I would consider the source. Multiple links, from different vertical sections of a major authority - say the National Institutes of Health (NIH.gov) website - to different relevant vertical sections of your health related website?
I wouldn't doubt the benefits of multiple links.
A NIH directory, if such existed/s, which itself is highly "juiced up" across all its sub-sections (distributed juice), since its listings are reviewed and selected by world class health experts, and which directory links out very selectively, and which - due the quality of your website - chooses to link to 4 or 5 sections of your site?
I wouldn't doubt the benefits.
And so on - downwards from sites of the NIH's level of authority: less authority, take-all-comers if they pay directories, generic directories of no particular repute, etc.
IF you are going to target a directory then perhaps you might want to target one that focuses on and shows signals of quality for a specific vertical, perhaps the tighter the focus and the more signals of quality the better.
If what I've described is not how the algo sizes up where and when to pass juice from multiple links from one site to another site then the algo is broken. If broken it may be fixed, so plan accordingly when spending money for links.
