For as long as I can remember I have always been given one specific number in regards to my phe tolerance. I have always been told to consume X amount of phe—no more and no less. As you can imagine, and if you have PKU I am sure you understand, this leaves little room for flexibility. Sticking to this allowance so rigidly can mean adding high phe items to your formula if you are short some phe. Often times it also means not eating at the end of the day even when you are hungry.
For nearly two years my levels have been coming back ridiculously low; never higher than 1.7 mg/dl. As wonderful as this might sound sometimes low levels can cause just as many issues as high ones. For nearly two years I did exactly as I was told, and my phe levels continued to come back extremely low. Each time I was told that I need to get all of my phe in. No one ever thought ‘gee if her levels are coming back consistently low maybe her tolerance is actually higher than what we have been telling her.’ It never occurred to anyone on my medical team that maybe they were giving me the wrong number to aim for.
Have no fear though, because I eventually figured the problem out, albeit on my own. I just wasn’t okay with accepting that I was apparently doing something wrong and not complying with my diet. Being the stubborn person that I am after my level came back as 0.3 mg/dl and I was once again told I need to follow my diet better I decided enough was enough. To make a long story short I told my dietitian that I was increasing my phe intake, because clearly I needed more. I took things into my own hands and increased my tolerance by 300 mg of phe. Surprise! Surprise! My level came back as 3.6 mg/dl! That was the highest it had been in two years! After that I decided to be adventurous, and I increased my phe again. I did two blood tests at this higher allowance after my second increase, and both levels came back on the lower end of five.
Here’s my question: my level was good when I was consuming both 1200 and 1500 mg of phe, so why do I need to stick to one specific amount? I tend to aim closer to 1200 mg of phe, because I would prefer my levels to be lower. However, on days when I am still hungry late at night why can’t I go up to 1500 mg of phe since I know my level will still come back in a safe range? What’s wrong with eating a little more if you know your level will still come back okay? It just makes me wonder how high can others with PKU go before their levels get too high, and should I be thinking about my tolerance as 1200-1500 mg of phe each day rather than just 1200 mg of phe? This new thinking allows so much more flexibility in my diet. I wonder if we would have more people ‘complying’ with the diet if we thought about it in these terms and were able to find a lower and upper limit for phe and aim for something in the middle knowing that we could go slightly lower or higher if needed. This just seems more realistic then saying ‘eat this amount and only this amount.’ It seems more flexible for the busy lives that I am sure we all lead.
Any thoughts? Has anyone else ever decided to push the limits a little bit and think about their tolerance more as a range rather than one specific amount? Just curious if I am the only one who has found that they can actually tolerate more phe while still having good levels. I guess this is another reason why we need to be our own/our children’s advocates. If I hadn’t taken charge of figuring out what my tolerance really was I never would have made this discover, although the reason why I had to do the figuring out in this case is a blog for another day :|.
((Just to clarify my tolerance was 900 mg of phe. I admit increasing by 300 mg of phe was pretty ambitious, but this increase wasn’t nearly as insane as it would be for someone with a lower tolerance))