I am a 65 yr old woman , have been taking Nutri-flex for about 10 days and then I started for a week now black tarry stools , (I have diverticulitis ) so the pattern I believe to be from that but the black tarry stool , would it be from this Nutri fles joint care , ( I am taking this because my knee is bone on bonme and going to be long time before knee replacement , waiting list , ty sorry cannot afford to pay for this but ty anyway