Stay calm.
It is only _because_ we have conquered all those dreaded diseases that diet starts to matter.
If you were going to die as a child or young adult from some dread disease then food is of course irrelevant.
The reality is we are all going to die of something—my grandma lived in excellent health until her brain just stopped working—at age 107.
Her favorite food was caviar.
So, I guess we could claim the Russkies poisoned her. ;-)
Obviously you don't know the history of food and disease well enough to begin to have a rational discussion on it; sadly.
Children and adults developed all kinds of food related/lack thereof, problems and even died from some of them, well into the 20th century.
Have you ever heard of RICKETS, for example? What about goiters, anemia, scurvy, malnutrition?
And prior to the PURE FOOD AND DRUG ACT of 1906, adulterated milk, bread, and color added to putrefying meat sickened and even killed many!
For those not living off the land, buying food in store was what they did and still do. Some greedy, unscrupulous people would lace milk with chalk, water, and a blue dye, to make more of it and this make more money.
Many foods were NOT wrapped, but just put out on shelves ( barrels of pickles, salted fish, bread, rolls, etc.) where bugs, dust, germs, etc. would land on them and didn't do much good for those who ate these foods. And refrigeration is a more or less "recent" thing! Before it was in common usage, some foods were just kept on ice blocks...unwrapped!
FYI...at one time, caviar was actually NOT all that expensive and was prescribed and a sort of medicine for certain types of illnesses. I know this, because it's part of my "family stories", that when she was little and very sick ( I do NOT know what she had ), my beloved maternal Great Aunt was prescribed caviar to help build her up. This was in the early part of the 20th. century.