Benefits
Water elimination and lighter-feeling legs
Nexira reports an unpublished randomized, double-blind, placebo-controlled trial in 47 women given 2 g a day for 28 days, with more water elimination, better body shape and less heaviness and swelling in the legs. No numbers have been published, so this cannot be checked. In rats, the extract raised urine volume over 7 days without changing urinary sodium or potassium. Not for diagnosed edema.
Antioxidant status (prickly pear fruit)
In a randomized crossover study, 18 healthy adults ate 250 g of fresh prickly pear pulp twice a day for 2 weeks. Malondialdehyde fell by about 75% and 8-epi-prostaglandin F2-alpha by about 30%, while 75 mg of vitamin C twice a day did not significantly change any oxidative stress marker. This was whole fruit, not the Cactinea extract.
Blood pressure and total cholesterol (pooled Opuntia trials)
A meta-analysis of five randomized trials of various Opuntia ficus-indica preparations found significant reductions in blood pressure, total cholesterol, body mass index and percentage body fat, but no significant change in body weight. The trials varied in design and reporting quality, and none of them tested Cactinea.
Mechanism of action
Betalain pigments
Prickly pear fruit contains vitamin C and betalain pigments such as betanin and indicaxanthin, which scavenge free radicals in laboratory tests. In the human fruit study, vitamin C alone did not reproduce the drop in oxidative stress markers, so the authors suggested other fruit components are involved.
Higher urine output in rats
Given at 240 mg/kg a day for 7 days, the extract increased urine volume in rats compared with untreated rats, without changing urinary sodium, potassium or uric acid concentrations, and it raised blood glutathione peroxidase. This has not been measured in a published human study.
Inflammation markers
In a crossover trial of a different Opuntia ficus-indica extract taken before drinking alcohol, C-reactive protein was 40% higher after placebo than after the extract, and the authors linked its effects to lower production of inflammatory mediators.
Acacia gum carrier
Nexira uses acacia gum as the carrier for the dried fruit extract.
Clinical trials
Randomized, double-blind, placebo-controlled parallel-group trial of 2 g a day for 28 days, run in 2009 and never published. (Nexira, unpublished 2009 trial described on the Nexira website)
47 women.
Nexira states that the extract improved water elimination, body shape and sensations of heavy, swollen legs versus placebo. No data, effect sizes or statistics are available, and no independent group has repeated the trial.
Randomized crossover trial: 250 g of fresh fruit pulp or 75 mg of vitamin C twice a day for 2 weeks each, with a 6 week washout. (Tesoriere et al. 2004, The American Journal of Clinical Nutrition)
18 healthy volunteers.
After the fruit, plasma 8-epi-prostaglandin F2-alpha fell about 30% and malondialdehyde about 75%, the glutathione ratio shifted toward the reduced form and LDL hydroperoxides nearly halved, compared with baseline. Vitamin C did not significantly affect any oxidative stress marker. Both raised plasma vitamins C and E. Whole fruit was tested, not Cactinea.