FDA Evaluation of Mercury Health Risks Versus Benefits of Eating Fish Causes Industry Alarm

Have you heard about news stories suggesting the FDA may consider amending its advisory for how much fish pregnant women and children should eat — and might relax guidelines? The agency has circulated an internal draft of a report reviewing the risks versus benefits of eating mercury-containing fish, and the distribution “for peer review” has stirred up some controversy.

Just a few years ago, nutritionists, scientists and others worried about public health risks praised the FDA for working with the EPA (Environmental Protection Agency) to establish a joint consumer advisory warning pregnant women (or those who might become pregnant), nursing mothers and young children not to eat shark, tilefish, swordfish or king mackerel because they contain high levels of mercury. The FDA further advised an upper limit not to exceed two six-ounce servings per week of fish… or six ounces of albacore tuna a week… for this vulnerable population. Mercury has such a strong toxic effect on the developing nervous system of fetuses, babies and toddlers, experts in the matter felt the guidelines were entirely appropriate. Now the FDA appears to be questioning what the risk threshold is — and the preliminary assessment in the draft has triggered outrage at the possibility that the current guidelines could end up being relaxed, especially worrisome for children and women of child-bearing age. I called frequent Daily Health News contributor Mark Stengler, ND, to ask what he thinks of all this.


It’s true that fish contains omega-3 fatty acids essential to developing nervous systems and brains — but there are lots of other ways to obtain these valuable essential fatty acids. An internal EPA memo, posted on the Environmental Working Group Web site, stated its concern over the FDA draft, calling the information “scientifically flawed and inadequate in several aspects.”

Dr. Stengler, who sees many patients with mercury and other heavy metal toxicity, says that he believes any change to the FDA advisory would make the FDA look “foolish and untrustworthy.” He is concerned that the FDA and indeed most conventional medical doctors underrate the dangers of mercury toxicity in general. Dr. Stengler told me he finds about half of the people he screens for toxic metals (which includes mercury, aluminum, arsenic, lead, etc.) have elevated mercury levels. Genetics and overall good health enable some individuals to tolerate or more easily eliminate mercury from their bodies, but many others cannot. He believes that mercury toxicity triggers many chronic illnesses including autoimmune diseases and those affecting neurological and digestive systems. “Mercury damages the brain and decreases memory,” says Dr. Stengler. He is dismayed that researchers have ignored this possibility.


Even miniscule amounts of mercury are potentially very damaging, says Dr. Stengler. Among the ways mercury can harm us…

  • It attaches itself to protein and enzymes, creating interference with the nervous, endocrine, immune, enzymatic, gastrointestinal, reproductive and urinary systems.
  • It displaces essential minerals (mostly zinc and copper) in cells, thereby creating free radicals believed to be a cause of degenerative diseases such as cancer, atherosclerosis and chronic fatigue syndrome.
  • It turns the immune system against itself.
  • It interferes with transportation of oxygen and waste products, impairing blood flow, harming the cardiovascular system and dramatically depleting the body of its most important antioxidants.

When pregnant women ingest mercury, there is enormous potential danger to the fetus. A recent study found that women of childbearing age who exceeded the recommended limit of more than the two servings of fish a week would have mercury concentrations seven times higher than women who avoided fish entirely. An increase in fish consumption in pregnant women would certainly increase the number of pregnancies at risk of mercury-related health effects resulting in birth defects and irrevocable damage to cognitive thinking, memory, attention, language and fine motor skills, points out Dr. Stengler.


The truth is that everyone — including women and children — can get the benefits of fish without risking the danger of mercury toxicity. Dr. Stengler advises patients to avoid eating any of the large fish included in the FDA guidelines, saying doing so is not worth the danger. He recommends limiting consumption of fish known to be high in mercury, including tuna (especially albacore), to no more than one six-ounce portion once every other week and does not recommend tuna at all for pregnant women and young children. Instead, get the benefits of fish by eating those known to be low in mercury. This list includes wild salmon — available fresh, frozen and, most affordable, in cans — as well as sardines (fresh or canned) and farmed trout. Finally, supplement regularly with high-purity fish oil in such brands as Nordic Naturals (www.nordicnaturals.com) or Carlson Nutritional Supplements (www.carlsonlabs.com), which are 99% mercury free and, according to Dr. Stengler, quite safe.