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Likely it was the diet. My husband was diagnosed as an infant, but was
told he'd outgrow it and went back to a regular diet at age 6. His adult
teeth are bad. During his remission he must have absorbed enough to
live, but not calcium.Also being lactose intolerant milk meant cramps
and was avoided. I've read where if your body doesn't get enough calcium
it will leach it out of your bones and teeth. We figure this is the
problem with my husbands, and sound like the same for your mum. The diet
was good enough to keep her alive, but she wasn't absorbing everything.
Malt is not glutenfree. Let us know if you find out otherwise. Our
dentist is getting rich - 16 fillings every 6 month checkup (no
joking!)  Susan