I've been reading the study about influenza outbreaks
in 1918 and 1920 on Kelleys Island with attack-rates
of 20% and 54% respectively.
They write that in 1918 there was more traffic
due to limestone production.

Now, I wonder whether there was maybe a difference in nutrition
on Kelleys Island in 1920 vs. 1918 ?
Someone remembers the stories from the grandparents ?
What did they eat, were there frequent imports
of vitamins (i.e. vitamin D) etc. ?