Onions to help the heart, more evidence

More evidence to support the view that the dietary intake of onions is of benefit to cardiovascular health and may inhibit human platelet aggregation was released recently following research by American scientists. Researchers at the University of Wisconsin-Madison studied 11 dogs with mechanically damaged and stenosed coronary arteries. Periodic platelet-mediated thrombus formation followed by embolisation produced cyclic flow reductions (CFR). In five dogs, 0.09 ± 0.01 mL/kg onion juice administered intravenously abolished CFR within 20 min. This was followed by a 60 ± 14% (P = 0.002) reduction in collagen-induced ex vivo whole-blood platelet aggregation. Six dogs were given 2.0 g/kg raw onion homogenate intragastrically. CFR were eliminated within 2.5-3 h in five of the dogs. This was accompanied by a 44 ± 24% (P = 0.04) reduction in ex vivo aggregation. According to the scientists the findings suggest that the consumption of raw onion may help prevent platelet-mediated cardiovascular disorders. However, in vitro incubations of onion juice demonstrated that the platelet inhibitory response was significantly greater in dog blood than in human blood. Full findings are published in the October issue of the Journal of Nutrition 2001;131:2619-2622.