Too much Fish Oil (not good)

[Ivona]

Too much fish oil may increase cancer risk, study says

--------------------------------------------------------------------------------

While vitamins and other dietary supplements can yield numerous health benefits, too much of a good thing is possible, says a Canadian dietitian.

On the heels of new research from Michigan State University, which shows high dosage levels of fish oil can lead to an increased chance of colon cancer and colitis in mice, dietitian Rosie Schwartz says the omega-3 fatty acids in fish oil remain beneficial in most cases -- if consumed in reasonable amounts.

"People think when a nutrient is good, more is better. Research does show that omega-3s have antiinflammatory effects, but the dosage is key," said the Toronto-based Schwartz. "I agree with what they're saying that the average person needs to get more omega-3s in their diet ... but more does not mean an unlimited amount. There is research that [suggests] omega-3s, in high doses, can suppress immune system function, so if a person does have any colon cancer cells and they're taking too much, that could be a problem."

In the new U.S. study, which lobbies for a dosage limit for fish oil supplements, the researchers found that high doses of fish oil had alarming results in some test mice, many of which were more prone to inflammatory bowel conditions. Many mice in the test group developed aggressive late-stage cancer. This was observed in the mice taking the highest doses of docosahexaenoic acid (DHA), but also in mice subjected to lower levels.

"We found that mice developed deadly, late-stage colon cancer when given high doses of fish oil," lead researcher Jenifer Fenton said in a news release. "More importantly, with the increased inflammation, it only took four weeks for the tumours to develop."

Schwartz said there are health risks associated with unrestricted supplement use and they are not limited to fish oil or to omega-3 fatty acids such as DHA, which are often touted for the benefits to joint and heart health.

She said fish oil can also act as a blood thinner when taken in high doses, which can cause problems when combined with certain medications.

Citing research linked to the use of folic acid, which is promoted for women trying to conceive to decrease the risk of birth defects, Schwartz said in high doses, folic acid has links to colon cancer, breast cancer and prostate cancer in non-pregnant individuals.

[surfingon]

Very interesting-- timely for me because I 've been noticing how easily I bleed with the slightest little scratch-- and that does coincide with the fairly recent addition of fish oil supplements to my diet.

What this article does not address is how much is considered "high dosage"? Critical question...

[Rick7]

Thanks for the info Ivona.

It's hard to comprehend without specifics.
I read many articles just like this.
One persons idea of a reasonable amount may seem like a a boat load to the next person.

If anyone knows the reasonable or unreasonable amounts for either Omega-3 or Folic Acid, please fill us in.

Rick

[Terry]

Interesting article. Fish oil pills were pulled in the U.S. not to many months ago due to contamination. My husband switched to flax but he doesn't take to many (I checked after reading this:)

Thanks for posting Ivona!

[minolfa]

maybe mice results cannot be extrapolated to human beings.....after all, usually rats do not eat fish and maybe
genetically they cannot process "fish" oil....

FOODNAVIGATOR.COM
25/10/2007
Omega-3 to cut colon cancer: meta-analysis
By Stephen Daniells
A pooled analysis of the small but ever-growing body of science
of omega-3 and colorectal cancer indicates more fish oil does
protect against the cancer. The incidence of colorectal cancer
can be cut by 12 per cent by consuming more fish per week, says a
new meta-analysis published in the American Journal of
Epidemiology. In addition, for every additional serving of fish
consumed per week the risk of developing the cancer could be cut
by four per cent, state the researchers from Wageningen
University in the Netherlands. "Existing evidence that n-3 fatty
acids inhibit colorectal carcinogenesis is in line with these
results, but few data are available addressing this association,"
wrote lead author Anouk Geelen. The research adds to the healthy
reputation of omega-3 fatty acids that is seeping into consumer
consciousness, based largely on evidence that it can aid
cognitive function, may help protect the heart against
cardiovascular disease, and could reduce the risk of certain
cancers. In terms of colorectal cancer, a disease response for
about 492,000 deaths each year around the world, the potential
benefits have only been investigated in a small number of
studies, note Geelen and co-workers. A meta-analyses of
prospective cohort studies was performed, including 14 studies
reporting the effects of fish consumption or n-3 fatty acids and
colorectal cancer incidence and four studies reporting colorectal
cancer mortality. The Dutch reviewers report that the highest
consumption of fish oil was associated with 12 per cent reduction
in the incidence of colorectal cancer, while no significant
benefits were observed with respect to mortality. Furthermore,
for each extra 100 g of fish consumed per week the risk of
colorectal cancer incidence was reported to be reduced by three
per cent. Geelen and co-workers also report that the benefits
were more pronounced for women, although the number of studies
could not allow for definitive conclusions to be drawn. The
reviewers noted that animal studies have shown favourable results
in terms of omega-3 and colorectal cancer. Indeed, a study by
researchers from Harvard Medical School and Charit� University
Medicine, Germany, published earlier this year in the journal
Carcinogenesis, reported that supplementation with omega-3 cut
inflammation in the colon that may lead to tumour formation by 15
per cent. The burgeoning body of science supporting the potential
health benefits of omega-3 has seen the number of omega-3
enriched or fortified products on the market increase. However,
fears about dwindling fish stocks and the presence of pollutants,
such as methyl mercury, dioxins, and polychlorinated biphenols
(PCBs), have pushed some academia and industry to start producing
omega-3s from alternative sources, such as algae extraction or
transgenic plant sources. Most extracted fish oils are
molecularly distilled and steam deodorised to remove
contaminants. According to Frost and Sullivan, the European
omega-3 market was worth around _160m (�108m) in 2004, and is
expected to grow at rates of 8 per cent on average to 2010.





