The juice of blood oranges and blonde oranges appears to down-regulate blood clotting.
Italian researchers have performed what they claim is the first in vivo study showing that orange juice supports healthy blood clotting.
Abnormal blood clotting is likely a factor in various heart conditions, such as angina and thrombosis. At the same time, flavonoid-rich fruits such as citrus have shown heart-healthy potential in clinical trials and epidemiological studies. But data supporting a link between these fruits and blood clotting specifically is lacking.
At the Catholic University in Campobasso, Italy, researchers assigned 17 healthy subjects to drink blood orange juice or blonde orange juice for four weeks daily and in crossover fashion. Some of the orange juice samples were enriched with anthocyanins, to determine if these flavonoids would be especially responsible for any cardiovascular changes.
Orange juice appeared to prolong blood-clotting times in subjects-an effect the researchers deem to be beneficial. The juices also increased blood presence of tissue factor pathway inhibitor (TFPI), which regulates normal blood clotting. The type of orange juice-blood orange or blonde orange-did not influence results, and neither did enrichment with anthocyanin flavonoids. For this reason, the researchers speculate that juice components other than anthocyanins are responsible for the effect of orange juice on blood clotting.
The researchers prepared blood orange juice with Moro, Tarocco, and Sanguinello orange varieties, and blonde orange juice with Valencia, Navel, and Belladonna varieties.