RE: Phenylalanine allergy(what do u know about it)
I have never herd of phenylalanine (phe) allergy. Only inborn errors of metabolism which are phe related, like PKU. However it is possible to be heterozygous PKU (ie one of the pair of genes is defective as opposed to the homozygous condition which is the classic case), and although this is a recessive gene, there maybe reduced activity and possibly 20% reduction in activity.
This manifests asymptomatically in most people for their whole life and they never even know they are heterozygotes, but in others it is evident with minor confusion, and other minor symptoms. However this is NOT an allergy!
I notice you refer to Pepsi Max - due to the aspartame which is 2 phe molecules bonded and the bond causes sweetness. However what you have read is just probably a load of anti-aspartame crap on the net (please everyone no debate on aspartame in this topic) - I'd ignor this.
However even heterozygotes are picked up with the Guthrie test which is one of the compulsary post natal tests where PKU is tested for, and if significant the infant may foollw a PKU diet for a few years. The chances are you had that test.
And you make the correct observation that all foods contain phe, so yes you'd have problems without aspartame
Odd but I think they're just scaremoungering you about aspartame from what you've read