Measures of atherosclerosis were reduced in hamsters with high cholesterol levels following consumption of the fruit and their respective juices, but the benefits were significantly greater for the juices, report researchers from the University of Montpellier 1 and 2, and the Victor Ségalen University in Bordeaux 2 in the journal Molecular Nutrition & Food Research .
"The present results clearly show for the first time that apple and purple grape prevent diet-induced atherosclerosis in hamsters, and that the fruit processing can have a major impact on the potential health benefits of fruit in pathological conditions," wrote the researchers, led by Jean-Max Rouanet.
"These findings, therefore, provide encouragement that fruit and fruit juices may have a significant clinical and public health relevance."
Atherosclerosis, or hardening of the arteries, is a major risk factor for cardiovascular disease (CVD), which causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy about €169bn ($202bn) per year.
New data Rouanet and co-workers took 40 male Syrian golden hamsters and randomly divided them into five groups.
The animals were fed a diet to promote the development of artery hardening, and supplemented with mashed apple or purple grape, or the same volume of apple juice or purple grape juice, or water (control group) for 12 weeks.
At the end of the study, they found that total cholesterol levels were significantly reduced in the animals fed the fruit-supplemented diets, by 11 per cent in apple group and 24 per cent in the apple juice group, and 30 per cent in the purple grape and 34 per cent in the purple grape juice group.
This was attributed to the reductions in levels of non-HDL cholesterol.
The juices also outperformed the fruit for protecting against atherosclerosis, measured by the aortic fatty streak lesion area or AFSA.
This value was reduced by 93 and 78 per cent for the purple grape juice and the fruit, respectively, and by 60 and 48 per cent for apple juice and apple, respectively.
"The results show for the first time that long-term consumption of antioxidants supplied by apple and purple grape, especially phenolic compounds, prevents the development of atherosclerosis in hamsters, and that processing can have a major impact on the potential health benefits of a product," stated the researchers.
Mechanism of protection Commenting on the underlying mechanism, Rouanet and co-workers stated that the greater potency of the purple grape and its juice may be due to the flavonoids content "Flavonoids, especially anthocyanins and catechins in purple grape and purple grape juice, generally have more hydroxyl groups than phenolic acids found in apple and apple juice," wrote the authors.
"This could explain why purple grape juice and purple grape displayed a better efficacy than apple and apple juice against early atherosclerosis.
"Nevertheless, these beneficial effects cannot only be attributed to their phenolic contents, but to the result of the action of different antioxidant compounds present in the fruits (vitamin C, carotenoids, polyphenols) and to possible synergistic and antagonist effects still unknown," they added.
Source: Molecular Nutrition & Food Research 2008, Volume 52, Pages 400-407, doi: 10.1002/mnfr.200700141 "Phenolics from purple grape, apple, purple grape juice and apple juice prevent early atherosclerosis induced by an atherogenic diet in hamsters" Authors: Kelly Décorde, P.-L. Teissèdre, C. Auger, J.-P. Cristol, J.-M. Rouanet