Omega-3s have been shown to help reverse heart disease, boost immune function, and improve mental health. An adequate supply of omega 3s makes you less vulnerable to inflammation, depression and Alzheimer’s disease. But is eating enough fish to obtain an adequate amount of omega-3s really safe?

The omega-3s in fish

Fish is the best source of two omega-3s, EPA and DHA. Both EPA and DHA are important for the good functioning of the heart and DHA is especially important for the brain development of fetuses and newborns. DHA makes up 15 to 20 percent of the brain and 30 to 60 percent of the retina. Plus, omega-3s from fish (not from plants) may help prevent prostate cancer.

Fish (or any other animal for that matter) doesn’t manufacture omega 3s, but wild fish get them by eating certain algae that contain this important nutrient. Wild fish such as salmon store the omega 3s in their body fat and they are a great source of omega-3s; farmed fish, on the other hand, have very low amounts of these nutrients.

Is farm fish dangerous?

The salmon and fish we are eating today come mainly from fish farms. Most catfish, rainbow trout, and most shrimp and salmon eaten in the United States are raised by fish farmers. Alaska salmon is always wild, but all the Atlantic salmon currently available in supermarkets or restaurants is farmed.

Canned salmon may be either fresh or farmed, although if it Atlantic, it is farmed. If it doesn’t say whether it is wild or farmed, chances are it is farmed.

Farmed fish should be avoided for several reasons. Wild salmon spend part of their lives in freshwater streams and part in the salty sea.

Farmed salmon is a totally different story. About 50,000 salmon are kept confined in underwater cages, they water they breathe and drink becomes very fast contaminated with their accumulated wastes. As a result, they must be routinely administered tons of drugs, hormones, antibiotics, and vaccines to keep them alive under these conditions.

Fresh salmon gets its pinky-orange color from eating krill. The flesh of farmed salmon, on the other hand, has a kind of grey color, not too attractive to consumers. So, fish farmers add a synthetic color, astaxanthin, to the food they feed salmon to obtain a more “natural” color.

Farmed fish has more toxic chemicals than wild fish

Many studies have found that farmed fish have their share of toxic chemicals that affect the central nervous system and the immune system. These chemicals can also cause cancer and birth defects. The farmed salmon industry insists that these studies are too small to be significant.

In 2004, however, the results of a study conducted during two years about salmon from around the world were released. The study was conducted by some of the world’s leading experts on industrial pollution and was published in the journal Science. (Ronald Hites et al. “Global Assessment of Organic Contaminants in Farmed Salmon”, Science, Jan 2004.).

The study found that the levels of:

  • PCBs, (Polychlorinated biphenyls) are a group of man-made compounds that were widely used in the past, mainly in electrical equipment, but which were banned at the end of the 1970s in many countries because of environmental concerns. Because these compounds are generally very stable, they remain present in the environment today.
  • Dioxins, a group of chemical pollutants found in the environment; they accumulate in the food chain, mainly in the fatty tissue of animals. More than 90% of human exposure is through food, mainly meat and dairy products, fish and shellfish.
  • Banned insecticides such as toxaphene. Toxaphene , an insecticide used heavily in the United States and banned by the Environmental Protection Agency (EPA). At some point, toxaphene levels in farmed fish were so high that, based on the EPA guidelines, no one should be eating farmed salmon more than once a month. Farmed filets bought in supermarkets in Boston and San Francisco were so heavily contaminated that even half a serving a month might be too much.

The Association of Salmon and Trout Producers called the new study “dangerous, alarmist, and a shot in the dark”. However, according to George Lucier, a former director of the U.S. Department of Health toxicological program, the results were undeniable.

The hazards of mercury

Unfortunately, a lot of the fish we eat nowadays is contaminated with methyl mercury. This is a serious problem because methyl mercury has been found to affect the following areas in our body:

  • It attacks the brain and the nervous system.
  • Causes behavioral problems and loss of intelligence in children
  • Affect the immune and reproductive systems
  • It promotes cardiovascular disease
  • At high concentrations, it causes mental retardation and cerebral palsy, deafness, blindness and death.
  • It can damage a developing fetus

Fish most contaminated with methyl mercury are:

  • Swordfish
  • Sea bass
  • Halibut
  • Ahi tuna steaks

What to do?

Fish are the greatest sources of EPA and DHA, two omega-3s that we need for good health, but they are also a good source of PCBs, DDT, and dioxins, in addition to mercury and other heavy metals. So, what can we do? We have several alternatives:

  • Eat fish that doesn’t accumulate mercury such as wild salmon, sardines, sole, tilapia or small shellfish.
  • Take fish oil capsules. According to doctor Alexander Leaf, one of the world’s leading experts in fish oils, three grams a day of fish oil provides one gram of DHA and EPA, which is all you need. Brands like Arctic Pure, Nordic Naturals, and Xtend-Life use oil fish caught in the cleanest and coldest waters. Their products have been molecularly distilled, removing any mercury or other heavy metals, dioxins, PCBs, and other contaminants.
  • If you prefer not to eat fish in any form, you may want to consider taking DHA supplements from algae. DHA derived from algae is presently available commercially as Omega-Zen-3 or Neuromins DHA.

Keep your intake of omega-6s from going to high

It is important you keep your intake of omega-6s from going to high because they can interfere with your levels of omega-3s. The ideal ratio between omega-6s and omega-3s is 2:1; at the most, 4:1. Unfortunately, the standard American diet today typically has a ratio of 15:1.

To make sure your intake of omega-6s is not excessive, you can do the following:

  • Get most of your fat from whole plant foods such as nuts, seeds and avocados.
  • Use extra virgin olive oil or canola oil rather than oils high in omega-6s such as sunflower, safflower, or corn oil.
  • Limit your consumption of processed and fried foods.
  • Avoid anything that has partially hydrogenated oils because these oils are high in omega-6s.
  • And last, but not least, avoid by all means fast food restaurants.

The diabetes club has a new born sister

Because many of you write to me asking me questions or telling me health experiences you have had that have worked or not worked for you, I thought many of us could profit from knowing about them. And with this thought in mind, I have created a sister site to the Diabetes Club.

Now you have a forum, where you can leave your question or you can tell us about health experiences you may have had so that all of us can benefit from “listening” to you.

Final word

In the past, people got enough omega-3s by eating a variety of wild plants or from wild game. But today, we eat few wild plants and modern farming practices produce meats, dairy products, and eggs that barely contain these fats. As a result, people living in the industrialized world, can be deficient in these nutrients.

Do not stop eating fish because there is danger of contamination. Just look for fish that doesn’t accumulate methyl mercury in their flesh like salmon, sardines, sole, tilapia or small shellfish.


I am Andy Carpenter and I would start by saying that I have a Bachelor Degree in Nutrition Science conferred by California State University, Los Angeles and that I am certified as a Registered Dietitian.

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