Potatoes may help people live longer

Potatoes are often considered to be less healthy compared to other vegetables. In 2000, doctor Fedon A. Lindberg caused quite a stir in Norway when he announced that a large proportion of the population ought not to eat so many potatoes. He believed that many could gain weight and develop type 2 diabetes.

A major study has now looked at how 77,000 Norwegians have fared over a period of 40 years.

“Those who ate at least two potatoes a day during the 1970s and 80s turned out to have a 12 per cent lower mortality rate during the subsequent 40 years. Eating more potatoes was also linked to a lower mortality due to heart disease. This lower mortality rate is roughly the same as we find amongst people with a high consumption of vegetables in general,” says Erik Arnesen.

He is a researcher at the University of Oslo's Institute of Basic Medical Sciences.

Potatoes are not part of the 5 A Day recommendation

In the past, people thought that a proper dinner had to include potatoes. It was common to have them on the dinner table six days a week. 

According to consumer surveys from the 1980s, nine out of ten fish dinners and eight out of ten meat dinners were eaten with potatoes.

Arnesen explains that potatoes have often been viewed as less healthy than other vegetables. The Norwegian dietary guidelines do not include potatoes among the recommended 5 A Day fruits and vegetables. 

"However, though the most recent Nordic dietary recommendations do say that people can include potatoes as an important part of a healthy diet, there is not enough evidence to conclusively determine that potatoes in themselves affect the risk of chronic diseases. That's why we wanted to investigate this particular question,” he says. 

The correlations were the same among women and men

For the study, Arnesen, along with colleagues from the University of Oslo and the Norwegian Institute of Public Health, gathered data from county-wide surveys conducted by Norwegian National Health Surveys.

These surveys were carried out between 1974 and 1988. The researchers then linked the participants to the Cause of Death Register 40 years later to see how things had turned out.

“Those who ate on average two potatoes a day were shown to have a reduced risk of dying. Our estimates are also that for every 100 grams of higher potato intake, the mortality risk and the risk of dying from heart disease spesifically, were 4 per cent lower,” the researcher explains.

Arnesen points out that the study accounted for factors like age, gender, smoking habits, physical activity, and the participants' intake of meat, fish, and melted butter or margarine with dinner.

The correlations were the same for both women and men and across the various categories of body mass index, smoking, and physical exercise.

Potatoes provide vitamin C, potassium, and dietary fibre

In the 1970s and 80s, boiled potatoes were one of the primary sources of dietary fibre in Norwegian food. They also provide vitamin C and potassium, both of which are beneficial for heart health. 

Professor Kjetil Retterstøl at the University of Oslo says that one of the strengths of the study is the large number of participants and the long follow-up period.

“This is probably the largest study ever on the link between potatoes and heart disease,” says Retterstøl.

Other studies include french fries and mashed potatoes

A number of previous studies have indicated that you run a higher risk of developing type 2 diabetes if you eat a lot of potatoes. 

Arnesen points out that a consistent weakness of these studies is that they also include products derived from potatoes such as french fries and mashed potatoes.

“Nutritionally, these products are very different from simple, boiled potatoes. They are high in both fat and salt,” he says.

The researcher emphasises that more research is needed in order to understand the underlying mechanisms involved, so that we can find out just how healthy potatoes are from all points of view. 

Reference:

Arnesen et al. Potato Consumption and All-Cause and Cardiovascular Disease Mortality – A Long-Term Follow-Up of a Norwegian Cohort, The Journal of Nutrition, vol. 154, 2024. DOI: 10.1016/j.tjnut.2024.05.011

———

Read the Norwegian version of this article on forskning.no

This content is paid for and presented by the University of Oslo

This content is created by the University of Oslo's communication staff, who use this platform to communicate science and share results from research with the public. The University of Oslo is one of more than 80 owners of ScienceNorway.no. Read more here.

More content from the University of Oslo:

• 

  Why is the outer layer of the Sun's atmosphere the hottest?

• 

  Music artists are dependent on social media

• 

  20th century literature shows that portrait photography has changed our understanding of each other

• 

  Islamic women's organisations confront Western feminism

• 

  Court case in Strasbourg becomes historic: "Courts are becoming important in the fight against climate change"

• 

  Norway's relationship with Russia: "The fundamental principle still applies"