EAL

Disorders of Lipid Metabolism and Nuts

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the effects of almond-enriched diets on insulin sensitivity and lipids in patients with diabetes. (Study 1 published in the same article is found in a separate worksheet).

Inclusion Criteria:

Type 2 diabetes diagnosed by physician or fasting serum glucose >78 mmol/dL

Moderately good glucose control (fasting glucose <11.1mmol/dL)

Exclusion Criteria:

Use of insulin

Use of meds to lower cholesterol

Clinically sig nephropathy, neuropathy, cardiovascular disease

Serum lipids:

LDL-C > 5.2mmol/dL
TG >78mmol/dL
HDL-C <0.65mmol/dL

Pregnant or breast-feeding

Food allergies or sensitivity to nuts

Description of Study Protocol:

Randomized double-blind double crossover design: subj had 4 wk on each of 4 diets with 2 wk break between diets.

Diets:

high fat , high almond (37% total fat, 10% from almonds)
low fat, high almond (25% total fat, 10% from almonds)
high fat control (37% total fat, 10% MUFA from olive or canola oil)
Low fat control (25% fat, 10% from olive or canola oil)

All foods provided and most meals eaten under supervision. Daily food records kept

Data Collection Summary:

Serum lipids: TC, LDL-C, HDL-C, TG, LDL:HDL-C, TC: HDL-C, HDL subpopulations.

Measures of glycemic control: fasting glucose, 2-h glucose, fasting insulin, 2-h insulin, hemoglobin A1C.

Description of Actual Data Sample:

17 women, 13 men completed study

mean age 53.8 y
mean BMI 33
baseline values (mmol/L): TC 5.1+0.15; LDL-C 2.91+0.3; HDL1.25+0.04; fasting glucose 8.85=0.48

Of original 32 subjects, 12 African American, remainder white

Of original 17 women postmenapausal

14 postmenopausal
11 taking HRT
16 taking oral contraceptives

4 dropouts: 3 personal reasons or time conflicts; 1 had gall bladder surgery

Summary of Results:

Sig main effect of fat level:

TC lower in high fat diets (p=0.0004)
TG lower in high fat diets (p=0.0001)

Sig main effect of fat source:

HDL-C lower in diets containing almonds
LDL-C lower in almond diets approached sig (p=0.06)

TC lowest in high fat high almond diet (approx 3 % lower); due primarily to decreases in HDL-C.

No effects on HDL subpopulations

Changes in serum lipids were greater than predicted from fatty acid comp of diet.

Various measures of glycemia: no main effect of fat source or fat level; sig interaction of source and level on fasting glucose and 2 hr glucose (p=0.006-0.008)

For more see Table 1

					P values
	High fat high almond	High fat control	Low fat almond	Low fat control	Main effect fat source	Main effect fat level	Interaction of fat source & level
Cholesterol (mmol/l)
Total	4.46 ± 0.14	4.52 ± 0.14	4.63 ± 0.14	4.63 ± 0.14	ns	0.0004	ns
LDL	2.51 ± 0.10	2.58 ± 0.10	2.53 ± 0.10	2.53 ± 0.10	0.06	ns	ns
HDL	1.13 ± 0.04	1.17 ± 0.04	1.13 ± 0.04	1.16 ± 0.04	0.002	ns	ns
Triglycerides (mmol/l)
	1.77 ± 0.18	1.68 ± 0.18	2.10 ± 0.18	2.0 ± 0.18	ns	0.0001	ns
LDL/HDL ratio
	2.30 ± 0.1	2.30 ± 0.1	2.30 ± 0.1	2.30 ± 0.1	ns	ns	ns
Total:HDL ratio
	4.1 ± 0. 1	4.0 ± 0.1	4.2 ± 0.1	4.2 ± 0.1	0.06	0.0002	ns
Fasting glucose (mmol/l)
	8.14 ± 0.49	8.73 ± 0.48	8.63 ± 0.48	8.00 ± 0.49	ns	ns	0.006
2-h glucose (mmol/l)
		15.2 ± 0.7	15.7 ± 0.7	15.2 ± 0.7	14.6 ± 0.7

Data are means ± SD, unless otherwise indicated.

[1] Other measures of glycemic control (fasting insulin, 2-hr insulin, and hemoglobin A1C, as well HDL subpopulation distribution showed no main effect of fat source or fat level or interaction of fat and level and are not shown in the table.

Author Conclusion:

Almonds produced changes similar to high mononunstaturated fat oils in diabetic patients. The lowest TC level occurred with the High Fat, High Almond diet. HDL-C also lowered with almond diets. No sig effect of fat source on LDL:HDL ratio.

Neither fat source or level had a sig effect on glycemic control.

Because changes in serum lipids were greater than predicted from fatty acid comp of diet., differences in intakes or fiber or other dietary components are suggested.

Funding Source:

Industry:

Almond Board of California

Commodity Group:

University/Hospital:

Louisiana State University

Reviewer Comments:

Given that the changes in TC were modest and primarily due to decreases in HDL-C, there seems to be very little advantage to the use of almonds with diabetics, especially in light of the risk of weight gain

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
	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
	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
	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
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
	1.	Was the research question clearly stated?	Yes
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
	1.1.	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
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	N/A
	1.3.	Were the target population and setting specified?	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.	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
	2.1.	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
	2.2.	Were criteria applied equally to all study groups?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	N/A
	2.3.	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
	2.4.	Were the subjects/patients a representative sample of the relevant population?	N/A
	3.	Were study groups comparable?	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)	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
	3.2.	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
	3.3.	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
	3.4.	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
	3.5.	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
	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.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	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
	4.2.	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
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	N/A
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.4.	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
	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.	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
	5.1.	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
	5.2.	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
	5.3.	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
	5.4.	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
	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.	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
	6.1.	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
	6.2.	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
	6.3.	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
	6.4.	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
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments 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
	6.7.	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
	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.	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
	7.1.	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
	7.2.	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
	7.3.	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
	7.4.	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
	7.5.	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
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	N/A
	7.7.	Were the measurements conducted consistently across groups?	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.	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
	8.1.	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
	8.2.	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
	8.3.	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
	8.4.	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
	8.5.	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
	8.6.	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
	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.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	N/A
	9.1.	Is there a discussion of findings?	N/A
	9.2.	Are biases and study limitations identified and discussed?	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.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	N/A
	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
	10.2.	Was the study free from apparent conflict of interest?	N/A