Brief Answer: Conditions that interfere fat absorption... Detailed Answer: Hi, Vitamin D is absorbed through small intestines. As it is a fat soluble vitamin, it is absorbed through fat and cholesterol via small intestines and transported to the liver where it starts its further journey. Accordingly a few conditions that causes poor vitamin D absorption are: 1. Diet very low in fats. 2. People who have had intestines resected (removed) 3. Chronic pancreatitis - where enzymes required for fat absorption are not sufficient. 4. People with biliary obstruction 5. People suffering with malabsorption - especially fat malabsorption 6. Inflammatory condition like Chrons also cause vitamin D malabsorption. Hope this answers your question. Let me know if you need clarification. Regards

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