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In the news: does palm oil increase cancer spread?

03 December 2021

Recent news stories reported that palmitic acid - a fatty acid found in palm oil – could increase cancer spread. While this study brings relevant findings, there are a few things to keep in mind when reading the headlines.

The study behind the headlines

The study behind the news reports was carried out by two research Institutes in Spain, in collaboration with other international researchers to understand if the consumption of specific fats could increase the spread of cancer in the body, known as metastasis.

Using human cells of mouth cancer in mice, the researchers fed the mice diets several fatty acids (the building blocks of fats): palmitic acid, found in palm oil, or linolenic and oleic acids, present in vegetable oils, like olive oil. They found that when mice were fed with a diet rich in palm-oil, the cancer cells grew and spread more – an effect that was not observed for linoleic or oleic acids. The researchers made the same experiments in mice with skin cancer and saw similar results.

Ultimately, the researchers concluded that their findings highlight potential health risks linked to palmitic acid and also give insights that could lead to new treatments to reduce cancer metastasis.

While this is a good quality study, a few points should be kept in mind when reading the headlines.

Which factors to consider when looking at the study conclusions?

  • The studies were not carried out in humans, only mice.

Even if animal studies are helpful to understand biological processes that may apply to humans, they still have limitations. For example, the conditions of this experience may not be representative of the typical amounts of palm oil consumed in the human diet.

  • The spreading (metastatic) effect of palmitic acid was only shown with two specific types of cancer cells.

The study involved only mouth (oral squamous cell carcinoma) and skin (melanoma) cancer cells and can’t be generalised for other types of cancer.

  • The study does not suggest that palm oil causes cancer, as claimed in some of the reporting.

The study did not assess if palm oil or palmitic acid causes cancer, only if it affects the spread of cancerous cells. Certain media reports stated that palm oil could “cause 90% of cancer cases”, but this appears to be a misinterpretation of an experts’ statement that metastasis in general causes 90% of cancer deaths.    

  • This is early-stage research and more studies are needed to be certain of the impact of palm oil consumption on the spread of cancer in humans and to understand if findings could pave the way to new treatments to prevent or slow cancer metastasis.

What do the authorities advise?

Food consumption data at European level highlights that the overall level of fat intake is generally higher than the recommended. Keep in mind that:

  • WHO recommends that less than 30% of our energy intake should come from fats. Of those, only a maximum of 10% should come from saturated fats, commonly present in fatty meat, butter, cheese, cream and other full-fat dairy, palm oil, coconut oil.2
  • National advice on the use and consumption of palm oil varies within EU countries.3 You can find out more about your national dietary guidelines here.
  • The European Commission recognises the production of palm oil is among some of the main drivers of deforestation and forest degradation, together with other food products such as soy, beef, cocoa and coffee.

Further readings

Sources

  1. Pascual G et al. (2021). Dietary palmitic acid promotes a prometastatic memory via Schwann cells. Nature 599, 485–490.
  2. World Health Organisation (2015 updated). Healthy Diet Factsheet No 394.
  3. EU Joint Research Centre. Health Promotion & Disease Prevention – Food-based Dietary Guidelines in Europe. Accessed on 26 Nov. 2021
  4. European Comission. Questions and Answers on new rules for deforestation-free products. Accessed on 26 Nov. 2021