Vitamin D supplements are used in the treatment of nutritional rickets. Supplements may also be used in the treatment of conditions associated with poor absorption such as diarrhea and biliary obstruction, and in metabolic disorders involving abnormalities of vitamin D metabolism. Other uses are in patients with hyperparathyroidism and osteoporosis . Calcium supplements frequently contain vitamin D. Other nontraditional uses of vitamin D are being investigated. Toxicity Excessive consumption of vitamin D, known as hypervitaminosis D, can cause calcium levels in the blood to reach toxic, life-threatening levels.
Toxicity can also occur in the fetus.
Vitamin K is essential for the formation of several blood clotting factors, therefore the main symptom of a deficiency is an increased tendency to bleed. Deficiency Defective blood clotting is present in vitamin K deficiency. Symptoms can be produces by coumarin anticoagulants and by antibiotic therapy. Inadequate vitamin K may be absorbed with obstruction to bile flow since the vitamin is poorly absorbed in the absence of bile. Other forms of malabsorption from the gastrointestinal tract and certain types of liver disease may also lead to a vitamin K deficiency.