Vitamin D is said to be associated not only with osteoporosis, but also with infections, cardiovascular diseases, neuromuscular diseases, and the onset of autoimmune diseases, and is an important nutrient that is attracting attention as a factor that aggravates COVID-19.While interest in the deficiency/sufficiency of this nutrient has increased worldwide, it has been a problem that the required reference range has not been completely established.

　Using a newly developed fully automated liquid chromatography-mass spectrometry (LC-MS/MS) system with Shimadzu Corporation, the research group was the first in Japan to detect 25-hydroxyvitamin D [25(OH)D] in serum. Calculate the reference concentration ofAs a result, 7–30 ng/mL for females and 5–27 ng/mL for males (total 6–29 ng/mL), 5,518% of the 98 surveyed were advocated by the Japanese Society of Metabolism and Endocrinology and the Japanese Orthopedic Society. It was found to correspond to vitamin D deficiency (<30 ng/mL).Most of the measured vitamin D was animal or sunlight-derived vitamin D3, and plant-derived vitamin D2 such as shiitake mushrooms was almost non-detectable.In addition, the younger the age, the higher the prevalence of vitamin D deficiency.From the results of this study, it is inferred that changes in the Japanese diet have led to a decline in the intake of plant-derived vitamin D in particular.With the super-aging society of the future, the intake of vitamin D, which leads to the prevention of osteoporosis and bone fractures, will become increasingly important.Along with urgent intervention in the current situation of vitamin D insufficiency, other causes of vitamin D deficiency also need to be analyzed.Paper information:[The Journal of Nutrition] Determination of a Serum 25-Hydroxyvitamin D Reference Ranges in Japanese Adults Using Fully Automated Liquid Chromatography–Tandem Mass Spectrometry