fish oil may prevent some types of chemotherapy from working

[Lani]

from the BBC


12 September 2011 Last updated at 12:14 ET

Fish oils block chemotherapy drug
By James Gallagher
Health reporter, BBC News

Fish oils may block cancer drugs

Fats found in fish oil supplements can stop chemotherapy drugs working, according to researchers.

Writing in the journal Cancer Cell, they advise cancer patients not to take the supplements.

The two fatty acids involved, which are also produced by stem cells in the blood, lead to tumours becoming immune to treatment.

Cancer Research UK advised patients to ask their doctor whether they would be affected.

Scientists in the Netherlands were investigating how tumours develop resistance to treatments.

Fat shield
Experiments on mice showed that stem cells in the blood responded to the widely-used cancer drug cisplatin. The cells started producing two fatty acids, known as KHT and 16:4(n-3).

These fatty acids begin a series of chemical reactions, which mean cancerous cells become resistant to chemotherapy.


We currently recommend that these products should not be used whilst people are undergoing chemotherapy”

Prof Emile Voest
University Medical Centre Utrecht


Using drugs to block the production of the fatty acids prevented this form of resistance which "significantly enhances the chemotherapy," the study says.

However, researchers warned that these fatty acids were "abundantly present in commercially available fish oil products". They showed that off-the-shelf fish oil supplements, given to mice, could stop chemotherapy working against some tumours.

Prof Emile Voest, lead researcher at University Medical Centre Utrecht, said: "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."

Jessica Harris, health information manager for Cancer Research UK, said: "This interesting study suggests one possible option for stopping cancers becoming resistant to treatment, but it is at an early stage and much more research would be needed to develop ways to halt resistance.

"The results also suggest that fish oil preparations may reduce the effectiveness of chemotherapy drugs.

"Cancer patients who are taking or thinking of taking these supplements should talk to their doctors to find out whether they could affect their treatments."

[Rich66]

Hmmmm.
Here's some previous info on fish oil:
http://her2support.org/vbulletin/showthread.php?p=218918#post218918

[Ellie F]

Hmmm
Thought I had read some research that indicated fish oil was particularly synergistic with taxotere and increased it's efficacy?
Ellie

[Laurel]

In this article they were referring to Cisplatin, a drug rarely used for BC in the U.S. I am a skeptic on this one.

[hutchibk]

This is exactly why I consult with a cancer specific naturopathic doctor who has been researching vitamins and supplements and their pro or anti effects w/ chemotherapy for 25 years... when I change chemo, we adjust what I am taking.

[kiwigirl]

I take Neptune Krill oil which is a small tablet but very very high in omega 3. Since I have just started Tykerb/xeloda is the combination a problem with omega3. When you don't have many shots left you really want to get the right one.

[schoolteacher]

Kiwigirl,

I wondered the same thing. I took Xeloda and Tykerb for nine months and fish oil with my vitamin D.

Amelia

[hutchibk]

Dr. Keith Block's response to this study:
http://www.lifeovercancerblog.com/life-over-cancer-blog/2011/09/fish-oil-and-chemotherapy-the-bigger-picture.html

"There are several major problems with this line of thinking. First and foremost, this study must be put in its proper context. It is just one mouse study, and it is inconsistent with the lion’s share of human and animal evidence to date. At least 17 clinical studies indicate that cancer patients undergoing chemotherapy will significantly benefit by taking either fish oil or purified omega-3 fatty acids like DHA during chemotherapy treatment." ~ Dr. Keith Block

[schoolteacher]

Thank you, Brenda.

Amelia

[Rich66]

Another case where having access to the entire paper is important:

The Dutch researchers acknowledge that when including either pure EPA or DHA or both fatty acids in combination, they showed no adverse effects on chemotherapy treatment (and, in fact, they used EPA/DHA exposure as their control group).


it should be noted that since only two fish oil products were analyzed, the Dutch researchers are now moving ahead with research to determine whether other fish oil products also contain the PIFAs. Neither of the fish oil products analyzed in their published study was molecularly distilled, which is now the norm for almost any high-quality fish oil available in the marketplace. It is quite possible that there are no PIFAs in molecularly distilled fish oils (which are virtually devoid of metals or any other contaminants).


So if there's anything at all to this, it would seem to be whether the fish oil supplement had the offending PIFAs filtered while retaining the welcome EPA and DHA.

