1918 Spanish Flu

The Black Plague and the 1918 Spanish Flu share the same signature: concurrent major war, winter or low-vitamin-D timing, and malnutrition leading to immune compromise. The convergence of the Black Plague and 1918 Spanish flu — same death toll, same pre-existing nutritional collapse — supports the hypothesis that nutritional status was a primary determinant of pandemic severity. The 1918 Spanish flu killed approximately 50 million people worldwide, the same order of magnitude as the Black Plague. The 1918 Spanish Flu killed an estimated 50 to 100 million people globally. The Spanish flu peaked in January, the month with the lowest solar angle and therefore the lowest possible vitamin D production from sunlight in the Northern Hemisphere. The 1918 Spanish Flu pandemic peaked in January, when vitamin D levels in human bodies are at their annual lowest. WWI adoption of canned food introduced a population-wide zinc deficit because the canning process destroys approximately 85% of the zinc content of food. World War I drove soldiers and civilians onto preserved and canned foods, which dramatically reduced their nutritional intake due to vitamin loss during food preservation. Because Wo…