This is going to be a long article and I know not everyone will have time to read it. So I’m going to summarize the key points right up front because I think this information is so important:
Overview
- Selenium protects against mercury toxicity, and 16 of the 25 highest dietary sources of selenium are ocean fish
- If a fish contains higher levels of selenium than mercury, it is safe to eat
- Most species of commonly eaten fish in the U.S. have more selenium than mercury
- Fish are not significant sources of PCBs and dioxins when compared to meat, dairy or vegetables
- The benefits of eating fish regularly far outweigh the potential risks, which are negligible
- Pregnant mothers and young children should eat 2-3 servings of oily ocean fish each week
These days a lot of people are scared to eat fish. They’ve been told that fish are full of contaminants like mercury, PCBs and dioxins that cause neurological problems and may increase the risk of cancer. Pregnant women have been especially warned due to the supposed risk of these toxins to the developing fetus.
In the last few articles I’ve established the importance of the long-chain omega-3 fatty acids EPA and DHA in human health. I’ve argued that the conversion of plant-based omega-3 fats like ALA into the longer chain EPA and DHA is extremely poor in most people.
The conclusion is obvious: fish should be a part of our diet. But is it safe to eat fish?
You might be surprised to learn that the answer is a resounding yes. In this article I’ll demonstrate that concerns about toxins in fish have been overblown, and that there is almost no risk associated with eating fish when a few simple precautions are taken.
The selenium story
Although people are increasingly concerned about the effects of mercury levels in fish, recent evidence suggests that the trace amounts of mercury in the fish Americans eat aren’t high enough to pose a health risk.
But measuring only mercury significantly exaggerates this risk, because it ignores the important role of selenium.
This new substance makes it hard for the body to absorb the mercury separately. Simply put, when selenium binds to mercury, mercury is not longer free to bind to anything else – like brain tissue.
Studies have shown that relevant amounts of selenium (Se) can prevent oxidative brain damage and other adverse effects associated with mercury toxicity. (PDF)
University of North Dakota researcher Nicholas Ralston has published several papers on the protective effects of selenium. He describes the relationship between selenium and mercury as follows:
Think of dietary selenium as if it were your income and dietary mercury as if it were a bill that you need to pay. Just as we all need a certain amount of money to cover living expenses such as food and rent, we all need a certain amount of selenium.
And guess what foods are highest in selenium? You’re right! 16 of the 25 best sources of dietary selenium are ocean fish.
He goes on:
Only one major study has shown negative effects from exposure to mercury from seafood, and that seafood was pilot whale meat. Pilot whale meat is unusual in that it contains more mercury than selenium. When you eat pilot whale meat it’s like getting a bill for $400 and a check for less than $100. If that happens too much, you go bankrupt. On the other hand, if you eat ocean fish, it’s like getting a check in the mail for $500 and getting a bill for $25. The more that happens, the happier you are.
What Ralston is telling us is that as long as the fish we’re eating has more selenium than mercury, there’s nothing to worry about.
Fortunately, studies by several independent organizations have consistently shown that most of the fish we eat contain significantly more selenium than mercury. Fish that contain more mercury than selenium include pilot whale, tarpon, marlin, swordfish and some shark.
The following chart illustrates the relative levels of selenium and mercury in commonly eaten ocean fish:
The selenium health benefit value (SeHBV)
Researchers have proposed a new measure of seafood safety called the Selenium Health Benefit Value (SeHBV) that takes the protective role of selenium into account.
Fish with a positive (above zero) SeHBV ratio would be safe to eat, whereas fish with a negative ratio would be unsafe. Using these criteria, most varieties of ocean fish have positive SeHBV ratios and are thus safe to eat.
A study conducted by the Energy & Environmental Research Center (EERC) and the Environmental Protection Agency (EPA) also found that an estimated 97% of the freshwater fish from lakes and rivers in the western U.S. are safe to eat. It is the only study I’m aware of that has measured both mercury and selenium levels in the tissues of freshwater fish. 1
So how much fish is safe to eat?
The joint recommendation for fish consumption of the EPA and FDA as of 2004 is as follows:
- Eat up to 12 ounces (2 average meals) a week of a variety of commonly eaten fish and shellfish found consistently low in mercury, including shrimp, canned light tuna, salmon, pollock, and catfish
- Limit albacore tuna to 6 oz. per week
- Do not eat shark, swordfish, king mackerel, or tilefish because they contain high levels of mercury
Notice that these recommendations are already quite liberal compared to the fish-phobes who suggest we avoid fish entirely.
