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August 31, 1929


JAMA. 1929;93(9):694-695. doi:10.1001/jama.1929.02710090034012

The demonstration that many food materials can acquire unique physiologic potencies when the products are subjected to the direct influence of ultraviolet rays or even to concentrated sunlight is a contribution of recent scientific investigation. The effects of the irradiated substances within the body are identical with, or equivalent to, those that have been ascribed to vitamin D, the antirachitic food factor. The latter is known to induce the healing of rickets or to prevent the latter when suitable foods containing vitamin D, such as cod liver oil, are employed in a prophylactic way. Tetany and probably other diseases may be favorably influenced in a comparable manner. As might have been expected, investigators were not slow in searching for the chemical entities that represent the potent principle and its precursor in "unactivated" foods. Success came with unexpected speed, so that more than three years ago ergosterol, a sterol widely present