They found significant lowering of platelet aggregation - the blood's ability to clot - after a daily dose of juice for three weeks, according to the research letter in this week's JAMA (Aug 18;292(7):805-6).
Diabetic patients are more prone to blood clots, which contributes to their increased risk of developing cardiovascular complications, according to the authors. Blood clots can cause strokes, heart attacks and other life-threatening problems.
In the trial, 20 patients (aged 43-82) with type 2 diabetes drank either 250 ml of tomato juice or a placebo - tomato-flavoured drink - everyday for three weeks. They had no prior history of clotting problems and were not taking aspirin, nonsteroidal anti-inflammatory drugs or other medications that might influence clotting.
Platelet aggregation turned out to be significantly lower at the end of the trial for the group drinking tomato juice. There was no significant difference in platelet aggregation in the placebo group.
The researchers from the University of Newcastle in Australia do not yet understand why tomato juice reduces platelet aggregation, although other groups have reported similar results.
In the UK, nutraceutical firm Provexis is currently developing a water-soluble, concentrated tomato extract that can be added to drinks to make them beneficial for heart health. Trials on the extract, which contains none of the antioxidant lycopene, also reported to improve heart health, suggest that its different compounds inhibit blood platelet aggregation.Nobody at the company was available to comment on the Australian research.
Diabetes has already increased by one-third during the 1990s, due to the prevalence of obesity and an ageing population. There are currently more than 194 million people with diabetes worldwide but if nothing is done to slow the epidemic, the number will exceed 333 million by 2025, according to the International Diabetes Federation.
If the Australian research is corroborated by larger studies, it may also help other people with increased clotting tendency such as smokers and long-distance travellers, as well as those with heart disease, one of the most widely occurring chronic diseases in the world.