Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05282355 |
| Other study ID # |
AX2021 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
May 12, 2021 |
| Est. completion date |
July 2, 2021 |
Study information
| Verified date |
March 2022 |
| Source |
University of North Alabama |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Briefly, this study involved 2 trials: baseline (Trial 1) and post-astaxanthin intervention
(Trial 2). Both trials included participants completing a graded exercise test while
connected to a metabolic cart, to measure cardiorespiratory measures. Between trials,
participants were supplemented with either 12 mg of astaxanthin or placebo for 4 weeks. It
was hypothesized astaxanthin supplementation would increase rates of fat oxidation, while
decreasing carbohydrate oxidation and blood lactate accumulation.
Description:
METHODS
Experimental Design
The current study implemented a double-blind, between-subject study design with dependent
variables examined at multiple timepoints across each trial. To best observe changes in our
selected dependent variables, subjects reported to the laboratory on two separate occasions
(i.e. pre-post) following 4 weeks of astaxanthin supplementation.
Subject Approval from the Institutional Review Board was granted before recruiting subjects
(University of North Alabama, Institutional Review Board #: 20-21-071). Each subject
completed a Physical Activity Readiness Questionnaire, a medical questionnaire, and provided
their written and verbal consent to voluntarily participate in the present study. Inclusion
criteria for each subject included the following: 1) between the ages of 18-45; 2) free of
any cardiometabolic disease medication; 3) classified as overweight with a bodyfat percent of
≥ 20% for males and ≥ 25% for females; 4) and not currently pregnant or actively trying to
become pregnant. Additionally, subjects eliminated all dietary supplements at least two weeks
prior to the start of the study. Using G-Power software and changes to bodyfat as a primary
dependent variable, we determined a priori that 20 subjects would be sufficient to achieve a
desired power of 0.85, using a moderate-high effect size, and an alpha level set at 0.05.
Although 46 individuals were recruited, only 21 fit the inclusion criteria and were
randomized into either an astaxanthin or placebo group following their first visit. Due to
two participants withdrawing from the study as a result of health concerns not related to the
study procedures, 19 subjects were included in statistical analysis.
Preliminary Data During the first visit, subjects had their body composition assessed via
bioelectrical impedance analysis as well as height, mass, and blood pressure by the same,
trained investigator pre-post intervention. Following the collection of anthropometric data,
subjects who met inclusion and exclusion criteria were then asked to attempt to maintain
their current dietary habits for the duration of the intervention. Dietary intake was then
recorded pre-post intervention via 3-day food logs which consisted of 2 weekdays and 1
weekend day (i.e. Thursday, Friday, Saturday) to better reflect typical intakes. Subjects met
with the primary investigator and were instructed how to complete the food logs, regarding
quantity size and liquid amount estimations. Total energy intake, carbohydrate, protein, and
fats were analyzed for nutrient amounts using MyFitnessPal and were then used in statistical
analysis.
Experimental Trials (Trials 1-2) Following the collection of preliminary data, subjects
completed a graded exercise test on a cycle ergometer. Prior to the start of exercise,
subjects donned a heart rate monitor, established seat height, and were then connected to a
metabolic cart to record cardiorespiratory measures for the calculation of fat and
carbohydrate oxidation rates. Following connection to the metabolic cart, subjects sat
quietly for 5 min to collect resting oxidation rates ('rest'). Subjects then straddled the
cycle ergometer and began pedaling at an initial 30 W (females) or 50 W (males) for 5 min
(Stage 1). For each subsequent stage, resistance increased by 15 W and lasted for 5 min
(Stages 2-5). Following completion of 5 stages (90 W total for females and 110 W total for
males), resistance then increased by 15 W every minute, until volitional exhaustion was
achieved and the subjects' volume of oxygen (VO2) peak was recorded. The present protocol was
pilot tested (n = 6) prior to the initiation of the present study and determined by the
investigative team as acceptable for non-exercising and overweight individuals to all
complete with minimal fluctuation in heart rate (±2 bpm) during the last min of each stage.
During the last 30 s of each stage, subjects had their finger pricked (detailed further
below) for the measurement of capillary lactate and glucose. Furthermore, heart rate and
overall ratings of perceived exertion were recorded at the end of each stage. Due to the
collection of oxidation rates, subjects were required to fast for 5 h and avoid alcohol
consumption for 48 h prior to each trial. Subjects were also required to abstain from
caffeine on the day of testing and avoid strenuous lower body exercise 48 h prior to each
experimental trial.
Fat and Carbohydrate Oxidation Rate Measurements All cardiorespiratory measures were averaged
from expired gas collected by the metabolic cart. The first 240 seconds of each stage were
excluded and the remaining 60 seconds were recorded using breath-by-breath data and averaged
in two, 30-second cycles. Stoichiometric equations were utilized when measuring total fat and
carbohydrate oxidation rates (g · min-1). These equations assumed protein oxidation rates
were negligible (~5%) and therefore, were ignored.
Fat oxidation (g ∙ min-1) = 1.67 VO2 (L ∙ min-1) - 1.67 VCO2 (L ∙ min-1) Carbohydrate
oxidation (g ∙ min-1) = 4.55 VO2 (L ∙ min-1) - 3.21 VCO2 (L ∙ min-1)
Lactate and Glucose Concentration Measurement At the end of each stage during the graded
exercise test, a sample of capillary blood was collected from the subjects' finger. The
subjects had their finger wiped with an alcohol swab and then allowed to air dry prior to a
prick with a self-withdrawing safety lancet. The first drop of blood was wiped away and the
second drop of blood was analyzed using a Lactate Plus Meter Blood Analyzer. Additionally,
capillary blood glucose concentrations were analyzed using a Precision Xtra Blood Glucose
Analyzer
. Supplementation Schedule The supplementation intervention was scheduled following Trial 1
and took place for 4 weeks before subjects reported back to the laboratory for Trial 2.
Subjects were randomly assigned to supplement with either 12 mg of encapsulated astaxanthin
(astaxanthin and sunflower oil; 6 mg per capsule) or placebo (sunflower oil only) daily in
the form of two gel capsules. Subjects were advised to ingest one capsule in the morning and
one capsule at night. Both the astaxanthin and placebo pills were similar in appearance (red
and oval shaped) and size and all supplements were provided by AstaReal.
