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Modulation of postprandial oxidative stress by rooibos (aspalathus linearis) in normolipidaemic individuals
Author(s)
Francisco, Ngiambudulu Mbandu
Date Issued
2010
Type
Thesis
Publisher
Cape Peninsula University of Technology
Abstract
Consumption of sucrose with a meal containing oxidised and oxidisable lipids cause an
increase in oxidative stress which is referred to as postprandial oxidative stress. The
modulating effect on postprandial oxidative stress by an antioxidant-rich beverage, fermented
rooibos (Aspalathus linearis) was compared to that of a commercial soft drink (soda). Both
study beverages contained sucrose and were consumed with a standardised fat meal.
The study consisted of two parts, a pilot study (Phase One) where participants
consumed either a standardised fat meal with water (control group n = 5) or a standardised fat
meal with a sucrose-containing commercial soda (treatment group n = 8) using a parallel
design, and the experimental study (Phase Two) where participants (n = 14) consumed the
standardised fat meal with the commercial soda (control group) or the rooibos beverage
(treatment group) using a crossover design. Specific analytical techniques and methods for
determination of plasma glucose, serum insulin, lipid profile, an inflammatory indicator (high
sensitive C-reactive protein), plasma antioxidant capacity, whole blood redox status and
plasma lipid oxidation biomarkers were used. Results from the pilot study indicated
significantly (P<0.05) higher postprandial levels of glucose in the control group at 4 hr and 6hr
postprandially. The inflammatory biomarker and triglyceride levels were significantly (P<0.05)
elevated in both groups when compared to their respective baselines. Results also showed the
total antioxidant capacity and total glutathione levels in the plasma of both groups to be
significantly (P<0.05) lowered when compared to the baseline values. The level of lipid
oxidation biomarkers in the plasma was significantly (P<0.05) higher at 2 hr, 4 hr and 6 hr post
time intervals for thiobarbituric acid reactive substances and 4 hr post time interval for
conjugated dienes in the participants consuming the standardised fat meal with soda when
compared to the baseline value, while this was reflected only at 2 hr post time interval for
thiobarbituric acid reactive substances, with the conjugated dienes levels being significantly
(P<0.05) lowered at 6 hr post time interval in the control group. No differences were shown on
inter group level for the pilot study. On inter group level, results from Phase Two showed
significant (P<0.05) lower levels of plasma glucose at 6 hr post time interval in the treatment
group when compared to the control group, with insulin levels being significantly (P<0.05)
higher in the control group at 4 hr post time interval.
increase in oxidative stress which is referred to as postprandial oxidative stress. The
modulating effect on postprandial oxidative stress by an antioxidant-rich beverage, fermented
rooibos (Aspalathus linearis) was compared to that of a commercial soft drink (soda). Both
study beverages contained sucrose and were consumed with a standardised fat meal.
The study consisted of two parts, a pilot study (Phase One) where participants
consumed either a standardised fat meal with water (control group n = 5) or a standardised fat
meal with a sucrose-containing commercial soda (treatment group n = 8) using a parallel
design, and the experimental study (Phase Two) where participants (n = 14) consumed the
standardised fat meal with the commercial soda (control group) or the rooibos beverage
(treatment group) using a crossover design. Specific analytical techniques and methods for
determination of plasma glucose, serum insulin, lipid profile, an inflammatory indicator (high
sensitive C-reactive protein), plasma antioxidant capacity, whole blood redox status and
plasma lipid oxidation biomarkers were used. Results from the pilot study indicated
significantly (P<0.05) higher postprandial levels of glucose in the control group at 4 hr and 6hr
postprandially. The inflammatory biomarker and triglyceride levels were significantly (P<0.05)
elevated in both groups when compared to their respective baselines. Results also showed the
total antioxidant capacity and total glutathione levels in the plasma of both groups to be
significantly (P<0.05) lowered when compared to the baseline values. The level of lipid
oxidation biomarkers in the plasma was significantly (P<0.05) higher at 2 hr, 4 hr and 6 hr post
time intervals for thiobarbituric acid reactive substances and 4 hr post time interval for
conjugated dienes in the participants consuming the standardised fat meal with soda when
compared to the baseline value, while this was reflected only at 2 hr post time interval for
thiobarbituric acid reactive substances, with the conjugated dienes levels being significantly
(P<0.05) lowered at 6 hr post time interval in the control group. No differences were shown on
inter group level for the pilot study. On inter group level, results from Phase Two showed
significant (P<0.05) lower levels of plasma glucose at 6 hr post time interval in the treatment
group when compared to the control group, with insulin levels being significantly (P<0.05)
higher in the control group at 4 hr post time interval.
Additional information
Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2010
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