The study identified a significantly lower risk of premature death among people who ate a lot of plant-based oils over three decades.
Replacing butter with plant-based oils may boost your health and reduce the risk of dying early, new research suggests.
The study, which was published in the journal JAMA Internal Medicine, included about 221,000 people in the US who were middle-aged or older. Their diets and health outcomes were tracked for up to 33 years.
During that time, people who ate the most butter had a 15 per cent higher risk of death than those who ate the least amount of butter.
People who ate the most plant-based oils had a mortality risk that was 16 per cent lower than those who ate the least plant-based oils.
Swapping butter with plant-based oils was associated with a 17 per cent lower risk of death, the analysis found.
“That is a pretty huge effect on health,” Yu Zhang, the study’s lead author and a research assistant at Brigham and Women’s Hospital in the US, said in a statement.
Not all plant-based oils are created equal. Olive oil, soybean oil, and rapeseed or canola oil were all tied to lower risks of death overall as well as from cancer and heart disease – but the study did not find any link between health risks and corn or safflower oil.
They also did not analyse palm or coconut oils, which are high in saturated fats that have been linked to cardiovascular diseases.
Notably, some of these plant-based oils are considered seed oils, which have drawn the ire of wellness influencers – and some politicians – in recent years.
Seed oils are made from whole seeds that are processed to extract oil.
Critics have labelled oils from corn, cottonseed, rapeseed, soy, safflower, sunflower, grapeseed, and rice bran as the “hateful eight,” alleging that they are behind the surge in chronic diseases like type 2 diabetes and heart disease.
But many foods that use seed oils – such as ultra-processed and fast foods – are also high in sodium and processed carbohydrates, making them unhealthy for other reasons.
“There has been much negative publicity about vegetable oils on social media, which are based on unfounded claims of potential harmful effects,” Tom Sanders, a professor emeritus of nutrition and dietetics at King’s College London who was not involved with the study, said in a statement.
Health risks tied to different fat sources
By focusing on mortality risks, the new study injects some clarity into the debate – but has limitations.
It’s also in line with findings from a research team that analysed studies and made dietary recommendations for the Nordic and Baltic countries.
They said oils rich in unsaturated fats, like olive and rapeseed oil, appear better for health than those rich in saturated fats, such as butter and palm and coconut oils.
Saturated fat mostly comes from animal sources and is tied to elevated levels of low-density lipoprotein (LDL) cholesterol, known as the “bad” cholesterol. That in turn is linked to a higher risk of heart disease and stroke.
Meanwhile, plant-based oils have more unsaturated fatty acids. One type is omega-3, which can help reduce inflammation.
Another is omega-6, which is tied to lower risks of cardiovascular disease, type 2 diabetes, and cancer but a higher risk of inflammation.
It can be difficult to identify how much butter or plant-based oil shapes health relative to other factors.
In the new study, people who ate more butter were also more likely to be obese and smoke, and they were less likely to exercise compared with those who ate more plant-based oils.
The study authors tried to take these differences into account in their analysis, but independent researchers warned that they could still skew the results.
Further, most people included in the study were health professionals, who may not be representative of the overall population.
Despite these limitations, Sanders said it “remains possible” that the type of fatty acids in vegetable oils could have curbed health risks “by a variety of mechanisms”.
“The take home message is that it is healthier to choose unsaturated vegetable oils rather than butter,” Sanders said.
