How to detect native memory leaks on iOS?

I noticed that my Unity app allocates approx. 0.2 MB each second. After a couple of minutes, it reaches the allowed limit and crashes.

So I connected Unity's profiler to the device, but everything seems to be ok here. It seems as if some native process is causing the memory leak, not my app code itself. I've quite a number of native plugins in place, but how do I find out which one is responsible (or even Unity itself)?

I am not familiar with the Xcode memory debugging tools. Is there a recommended way to find out what part of the app is causing these problems?