—André Gide, French novelist (1869-1951), Journals
Fish presents a unique dilemma
to us Renewal seekers. It's packed with vitamins (A, B12, D,
But that's not the case. On closer examination, fish begins to lose its nutritional luster. In fact, it poses such serious problems that the risks of eating it can far outweigh the benefits.
Fish might fare better if only they weren't so mobile. Terrestrial foods--grains, legumes, produce, even beef and chicken--stay in one place, where we can easily keep an eye on them. Fish, on the other hand, swim around a lot. We can't control their environment, nor can we know for certain where they've been.
In the course of their travels, fish ingest a host of toxic substances that are commonly flushed into their watery environment. As a result, they're often contaminated with a sickening soup of industrial waste, sewerage, pesticides, and insecticides. Polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), dioxin, chlordane, lead, and methylmercury routinely show up in inland freshwater fish as well as in fish from the uniformly polluted bays near large coastal cities. Although PCBs and methylmercury are among the most persistent and troublesome of these contaminants, the others are just as likely to turn up on your plate.
The patterns of contamination are totally unpredictable, so you have no way of knowing which fish have been poisoned and which are clean. But scientific research has demonstrated beyond any reasonable doubt that contamination is extensive, with perhaps as much as half of the world's fish population affected in one way or another.
Just like cattle and chickens (and even humans), fish accumulate toxins in their fatty tissues throughout their lifetimes. Large fish are most vulnerable: Because they ingest small fish, their toxin concentrations may be up to 10,000 times greater than those of the water in which they swim.
But fish aren't just carriers of chemicals. They can harbor disease-causing microorganisms, too. In fact, they're responsible for a disproportionate number of cases of food-borne illness--about seven times as many cases as beef and chicken.
The only way to be absolutely sure that your fish is microbe- and chemical-free is to have it tested. Of course, sending a fillet to a laboratory for analysis requires time and money. The alternative is to simply take your chances that the fish you're eating is safe.
You've heard of Russian roulette? I call this ocean roulette. And you play every time you put fish on your plate.
As I mentioned earlier, coastal waters, especially those near large cities, have disturbingly high toxin concentrations. They receive the bulk of the billions of tons of chemicals that are dumped into our nation's waterways each year, primarily from the polluted rivers that drain into them. Among the U.S. coastal "hot spots" where toxin concentrations have reached dangerous levels are the Boston and New York harbors and Chesapeake Bay in the east, and San Francisco and Santa Monica Bays in the west.
The fish that reside in these waters are routinely exposed
to chemicals, particularly from industrial waste. These chemicals then get
passed along to us humans, with potentially devastating consequences.
Dioxin from pulp and paper mills, for instance, has been linked to birth
defects in children and to nerve disorders in adults.
While coastal fish may face the greatest threat from toxins, other fish are at risk as well. Farm-raised fish, for instance, have a reputation for being safe because they live in a more controlled environment. Unfortunately, their ponds are often contaminated by pesticide and herbicide runoff from nearby fields.
The safest fish, relatively speaking, are cold-water species such as cod, haddock, perch, and salmon. They live in the open sea, far away from polluted coastal waters. They also tend to be more expensive, since fishermen have to travel farther to catch them. But even a higher price tag doesn't guarantee where a fish came from or how safe it is.
One of the most tragic episodes of human poisoning by toxin-laden fish occurred in Japan in the 1950s, when a mysterious epidemic infiltrated the population around Minimata Bay. Autopsies on 100 victims of the epidemic, which has claimed 1,500 lives to date, revealed extensive damage to the brains and central nervous systems. The diagnosis: chronic methylmercury poisoning.
As officials later discovered, local industries had been dumping methylmercury into the bay. Fish ingested the toxin, then local residents ate the contaminated fish. The methylmercury slowly accumulated in people's bodies, causing serious illness and even death.
Similar incidents in Iraq and in Niigata, Japan, confirmed the calamitous effects of chronic methylmercury poisoning. And because bodies of water around the world continue to be polluted with the compound, low-grade poisoning remains a very real risk, particularly among frequent fish-eaters.
Chronic methylmercury poisoning is an insidious affair, affecting not only the brain and central nervous system but also the reproductive system and other organs. Both the extent of internal damage and the severity of symptoms depend on how much methylmercury a person ingests and how long the toxin is present in the body. In fact, internal damage can progress for some time without being detected.
The earliest symptoms of poisoning include numbness and tingling in the extremities, difficulty walking and talking, poor concentration, weakness, and fatigue. Over time, these symptoms can give way to spasms, tremors, and eventually coma and death.
People who eat fish no more than once a week are not at risk for chronic methylmercury poisoning. More frequent consumption can cause problems. Scientists know without question that methylmercury produces toxic effects in doses as low as 150 micrograms per day (an amount barely visible to the human eye) if ingested over several months.
Various countries, including Finland, Sweden, and Japan, have set safe limits for methylmercury in fish ranging from 0.5 to 1.0 part per million (or 0.5 to 1.0 microgram per gram of fish). In the United States, the safe limit is at the low end of the scale: 0.5 microgram per gram of fish, as established by the Food and Drug Administration (FDA).
Having a standard sure seems like a great idea. Unfortunately, we have no practical way of measuring the amount of methylmercury in the fish we eat. As a result, tallying a day's intake is virtually impossible.
In areas of the country where acid rain is a problem, larger lake fish such as bass, pike, and lake trout often have methylmercury levels that substantially exceed the official safe limit. The acid rain dissolves deposits of mercury in rocks and soil and washes the substance into lakes and streams. There, bacterial action converts mercury into methylmercury.
Because chronic methylmercury poisoning does so much internal damage, it dramatically accelerates the aging process. Its symptoms become evident only after substantial cellular breakdown has occurred. Rather than waiting until you reach that point, you're better off doing what you can to minimize methylmercury exposure in the first place.
