Among the guidelines: generally Biotic Balance Probiotics Review it's best not to mix fruits with vegetables, or fruit juices with vegetable juices. There are exceptions, but fruits and vegetables are different classes of foods best kept separate. Apple is one exception to the rule of not mixing fruit with vegetable. My mother claimed there's something in apple that releases more of the nutrients in carrot. A friend suggested it might be the acid in apples that does it.
It's more work to chew and digest vegetables than to chew and digest fruits, and the soft fiber from fruits harbors valuable nutrients, so if we had to choose, it would be better to juice the vegetables and eat the fruits.
Fruits, and fruit juices, are among the best foods for us (I sometimes call them "Nature's candy"), but are best consumed on an empty stomach. If a fruit is consumed after a heavy food, digestion of the fruit is delayed and it will ferment or putrefy in the stomach, making it less useful.
Another consideration is that most foods of plant origin are most nourishing when not cooked. Cooking kills enzymes and denatures complex molecules, making their components useless for cell repair.
There are good juices available at stores, but they're never as invigorating and therapeutic as freshly-made juice, and may contain additives to increase shelf life that, though not toxic, don't really help the body either. If you're pressed for time, get the store-bought juice, but make the time occasionally to get freshly-made at home. It may aid assimilation also if a little water is mixed with fruit juice.
The juices of green leafy vegetables contain concentrated nutrients, but the juice tastes bitter or otherwise unpleasantly strong. This can be masked if the juices are mixed with other pleasanter juices. That's why some people recommend mixing the juices of wheat grass, spinach, or parsley with carrot and other milder-tasting, sweet juices. The body absorbs most easily that which it likes.
Many vegetables have a constellation of benefits. Just be careful in some cases. Green, red, and yellow bell peppers contain iron, and silicon which is good for the skin, and a few other varieties of peppers have their value. I found these exotic, http://binarymetabot.com/biotic-balance-probiotics-review/ funny-looking green peppers (okay, you know where this is going, but continue reading anyway), and decided they would make a nice juice. I juiced them along with carrots, celery, and one or two other things, and when I was finished, I took a big chug-a-lug...