CWS4322
Chef Extraordinaire
Loss of taste has indeed been reported as a side effect of Asacol. It is a very small number, about one-half of one percent of all people reporting Asacol side effects of all kinds. 70% of them were women. A third were over 60. That was an informal study, but taste perversion is an documented side effect and includes both loss of taste and metallic or bad tastes.
There are, of course, other possible causes, a number of them being risks for the elderly. So it's worth making sure the primary physician knows of this and can screen for other causes. Loss of taste is far more serious than one would suspect. It can contribute to depression and, as you worry about, to weight loss. If the defect is one that affects the ability to even recall tastes, there can be no appetite, because there can be no imagining any pleasure from food. Those who have certain color vision defects report similar problems. Food looks horrible. And one aspect of loss of taste can be that all food has a "bad" taste.
And you don't say if her physician has been informed. In the priority list for medical consults, a foodie forum is far from the top. Maybe she's one of the few unlucky ones who suffer this side effect. Maybe there's an alternative medication.
The food has a bad taste was about which my mom complained. I was lucky if I could get her to eat 1/4 of a sandwich at lunch. And, things she always liked, "I don't like this, it doesn't taste good." It was so frustrating.