No, introducing a diluted fruit juice is not the same as a solid fruit. The food tends to be a bit harsher on the tummy. My daughter is 13 months and she doesn't get juice often at all. I stick with milk. Introducing sweet juices can cause them not to want the milk/formula.
I would suggest talking with your pedi if you haven't already about introducing solids and fruit juice. Here is an excerpt from What to Expect the Toddler Years:
Yup, apple is the worst It's because there are hardly any nutrients in that juices and there is a lot of sugar (well, in all juices). So the amount of nutrients they get doesnt outweigh the amount of sugar. They do say that appie juice enriched w/ vitamin C is better if they are going to drink apple.
I haven't read that grape juice isn't good, but when I give grape, I usually get white peach or mixed with another kind
The BEST juices are (from "What to Expect in the Toddler Years")
Orange juice
Papaya juice
Pineapple juice
apricot nectar
mango juice
vegetable juice (v8 splashers are great!)
& "other" 100% fruit juice/nectars w/ the exception of apple.
Nectars are more expensive, but they are worth it in my opinion. You can find a lot of nectars in the juice section, in separate cans.
I've also found a lot of great juices in Organic Markets. AND - in the display case in the fruit section at the regular grocery store by the odwalla. I buy the ~large~ odwalla containers of lots of different juices.
I hope that helps. GOOD LUCK!