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| Date: 03-15-2016 | HC# 091535-540 |
Kardum
N, Milovanović B, Šavikin K, et al. Beneficial effects of polyphenol-rich
chokeberry juice consumption on blood pressure level and lipid status in
hypertensive subjects. J Med Food. October
2015;18(11):1231-1238.
Epidemiological
studies have found the intake of foods rich in antioxidants to be associated
with lower incidences of cardiovascular disease. Among plant foods, berry
fruits tend to have the greatest antioxidant potential due to their high
polyphenol content. Compared with other berries, chokeberry (Aronia melanocarpa, Rosaceae) has a significantly higher
content of polyphenols and, thus, higher antioxidant activity. The goal of this
study was to evaluate the effects of daily chokeberry juice consumption on
blood pressure (BP), biochemical parameters, and function of the autonomic
nervous system in subjects with high normal BP or grade I hypertension. In a
previous study conducted by these authors, chokeberry juice consumption had a
positive impact on cellular oxidative status in healthy subjects by stimulating
antioxidant enzyme activities and improving membrane fatty acid composition.1
The
current study was conducted at Clinical Hospital Center Bezanijska Kosa in Belgrade,
Serbia. Twelve men and 11 women (mean age, 47.5 ± 10.4 years) not using
antihypertensive drugs were included. The subjects had high normal BP or grade
I hypertension according to the European Society of Hypertension and the
European Society of Cardiology classification, meaning a systolic BP (SBP) of
130-159 mm Hg and diastolic BP (DBP) of 85-99 mm Hg. The subjects were
instructed to drink 200 mL of polyphenol-rich organic chokeberry juice (donated
by Conimex Trade d.o.o.; Belgrade, Serbia) daily for 4 weeks as part of their
usual diet. The chokeberry juice contained 386 ± 9.7 mg of total phenolics,
expressed as gallic acid, per 100 g. Results of phenolic content analyses
revealed cyanidin 3-galactoside to be the most abundant anthocyanin (107.6 ± 7.8
mg per 100 g).
At
baseline and after 4 weeks of treatment, the subjects underwent blood draws for
biochemical analysis, as well as assessment of the autonomic nervous system and
hemodynamic status. Short-term heart rate variability (HRV) and 24-hour electrocardiogram
(ECG) monitoring with long-term HRV analysis were included in the assessment. Biochemical
parameters included cardiovascular disease markers such as lipid profile,
C-reactive protein (CRP), and glucose levels.
After
4 weeks, there were reductions in total cholesterol, low-density lipoprotein
cholesterol (LDL-C), and triglycerides; however, the only significant reduction
was in the triglyceride levels (P<0.05). Markers of kidney and liver
function remained within normal limits during the study. Significant reductions
(P<0.05) were also observed in the average 24-hour and awake SBP and DBP, and
24-hour pulse pressure.
Because
the autonomic nervous system plays a central role in BP regulation, the authors
divided the subjects into 2 groups based on sympathetic or parasympathetic
activity. The authors used low-frequency power (LF) and high-frequency power
(HF) analysis to assign subjects into either the sympathetic (n=12) or
parasympathetic (n=11) group. In the sympathetic activity group, a
statistically significant reduction (P<0.05) was observed in 24-hour and
awake SBP, awake DBP, standard deviation (SD) of awake SBP, and awake pulse
pressure. No significant changes were seen in the parasympathetic activity group.
Short-term
HRV analysis revealed significant decreases in both very low-frequency power (P<0.05)
and HF (P<0.01) after 4 weeks of chokeberry juice consumption. Long-term HRV
analysis revealed a decreasing effect (P<0.01) on the SD of normal RR
intervals. The RR interval, or 1 complete cardiac cycle, is used to assess
ventricular rate. No significant changes were observed in 24-hour ambulatory
ECG recordings after 4 weeks. The authors point out that measures of HRV, particularly
the RR interval, could be used as independent indicators for risk of coronary
deaths.2 After 4 weeks, CRP levels were reduced, but not
significantly.
These
findings agree with previously published data, which show significant
reductions in DBP and SBP after chokeberry consumption.3,4
The
authors attribute the beneficial effects of chokeberry juice consumption on BP
levels to its high polyphenol content, which reduces vascular oxidative stress
not only by directly interacting with reactive oxygen species, but also by
stimulating endogenous antioxidant defense. Other cardioprotective effects of
polyphenols could be exerted through improved endothelial function, based on an
increase in endothelium synthesis of nitric oxide.
In
this study, the consumption of polyphenol-rich chokeberry juice improved BP
levels and lipid status in subjects with pharmacologically untreated high
normal BP or grade I hypertension. And because a greater decrease of BP was
noted in subjects with prevalence of sympathetic activity, the use of chokeberry
juice to prevent cardiovascular disease could be more effective in subjects at
higher risk. The study was limited by small sample size and short duration.
—Shari Henson
References
1Kardum N, Takić M,
Šavikin K, et al. Effects of polyphenol-rich chokeberry juice on cellular
antioxidant enzymes and membrane lipid status in healthy women. J Funct Foods. 2014;9:89-97.
2Bigger JT Jr, Fleiss
JL, Steinman RC, Rolnitzky LM, Schneider WJ, Stein PK. RR variability in
healthy, middle-aged persons compared with patients with chronic coronary heart
disease or recent acute myocardial infarction. Circulation. 1995;91(7):1936-1943.
3Skoczyńska A, Jędrychowska
I, Poręba R, et al. Influence of chokeberry juice on arterial blood pressure
and lipid parameters in men with mild hypercholesterolemia. Pharmacol Rep. 2007;59(Suppl 1):177-182.
4Naruszewicz M, Łaniewska
I, Millo B, Dłużniewski M. Combination therapy of statin with flavonoids rich
extract from chokeberry fruits enhanced reduction in cardiovascular risk
markers in patients after myocardial infraction [sic] (MI). Atherosclerosis.
2007;194(2):e179-e184
