Practical Issues in Vitamin D Replacement.

Practical clinical guidance for vitamin D assessment and management relies on a strong evidence base, but unfortunately there are many deficiencies in our current knowledge. For the general population the Institute of Medicine recommendations are likely to provide adequate vitamin D levels without harms. Thus, most adults should ingest 600-800 IU (international units) in diet and supplements with up to 4,000 IU daily likely to be safe. In certain populations, such as those with osteoporosis or after bariatric surgery, it is important to know the levels of circulating 25-hydroxyvitamin D, but general screening has not been shown to improve health. One expert group has recommended a "reasonable" level of 30 ng/mL in those individuals for whom testing is required.