EAL

EE: Ephedra (2005)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the magnitude of coffee-induced thermogenesis
To investigate the influence of coffee consumption on substrate utilization and urinary catecholamine excretion in lean and obese women by means of a respiration chamber over a period of 24 hr.

Definitions

Normalized body weight: 22.5 kg/m² times height squared. (NOTE: the mean BMI of 10 lean subjects studied was 22.5).

Inclusion Criteria:

Understand and give written consent
Healthy
Medications allowed: Contraceptives in 4 women.

Exclusion Criteria:

Refusal to consent
All Medications excluded except oral contraceptives.

Description of Study Protocol:

ANTHROPOMETRIC

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

CLINICAL

Monitored heart rate? Yes
Body temperature? Yes
Medications administered? None administered.

Resting energy expenditure

IC type: Room calorimeter and BMR measure (ventilated hood system)
Equipment of Calibration: NS
Coefficient of variation using std gases: No
Rest before measure (state length of time rested if available): Yes, BMR indirect calorimeter measure
Measurement length: respiration chamber 24 hr and mean of 15 min measurement intervals; indirect calorimeter: ns
Steady state: NS for indirect calorimeter
Fasting length: Yes
Exercise restrictions XX hr prior to test? Not specified
Room temp: Continuously monitored
Were some measures eliminated? No
Were a set of measurements averaged? Averaged 15-min in room calorimetry
Coefficient of variation in subjects measures? Cited intra-individual variability of 2.5%
Training of measurer? Most likely
Subject training of measuring process? Not specified.

DIETARY

Provided diet while in the room calorimeter

Intervening factor:

Data Collection Summary:

Outcome(s) and other measures

Measured REE [(VO₂, l/min), VCO₂ (l/min; ml/kg/min), RQ, ventilation (l/min)].
Urineary nitrogen, epinephrine and norepinephrine, and caffeine metabolites
Saliva samples of methylxanthines
Independent variables of weight, height, age, BMI,and fat-free mass, fat mass.

Blinding used: Yes (between caffeinated va. Non-caffeinated coffee).

Description of Actual Data Sample:

N=20, healthy, nonsmoking women (10 lean and 10 obese) aged 20-35 y
Moderate coffee drinkers: 1-4 cups/d.

Statistical tests

Comparing values of energy expenditure, RQ, subsrate oxidation, and heart rates during the two tests by means of Student’s paired t-test; ANOVA using Bonferroni’s correction; Meant ±SE; P value of <0.05 was considered significant.

Summary of Results:

ANTHROPOMETRIC

Lean Women	Mean±SEM
Age	24.0±1.0
Wt, kg	62.4±3.1
Ht, cm	167.3±1.7
BMI	22.35±1.02
Body fat, %	27.6±1.9
Fat-free body mass	44.8±1.3
Fat mass	17.7±1.9

Obese Women	Mean±SEM Range
Age	25.0±1.2
Wt, kg	80.2±2.6
Ht, cm	169.5±2.3
BMI	28.01±0.92
Body fat, %	36.1±0.8
Fat-free body mass	51.2±1.6
Fat mass	29.2±1.4

MEASUREMENT PROCESS

Number of measurements: Hourly measures reported
Length of measurements: Continuous in a room calorimetery; unknown in ventilated BMR hood measure
Steady state: NA room calorimetery; most likely yes in BMR ventilated hood measure
RQ: Overall RQ values were nearly identical during caffeinated vs. decaffeinated coffee administration in both groups of subjects; during sleep there was a tendency for the RQ to be slightly lower, but not significantly so with the caffeinated coffee in both groups of subjects.
Post absorptive conditions during the next morning, caffeinated coffee resulted in a modest fall in RQ which was stastistically-significant in lean and obese women.

MEASUREMENT TIMING

Sleep or rest: Yes
Physical activity: Yes-two physical activity periods prescribed
Food intake: Yes, Normal food usually consumed by subject, i.e., meat, green vegetables, fruits, and starchy and dairy products; 50% total energy was from CHO, 32% form lipids, and 18% from proteins.
Various times in the day: Yes, all day.

CAFFEINE AND RMR

Dosing: 5 cups of coffee consumed during the day, contained a dose of 4 mg caffeine/kg of actual body weight in the lean women; 4 mg/kg normalized body weight in the obese women
The net increase in 24-hr expenditure averaged 728±124 kJ/d (174±30 kcal/d) in lean and 410±175 kJ/day (98±42 kcal/day) in obese subjects, respectively representing an increase of 7.6±1.3% and 4.9±2.0% respectively.
In lean women, this effect was observed both during daytime and nighttime (sleeping period). No significant change was demonstrated during the sleeping period in obese. The increase in energy expenditure observed was not attributed to an increase in spontaneous physical activity.
Waking BMR measured on the next morning was not influence by caffeine consumption in either group of subjects.

Author Conclusion:

“In our study, ingestion of large amounts of caffeinated coffee increase 24-hour energy expenditure by an average of 7.6 and 4.9% in lean and obese women, respectively. This corresponds to the thermogenic effect of coffee.”
“Previous findings suggest that the magnitude of caffeine’s effect is variable and primarily attributed to differences in caffeine dosage, duration of calorimetric measurement, or in body composition of the subjects.”
Poehlmann et al, 1985: In ~12 non-trained individuals given 300 mg single doses, and RMR changed during 90 min had 0.085 kcal/kg/hr or 122 kcal/d.

[Analyst’s note: these citations did not meet study sorting criteria]

Dulloo et al, 1989: in 9 lean and 9 obese given 100 mg each 2 h for 12 h (total 600 mg) demonsted 109 kcal/24 h (+5.5%) in lean and 78 kcal/24 (+4.9%) in postobese subjects;

LeBlanc et al, 1985: In ~8 untrained individuals given 4 mg/kg as single dose had an increase of 0.07 kcal/kg/hr or ~103 kcal/24 hrs;

Astrup et al, Acheson et al, 1980 and Jung et al had sample sizes=8.

“This study provides the first evidence that the magnitude and the duration of the thermogenic effect of caffeine are less in obese women than in lean subjects.

[Analysts note: No limitations noted.]

Funding Source:

Reviewer Comments:

Strengths

“Study controlled for physical activity by having subjects record what they did every 5 minutes that was repeated on the follow-up visit”
Appropriate statistical analysis
Comprehensive discussion of how to measure urinary metabolites of caffeine and accurately associated with energy metabolism divided into daytime hrs (i.e., diurnal), exercise components, sleep and basal.
Diet provided by “experienced dietitians”
Provided a nice summary of comparative studies in discussion.

Generalizability/Weaknesses

“Generalizability to younger middle-aged women ; caution is due to allowance of 4 women on oral contraceptives which prolongs half-life of caffeine”
“Study biases include self-selection of subjects’ also on the first visit-recording of physical activity every 5 minutes most likely affected spontaneous physical activity"
An intervening variable not measured: did not specify if subjects were physically active or not prior to measures (i.e., trained or untrained)
"These are important variables on REE measurement accuracy: Indirect calorimetry measurements were not described with great detail and especially with reference to steady state.”

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?	No
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?	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?	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
	3.1.	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?	No
4.	Was method of handling withdrawals described?		No
	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?	No
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
	7.1.	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?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		No
	9.1.	Is there a discussion of findings?	N/A
	9.1.	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