Harvard study finds seed oils healthier than butter

Harvard study finds seed oils are healthier

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Published: March 18, 2025

A hand holds a bottle of No Name canola oil with a canola field in the background.

WINNIPEG — Consuming plant-based oils such as canola oil is much healthier than butter, says a group of scientists from Harvard University and other institutions around Boston.

In fact, it can prevent premature death.

The researchers published these findings in JAMA Internal Medicine — a journal from the American Medical Association — in early March.

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They wanted to compare consumption of butter to plant based alternatives such as soybean, canola, sunflower and olive oil. They looked at large cohorts with thousands of people from three epidemiological studies: the Nurses’ Health Study, which began in 1990, the Nurses’ Health Study II, which started in 1991, and the Health Professionals Follow-up Study from 1999.

“Women and men who were free of cancer, cardiovascular disease (CVD), diabetes or neurodegenerative disease at baseline were included,” wrote lead researcher Yu Zhang from the Harvard School of Public Health’s department of epidemiology.

The main objective of the analysis was to count how many people died of cardio-vascular disease or cancer and then try to connect that outcome to consumption of butter or plant-based oils.

Participants in the three studies filled out surveys every four years on how often they ate certain foods.

The crucial finding from those surveys? Eating more butter increases the likelihood of premature death.

“After adjusting for potential confounders, the highest butter intake was associated with a 15 per cent higher risk of total mortality compared to the lowest intake,” says the paper.

“In contrast, the highest intake of total plant-based oils compared to the lowest intake was associated with a 16 percent lower total mortality… There was a statistically significant association between higher intakes of canola, soybean, and olive oils and lower total mortality.”

This paper and clear finding comes at a time when plant-based oils are under attack.

U.S. health secretary Robert F. Kennedy Jr., is an aggressive critic of seed oils like soybean and canola oil.

He claims the oils are associated with a list serious illnesses including body-wide inflammation.

“Seed oils are one of the most unhealthy ingredients that we have in foods and the reason they’re in the foods is that they’re heavily subsidized,” he said in an October 2024 interview on Fox & Friends.

Kennedy’s campaign against seed oils is part of a larger movement of online influencers and C-List celebrities who firmly believe that animal fat is healthier than seed oils.

Some restaurant chains have responded by removing sunflower or canola oil from their deep fryers and replacing it with beef tallow.

The Harvard study refutes what Kennedy and others believe is the truth.

“Higher intake of butter was associated with increased mortality, while higher plant-based oils intake was associated with lower mortality,” the paper concludes.

“Substituting butter with plant-based oils may confer substantial benefits for preventing premature deaths.”

That’s an extremely clear finding and it should be taken seriously, said Sarah Berry, a nutrition professor at King’s College in London, U.K., but it probably won’t.

“This research is very timely. Social media is currently awash with influencers promoting butter as a health food and claiming that seed oils are deadly,” Berry said on www.sciencemediacentre.org.

“In a sane world, this study would give the butter bros and anti-seed oil brigade pause for thought, but I’m confident that their brand of nutri-nonsense will continue unabated.”

Contact robert.arnason@producer.com

About the author

Robert Arnason

Robert Arnason

Reporter

Robert Arnason is a reporter with The Western Producer and Glacier Farm Media. Since 2008, he has authored nearly 5,000 articles on anything and everything related to Canadian agriculture. He didn’t grow up on a farm, but Robert spent hundreds of days on his uncle’s cattle and grain farm in Manitoba. Robert started his journalism career in Winnipeg as a freelancer, then worked as a reporter and editor at newspapers in Nipawin, Saskatchewan and Fernie, BC. Robert has a degree in civil engineering from the University of Manitoba and a diploma in LSJF – Long Suffering Jets’ Fan.

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