Regarding the harmala MAOI+food, as the OP already said, there is no real interaction danger. The
FAQ has a bit more to say about it.
Regarding MAOI's health benefits, I have experimented a bit with harmalas either purified by themselves, in pharma or in the full plant brews (ayahuasca), but it would be very hard for me to separate any specific effects that they have. Since there are so many things involved such as set and setting, my beliefs regarding these substances, my daily health habits, the other psychedelics I consume, etc, how could I really know what is specifically the harmalas? I do know that they definitely dont feel negative in any way.
Nevertheless, there are some researches relating to harmalas, and I think
this thread is a good place for you to start digging

There are some other publications such as
this which indicate harmalas may be useful in fighting certain neurogenetic disorders, but thats preliminary information, still a far cry from actually claiming with certainty they do by themselves cure or significantly help anything. Always important to exercise caution when making claims.
The ingestion of ayahuasca has been shown in
scientific investigation to upregulate serotonin platelets uptake sites, which could potentially mean people become more sensitive to serotonin (and maybe thus being less prone to depressions), but again, these are all hypothetical conclusions from certain results of which we dont really know much about, so we have to be cautious in making these claims. Also we dont know whether this upregulation is related specifically to all harmalas, to some specific harmala alkaloids, to dmt, to a mix of it all, or what.
Another aspect which can point out to the fact that harmalas may be of benefit in anti-depression treatments is the fact that certain MAOIs (not harmalas) are actually sold as anti-depressive medication by pharmaceutical companies (since MAOs also metabolizes serotonin, so inhibiting them would increase serotonin levels). Though nowadays Big Pharma more commonly uses newer anti-depressants which belong to another chemical category, such as SSRIs. In any case it does show how harmalas can potentially be of help one's health in this chemical sense.
With that all being said, I really dont know how one would react with taking harmalas every single day. Maybe there would be an upregulation of natural MAOs ? Or maybe not, but maybe the fact that harmalas are slightly sedating would be a hindrance to someone's well-being if they take them at an unnapropriate daily time?
Im curious if anybody else does have experience with daily or very regular harmala ingestion.