Fish Oil May Fight Breast Cancer

Carper is a medical and nutrition writer and the author of 15 books, including "The Food Pharmacy."

Could eating more fish or taking fish-oil capsules help thwart breast cancer?

Some researchers think so. Dr. Rashida Karmali, associate professor of nutrition at Rutgers University, has found that supplements of fish oil, equal to what Japanese women commonly eat in fish, did suppress biological signs of developing cancer in women most apt to get breast cancer.

Karmali also cites a new Canadian study showing that the death rate from breast cancer is lower in countries where women eat more of their calories in fish. In Japan, for example, where consumption of fish is high, the breast cancer rate is low.

Dr. George Blackburn, associate professor of surgery at Harvard Medical School, says he would be "dumbfounded," based on present knowledge, if the oil from fish did not help thwart the spread of malignant cells in women undergoing breast cancer surgery. In a new study, he is asking a group of women immediately after learning that they have breast cancer to start eating more fish and taking low doses of fish-oil capsules.

He speculates the fish oil may strengthen their immunity, killing wandering cancer cells before they can start new tumors.

Eating seafood may also be critical in protecting older women from bone fractures--especially in winter.

That's the conclusion of a new study by Elizabeth A. Krall, at the U.S. Department of Agriculture's research center at Tufts University. The reason: Without adequate amounts of Vitamin D, older women lose bone calcium, weakening bones. Since sunlight is a good source of Vitamin D, human levels of the vitamin fall in winter, even to some degree among people living in the South.

In her study of 333 post-menopausal women, Krall found they need 10% more Vitamin D to prevent calcium loss than the recommended dietary allowance (RDA) calls for.

Worse, she says, most women don't even come close to getting the RDA for Vitamin D. The average intake in her study was only 112 international units; the RDA is 200 IU.

"It appears that older women need at least 220 IU," says Krall. Also ability to absorb Vitamin D decreases with age.

Best sources: fatty fish. Three and a half ounces of canned salmon contains 500 IU of Vitamin D; the same amount of canned sardines contains 300 IU. A cup of milk has 100 IU.

One way to raise immunity -- become a vegetarian.

Researchers at the German Cancer Research Center in Heidelberg compared substances in the blood of male vegetarians and meat eaters. They documented that the vegetarians had a more active immune system. In fact, the white blood cells of vegetarians were twice as deadly against tumor cells as those of meat eaters. It took half the white blood cells to do the same job.

Vegetarians, however, did not possess more white cells. But researchers suspect their white cells may harbor more "natural killer cells," to attack cancer cells. Another possibility: Vegetarians' natural killer cells may be more powerful.

In any event, the more ferocious immune system may help explain why vegetarians have lower cancer odds.

The vegetarians also had higher blood levels of carotene, a vegetable compound that blocks cancer in animals. Studies show that high-carotene eaters have about half the risk of lung cancer as low-carotene consumers. Richest in carotene are orange and deep-green leafy vegetables -- like carrots and spinach.

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