I wonder if the paper mentions the brands tested.

[Joan M]

Thanks for this post, as I take fish oil. But it also raises the question of how does a patient find out that they are using, according to Dr. Block:

"only those fish oils that have been molecularly distilled, while confirming that any and all supplements they take have undergone and passed independent testing."

I find these disclaimers often. I guess finding out would entail yet another research project, unless a company offers this information on their website.

Joan

[hutchibk]

One quick search, and here's some info to help you on your path to finding the good stuff: (no endorsement of any brands they might be selling)

http://www.nutritional-supplements-health-guide.com/molecularly-distilled-fish-oil.html

[Rich66]

from the xtend life brand site above:

Molecular distillation is the only process that can effectively remove metals, PCBs and other harmful toxins to a level that is perfectly safe for human consumption. Better fish oil supplement manufacturers use ethanol (food grade) which does not leave residual component.Ok..so molecular filtering good, molecular filtering with ethanol (fill 'er up) possibly better than hexanes.
What I still wonder about is whether a process designed to remove toxins and metals removes the pifas in question...i.e. the half empty interpretation of Dr. Block's half full statement "It is quite possible that there are no PIFAs in molecularly distilled fish oils". Ok..maybe..maybe not.

Having looked at a number of fish oil/cancer abstracts, I get the sense that DHA is the most potent component of this fishy oil. There are DHA only (http://www.google.com/products/catalog?q=purified+DHA&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&tbm=shop&cid=17218256215368102620&sa=X&ei=DCBwTpDBE4XViAKPwaSZBw&ved=0CG0Q8wIwAw) supplements available. Could it be that DHA isolated supplements have been further filtered/isolated and more "likely" to have had the offending pifas removed? Maybe..maybe not.

I asked Nature's Bounty brand about molecular filtering and independent testing and they responded in depth about testing without mentioning filtering. I rebounded the filtering question back to them..we'll see. Of course, I didn't ask what kind of molecular filtering it is. Oy. Maybe it's better to ask specifically about presence of the pifas, identified in this late arrival, but more detailed medscape article:
http://www.medscape.com/viewarticle/750026
The fatty acids were identified as polyunsaturated fatty acids (PIFAs), 12-oxo-5,8,10-heptadecatrienoic acid (KHT), and hexadeca-4,7,10,13-tetraenoic acid [16:4(n-3)]. In minute amounts, these fatty acids were able to induce resistance.

"The resistance is due to these two specific PIFAs," Dr. Daenen told Medscape Medical News. "EPA and DHA [eicosapentaenoic acid and docosahexaenoic acid] were used as controls and, importantly, did not induce resistance in our mouse models."
"Therefore, there is no need to avoid these fatty acids, or products containing these fatty acids, even in high doses," she added.

"The conditioned media contain a mixture of fatty acids, and these products are capable of inducing resistance to various chemotherapy agents," said Dr. Chabner, a professor of medicine at Harvard Medical School and director of clinical research, Massachusetts General Hospital Cancer Center, Boston. "These studies are done in mice with relatively high doses of drug, and have uncertain but potential applicability to clinical chemotherapy."
In a mouse model, they noted that both intravenous and subcutaneous injections of MSCs induced resistance to cisplatin. Interestingly, in vivo resistance was induced by MSCs not only for cisplatin but for oxaliplatin (10 mg/kg) and carboplatin (100 mg/kg), but not with 5-fluoroucil (100 mg/kg) or irinotecan (100 mg/kg).
to validate the findings in patients with cancer, levels of MSCs were measured in the whole blood of 50 patients with different types of tumors. The authors found a significant increase in MSC counts in the peripheral blood of patients with metastatic disease compared with those who had undergone a radical resection of the tumor and had no residual disease. These results indicated that MSCs are present in the circulation and will subsequently be exposed to chemotherapy. Also, the authors note that the number of circulating MSCs was similar to the number of MSCs sufficient to confer chemoresistance in mouse models.



But all the minutia and stone turning may be unnecessary if positive animal and human studies were done with relatively standard fish oil. It would be great if the brands or characteristics of the previously positive result fish oil were revealed.

[Joan M]

Thanks for the link and checking into this. My own CVS brand fish oil canister notes,

"Laboratory tested to meet strict quality control standards for potency, purity and disintegration."

But that doesn't really get to the point. Oy, is right, Rich.

Joan