Historical Events

Dayton releases Los Angeles Veterans trial where seed oils replaced animal fats, but the seed oils caused cancer.

The first study mentioned by that AHA specialist is the Los Angeles Veterans Trial. It was conducted by UCLA professor of medicine Seymour Dayton on nearly 850 elderly men living in a local Veterans Administration (VA) home in the 1960s. For six years, Dayton fed half the men a diet in which corn, soybean, safflower, and cottonseed oils replaced the saturated fats in butter, milk, ice cream, and cheese. The other half of the men acted as controls and ate regular foods. The first group saw their cholesterol levels drop almost 13 percent more than did the controls. More impressively, only forty-eight men on the diet died from heart disease during the study, compared to seventy on the regular diet.

This would appear to be extremely good news, except that the total rates of deaths from all causes for the two groups were the same. Worryingly, thirty-one men on the vegetable oil diet died of cancer, compared to only seventeen of the controls.

Dayton was clearly concerned about this cancer finding and wrote about it at length. Indeed, the unknown consequences of a diet high in vegetable oils were the reason for undertaking the study in the first place: “Was it not possible,” he asked, “that a diet high in unsaturated fat . . . might have noxious effects when consumed over a period of many years? Such diets are, after all, rarities.” This was an odd new reality: vegetable oils had been introduced into the food supply only in the 1920s, yet suddenly the oils were being recommended as a cure-all. In fact, the upward curve of vegetable oil consumption happened to coincide perfectly with the rising tide of heart disease in the first half of the 

wentieth century, but researchers and doctors at the time barely discussed this coincidence. It was just an association, of course, and there were so many other changes occurring in American life during that time (including car ownership and refined carbohydrates, as we’ve seen).

Because researchers in the field were focused on the role of saturated fat in heart disease, Dayton’s study received a largely enthusiastic reception in the United States when it came out in 1969. The bottom line for most experts was simply that a prudent diet had reduced the risk of heart attacks. A number of European scientists were more skeptical, and the editors of Britain’s oldest and most prestigious medical journal, The Lancet, wrote a withering critique. They cited such problems as the rate of heavy smoking being twice as high among the controls as it was in the experimental groupI and that people on the special diet ate only about half their food in the hospital (nothing was known about the food they ate outside). Moreover, as even Dayton admitted, only half the men in the experimental group stayed on the diet successfully during the six years of the study. The results were also skewed because there was a tendency for men who got well to leave the VA center and be lost to the trial. Dayton defended his study in a letter to The Lancet, standing squarely by his conclusion that a “prudent diet” could lower heart disease risk. And “LA Veterans” has since frequently been cited as evidence for that point, even as the original controversy surrounding the trial has been forgotten.

-Nina Teicholz - page 75

  • Facebook
  • Twitter
  • Instagram
  • Reddit's r/Ketoscience