EAL

DM: Carbohydrates (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To evaluate the metabolic and beta-cell secretory effects of isocaloric modifications of the standard polysaccharide-rich diet recommended for diabetic patients by increasing its fructose or sucrose content.

Inclusion Criteria:

Well-controlled Type II diabetes

Exclusion Criteria:

history of poor clinic attendance
chronic alcohol abuse
hepatic or renal disease
severe micro- or macroangiopathy

Description of Study Protocol:

Recruitment: not specified

Design:

Nonrandomized crossover trial, diet order was planned
all patients consumed each of three diets for a 28-day period, with 14-day washout periods between.

Blinding used (if applicable): not possible; diets were easily distinguished

Intervention (if applicable)

Test diets:

high starch diet: 92% of CHO derived from polysaccharides, which made up 45% of calories
high-sucrose diet: 32% of total CHO (19% of total calories) derived from sucrose
high-fructose diet: 28% of total CHO (20% of total calories) derived from fructose
Diets were isocaloric and designed for each subject to maintain current weight
each diet was 50-55% CHO, 15% protein, and 30-35% fat.
each diet contained nearly identifcal amounts of dieatry fiber, cholesterol, PUFA, MUFA, and saturated fat.
the fructose in the high-fructose diet was provided in the form of a sorbet given three times per day

Statistical Analysis

Student's t-test used to make comparisons among the study diets on days 1, 14, and 28.
Bonferroni procedure used to protect against the efects of multiple comparison.
Study had 80% power to detect a 2.61 x SE difference for each endpoint comparison between two diets

Data Collection Summary:

Timing of Measurements

metabolic evaluations on days 1, 14, and 28 of each diet period

Dependent Variables

fasting blood values:
- glucose
- insulin
- C-peptide
- total and HDL cholesterol
- triglycerides
- glycolsylated protein
2-hour post-prandial samples after lunch and dinner:
- glucose
- insulin
- C-peptide
- triglyceride
24-hour urine collection for glucose
HbA1c on days 1 and 28

Independent Variables

high starch diet: 92% of CHO derived from polysaccharides, which made up 45% of calories
high-sucrose diet: 32% of total CHO (19% of total calories) derived from sucrose
high-fructose diet: 28% of total CHO (20% of total calories) derived from fructose
dietary adherence assessed by recall and review of food records at clinic visits every 2 weeks
subjects advised to continue with their regular physical activity

Control Variables

Description of Actual Data Sample:

Initial N: 16; 9 women, 7 men

Attrition (final N): 16

Age: 34-66 yrs

Ethnicity: not specified

Other relevant demographics: duration of diabetes: 2 months to 15 yrs; 10 subjects received oral sulfonylureas and 6 were treated with diet alone; mean HbA1c 7.5 ± 0.3

Anthropometrics: BMI range 21.2-28.5

Location: Brazil

Summary of Results:

No statistically significant differences were found from the start to the end of the study for mean body weight, HbA1c, fasting protein

Effects of diet on metabolic control at 28 days

Variables	High-fructose diet	High-sucrose diet	High-starch diet	Statistical Significance of Group Difference
Fasting plasma glucose, mmol/l	6.7±0.3	7.5±0.3	7.2±0.3	NS
Postprandial plasma glucose, mmol/l	7.2±0.4	8.1±0.4	7.6±0.3	NS
Fasting plasma insulin, pmol/l	54.0±9.9	66.0±2.1	65.3±2.0	NS
Postprandial plasma insulin, pmol/l	166.2±21.7	192.0±37.8	183.6±29.8	NS

Other Findings

No significant differences for lipid values were found between diet treatments.

Author Conclusion:

In well-controlled, normolipidemic, nonobese type II diabetic patients, substitution of up to 20% of daily calories as sucrose or fructose from starch has no significant effect on blood glucose control or serum lipids.

Funding Source:

Industry:

Capes Med (New Zealand), Coper Sugar

Food Company:

Other:

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?	N/A
	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?		N/A
	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?	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?	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?	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?	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)?	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?	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