I found this reading particularly interesting, according to this article in the Netherlands Journal of Medicine, according to their review, most of the reasoning behind the "Diet for life" comes from the lack of evidence that those with PKU will do well as adults off the diet, as opposed to positive evidence that they do poorly. IOW just recently have we had a crop of adults both on and off the diet to study regarding pku, who had been on the diet during childhood, the time when majority of the brain myelinisation was taking place. (I believe this is referring to the myelin sheath around the axon of the nerves) that would be hypothesised to protect against the toxicity effects of the phenylalanine. Also, there is an interesting treatment I wasn't aware of... apparently, taking high doses of Large Neutral Amino Acids can crowd out uptake of Phe into the blood. Lastly on the off topic issues, they say, there was always the liver transplant option, however, as noted that requires immune suppressing drugs. (I recently had a discussion with a lady who recieved a new lung taking these drugs, she wore a mask over her mouth as she walked around similar to the cloth masks doctors wear as they are operating. I am aware that this can be very frustrating, even depressing for some people, as she informed me albeit she had decided to be particularly upbeat and keep a high quality of life. (and good for her!) This idea however gets my imagination running, would it be possible perhaps at some point in the future, to perhaps clone a particular organ with merely one genetic difference, for example the new liver from the same individual with a particular genetic alteration that the body would not reject? If this is ever the case, PKU could be effectively fixed, or 'cured' with surgery. Granted, cloning organs seems a little futurish, but at the same time, I don't think it is particularly wild, or somehow unrealistically speculative. As per the main thrust of the article, the normal PKU diet has been linked to a vitamin B12 deficiency due to the fact that this particular vitamin is mainly found in animal protiens, even those in their teens who tend to relax their diet may suffer from this particular deficiency due to the tendency to stay away from animal protiens. The PKU diet has also been linked to Osteoperosis apparently, albeit, the PKU formula, at least the one I am using contains both Vitamin D and calcium, as well as vitamin B12. A personal test regarding vitamin B12, My formula contains about .42 micrograms per 17.6 grams of powder, (scoop) and the reccomended daily intake is about 2 or 3 micrograms per day according to the Dietary Reference Intake of the Institute of Medicine. Now I generally take about 210 grams of powder per liter (and I run usually about 3 liters or 2 liters a day on the formula) To make this easier, there is about 2.4 mcg per 100 grams of the formula, so liberally and on a good day, (going with two micrograms as the reccommended daily intake and taking my 3 liters ) that is over 14 micrograms, about 7 times the daily recommended amount. Conservatively, on a poor day having only 2 liters, I am taking over 9 micrograms which would be 3 times the recommended daily amount. Qualifications: 1 Firstly those were rough estimates, I wasn't doing exact math. 2 There tends to be a powder residue at the bottom of the jugs that I do not consume, so I am not consuming all of the powder that I measure. 3 My estimate was on formula alone, I also take a daily multivitamin, alternating between one containing 6 micrograms, and one with 7.5 micrograms of B12. 4 Lastly, I tend to have energy drinks which contain vitamin B12, and the particular amounts tend to vary, not every day, and not always only once a day. At any rate, I am curious as to other folks with PKU, how much formula do you take, do you think you might be in danger of such a deficiency?