If you've been eating fish more than once a week for a long
time, or if you'd rather not give up fish for good, certain supplements
can defend your body against the effects of methylmercury.
All of these nutrients have been included in the Anti-Aging Supplement Program outlined in parts 3 and 4 of this book. You'll find dosage recommendations there as well. Be aware, though, that while these supplements minimize damage from methylmercury exposure, they don't offer complete protection. For that, you should seriously consider eliminating fish from your diet.
There's another kind of industrial waste that makes eating fish a crapshoot. Radioactive materials routinely show up in waters surrounding nuclear dump sites. Fish harvested near these sites can have radioactive contamination.
Windscale, a nuclear reprocessing plant in England, has released more than one-quarter ton of plutonium--a radioactive substance so deadly that even microscopic doses can induce cancer--into the Irish Sea. Today, the Irish Sea is believed to be the most radioactively contaminated body of water in the world. Among children who live in the area, the death rate from leukemia is five times higher than normal.
Closer to home, the Farallon Islands, located in the Pacific about 40 miles west of the San Francisco Bay, once served as a nuclear dump site. Fish in the area pick up radioactivity from the water, then are caught and sold for human consumption.
As with methylmercury, radioactivity cannot easily be measured--unless you happen to have a Geiger counter handy. So you really can't be sure that the fish on your plate hasn't been contaminated.
Even if a fish is fortunate enough to live out its life in pristine, toxin-free waters, it still may not escape chemical assault.
Once caught, fish may lie aboard a boat for up to two weeks before being taken into port. They can rapidly rot while awaiting their final journey, because they're so high in polyunsaturated fatty acids.
To retard spoilage and preserve freshness, fishermen often spray their catch with preservatives such as polyphosphates and sulfites (to control mold and yeast), sodium benzoate (to kill bacteria), and polytrisorbate (to keep fish from becoming slimy). Fish flown in from faraway places are especially likely to be treated. That way, they won't decompose before they reach their destination.
All of these preservatives appear on the FDA's "generally recognized as safe" list. The FDA doesn't monitor the amounts used, nor does it require the preservatives to be mentioned on food labels.
Still, preservatives are foreign chemicals. As such, they have the potential to be at least mildly toxic. At this point, we can't predict their long-term effects.
For all its weaknesses, fish has one undeniable nutritional
strength: It's a top-notch source of
These fatty acids have gotten a lot of attention for their ability to protect against heart disease. Indeed, research has suggested that they not only prevent blood clots but also reduce levels of heart-harming blood fats called triglycerides.
And that's not all. Omega-3's help relieve arthritis by suppressing production of interleukin-1 and tumor necrosis factor, two inflammation-promoting chemicals manufactured by white blood cells. Omega-3's also strengthen the immune system and boost production of pain- and inflammation-fighting prostaglandins.
The trouble is, when you eat fish, you're ingesting a lot
more than
In fact, when Harvard University researchers tracked more than 44,000 male health professionals for six years, they made a surprising discovery. The men who most often ate fish were more likely to develop heart problems than the men who seldom ate fish.
Fortunately, you don't have to eat potentially toxic, fat- and cholesterol-laden fish to reap the benefits of omega-3's. You can get these fatty acids from other, more nutritious sources.
flaxseed oil, for instance, supplies even more
While finfish have their problems, shellfish--clams, crab, lobster, oysters, scallops, shrimp, and the like--fare even worse. These seafoods have already weathered a storm of criticism, thanks to much-publicized reports of their high cholesterol contents. But you may not believe what else is lurking beneath their shells.
Shellfish are scavengers. They sit on the ocean floor, often in coastal waters, and eat whatever settles there. Their regular diets may include not only industrial waste but also sewerage and fish excrement, both of which carry viruses and bacteria. Contaminated shellfish have been blamed for outbreaks of gastroenteritis (inflammation of the stomach and intestinal lining), hepatitis, and typhoid fever.
Between May and October, shellfish living in the waters of the Northern Hemisphere also face contamination during a curious phenomenon known as red tide. Microscopic red sea creatures rapidly multiply at this time of year, making the water appear an eerie crimson. In the process, these microorganisms produce toxins that are then ingested by shellfish and eventually passed along to humans, causing an alarming and potentially fatal illness known as paralytic shellfish poisoning.
Symptoms of paralytic shellfish poisoning usually show up within a half-hour of eating contaminated seafood--most likely clams, mussels, oysters, or scallops. Mild cases may cause numbness and tingling in the head and extremities, accompanied by nausea, vomiting, and diarrhea. In more severe cases, there may be muscular paralysis, characterized by difficulty breathing, swallowing, and talking. Extreme cases of paralytic shellfish poisoning may lead to suffocation and death.
Clearly, shellfish can be hazardous to your health. Because they are so frequently contaminated, and because they cause some very nasty diseases, all are off-limits in the Anti-Aging Diet.
As for finfish, I personally don't eat it. It's just too much of a crapshoot. Short of testing each and every fillet for contaminants, there's no way to be sure that fish is safe. And besides, it's loaded with saturated fat and cholesterol.
My advice to you is to avoid fish altogether. Short of that, you can at least minimize the risks of eating fish by adhering to the following guidelines.
And finally, if you continue to eat fish, be sure to take
supplements of vitamins C and E,
*
So far you've read a lot about the best and worst food choices for preventing disease and promoting Renewal. But not everything in the Anti-Aging Diet is quite so cut-and-dried. Take alcohol, caffeine, and sugar, the topics of the next chapter. Expert opinion is sharply divided on whether these substances are good, bad, or a little bit of both. Join me as we venture into this nutritional gray area.