It's possible. Read Vitamin D council's article: "Vitamin D3: Treatment for irritable bowel syndrome?"
It may be low magnesium....with this being low ur body does not absorb the vit D.....magnesium is in all items to help with bowel issues....Milk of Magnesia, which helps when constipated....I also find the other side of IBS is best to allow to run it's course if u know what I mean....if I take something to slow things down, then I go from one extreme to another....
Do talk to ur Dr and do not take ne supplements without having blood labs ....and ur Dr being aware of what u r taking....
Do post how u r doing, good Luck.