Natural Experiments of Wartime Deprivation Show Diet Trumps Stress

Perhaps the most poignant illustration of the subordinate role of stress to lifestyle behaviors are the natural experiments set up by wartime deprivations. After all, what could be more stressful than living under Nazi occupation? Heart attack rates must have skyrocketed, right? No, studies in Nazi-occupied Norway… Finland, and blockaded Sweden showed the rates plummeting, dropping down to as little as only about one-fourth the preceding rate.

What could explain fewer heart attacks in the context of greater stress? Meat, eggs, and butter were rationed and food shortages resulted in diets dominated by whole or poorly milled grains and garden produce, dropping protein levels down close to Okinawan levels around 10 percent of calories. As Walter Cronkite put it “People are living almost wholly on cabbages, turnips and backyard vegetables.”

Tobacco also became scarce, but the heart disease mortality seemed to more closely parallel the changes in animal proteins, fat, and cholesterol. Furthermore, Scandinavian women were rarely smokers during that time yet they experienced a similar drop in mortality. Denmark is an example of a country that had a similar cigarette shortage but no significant reduction in saturated fat, and the Danes had no decline in their atherosclerotic death rates during World War II.

During World War I, however, the Allied blockade of Denmark cut off imports, leading to a diversion of domestic grain (largely barley) from farm animals to humans to eat, as meat consumption was virtually eliminated. Having to depend “primarily on vegetable foods” led to complaints that the populace was forced to live “on pig-food and hen-food,” but the overall mortality rate across the board dropped by more than a third. The head of the Danish National Laboratory for Nutrition Research concluded “It would seem, then, that the principal cause of death lies in food and drink.” (Grains were also diverted away from brewers resulting in the country’s beer output getting cut in half). “It may be said,” he concluded, “that a vegetarian diet is more healthful diet than the ordinary diet.” In reference to the Nazi occupation of Norway, an editorial in the Journal of the American Medical Association noted “For those who have, or who dread, coronary disease, it would seem that avoiding food which nature provides for infants, calves, and embryonic birds might be far more effective than tranquilizers…. stress may have little or no effect if the diet is poor in animal fat.”