Consumption of cactus pear fruit, or Opuntia ficus indica, was found to positively affect the body's redox balance, decreasing oxidative damage to lipids, and improving antioxidant status.
Meanwhile, supplementation with vitamin C at a comparable dosage "enhances overall antioxidant defense but does not significantly affect body oxidative stress," report the researchers from the University of Palermo in the 1 August issue of the American Journal of Clinical Nutrition (vol 80, no 2, pp391-395).
The team said that components of cactus pear fruit other than antioxidant vitamins may play a role in the observed effects. The fruit is known to contain high levels of polyphenolic compounds called betalains, which give the fruit the purple-red and yellow-orange colours. Their free radical scavenging activity has been demonstrated in in vitro studies.
The researchers compared the effects of a twice-daily dose of 250 g fresh cactus fruit pulp with 75 mg vitamin C on biomarkers of oxidative stress in a randomized, crossover study on 18 healthy volunteers.
The supplements were fed for two weeks, with a six-week washout period between the treatments. Before and after each treatment, the researchers measured biomarkers of oxidative stress, antioxidant activity and plasma levels of vitamins A, E, and C.
Both treatments caused comparable increases compared with baseline in plasma concentrations of vitamin E and vitamin C but vitamin A and antioxidant activity did not change significantly.
After supplementation with cactus pear fruit, several different markers of oxidative stress decreased significantly while supplementation with vitamin C did not affect any marker of oxidative stress.
Researchers from Tulane University and the University of California, San Francisco recently reported that an extract of the Opuntia ficus indica plant lessened hangover symptoms such as nausea and a dry mouth in a group of young adults.
Opuntia cactus powder is also used in supplements and increasingly in healthy beverages in the US.