Ignorance and Profit: Margarine and the Heart

“Avoid butter, use margarine” was standard medical advice in the 1970s to reduce the risk of heart attack. This advice was based on ignorance of the dangers from margarine made from hydrogenated vegetable oil and millions of dollars of profit from selling “healthy” margarine. By 1990 margarine consumption was about 10 pounds per person compared with 5 pounds per person for butter. Today people want to ban margarine with hydrogenated vegetable oils because they cause heart disease! What was the reason for this change and what can be learned from this history?

World Health Organization statistics show heart disease is now the leading cause of death in the world. In 1900, people were more likely to die from other causes like infections. By the 1950s, with better treatment of infections, heart disease became the leading cause of death. Dietary guidelines published by the American Heart Association (AHA) in 1957 to prevent heart disease were vague. They stated “diet may play an important role in the pathogenesis of heart disease.” With time, the guidelines became more specific. The 1961 AHA guidelines advised reducing the intake of total fat, saturated fat, and cholesterol and increasing the amount of polyunsaturated fat. This led to the labeling of butter as bad and the promotion of “healthy margarine” made from hydrogenated vegetable oil.

Although margarine can be made using other methods, during the 1970s nearly all margarine was made using hydrogenated vegetable oils. Brands included Parkay, Fleischmann’s, Blue Bonnet, Imperial and Country Crock. Margarines made this way were deemed healthy because they are high in polyunsaturated fats. This advice was wrong because people did not understand the harmful effects of trans fats.

Hydrogenating vegetable oil creates a cholesterol-raising type of fat called trans fat. When margarines with hydrogenated oils first appeared, experts thought foods with trans fats reduced heart attacks. It was not until 1990 that evidence started to accumulate that trans fats increased the risk of heart attacks. Trans fats increase the “bad” LDL cholesterol, and lowered the “good” HDL cholesterol. Trans fats have been estimated to cause 50,000 premature heart-attack deaths each year.

Currently experts are asking to have foods with trans fats banned. Margarine sold today has little or no trans fat, butter consumption has been rising and margarine consumption has been dropping. In 2014, consumption was 3.5 pounds of margarine a year, compared to 5.6 pounds of butter.

How damaging was our ignorance about trans fats? From 1950 to 1990 deaths from heart disease dropped by 53 percent. Although it is not possible to calculate how many heart attack deaths would have dropped with better advice, the improvement provides reassurance the error was not as harmful as it could have been.

One important lesson from the “margarine vs. butter” story is we don’t know everything about diet, and there is always more to learn. The American Heart Association should be applauded for periodically updating its recommendations to the latest scientific evidence. On the other hand, a search found only one article on the AHA website that documented the changing understanding of trans fats, and it made no mention of the role of AHA dietary recommendations. Believe AHA is missing an opportunity to emphasize its part in advancing knowledge about trans fats.

Perhaps the biggest lesson from this history is to be skeptical about all dietary advice and use caution before making big changes in your own diet.

Selected References

1. David Kritchevsky: History of Recommendations to the Public about Dietary Fat. J Nutr. 1998
2. Ten Leading Causes of Death in the World complied by the WHO. http://www.who.int/mediacentre/factsheets/fs310/en/
3. History of Margarine. https://en.wikipedia.org/wiki/Margarine
4. History of Margarine: http://theplate.nationalgeographic.com/2014/08/13/the-butter-wars-when-margarine-was-pink/
5. Page, I. H., Stare, F. J., Corcoran, A. C., Pollak, H. & Wilkinson, C. F., Jr: Atherosclerosis and the fat content of the diet. 1957 Circulation 16: 164–178.
6. Overview of trans fat. http://www.cspinet.org/transfat/
7. Unhealthy Fats Finally Falling Out of Favor. http://blog.heart.org/unhealthy-fats-finally-falling-out-of-favor/
8. Willett W, Ascherio, A (1994). “Trans Fatty Acids: Are the Effects Only Marginal?”. Circulation 84 (5): 722–724.
9. http://www.theatlantic.com/health/archive/2013/11/when-trans-fats-were-healthy/281274/ When Trans Fats Were Healthy.   Olga Khazan Nov 8, 2013
10. R P Mensink and M Katan, “Effect of Dietary Trans Fatty Acids on High-Density and Low-Density Lipoprotein Cholesterol Levels in Healthy Subjects,” N Eng J Med, 1990, 323:439-445