Fish and Cancer

[Guest guest]

Hi folks:

The following, while clearly not from an unbiased source, is quoting

published sources. So it is presenting good information, but no

doubt only one side of the argument. So, fwiw:

" Fish consumption reduces lung cancer risk:

NAGOYA, JAPAN. Lung cancer is the leading cause of cancer deaths in

Japan even though the incidence and mortality is still less than two-

thirds of that found in the USA and the UK. Japanese researchers have

just completed a study aimed at determining the association between

lung cancer and diet. Their study involved 748 men and 297 women aged

40 to 79 years who had been diagnosed with lung cancer and 2964 male

and 1189 female cancer-free controls.

The researchers found that both men and women who ate cooked or raw

fish five times a week or more had half the incidence of lung

adenocarcinoma when compared to participants who ate cooked or raw

fish less than once a week. Women who consumed tofu (soybean curds)

five times a week or more were found to have half the risk of

adenocarcinomas, as compared to women who consumed tofu less than

once a week. Frequent consumption of carrots was found to be

beneficial for women, but detrimental for men especially smokers.

Green vegetables were found to be highly beneficial for men, but not

statistically so for women. There was also some evidence that

increased coffee consumption is associated with an increased risk of

squamous cell and small cell lung carcinomas in men. Increased

consumption of dried or salted fish was not beneficial for men or

women. The researchers speculate that this is because the processing

destroys the healthy omega-3 oils (eicosapentaenoic acid and

docosahexaenoic acid) present in raw and cooked fish.

Takezaki, T., et al. Dietary factors and lung cancer risk in Japanese

with special reference to fish consumption and adenocarcinomas.

British Journal of Cancer, Vol. 84, No. 9, May 4, 2001, pp. 1199- 1206

Fish oils and the immune system:

OXFORD, UNITED KINGDOM. Animal studies have shown that an increase in

fat intake can decrease the number of natural killer (NK) cells found

in the blood and spleen. NK cells are an integral part of the natural

immune response to virus infections and certain types of cancer.

Researchers at Oxford University now report that fish oil

significantly decreases NK cell activity in healthy human subjects.

Their clinical trial involved 48 men and women aged 55 to 75 years.

The participants were randomized to receive one of six supplements

for 12 weeks. The supplements were all provided in the form of

capsules, three of which were to be taken with each meal. The nine

capsules (daily intake) contained either a total of 2 g alpha-

linolenic acid, 770 mg gamma-linolenic acid (from evening primrose

oil), 680 mg arachidonic acid, 720 mg docosahexaenoic acid (DHA), 720

mg eicosapentaenoic acid (EPA)+ 280 mg DHA (fish oil) or a placebo

(an 80:20 mix of palm and sunflower oils). All the participants had

blood samples taken four weeks before start of supplementation,

immediately before start of supplementation, and then every four

weeks during the trial as well as after a four-week washout period.

The researchers found no changes in killer cell activity except in

the group taking fish oil. Here they observed an average decline of

20 per cent after 8 weeks and 48 per cent after 12 weeks. The decline

was completely reversed after the washout period. The fact that no

decline was observed with pure DHA strongly suggests that EPA was

responsible. The researchers conclude that an excessive EPA intake

could have adverse effects for people at risk of viral infections and

some cancers. Editor's Note: The British researchers' speculation

about fish oils perhaps affecting the effectiveness of NK cells in

killing cancer cells is at odds with the results of many other

studies. There are at least a dozen studies that show a clear

protective effect of fish or fish oil against breast, colon, and

prostate cancer. NOTE: This study was partly funded by Unilever. [54

references]

Thies, , et al. Dietary supplementation with eicosapentaenoic

acid, but not with other long-chain n-3 or n-6 polyunsaturated fatty

acids, decreases natural killer cell activity in healthy subjects

aged >55 years. American Journal of Clinical Nutrition, Vol. 73,

March 2001, pp. 539-48

Docosahexaenoic acid halts melanoma:

We do not usually report on animal or test tube experiments, but

found the results of this study so intriguing that we decided to make

an exception.

VALHALLA, NEW YORK. The incidence of cutaneous malignant melanoma is

growing rapidly among persons with fair skin. It is estimated that

one in 75 Americans will develop melanoma within their lifetime.

Melanoma has a pronounced tendency to spread to other organs

(metastasis) and the 5-year survival rate for metastatic melanoma is

less than 10%. There is growing evidence that diet can influence the

risk of developing melanoma. It is now believed that a high intake of

omega-6 fatty acids stimulates the growth of melanoma and other

cancers whereas omega-3 fatty acids suppress the growth of cancer

cells.

Researchers at the New York Medical College and the American Health

Foundation have just released the results of a laboratory experiment

which clearly shows that docosahexaenoic acid (DHA), a main component

of fish oil, is highly effective in inhibiting the growth of human

melanoma cells. The researchers treated 12 different human metastatic

melanoma cell cultures (in vitro) with DHA and found that more than

50% of them stopped growing. They urge further testing of their

findings in full-scale clinical trials involving patients with

melanoma. They conclude that " if DHA is capable of suppressing cell

and tumor growth and metastatic potential in in vivo models of

melanoma, a clinical trial of DHA would be warranted as an adjuvant

to current surgical and chemotherapeutic interventions " .

Albino, P., et al. Cell cycle arrest and apoptosis of

melanoma cells by docosahexaenoic acid: association with decreased

pRb phosphorylation. Cancer Research, Vol. 60, August 1, 2000, pp.

4139- 45 "

Source: http://www.oilofpisces.com/cancer.html

Rodney.