By Stephen Daniells,
Dietary supplementation with polyphenols from red wine may slow the decline in vascular function associated with age, suggests a new study with rats.
Animals fed red wine polyphenols were found to have less dysfunction of the endothelium – the cells lining blood vessels – as well as an improved ageing-related decline in physical exercise, according to findings published in Biochemical and Biophysical Research Communications.
Endothelial function naturally and gradually decreases over time, and it has been linked to range of age-related diseases, especially cardiovascular disease (CVD).
“The present findings indicate that regular intake of red wine polyphenols starting at a young age reduces the endothelial dysfunction and the impaired physical exercise capacity at an advanced age,” report researchers from the University of Strasbourg in France.
Commenting on the potential mechanism, the French researchers propose that the apparent benefits were linked to a reduction in vascular oxidative stress, which may occur by inhibiting the enzyme NADPH oxidase. The enzyme generates superoxide and has been linked to the hardening of arteries and an increased risk of heart disease.
Red wine and heart health
The heart health benefits of red wine led to the coining of the phrase ‘the French Paradox’ in 1992 by Dr Serge Renaud from Bordeaux University to describe the low incidence of heart disease and obesity among the French, despite their relatively high-fat diet and levels of wine consumption.
The focus of the French Paradox then shifted towards resveratrol, a powerful polyphenol and anti-fungal chemical, as being the bioactive compound in grapes and red wine.
The subject has been debated extensively, and the new study contributes to our understanding of the subject.
Led by Valérie Schini-Kerth, the researchers divided male Wistar rats into four groups: Group 1 received 3 percent ethanol (control); groups 2 and 3 received 25 or 75 mg of red wine polyphenols per kg of body weight per day in 3 percent ethanol; the final group received the antioxidant and NADPH oxidase apocynin at 100 mg/kg/day in 3 percent ethanol. The study started with rats aged 16 weeks and continued until they were aged 40 weeks.
Results showed that both polyphenol groups and the apocynin group showed significantly lower levels of aging-induced vascular oxidative stress in the endothelium.
Furthermore, the high dose polyphenol group, but not the lower dose group, displayed a lower decline in physical performance, compared to the control animals. When tested on a treadmill, the control animals had an endurance capacity of six minutes, while the high dose group had a capacity of 9.9 minutes, and the apocynin group had a capacity of 10.9 minutes.
“A major novel finding of the present study is that regular intake of red wine polyphenols by young rats prevented aging-induced endothelial dysfunction,”wrote the researchers. “The beneficial effect of red wine polyphenols is explained best by their ability to maintain oxidative stress in the old arterial wall to a level similar as that observed in young arteries.
“The protective effect of red wine polyphenols may be due to their direct antioxidant properties but possibly also to changes in the expression pattern of endogenous pro-oxidant and antioxidant enzymes in the arterial wall,” they added.