F is for Fish

Last month (3/02), a group of Swedish scientists discovered a relationship between eating fish and preventing cancer. Women who ate 6 to 8 ounces per week of fatty fish, such as herring and salmon, had 40 percent less cancer of the uterus (endometrium) than those who ate just lean fish or no fish at all. "Our results suggest that the consumption of fatty fish, but not other types of fish, may decrease the risk of endometrial cancer," they wrote.

The researchers speculated that the omega-3 oils found in fatty fish were protective. Other kinds of cancer may be similarly prevented. Last year, an article in The Lancet showed that men who regularly ate moderate to high amounts of fish had about half the chance of developing prostate cancer than those who didn't. "Fish consumption could be associated with decreased risk of prostate cancer," scientists reported.

Eating fish may also decrease the risk of a heart attack. Last November, American scientists published a huge survey of men in Shanghai, China. Older men who ate at least 7 ounces of fish or shellfish per week had 59 percent fewer fatal heart attacks than those who ate less than two ounces. Fifty-nine percent!

At the University of Washington, scientists found that eating broiled or baked fish is associated with a 22 percent reduction in the incidence of rheumatoid arthritis. Imagine if a drug were found to reduce the risk of cancer, heart disease and arthritis. It would be the discovery of the century. But fatty fish can't be marketed like a drug. The supply is limited and has no great publicity machine behind it. Like other healthful foods, it can hardly compete in the health marketplace with billion-dollar blockbuster drugs. For example, AstraZeneca spent more than $16 million promoting its new ulcer drug, Nexium, to the public in just the past month!

My strong recommendation is to eat six to eight ounces of fatty fish per week. That said, I realize there are difficulties in doing so. Healthful fish has become difficult to procure. In January, 2001, the FDA cautioned pregnant women, and those of childbearing age, not to eat shark, swordfish, king mackerel and tile fish. All of them are contaminated with methyl mercury, an extremely dangerous form of mercury, which can cause birth defects. Lactating women and small children were also advised to steer clear of these fish. What these four fish have in common is that they are at the top of the oceanic food chain. "These long-lived, larger fish that feed on smaller fish accumulate the highest levels of methyl mercury," said the FDA, "and therefore pose the greatest risk to the unborn child."

The FDA further advises these women "to select a variety of other kinds of fish, including shellfish, canned fish, smaller ocean fish or farm-raised fish" (FDA Consumer Advisory, March 9, 2001). The FDA's position is that, although childbearing women and young children should avoid these fish, it is safe for all others: "Most people have no reason to limit their fish consumption." This is strange, considering the vast data on methyl mercury's harm to adults as well as children. (See the National Academy of Science report, "Toxicological Effects of Methyl Mercury," freely available at: http://books.nap.edu/books/0309071402/html/index.html).

According to Maine's Natural Resources Council, the safest fish are haddock, cod, hake, flounder, pollock, Atlantic salmon, herring, smelts, clams, shrimp, scallops, lobster (except the tomalley, which can contain dioxin) and canned "light" tuna (safer than canned "white" tuna). The safest freshwater fish are brook trout, yellow perch and landlocked salmon.

Good luck in your quest. On a recent afternoon I went to the supermarket looking for a nice piece of fish for dinner but came away empty handed. Some fish was indistinguishable from styrofoam.

New England was once the source of a vast array of aquatic products. Around the peninsula where I live are numerous shell middens, which were the kitchen garbage dumps of the prehistoric Red Paint People. From 3,000 BC to today, people in these parts enjoyed an abundance of sea food. By the mid-1990s, the government needed to put stiff restrictions on fishing in the famous Georges Bank, when the codfish disappeared due to over-fishing. The big boat operators then moved to the Gulf of Maine, and by 1998, this fishery too had collapsed. My supermarket's cod is now flown in from Iceland and Canada. They also have shrimp from Thailand, lobster from South Africa and scallops from Antarctica. The fatty fish prescription turns out to be difficult to fill.

I look forward to the summer with hope. Last summer, we were in fish heaven. In July, my son and I took to our dinghy, armed with a simple rod and reel. Schools of young mackerel wheeled beneath our boat. When we cast our hooks into the water , the fish began leaping. The water was alive with fish. How we feasted that night! And how healthy we felt: even the FDA would have approved. Life can be good.

Lancet Letter

I'm happy to report that my letter on radiation appears in a recent issue of the Lancet: "Preoperative and postoperative radiotherapy and survival in colorectal cancer" (2002 Mar 23;359:1068-69). This is accessible free of charge at: www.thelancet.com. The Lancet is the world's oldest medical journal, founded in 1823, and is dedicated to the promotion of evidence-based medicine.

Correction

Last week I mentioned a web site that sold coffee but gave the address incorrectly. It is sawilsons.com (not sawilson.com).

--Ralph W. Moss, Ph.D.