Archive for September, 2011

Fish Oil Reduces Effectiveness of Chemotherapy

September 14, 2011 Leave a comment

ScienceDaily (Sep. 12, 2011) – Researchers at University Medical Center

Utrecht, the Netherlands, have discovered a substance that has an adverse

effect on nearly all types of chemotherapy — making cancer cells

insensitive to the treatment. Chemotherapy often loses effectiveness over

time. It is often unclear how or why this happens.


It now appears that chemotherapy is made ineffective by two types of fatty

acid that are made by stem cells in the blood. Under the influence of

cisplatin chemotherapy, the stem cells secrete these fatty acids that induce

resistance to a broad spectrum of chemotherapies. These substances are

referred to by researchers as ‘PIFAs’ which stands for platinum-induced

fatty acids. Cisplatin is a type of chemotherapy that is widely used for the

treatment of cancer, including cancer of the lungs and ovaries.


Tumors under the skin


The researchers studied the effect of PIFA’s in mice and human cells. The

mice studied had tumors under the skin. Under normal conditions, the tumors

would decrease in size following the administration of chemotherapy. In the

study, after administering the fatty acids to the mice, the tumors were

found to be insensitive to chemotherapy. The fatty acids were isolated from

the medium in which chemotherapy exposed stem cells were grown. But also

stem cells in the blood of patients produce the fatty acids that desensitize

tumors to chemotherapy.


The fatty acids are also found in commercially-produced fish oil supplements

containing omega-3 and omega-6 fatty acids as well as in some algae

extracts. In the experiments conducted in mice, the tumors became

insensitive to chemotherapy after administration of normal amounts of fish

oil. Natural products that include fish oil are frequently used by cancer

patients in addition to their regular treatment.


“Don’t use these products”


Professor Emile Voest, a medical oncologist at UMC Utrecht, supervised the

research. “Where resistance to chemotherapy is concerned, we usually believe

that changes in the cancer cells themselves have occurred. Now we show that

the body itself secretes protective substances into the blood that are

powerful enough to block the effect of chemotherapy. These substances can be

found in some types of fish oil. Whilst waiting for the results of further

research, we currently recommend that these products should not be used

whilst people are undergoing chemotherapy.”


Researchers at the University Medical Center Utrecht, the Netherlands,

describe these findings, that will appear online on September 12, in the

journal Cancer Cell.


Story Source:


The above story is reprinted (with editorial adaptations by ScienceDaily

staff) from materials provided by University Medical Center Utrecht, via

EurekAlert!, a service of AAAS.


Journal Reference:


Jeanine M.L. Roodhart, Laura G.M. Daenen, Edwin C.A. Stigter, Henk-Jan

Prins, Johan Gerrits, Julia M. Houthuijzen, Marije G. Gerritsen, Henk S.

Schipper, Marieke J.G. Backer, Miranda van Amersfoort, Joost S.P. Vermaat,

Petra Moerer, Kenji Ishihara, Eric Kalkhoven, Jos H. Beijnen, Patrick W.B.

Derksen, Rene H. Medema, Anton C. Martens, Arjan B. Brenkman, Emile E.

Voest. Mesenchymal Stem Cells Induce Resistance to Chemotherapy through the

Release of Platinum-Induced Fatty Acids. Cancer Cell, 2011; 20 (3): 370 DOI:


Categories: Cancer, Fish Oil