At the time, most people ate oranges rather than drinking their fruit. Coffee was the primary morning beverage. But consuming oranges in any form became an increasingly important part of a healthy diet largely because of the efforts of advertisers and an ambitious biochemist named Elmer McCollum. According to Harvey Levenstein’s book Fear of Food: A History of Why We Worry about What We Eat, McCollum became the unofficial nutritionist of the nation beginning in the early 1920’s when he heavily promoted the life-extending and healing capabilities of vitamins and warned against the deadly effects of a vitamin-deficient diet. This “Vitamania” gave producers the perfect marketing opportunity. The National Fruit Growers Exchange, under the Sunkist brand, created a national campaign promoting drinking daily doses of orange juice for its “health giving vitamins and rare salts and acids.” But McCollum soon cast aside vitamins in favor of acid.

McCollum ignited a panic over a nebulous condition called acidosis: an excess of acid in the bloodstream which supposedly caused fatigue and lassitude. He claimed the ailment was brought on by consuming meat, eggs and bread, which were acid producers. His advice: Eat lots of citrus fruit and lettuce. These foods rather counterintuitively were transformed from acid into alkaline in the stomach. Unsurprisingly, citrus producers seized upon this new health scare.

In this 1929 acidosis awareness booklet/Sunkist advertisement, the devastating effects of untreated acidosis are illustrated: “Estelle seemed to lack vitality; didn’t even make an effort to be entertaining; hence, she did not attract the men...‘Acidosis’ is the word on almost every modern physician’s tongue.” The cure was simple: Consume oranges in any form and at every possible opportunity. And Sunkist assured the acidosis-fearing reader that it was impossible to overindulge in oranges. By 1934, scientists began calling acidosis a fad and a rare ailment unaffected by drinking orange juice, and citrus producers redirected their marketing efforts back to vitamin C. When World War II broke out, the government also turned its attention to vitamin C. Orange juice’s journey to its exalted place at the breakfast table really begins here.

During World War II the U.S. Department of Agriculture encouraged Florida citizens to do their wartime duty and increase production of food staples such as oranges. But the government soon recognized a larger problem: American soldiers were rejecting the vitamin C-packed lemon crystals included in their food rations—they simply didn’t taste very good. The government needed to fulfill the nutritional needs of soldiers and ward off scurvy with a tasty and transportable vitamin C product. With the support of the federal government and the Florida Department of Citrus, a group of scientists went to work developing something superior to canned orange juice in the name of science and country. In 1948, three years after the war had ended and after nearly a decade of research, frozen concentrated orange juice was born. It was heralded as a symbol of American innovation and determination, and it arrived just in time.