There was a time, in the distant past, when studying nutrition was a relatively simple science.
In 1747, a Scottish doctor named James Lind wanted to figure out why so many sailors got scurvy, a disease that leaves sufferers exhausted and anemic, with bloody gums and missing teeth. So Lind took 12 scurvy patients and ran the first modern clinical trial.
The sailors were divided into six groups, each given a different treatment. The men who ate oranges and lemons eventually recovered — a striking result that pointed to vitamin C deficiency as the culprit.
Unfortunately, studying nutrition is no longer that simple.
This article originally appeared on Recode.net.