Can not taking care of low iron and low vitamin d be dangerous and land you in hospital

Yes, esp. low Vit D: Low vit. D reduces immune function (increasing risk of influenza etc.) & increases risk of osteoporosis (& thus fractures), autoimmune disease & many common cancers including breast & colon cancer- why take that risk when taking adequate d costs pennies a day? Most adults need 4000-5000 units/day for optimal levels. Low iron is less serious but if you are anemic you won't feel good! see comment:.

Anything is possible: Low iron can lead to (microcytic) anemia while low vitamin d can lead to rickets. While it's possible that someone is hospitalized for low blood (anemia), it's rare unless you're actively menstruating. It's less like for low vitamin d to be problematic. Still, there's really not too much side effects to worry about taking iron aside from constipation. Best to follow up w/your family doc.