Effects of Cacao Liquor Polyphenols on Cardiovascular and Autonomic Nervous Functions in Hypercholesterolaemic Rabbits

Abstract

Many epidemiological studies have shown that polyphenols can reduce the risk of mortality from cardiovascular diseases. This study tested the hypothesis that cacao liquor polyphenols have the properties to restore the cardiovascular and autonomic nervous function in an animal model of familial hypercholesterolaemia. Male Kurosawa and Kusanagihypercholesterolaemic rabbits were housed in individual cages in a room where a 12-hr light:dark cycle (lights-on at 8:00 and lights-off at 20:00) was maintained. At 3 months of age, they were divided into two groups (standard diet and cacao liquor polyphenol) and the animals received 100 g of the respective diets per day and were provided with tap water ad libitum . Heart rate and blood pressure were measured by a telemetry system. To clarify the autonomic nervous function, power spectral analysis of heart rate variability, baroreflex sensitivity and autonomic nervous tone were measured. After 6 months of dietary administration of cacao liquor polyphenols, heart rate and blood pressure were lowered but plasma lipid concentrations were unchanged. The area of atherosclerotic lesions in the aorta in the cacao liquor polyphenol group was significantly smaller than that in the standard diet group. The high-frequency power of heart rate variability in the rabbits in the standard diet group was significantly decreased with ageing, but that in the cacao liquor polyphenol group was not different between short-term and long-term treatment. Moreover, cacao liquor polyphenols preserved parasympathetic nervous tone, although that in the standard diet group was significantly decreased with ageing. We conclude that cacao liquor polyphenols may play an important role to protect cardiovascular and autonomic nervous functions.

Effects of high flavanol dark chocolate on cardiovascular function and platelet aggregation

“…Heart rate was not increased with HFDC even though it had similar methylxanthine content, indicating that flavanols modulate sympathetic activation. In agreement with this, treatment for six months with a diet enriched in cocoa flavanols resulted in ≈25% lower heart rate in a strain of rabbits, which are genetically prone to hypercholesterolaemia, compared to age-matched control rabbits of the same strain [31]. This difference in heart rate was attributed to cocoa flavanols preventing the decline in parasympathetic function observed in control hypercholesterolaemic animals [31].…”

Cocoa Polyphenols and Their Potential Benefits for Human Health

“…Akita et al [68] studied the effect of dietary intake of cocoa polyphenols on heart rate, blood pressure, and plasma lipid concentrations. The area of atherosclerotic lesions in the aortas of the polyphenol-treated group was significantly smaller than in the control group.…”

A single dose of dark chocolate increases parasympathetic modulation and heart rate variability in healthy subjects

“…Additionally, baroreflex regulation improved. These authors also observed that parasympathetic modulation was preserved in the group that consumed cocoa liquor, differently from the control group, which experienced lower cardiac parasympathetic 22 modulation.…”