Humans attain vitamin D from exposure to sunlight, diet and supplements. Vitamin D deficiency is common in children and adults. In utero and childhood, vitamin D deficiency may cause growth retardation, skeletal deformities and increase risk of hip fractures later in life. In adults, vitamin D deficiency may precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases.
According to Holick, a professor of medicine, physiology, and biophysics, and director of the General Clinical Research Center at Boston University School of Medicine and Director of the Bone Healthcare Clinic at Boston Medical Center, it has been estimated that 1 billion people world-wide are vitamin D deficient or insufficient.
Without vitamin D only about 10-15 percent of dietary calcium and about 60 percent of phosphorus is absorbed by the body. This is directly related to bone mineral density which is responsible for osteoporosis and fractures, as well as muscle strength and falls in adults. In utero and childhood, calcium and vitamin D deficiency prevents the maximum deposition of calcium in the skeleton.
Studies have shown people living at higher latitudes (where the angle of the sun’s rays are unable to sufficiently produce adequate amounts of vitamin D in the skin) are more likely to develop and die of Hodgkin’s lymphoma, colon, pancreatic, prostate, ovarian, breast and other cancers. According to Holick, both prospective and retrospective epidemiologic studies have also shown an association between low levels of vitamin D and an increased risk for Type 1 diabetes, multiple sclerosis, Crohn’s disease, hypertension and cardiovascular disease. |
