EAL

DM: Carbohydrates (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To compare the postprandial response to meals containing either sugars or starches in healthy subjects and subjects with diabetes.

Inclusion Criteria:

Type I or Type II diabetes.

Exclusion Criteria:

None specifically mentioned.

Description of Study Protocol:

Recruitment not specified

Design all subjects were served a breakfast composed of common foods on five different mornings.

Blinding used (if applicable):

the sugars and starches were added to conventional foods so that changes in carbohydrate composition would not be obvious to the subjects.
the healthy and Type II subjects were asked to follow a 300-g carbohydrate diet for 3 days before each test meal
Type 1 subjects administered their insulin at the medical center and were fed breakfast 30 minutes afterwards

Intervention (if applicable)

Breakfast composition

all breakfasts were prepared in a research kitchen
42 g of one type of sugar (glucose, fructose, or sucrose) were added to each of the first 3 breakfast meals
the fourth breakfast meal had 42g potato starch added
the fifth breakfast had 42g of wheat starch

Statistical Analysis

two-way ANOVA used to separate variability among the subjects from variability among the test meals.
mean responses after each test meal were then compared within subject groups using the "honestly significant difference " (HSD) between responses
to compare the time distribution of peak increments in plasma glucose level, the number of individual peaks occurring at each time point were tallied. These formed a two-way table (test meal by time points) for each group of subjects.
chi-square was computed for each table to test the hypothesis that the time distributions were the same for all test meals within the group.

Data Collection Summary:

Timing of Measurements

an indwelling catheter was placed in a forearm vein and blood samples were taken at -5, 15, 30, 60, 90, 120, 180, and 240 minutes

Dependent Variables

plasma glucose: because of the variability in fasting plasma levels of glucose among the Type I patients, postprandial increments in plasma glucose level were measured instead of absolute values
- individual peal glucose was computed by subtracting fasting plasma glucose levels from peak levels.
- area increments were computed by determining the total area under the plasma glucose curve and subtracting the area of a rectangle wth height equal to the fasting plasma level of glucose and length equal to 240 minutes
urinary glucose

peak serum insulin concentrations

Independent Variables

Breakfast composition

all breakfasts were prepared in a research kitchen
42 g of one type of sugar (glucose, fructose, or sucrose) were added to each of the first 3 breakfast meals
the fourth breakfast meal had 42g potato starch added
the fifth breakfast had 42g of wheat starch

Control Variables

Description of Actual Data Sample:

Initial N:10 healthy subjects, 12 subjects wieth Type ! diabetes, and 10 subjects with Type II diabetes

Attrition (final N): no attrition

Age: healthy subjects: mean age 39; type 1 subjects: mean age 26; Type II patients: mean age 62 years

Ethnicity: not specified

Other relevant demographics: mean duration of diabetes was 10 years for the Type I patients and 8 years for Type II patients

Anthropometrics all healthy and all Type I subjects were within 10% of desirable body weight; 30% of the Type II patientes were overweight.

Location: United States

Summary of Results:

Other Findings

In healthy subjects,

there were no significant differences among the five meal types in the time required for individual subjects to reach peak glucose concentrations ( P= 0.23).
None of the differences in peak insulin concentrations were significant.

In type I diabetic patients

None of the differences in peak increment or mean area increment were different by meal type.
There were no significant differences among the five meal types in the time required for individual subjects to reach peak glucose concentrations.
There were no significant differences in glucose excretion according to meal type.

In type II diabetic patients

No significant differences among the five meal types in the time required for individual subjects to reach peak glucose concentrations (P=0.49)
The fructose meal produced signficantly less urinary excretion of glucose than the potato, wheat, and glucose meals, and the sucrose meal produced significantly less glucose excretion than the wheat meal (HSD > 2.6 g/4 hours)
None of the differences in peak insulin concentrations were significant.

Author Conclusion:

The data do not support the belief that dietary sucrose aggravates hyperglycemia in diabetic patients. Sucrose, when combined in a mixed meal that contains protein and fat, did not produce a more rapid rise, a greater peak increment, or a greater area increment in plasma glucose than did comparable amounts of potato or wheat strach.

Funding Source:

Government:

GCRC, NIH

Not-for-profit

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?		No
	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?	No
	2.2.	Were criteria applied equally to all study groups?	???
	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?	???
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)	N/A
	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%.)	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?	???
	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?	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)?	Yes
	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?	Yes
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