New research has uncovered a link between the consumption of palm oil and cancer metastasis, which suggests a diet low in palm oil could help to slow down the spread of cancer.
Metastasis is the process of cancer spreading from the site of the primary tumor to other locations around the body, and it is this process that makes cancer so difficult to treat. Once cancer has metastasized, it is not usually possible to eradicate cancer, only to provide treatment to reduce the symptoms and potentially slow the spread. Cancer metastasis is the leading cause of death in cancer patients.
Previous studies have identified a link between diets high in fat and tumorigenesis in preclinical models of cancer, and there is also a link between obesity and highly aggressive cancers. While fatty acids are the building blocks of body fat, and fatty acids have been associated with cancer metastasis, the mechanisms involved are not understood and it is unclear whether all types of fatty acids contribute to cancer metastasis.
Researchers at Barcelona’s Institute for Research in Biomedicine (IRB) conducted a study to investigate the long-term health risks of consuming products containing palm oil, which is now used in a large number of foodstuffs such as cakes, bread, chocolate, biscuits, margarine, and other culinary fats. The researchers studied the effects of a variety of fatty acids on primary tumor formation and metastasis in mice, including palmitic acid, oleic acid, and linoleic acid. Palmitic acid is present in palm oil but not in many other oils, such as olive oil.
None of the fatty acids tested had any effect on the primary tumor location, but palmitic acid was found to promote metastasis in melanoma and oral carcinomas, whereas the other fatty acids did not. The researcher found palmitic acid promoted cancer metastasis as a result of altering the cancer genome. When cancer cells were exposed to palmitic acid in the diet for a short period, they remained highly metastatic, even when palmitic acid was removed from the diet, showing the effects were long-lasting. The cancer cells remained metastatic even after being serially transplanted, indicating exposure created a prometastatic memory.
“Our results indicate that dietary PA not only stimulates metastasis but that it also does so in a long-term stable manner through a transcriptional state that stimulates intratumoral Schwann cells,” explained the researchers. In addition to highlighting the long-term health risks of diets high in PA, the researchers also provide mechanistic insights to identify new epigenetic and neural/glial-related therapeutic strategies to attenuate and prevent cancer metastasis.
The findings suggest that cancer patients should adopt a diet that is low in PA, which could help to slow down metastasis or at least not accelerate that process, although further research would be required to determine which diets are best for cancer patients to slow down metastasis. By identifying the mechanism involved, it provides an opportunity to block metastasis and this is the direction the researchers are now taking rather than further investigating possible dietary restrictions.
Salvador Aznar-Benitah, Ph.D., lead researcher of the study, co-founded the startup ONA Therapeutics, which is developing antibody therapies for metastatic cancer and they expect to start testing their first antibody-based therapeutic in the next could of years.
You can read more about the study in the paper – Dietary palmitic acid promotes a prometastatic memory via Schwann cells – which was recently published in Nature. DOI: 10.1038/s41586-021-04075-0