Holick's Rule Implementation: Calculation of Produced Vitamin D from Sunlight Based on UV Index, Skin Type, and Area of Sunlight Exposure on the Body

Vitamin D is important to maintain cardiovascular, skin, bone, and mental health. Unfortunately, 63% of Indonesians have inadequate levels of vitamin D. One of its major causes is the lack of practical methods to measure the amount of produced vitamin D for each individual. This study constructs a practical, mathematical formula to measure the amount of the produced vitamin D from sunlight exposure. It is conducted based on Holick’s rule through skin type, body surface area exposed to sunlight, and ultraviolet (UV) index. Aided by correction from UV spectrum analysis, the formula enables practical measurement of vitamin D intake through sunlight for the general public. The future works of this paper may include corrections of measurement accuracy and on-device implementation of the algorithm.