We'll since I got my Juicer recently I have juiced BEETS a lot and infact when I finish on here very shortly I will be juicing 4 large beets amongst other things. The only thing with large beet intake is the red colour in both the Urine and Stool but its no big deal although if you had a internal bleed it would make it harder to spot ;-)
One of my favourite drinks is
1 medium cooking onion
3 sticks of celery
3 large carrots
2 large beets
1" Ginger root
2" cucumber