sterols (2010)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To investigate the effects of consuming croissants and magdalenas enriched with sterol esters, a-tocopherol and ß-carotene on plasma lipid and fat-soluble antioxidant concentrations in normocholesterolemic habitual consumers of bakery products.

Inclusion Criteria:

Normocholesterolemic, global cardiovascular risk according to the European Society for Atherosclerosis <20%, fasting plasma TC < 6.28 mmol/L (240 mg/dL), fasting plasma TG < 2.26 mmol/L (200 mg/dL), BMI < 40, habitual consumers of bakery products

Exclusion Criteria:

No alcohol abuse (<60 g ethanol/day), no medication or diet known to affect plasma lipids, no psychiatric disorders that make follow-up difficult, no metabolic, infectious, inflammatory or tumoral diseases and no antecedents of sitosterolemia, no pregnant or lactating women.

Description of Study Protocol:

-3 weeks (Screening):

Randomization to 2 groups: Control group (n=29) or sterol-ester group (n=28).  Sterol ester group received 1 croissant and 1 muffin every day, for 3.2 g/day free sterols, 5.3 mg/day a-tocopherol, and 0.9 mg/day ß-carotene.

-1 Weeks:  7 day food record, body wt, 2 blood samples

4 Weeks:  7 day food record, body wt

8 Weeks:  7 day food record, body wt, 2 blood samples

Data Collection Summary:

TC, HDL-C, TG, LDL-C calculated using Friedewald equation. ApoA-I and ApoB, plasma lipoproteins, plasma sterols (desmosterol, lathosterol, campesterol, ß-sitosterol), tocopherols (a-tocopherol and ?-tocopherol), carotenoids (a-carotene, ß-carotene, lycopene). Double blind.

Description of Actual Data Sample:

Of 70 recruited volunteers, 61 met criteria and were included in study. 4 subjects dropped out.  57 completed the study.  The groups did not differ in gender, age, weight, BMI, blood pressure, smoking habits or plasma lipid concentrations at the beginning of the study.

Summary of Results:

In terms of dietary intake, the 2 groups differed in their changes in total energy and cholesterol intakes.

Total and LDL-C decreased in the sterol ester group by 0.24 mmol/L (P < 0.001) and 0.26 mmol/L (P < 0.002), respectively, whereas these variables did not change in the control group.  The total difference in total and LDL-C changes between groups was 0.38 mmol/L (8.9%) and 0.36 mmol/L (14.7%), respectively (P < 0.001).  Changes in the TC/HDL-C ratio and the apoB concentration also differed between the groups (P= 0.002 and P=0.005, respectively), whereas changes in TG, apoA and lipoprotein (a) did not.  When individuals who ate bakery-modified products as part of a meal (n=14) were compared with those who are them separately from meals (n=14), the decrease in LDL-C did not differ between the 2 types of consumption (-0.26 +/- 0.53 vs –0.26 +/- 0.34 mmol/L, respectively).  Similarly, within-group changes over time in plasma tocopherol and carotenoid concentrations did not differ between groups.  

Author Conclusion:

Our results show that enriching bakery products with 3.2 g/day of sterols (1.55 g/croissant and 1.68 g/muffin) reduces TC by 5.5% and LDL-C by 10.4%, and does not significantly modify TG and HDL-C concentrations in normocholesterolemic subjects. In conclusion, the results of the present study show that the consumption of croissants and muffins enriched with sterol esters, a-tocopherol and ß-carotene significantly decreases the plasma levels of TC and LDL-C and does not affect the a-tocopherol and ß-carotene concentrations in normocholesterolemic subjects under normal lifestyle conditions.  Moreover, our study showed no differences in LDL-C changes induced by phytosterol-enriched bakery between different daily patterns of consumption.  Our findings suggest that bakery products are excellent carriers for phytosterols and are a practical option in helping to control cholesterol in a healthy population normally consuming these products.

Funding Source:
Industry:
Europastry S A
Food Company:
Reviewer Comments:

Well controlled study with low dropout rate.

After 8 weeks of 3.2 g sterols:

  • TC Baseline:  4.33 +/- 0.66 mmol/L (167.57 +/- 25.54 mg/dL) 
  • TC Ending:  4.09 +/- 0.62 mmol/L (158.28 +/- 23.99 mg/dL) 
  • % Change:  -8.9% (p< 0.001) 
  • LDL-C Baseline:  2.50 +/- 0.70 mmol/L (96.75 +/- 27.09 mg/dL) 
  • LDL-C Ending:  2.24 +/- 0.66 mmol/L (86.69 +/- 25.54 mg/dL)   
  • % Change:  -14.7% ( p < 0.01)
  • TC:HDL-C Baseline:  3.55 +/- 1.12
  • TC:HDL-C Ending:  3.25 +/- 1.04
  • % Change:  -10.7% (p < 0.01) 
  • HDL-C and TG: no statistically significant changes
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? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? N/A
  1.3. Were the target population and setting specified? N/A
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? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
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? N/A
  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? 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? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? 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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  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? N/A
  7.2. Were nutrition measures appropriate to question and outcomes of concern? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? N/A
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? N/A
  7.7. Were the measurements conducted consistently across groups? N/A
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? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  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? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A