Collaboration will improve the safe integration of all therapies during your experience with cancer. There is no definitive evidence that vitamin D is effective as a preventive agent or as a treatment for cancer in humans.
Further study is necessary.
The use of vitamin D may be limited by its toxicity. High doses of vitamin D are toxic which may cause an excess of calcium in the blood. Extreme cases may lead to death. Vitamin D is also made by the body upon exposure to sunlight. Vitamin D compounds are important components of the endocrine system - being largely responsible for calcium metabolism.