"Is it safe?  Is it safe?"  Why am I having visions of Laurence Olivier hovering over a squirming Dustin Hoffman??  LOL

Some folks have had questions about ketosis and whether or not it is safe for the kidneys.  They may have heard that ketosis is dangerous, or that it's "hard" on the kidneys.

KETOACIDOSIS

Well, there is a difference between being "in the pink" - in ketosis, that is spilling ketones into your urine, residue from fat metabolism, and a serious condition called KETOACIDOSIS.  Ketosis is perfectly safe. It shows that you are burning fat, and not "carbing up".  This is different than ketoacidosis.

Ketoacidosis, is a very dangerous condition - it is usually indicated by VERY dark urine, and frequent purple readings on ketostix can indicate that you might be edging towards ketoacidosis (that's what they're really intended for!). 

Other indicators are the same as the physical indicators of dehydration - such as sunken eye sockets, swollen tongue, etc. 

By not drinking enough water, to flush the ketones that are being produced by the breaking down of fat, the body is unable to clear the ketones through the kidneys, and they can build to toxic levels and eventually lead to ketoacidosis.

Some people have the idea that "purple" is best, it's not, really - if you are consistantly getting a dark purple reading on your ketostix, and your urine is very dark - drink water, drink lots of it, and make sure you keep doing it every single day!! 

Drink at least 8 8-oz. glasses of water a day, and add a glass for every 25 lbs. you want to lose. DO NOT skimp on your water!!!!

Ketosis

This is the term for the process by which your body burns fat for fuel. Excess ketones are shed through the breath and in the urine.  Thus we have "ketone" breath, that some complain of.  This is easily resolved by chewing parsley, taking low carb breath mints, such as Smints, or brushing your teeth more often.  Dr. Atkins suggests testing for ketones in your urine, as a way of monitoring your progress.  

Don't be confused by talk of attaining "high" levels of ketosis and "deep purple" readings on the test strips. Once you're past the initial stage, most ketogenic LC plans will have you maintaining a constant but light level of ketosis. Even a "trace" reading is perfectly fine. 
Caution: If you're getting consistently very high readings, it's likely that you're not drinking enough water!

There are extensive listings regarding the "Ketogenic Diet" available on the Internet. (see links below) This is a diet prescribed for children with epilepsy, and is one of the oldest forms of therapy for this. I have read nothing about kidney damage related to ketosis in anything discussing this long and very successfully used diet.

Kidneys

Despite dire warnings, low-carb dieters do not seem to be keeling over from kidney problems. According to Dr. Atkins "No study has ever shown that people with normal kidney function exhibit any kidney problems on a high protein diet." Dr. Bernstein's book suggests that for diabetics, a properly controlled LC diet can even reverse kidney damage if it has not progressed too far. BUT, anyone with impaired kidney function should work with their doctor if they wish to try starting a lowcarb diet plan.

The area of high protein diets harming the kidneys is discussed in the "Journal of Nutritional Biochemistry" in 1995 and in the "Archives of Internal Medicine" in 1987. 

The former found that weightlifters who consumed excessive amounts of protein actually experience IMPROVED kidney function, and the later cites a research paper by Dr. Miriam Blum. Her research team compared high protein eaters to vegetarians, and found no difference in the natural aging process of the kidneys from one group to the other.


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Useful links on these topics:

http://www.ivillagemoneylife.com/fitness/experts/wlcoach/diet/qas/0,5090,18822,00.html

http://www.ivillage.com/fitness/experts/nutrimd/diet/qas/0,5090,5776,00.html

http://www.stanford.edu/group/ketodiet/

http://www.yt.sympatico.ca/Contents/Health/HEALTHYWAY/feature_nut3.html

http://www.stanford.edu/group/ketodiet/ketolit.html

http://www.jneurochem.com/issues/v69n2/v69n2p682.html