They oxidize the food and yes, that destroys some nutrition.
One alternative is to use those small blender cups that go upside down, and fill them up to avoid some of the oxigenation. AV used a combination of different items to create the perfect glass jar size rather than the default plastic style, I can tell you what his trick was if you're interested.
Another alternative is simply to blend for shorter periods of time.
And yet another alternative is to pulse only. However, if you're standing there pressing the pulse button yourself, then you're getting all the electromagnetic radiation in your hand, which is arguably worse than the oxigenation itself. There are some high tech blenders that allow you to set it to pulse and walk away while it pulses.
It would be interesting if someone came up with a slow mixer to blend foods, similar to how slow masticator juicers work at a speed of 80RPM or so, where food is crushed and squeezed rather than blended at super high speeds.
I was looking for alternatives and found this, I have no idea if it works as well as it's advertised to work, and I'm a bit skeptical of it's ability to blend bigger chunks of food with less liquid, but it's an interesting concept nonetheless.
https://www.youtube.com/watch?v=3c5IRyvwAwk