But even these recommendations are too strict, because they don’t take the protective effects of selenium into account. As long as the fish is higher in selenium than it is in mercury, there’s no reason to limit consumption to 12 ounces per week.
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What about dioxins and PCBs?
PCBs are synthetic organochlorine compounds previously used in industrial and commercial processes. Dioxins are organochlorine by-products of waste incineration, paper bleaching, pesticide production, and production of certain plastics. Yummy!
While it makes perfect sense to try to avoid these toxins to the greatest extent possible, abstaining from fish isn’t a particularly good strategy.
The highest dietary sources of PCBs and dioxins are not fish, but beef, chicken and pork (34%), dairy products (30%) and vegetables (22%). Fish constitute only 9% of our dietary intake of these chemicals.
However, an analysis has shown that, per 100,000 individuals, consumption of farmed vs. wild salmon would result in 24 vs. 8 excess cancer deaths, respectively, while consumption of either farmed or wild salmon would result in 7,125 fewer coronary heart disease (CHD) deaths.
Another analysis of the same data suggested that, for all ages evaluated (25-35 to 85 years), CHD benefits outweighed cancer risks by 100- to 370-fold for farmed salmon and by 300- to more than 1000-fold for wild salmon.
It’s important to note that the benefits of fish consumption are based on prospective studies and randomized trials in humans, whereas estimated cancer risks include a 10-fold safety factor and are based on experimental data in animals and limited studies in humans at extremely high doses.
Cancer estimates also assumed lifetime salmon consumption of 1,000 mg/d of EPA & DHA (four 6-oz servings of wild salmon every week for 70 years). Of course virtually nobody in the U.S. currently eats this much salmon.
On the other hand, CHD mortality reduction may be achieved with lower intake (i.e. 250 mg/d – one 6-oz. wild salmon serving per week). At this intake, CHD benefits would be the same (7,125 fewer deaths) while lifetime cancer risk would decrease by 75% (6 and 2 estimated deaths per 100,000 for farmed and wild salmon respectively). The CHD benefits would outweigh cancer risks by more than 3500-fold in the case of wild salmon.
Once again, with few exceptions (the species of fish with more mercury than selenium), it’s not only safe but incredibly beneficial to eat fish regularly.
How beneficial? Let’s find out.
Fish consumption, cardiovascular disease and total mortality
In 2006 Mozaffarian & Rimm published a paper in JAMA called “Fish Intake, Contaminants and Human Health: Evaluating the Risks and Benefits“. They analyzed several studies that examined the impact of fish consumption on both coronary and total mortality. They found that modest fish consumption (e.g. 1-2 servings/wk) – especially of oily fish higher in EPA and DHA – reduced the risk of coronary death by 36% and total mortality by 17%, and may favorably affect other clinical outcomes.
The authors summarized their findings this way:
For major health outcomes among adults, based on the strength of the evidence and the potential magnitudes of effect, the benefits of fish exceed the potential risks.
And:
For women of childbearing age, benefits of modest fish intake, excepting a few selected species, also outweigh risks.
They also pointed out that the Japanese eat 900 mg/d of EPA & DHA on average, and have death rates from coronary heart disease 87% lower than those in Western populations (like the U.S.).
If you’re interested in learning more about this study, I recommend listening to the JAMA Audio in the Room interview with its lead author, Mozaffarian.
Fish consumption, pregnant mothers, and children
DHA is essential for proper development of the brain. It is preferentially incorporated into the rapidly developing brain during gestation and the first two years of infancy, concentrating in the gray matter and retinal membranes.
In a meta-analysis of 14 trials, DHA supplementation improved visual acuity in a dose dependent manner. In another trial of 341 pregnant women, treatment with cod liver oil from week 18 until 3 months postpartum raised mental processing scores at age 4 years.
This is consistent with observational studies showing positive associations between maternal DHA levels or fish intake during pregnancy and behavioral attention scores, visual recognition, memory, and language comprehension in infancy.
An FDA report issued in 2008 noted that the nutrients in fish – especially n-3 LCFAs, selenium, and vitamin D – could boost a child’s IQ by an estimated ten points. 2
The FDA report summarizes evidence suggesting that the greatest benefits to children would result if pregnant women of childbearing age, nursing mothers and young children ate more than the 12 ounces of fish per week currently recommended by the EPA.
