A report issued earlier this week, titled “Tuna Surprise: Hidden danger in school lunches” raises false, counterproductive alarms.
The non-profit Mercury Policy Project used test results and its estimates to urge a limit on tuna offerings in schools … and/or replace tuna with low-mercury species like salmon.
We agree that giving kids optimally safe and nutritious seafood makes sense, and that sardines or wild salmon – rich in omega-3s, protein, and vitamin D, but low mercury – would be great choices.
Tuna study author's
words belie his conclusions
Edward Groth, Ph.D., analyzed the test results to produce the estimates of harm.
But in a 2009 letter to the National Fisheries Institute (NFI) – a trade association dominated by the canned tuna industry – he noted that “Americans (essentially everyone) should be eating more fish than they do at the present.” (NFI 2009)
And he went on to say this: “If risks are overstated or presented in a frightening way, people may eat less fish and public health could suffer.” (NFI 2009)
Yet, Dr. Groth's report ignores the high levels of selenium in tuna and almost all ocean fish, which explains why the vast majority of epidemiological and clincial evidence finds no harm to kids – but clear benefits – from childhood fish intakes much higher than those in the U.S.
The great preponderance of evidence does not support the U.S. fish-intake guidelines used in most estimates of the risk of tuna to children ... which, judging by persuasive clincal evidence, may prevent optimal developmental and overall nutrition
But the idea that moderate intake of canned tuna poses risks is contradicted by virtually all independent academic and government analyses of the evidence.
No stake in the fight over fish and mercury
Frankly, we don't have a stake in this argument, for these reasons:
  • Most of our seafood is naturally low in mercury (e.g., salmon, cod, sablefish, sardines, and shellfish).
  • We offer only younger, smaller members of long-lived predators, which accumulate mercury as they grow large and old (halibut and albacore tuna).
Supermarket tuna brands often blend fish of various ages and sizes. And as shown by the Mercury Policy Project tests, even “light” tuna – which is generally lower in mercury versus albacore tuna – can be relatively high in the metal.
Independent lab tests of Vital Choice seafood find it free of hazardous levels of mercury.
But we feel compelled to respond to the Mercury Policy Project's misleading report, which seems driven by a laudable desire to cut mercury emissions from coal-burning … the source of about one-third of all human-generated mercury pollution.
Report grossly overstates the risk of tuna
Sadly, the Project's conclusions toss the baby out with the bathwater … and we've seen similarly misguided campaigns before … see “Fish-Mercury Fears Hyped, Despite Pesky Facts”.
The Mercury Policy Project purchased and lab-tested 59 samples of canned tuna brands often sold to schools: six brands of “light” (e.g., skipjack, tongol) tuna and two brands of “white” (i.e., albacore) tuna.
Unsurprisingly, the average mercury levels closely matched those found in canned tuna by other groups and by the U.S. Food and Drug Administration (FDA).
The results were expressed in micrograms per gram (µg/g), which is the same as parts per million (ppm):
  • The average mercury level in 48 samples of light tuna was 0.118 µg/g … lower than the FDA's reported average of 0.128 µg/g. (StarKist and Chicken of the Sea accounted for 60 percent of the light tuna samples.)
  • The average mercury level in 11 samples of albacore tuna was 0.560 µg/g … higher than the FDA's reported average of 0.350 µg/g.
  • Mercury levels were highly variable from sample to sample, within types of tuna, within brands and even within some packages: light tuna ranged from 0.020 to 0.640 µg/g, while albacore ranged from 0.190 to 1.270 µg/g.
  • 50 of the 59 samples contained tuna imported from other countries. The nine samples of US-caught light tuna had the lowest country-of-origin average mercury level, 0.086 µg/g, and light tuna from Ecuador had by far the highest average level, 0.254 µg/g. Light tuna imported from Thailand and the Philippines averaged 0.104 and 0.108 µg/g, respectively.
In some cases, the levels would result in mercury intakes higher than the federal guidelines for children, depending on a child's weight and tuna intake over time.
For example, the report estimates that a 44-pound child who ate two ounces of albacore tuna containing the highest levels of mercury detected would be getting almost half (47 percent) of the U.S. recommended maximum.
U.S. fish-intake standards ignore the best evidence
The best available evidence indicates that U.S. recommended fish intakes for children overstate the risk, at the expense of optimal child development.
But the U.S. intake guidelines for children form the basis for the calculations in the Project's report, which were performed by consultant Edward Groth, Ph.D.
In fact, the FDA issued a report in 2009 saying exactly that: see “FDA Analysis Supports More Fish for Moms and Kids”.
The findings of the FDA report fit with the position of the world's leading independent scientists in the field of omega-3s and child development.
For example, see Newsweek magazine's interview with researcher Captain Joe Hibbeln, M.D., clinical psychiatrist at the U.S. National Institutes of Health, on our Healthy Mom & Baby page.
And, as USA Today reported, Diane Pratt-Heavner of the School Nutrition Association said that her group “doesn't believe tuna is a big issue because it's not popular on school lunch menus. She only sees it as an item in deli-style counters, mostly in high schools, where it's one choice among many.”
That “reassurance” is unnecessary, because it assumes that Dr. Groth's calculations reflect the actual risks of tuna consumption … but they don't, as explained in “Why is seafood so clearly safe, despite mercury?”, below. 
Groups that fan fear of seafood ignore the evidence that current U.S. intake guidance for children and pregnant/nursing mothers is contradicted by the evidence and may harm child development.
Why is seafood so clearly safe, despite mercury?
The form of mercury found in fish (methylmercury) harms the nervous system and brain because it attaches to selenium in the body.
Every molecule of methylmercury you consume makes one molecule of selenium unavailable to antioxidant enzymes that protect your brain against free radicals, and require this essential mineral to function.
Non-U.S. children and adults who consume far more ocean fish than Americans show no signs of harm from mercury.
Why? Because almost all ocean fish contain much more selenium than mercury.
Overwhelming evidence indicates that the risks from mercury in ocean fish (not freshwater fish) are negated by their far higher levels of selenium.
Shark, whale meat, swordfish, tilefish, and king mackerel are the few exceptions to the near-universal rule that ocean fish have more selenium than mercury. (Note: Our Portuguese mackerel is a different species that has very little mercury and ample selenium.)
We highly recommend the videos and brochures at Fish, Mercury, and Nutrition, which reflect the latest findings and feature the leading scientific experts on these subjects.
The excellent brochures found there include “What's the Story with Ocean Fish?” and “Selenium and Mercury: Fishing for Answers”.
And, in two other videos, one of these experts – Nick Ralston, Ph.D. – explains why populations who eat far more ocean fish than Americans show no signs of harm ... click here to view Ralston on Seafood Safety & Selenium Part I and Ralston Part II.
You will find these links, and more information, on the Vital Choice website page titled “Our Purity Story”.
To explore our past coverage of this topic, see these articles in the Mercury Issues section of our news archive:
Again, we don't have a dog in this fight … we just hate to see the facts ignored in pursuit of any agenda … especially when that pursuit can harm those it's meant to help.
  • National Fisheries Institute (NFI). Edward Groth's Fish Facts. Accessed at http://www.aboutseafood.com/press/media-blog/new-information-mercury-and-fish-no-context-increased-confusion
  • The Mercury Policy Project (MPP). Tuna Surprise: Hidden danger in school lunches. September 18th, 2012. Accessed at http://mercurypolicy.org/?p=1611