Michael Pollan writes in the first chapter of In Defense of Food,
Vitamins did a lot for the prestige of nutritional science. These special molecules, which at first were isolated from foods and then later synthesized in a laboratory, could cure people of nutritional deficiencies such as scurvy or beriberi almost overnight in a convincing demonstration of reductive chemistry’s power. (21)
Pollan doesn’t dwell on the topic of nutrient deficiencies, but I will. In their article “In Defense of Food Science,” David Julian McClements, César Vega, Anne E. McBride, and Eric Andrew Decker point out that fortified foods have played important role in alleviating a number of diseases, namely pellagra, spinal tube defects, beriberi, goiter, and rickets.
The example of beriberi, which is detailed in Kenneth J. Carpenter’s book Beriberi, White Rice, and Vitamin B: A Disease, A Cause, and a Cure, is particularly instructive. Beriberi, which is often fatal when left untreated, was so prevalent in late nineteenth century Japan that one western doctor dubbed it “the national disease of Japan.” Moreover, western doctors visiting Japan after the Perry Expedition brought about the country’s opening to the West in 1854 found evidence that the disease had been around for a long time.
In the late 1800s, it was determined that beriberi was diet-related, and shortly thereafter it was discovered that beriberi was caused by a deficiency of the nutrient now known as thiamine (vitamin B1). In the case of the Japanese sufferers of beriberi, the thiamine deficiency was related to a diet based heavily on white rice. Although rice naturally contains thiamine, most of that thiamine is found in the husk, which is removed to produce white rice. Carpenter explains the preference for white rice, “In practice, nearly everyone who eats rice as their staple food, that is, the centerpiece for each of their daily meals, prefers white rice if it is available, and eating it can be a status symbol.”
Thus, the example of white rice is one in which longstanding cultural preferences resulted in dietary patterns that were demonstrably unhealthy. This should be reason to doubt an argument Pollan will make later, that the continued existence of a diet is proof of its healthfulness. Furthermore, the subsequent success of nutrition science in curing beriberi shows that science can help improve on a diet that tradition recommends.