Yes, mine was low last time it was checked. Supplementing with it orally seems to aggravate some symptoms and calm others down...hard to know what that's all about. However, IV vitamin D (200 IU/day) seems to be tolerated ok. I guess I'm just super sensitive to large amounts of things.
Chronic Lyme Disease, Gluten & Sulfite Sensitivity, Many Food/Inhalant/Medication/Chemical Allergies & Intolerances, Asthma, Gut issues (dysmotility, non-specific inflammation), UCTD ("Secondary Lupus-Like Syndrome"), Osteoporosis, Pancytopenia, chronic malabsorption/malnutrition, etc.; G-Tube; Currently TPN-dependent.
Meds: Zofran, Pulmicort, Heparin (to flush PICC line), Claritin, Colloidal Silver (used topically), probiotics.