EAL

EE: Ephedra (2005)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine whether the lipolytic effect of caffeine is associated with increased lipid oxidation or futile cycling between triacylglycerol and free.

Definitions

Steady state: Stable VO₂ and VCO₂ measures.

Inclusion Criteria:

Understand and give written consent
Healthy.

Exclusion Criteria:

Refusal to consent
Unwell.

Description of Study Protocol:

ANTHROPOMETRIC

Ht measured? NS
Wt measured? NS
Fat-free mass measured? NS.

CLINICAL

Monitored heart rate? No
Body temperature? No
Medications administered? NS.

Resting energy expenditure

IC type: Ventilated hood
Equipment of Calibration: Yes; per protocol
Coefficient of variation using std gases: Per protocol
Rest before measure (state length of time rested if available): Baseline after IV set up last 30 minutes of one hour measure for baseline; post-caffeine was 4 hour
Measurement length: 30 min
Steady state: Stable levels of oxygen and CO₂ achieved
Fasting length: ON
Exercise restrictions XX hr prior to test? Not specified
Room temp: Not specified
No. of measures within the measurement period: NS
Were some measures eliminated? Yes, initial unstable measures
Were a set of measurements averaged? Yes, 1-minute measures
Coefficient of variation in subjects measures? No
Training of measurer? Most likely.

DIETARY

Subjects ate “habitual diet.”

Data Collection Summary:

Outcome(s) and other measures

Measured REE [(VO₂, l/min), VCO₂ (l/min; ml/kg/min), RQ, ventilation (l/min)].
C13 plamitate to trace lipid oxidation
Blood urea, Caffeine, and paraxanthine
Breath samples of
Independent variables of weight, height, age, BMI,and fat-free mass, fat mass

Blinding used: No.

Description of Actual Data Sample:

N=9 males; mean 23.1±2.6 y.

Statistical tests

Means ±SEMs, repeated-measures ANOVA. Variables used were condition (baseline or stimulated state), treatment (caffeine + Beta blocker)], and subject (subjects 1-8). Pairwise differences between the means; P values <0.05 was considered significant.

Summary of Results:

ANTHROPOMETRIC (Men)

Wt, kg: 77.1±7.4
Ht, cm: 174.4±6.0
BMI: 25.5±3.1
Body fat, %: 14.5±3.1
Lean body mass, g: 65.8±4.9
Fat mass, g: 11.3±3.1.

MEASUREMENT PROCESS

Number of measurements
- Continuous RMR measure for 4 hr following normal caffeine ingestion;
- Continuous RMR measure for 210 minutes following propanol infusion and caffeine and then 30 minutes after propanol infusion stopped.
Length of measurements: Up to 4 hours for each arm
Steady state: Yes, but definition vague
RQ: Yes.

MEASUREMENT TIMING

Sleep or rest: Overnight at facility
Physical activity: Not specified
Food intake: Normal diet
Various times in the day: No.

INDIVIDUAL CHARACTERISTICS

Only caffeine and delayed caffeine use were abstracted; Dosage was caffeine (5 mg slow-release caffeine/kg + 5 mg caffeine/kg ); Since mean weight was 77.1 kg; Estimate average caffeine dose to be 385.5 mg caffeine and 385 5mg slow-release caffeine; total 771 mg caffeine.

CAFFEINE & RMR RESULTS:

[Analyst’s note: The response of caffeine administered with Beta-blocker (Propanolol) is not abstracted onto worksheet.]

There were significant treatment (P<0.001) and condition (P<0.001) effects and significant treatment-by-condition interactions (P<0.001).
After caffeine administration, energy expenditure increased significantly (P<0.001) and reached a value of 1.55±0.038 kcal/min during the last hour of the test which was significantly higher than the corresponding values obtained after administration of placebo (1.4±0.04 kcal/min; P<0.001)
The thermic effect of caffeine, ie. The mean energy expenditure during the last hour of the test expressed as a percentage as a percentage of fasting energy expenditure was 13.3±2.2% which was greater than the thermic effect of placebo (2.0±0.05%; P<0.001).

Author Conclusion:

As stated by the author in body of report:

“In our study, the results show not only that caffeine stimulates resting energy expenditure but that his increased cellular thermogenesis is accompanied by an increase in fatty acid turnover and lipid oxidation.
“Nonoxidative lipid turnover (triacylglycerol hydrolysis and reesterification) is far greater than the increase in oxidative lipid disposal, which indicates that large increase in turnover rate is necessary to cause a small increase in lipid oxidation.”
“The effect of caffeine on lipid and energy metabolism appears to have both sympathetic and nonsympathetic components.”
“In agreement with the results of previous studies (Acheson KJ, Zahorsk-Markiewica B et al, Caffeine and coffe: their influence on metabolic rate and substrate utilization in normal and obese individuals. Am J Clin Nutr. 1980;33:989-997; sample size n=10) and Arcerio (see abstracted Evidence Analysis Worksheet on ff), caffeine ingestion increased energy expenditure (~13%) and lipid turnover and oxidation.

Funding Source:

Reviewer Comments:

[Not used in Caffeine Conclusion Statement due to slow-acting caffeine was used and not available to consumers.]

Strengths

Researcher uses experience from 20 years ago to further advance substrate oxidation initiated by caffeine.
Appropriate statistical techniques
Continuous IC measures for four hours.

Generalizability/Weaknesses

Generalizable to healthy, lean males; Cannot be applied to overweight or obese males; Unclear of ethnicity
“Study biases include small sample size;, convenience sampling, and do not mention blinding of researchers with regards to placebo vs. caffeine pill ingestion; No blinding when propanolol was administered
Use of IC methodology referenced to a methodology used in burn patients receiving the same beta-blockade. Unable to determine if steady state conditions in healthy males reached.
These are important variables on REE measurement accuracy were not specifying exercise restrictions the night before (given the leanness of subjects).”
“Intervening variables include a medical procedure of inserting venous catheters immediately before beginning baseline RMR measure.”

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?		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?		No
	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?		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.)	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?		No
	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?		No
	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