A study conducted by the University of Oslo in Norway reveals that consuming two to three kiwifruit per day can work to thin the blood, reduce clotting and lower fat in the blood that can cause blockage, without negatively affecting cholesterol levels. In short, kiwifruit consumption has similar effects to the daily dosage of aspirin recommended by physicians to improve heart health, without the side effects.

"Platelet inhibitory drugs, such as aspirin, have been shown to reduce the incidence of myocardial infarction, stroke and death from cardiovascular disease," said Professor Asim K. Duttaroy, who spearheaded the research, at the Institute for Basic Medical Sciences at the University of Oslo, Norway. "Our study shows that consuming two or three kiwifruit per day for 28 days significantly reduced platelet aggregation [blood clotting] in human volunteers. Moreover, plasma triglyceride levels were also reduced in these volunteers."

In his research paper, published in the August 2004 issue of Platelets Journal, Duttaroy explains that certain phytonutrients, known as polyphenolic compounds, are widely distributed in fruits and vegetables. He notes that many of these have antioxidant as well as anti-thrombotic properties, which help prevent blood clotting. However, Duttaroy stresses that, although kiwifruit contains very significant amounts of antioxidants such as polyphenols and vitamins C and E, these were not included in the study.

"There is something in kiwifruit which creates an anti-platelet effect," said Duttaroy, who also notes that it appears the mode of action by which kiwifruit elicits this response is quite different from that of aspirin. "Further research on identification of the active compound is required for a more definitive conclusion on why kiwifruit consumption is so effective."

However, Duttaroy notes that one thing is clear: consuming kiwifruit is an effective way of inhibiting blood clotting and can improve cardiovascular risk profiles in healthy adults. Volunteers who participated in the study consumed two to three kiwifruit per day for a period of 28 days and experienced significant reductions in platelet aggregation when compared to controls. This is despite the fact that all the volunteers maintained their regular diets during the supplement period.

Furthermore, after a two-week wash out period in which the volunteers stopped kiwifruit consumption, their blood levels returned to pre-supplement period baseline.

Duttaroy explains that the dosage level in the study was restricted to two to three fruits per day to prevent any negative side effects. He also noted that it could be assumed kiwifruit consumption would not create any of those risk factors associated with aspirin such as stomach pain, excessive bruising or bleeding, nor does kiwifruit appear to disrupt the effects of any other medications.

"The results of our study are quite promising and are an indication that kiwifruit is an excellent choice for people trying to improve heart health through diet," said Duttaroy. "Further research is warranted, but for now, we would recommend kiwifruit consumption to help prevent or halt processes that lead to cardiovascular disease."

Duttaroy AK, Jøorgensen A. Effects of kiwi fruits consumption in human volunteers on platelet aggregation and plasma lipids in vitro. Platelets. 2004; 15:287-292.