|Bird damage to nopal fruit called tunas in Mexican Spanish.|
Bird damage to cactus fruits is a good indicator tunas will
have good quality for human consumption. Tunas are high
in vitamin C.
A. Sorry to hear about your health concerns. The fruit would definitely be edible BUT not all Opuntia type cacti are as desirable as others for eating. The nopal cactus is also a “bunny ears” type but the fruit may not be as edible.
In some nopal cactus the sugar content may be as high as 30% which would rival fully mature wine grapes in sugar content. I normally will get about 16 to 18% which would rival a really good apple or peach.
A good indicator about whether it is going to be a good one is how the birds use the fruit. If birds are devouring the fruit then it will have some really good characteristics for human consumption. If the birds leave it alone, well… it probably has low desirability.
So look for bird damage to ripe fruit. Nopal or bunny ears cactus is selected for edibility so not all of these cacti are as desirable as others for food.
As far as health benefits goes, I have heard that it is of course high in fiber content, helps to lower cholesterol, helps reduce high blood pressure, is normally high in Vit C (reds are the best) but I have not heard anything about auto immune system benefits unless you want to count the Vit C content as part of that. But I am no health expert and you would probably have to do some digging in the literature online for that information. There are some good papers out of the University of California with the University of Sonora on this subject in the past.
Also if you want to start growing cactus for food you will have to alter your irrigations to push new succulent growth starting in about March. A deep irrigation every two weeks is all that is needed along with a fertilizer application high in nitrogen in the spring. Compost applications at the time of planting and on the surface each year will also help push new growth.