EAL

Saturated Fat

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

Examine the effects of large servings of either oat or wheat cereal on plasma lipids, lipoprotein subclasses, lipoprotein particle diameters, and LDL particle number.

Inclusion Criteria:

*Male

*Sedentary or minimally active (< two 30-min aerobic sessions per week).

*BMI 25-35.

Age 50-75.

Exclusion Criteria:

*Having CVD

*Diabetes or fasting blood glucose >7mmol/L

*Systolic BP >160mm Hg

*Diastolic BP >99mm Hg

*Having asthma

*Having tobacco use

*History eating d/o

*History thyroid gland d/o

*Use of meds known to affect any of the dependent variables in study.

*Habitual intake of dietary fiber >30g/d determined by Block’s

questionnaires: the Fat Screener and the Fruit, Vegetable, and Fiber Screener.

*Before enrollment subjects must have tasted and liked the cereals used in study.

Description of Study Protocol:

A 12 week study.

Subjects recruited from community around Fort Collins, CO.

After screening were randomly assigned to whole-grain oat or whole-grain wheat cereal group.

Groups were matched on cereal’s energy, macronutrients, and dietary fiber.

Other than daily cereal subjects were instructed not to change their usual dietary habits.

Compliance was monitored by subject’s return of uneaten cereal every other week.

Subjects kept a 4-day food diary at baseline and during the final week of the study.

Anthropometrics were taken every other week throughout study.

Plasma lipids were measured at baseline and after treatment.

Data Collection Summary:

No blinding of any kind reported.

Description of Actual Data Sample:

36 overweight men aged 50-75 randomly assigned to either oat group (n=18) or wheat group (n=18).

150 men were screened for study, 39 were enrolled. Two were excluded after enrollment due to fasting glucose >7.0 mmol/L and one dropped out due to a broken limb requiring medications.

The 36 remaining men completed the study.

Summary of Results:

Lipids

No significant difference in lipid or lipoprotein blood concentrations between oat and wheat groups at baseline.

**A significant (p<0.05) time-by-treatment interaction was observed for:

**LDL (p=0.02)

**Small LDL subclass (p=0.01)

**LDL particle number (p=0.01)

**LDL:HDL (p=0.02)

The oat group had favorable changes and the wheat group had elevations in these lipid indexes.

Other lipid results:

TC:HDL (p=0.05)

TC (p=0.08)

HDL (p=0.41)

TG (p=0.07)

Paired sample t test indicated no significant change in HDL size in oat group (p=0.32) but a sig size reduction in wheat group (p=0.03).

Few subjects had detectable chylomicrons or intermediate-density lipoproteins and no sig change over time in either group (no data).

There was a trend toward lower [TG] in the oat group and elevated [TG] in the wheat group (see Table I).

There was a sig inverse relationship between changes in [TG] and changes in LDL particle size and HDL2.

[TG] was positively correlated with small LDL.

These data support the relationship found in the oat group (but not wheat group) for the decrease in [TG] being accompanies by an increase in LDL particle size.

There were significant differences in LDL subclass phenotypes A and B due to the treatment. (see Table 2).

Dietary

Compliance to treatment diets was not significantly different between groups.

There was a significant difference between the two groups at baseline of sat fat (p=0.02), myristic acid (p=0.02), and palmitic acid (p=0.01) intake however after using the changes in these dietary variables and the intakes of total fat, PUFA, chol, and P:S as covariates all significant blood lipid and lipoprotein changes remained significant.

Physical

There was no significant difference in subject’s physical characteristics between groups at baseline.

There was an increase in BMI, wt, and skinfold thickness in both groups over time but not statistically sig.

No change in caloric intake in either group over time but was stat sig increases in pro, CHO, and decreased fat in both groups over time.

Author Conclusion:

Two large servings per day of oat cereal reduce the concentrations of small dense LDL, chol, and LDL particle number more than wheat.

Findings also suggest that LDL subclass phenotype may be an important factor in how lipids and lipoproteins will respond to increased intakes of CHO and fiber.

This is important because many persons with normal traditionally measured lipid profiles go on to develop CVD. Perhaps the measurement of non-traditional indexes may provide a means for determining a person’s actual CVD risk that might have otherwise gone undetermined.

Understanding how to modify these indexes through diet recommendations can further serve to lower the risk that is identified.

Funding Source:

Government:

NIH

Industry:

Quaker Oates Company

Food Company:

Reviewer Comments:

No mention of how subjects were recruited.

No demographics or other information on the subjects was reported.

Many other statistical analyses were performed that seemed too numerous to report on the worksheet. I reported the ones r/t the purpose of this study.

The author’s did not explain what the abbreviations stood for that were used in reporting the insulin and glucose metabolism data.

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?	N/A
	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?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	No
	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%.)	N/A
	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?		No
	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.)	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?	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?	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)?	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?	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?	No