Atkins answers these questions at length in his book, which I recommend you read or re-read.

Who told you? Your doctor? Ask for the citations from the medical journals that show this result occurs. (there are none, btw)

If you're worried, ask your doc to test your liver and kidney function with blood and urine tests. They'll doubtless be normal, and you'll have a baseline then, which you can continue to check every six months as you continue to LC. Checking your blood lipids is also a good idea--most people have improvement in cholesterol and triglycerides on LC, but a few rare people have increases--and it would also be best to know if you're one of them.

There's an interesting dicussion at: http://forum.lowcarber.org/showthre...=&threadid=6781

HTH