FAO.ORG

[jscho]

I have a hard time believing this, as it is counterintuitive. Omega-3 oils (DHA, EPA) are known to have anti-inflammatory effects (cytokines) and also increase insulin sensitivity, thereby lowering insulin and free insulin growth factor levels (IGF-1). The mechanisms of action have recently been suggested to involve receptors on fat cells and macrophages that lead to a cascade of intracellular signals increasing glucose uptake independent of insulin, as well as blocking inflammation signals from both bacterial sources (lipopolysaccharide) and the tumor necrosis factor. (see http://www.ncbi.nlm.nih.gov/pubmed/15698426 for details). Both should help reduce growth rates in cancer rather than encourage it.

In other words, I'll wait for further clinical proof.

In any event, I will continue to take fish oil supplements because of their role in suppressing auto-immune disease associated inflammation (for reasons above).

Best,
Jeremy

[pollo65]

It seems to me that every time I get on a NEW regime regarding vitamins, tumeric, fish oil etc. some study comes along to refute the findings. Perhaps it comes down to everything in moderation. All I know is that it makes it confusing to try to take out the BEAST.
pollo65

[lisab3897]

everything in moderation is what I'm thinking too.....I started vit D and fish oil sup. last year because of the good research and write ups. How can research show such good results and than such bad results..... The articles I read on this new research on fish oil is high doses.I agree with surfingon... what is a high dose I don't know...I take 1 pill a day. Is that too much? That's the question we need answered...

[Kathryn in MN]

My oncology certified dietician had me cut back on the amount of fish oil I was taking a year ago for during chemo. I'd have to find the bottle to look up the amount in each capsule, but I was taking 5 per day (as recommended on the bottle) and she told me 3 or less would be the appropriate amount to not interfere with chemo.

I agree with the general philosophy of moderation in all things. Too much of anything can be bad. You can die from drinking too much water....

[jscho]

The articles I read on this new research on fish oil is high doses.I agree with surfingon... what is a high dose I don't know...I take 1 pill a day. Is that too much? That's the question we need answered...

Apparently the mice received the equivalent of 2-7 gm/day of DHA (in humans), which should correspond to taking between 12 to 60 capsules of 1000 mg fish oil capsules a day (depending on body size). This is indeed a lot of DHA. It is important to keep in mind that all supplements (or water, as mentioned previously) have an effect at some threshold dosage. The caution exercised by experienced oncologists is sensible.

Best,
Jeremy

[lisab3897]

12 to 16 capules a day......now that is a lot..... thanks.....

[hopeful]

Thanks for the info Ivona.

It's hard to comprehend without specifics.
I read many articles just like this.
One persons idea of a reasonable amount may seem like a a boat load to the next person.

If anyone knows the reasonable or unreasonable amounts for either Omega-3 or Folic Acid, please fill us in.

Rick

Agreed. And could it be the mercury or something other than omega-3's in fish oil that caused the problem? Ground flax seed is our choice for omega 3's. We grind it ourselves and store it in the freezer.

[Lillian]

I use Nordic Naturals purified fish oil. It's tested for pollutants, so I feel pretty safe with it. About 3-4 times a week I pour about 1- 1/2 teaspoons in either a smoothie or fresh juice (no fishy taste), but I'm not sure how that translates to capsules. I'd hate to think I'm doing more harm than good.

[Ivona]

Since chemo my GI is so sensitive I am unable to take most supplements....and fish oils or omegas give me the worst diarrhea. You guys must have guts of steel to take all this stuff....

[willtowin]

Just saw my gynecologist today who is a bit of a naturalist when it comes to medicine and taking care of me. I just think he is great. Anyway...he suggested heavily that i begin taking omega 3's today and promoted this brand... http://www.mynaturalsupplements.com/pages/omega_3.html which supposedly has a much higher concentration of purified omega 3 oil. I am hoping that is a good thing after reading this thread. He spoke of the British study that showed the reduction in polyp growth and wanted me on it. He also wanted me on DHea...anybody on that as well?