According to the National Fisheries Institute, Americans currently consume only five ounces a week of fish high in n-3 LCFA, which is less than half the recommended amount. The NFI also estimates that up to 14 percent of women of childbearing age eat no fish at all, despite the fact that n-3 LCFA are essential to proper fetal brain and eye development.
Based on the new understanding of selenium’s protective role, and the importance of DHA for fetal and early childhood development, pregnant mothers should be advised to eat oily ocean fish regularly.
Fish consumption and autoimmune and inflammatory disease
The first evidence of the significant role of dietary intake of n-3 LCFA in reducing inflammation came from epidemiological observations of the low incidence of autoimmune and inflammatory disorders in a population of Greenland Eskimos compared with gender- and age-matched groups living in Denmark. The Eskimos in this study had dramatically lower rates of psoriasis, asthma and type 1 diabetes, as well as a complete absence of multiple sclerosis.
Animal and human studies suggest that n-3 LCFA suppresses cell mediated immune responses. Increasing the amount of n-3 LCFA while decreasing omega-6 fatty acids leads to improvements and a decrease of steroid use in patients with rheumatoid arthritis and asthma.
This is because omega-3s have been shown to suppress the capacity of monocytes to synthesize interleukin-1 (IL-1) and tumor necrosis factor (TNF). IL-1 and TNF are the principal mediators of mediation in several different inflammatory and autoimmune conditions.
Summary
This is simply a re-cap of the overview presented at the beginning of the article. But it’s worth repeating.
- Selenium protects against mercury toxicity, and 16 of the 25 highest dietary sources of selenium are ocean fish
- If a fish contains higher levels of selenium than mercury, it is safe to eat
- Most species of commonly eaten fish in the U.S. have more selenium than mercury
- Fish are not significant sources of PCBs and dioxins when compared to meat, dairy or vegetables
- The benefits of eating fish regularly far outweigh the potential risks, which are neglible
- Pregnant mothers and young children should eat 2-3 servings of oily ocean fish each week
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- Energy & Environmental Research Center, University of North Dakota (EERC). EERC Research Finds Mercury Levels in Freshwater and Ocean Fish Not as Harmful as Previously Thought. June 22, 2009. Accessed at http://www.undeerc.org/news/newsitem.aspx?id=343 ↩
- Energy & Environmental Research Center, University of North Dakota (EERC). EERC Research Finds Mercury Levels in Freshwater and Ocean Fish Not as Harmful as Previously Thought. June 22, 2009. Accessed at http://www.undeerc.org/news/newsitem.aspx?id=343 ↩
Interesting Read
Hi Chris,
Personally, I am not convinced that the high levels of mercury in fish such as tuna and swordfish are safe even if they exist in the presence of equimolar or higher concentrations of selenium.
The definitive study on this issue is Chang’s1, in which 16 kittens were fed a diet of tuna containing 0.3 to 0.5 ppm mercury, plus supplementary nutrients and vitamins. After a period of seven months, two of the cats had mild ataxia and one had severe ataxia. The cats were sacrificed at 11 months and autopsy revealed extensive liver damage including damage to the mitochondria. In this case the selenium in the fish was not protective.
I agree with Dr Ralston’s statement in his review, Mercury: selenium interactions and health implications2, where he says “the ‘protective effect’ of selenium against mercury exposure may actually be backwards. Mercury’s propensity for selenium sequestration in the brain and endocrine tissues may inhibit formation of essential Se-dependent proteins (selenoproteins). Hence selenium’s ‘protective effect’ against mercury toxicity may simply reflect the importance of maintaining sufficient free selenium to support normal selenium-dependent enzyme synthesis and activity.” But even maintaining optimal levels of selenium may not be enough to completely nullify mercury’s toxic effects.
In the same review he mentions the study by Friedman into the protective effects of dried swordfish on methylmercury toxicity in rats. He states that rats fed a diet of swordfish and methylmercury showed no signs of neurotoxic effects, while rats fed a control diet spiked with methylmercury without swordfish did. Dr Ralston attributes this to the protective effects of selenium.
In spite of the proposed protective effect of selenium, both the control group and the experimental groups died, at 4.6 and 5.3 weeks respectively. It should also be noted that the control diet included 15% casein which has been shown to reduce mercury excretion in rats3, and thus may have exacerbated the effects of mercury toxicity in the control rats.
These studies do not take into account the long-term effects of mercury exposure. The lower the dose of mercury, the greater the delay in the manifestation of symptoms. Deborah Rice fed monkeys a diet which included 50 micrograms of methylmercury per day for 7 years4. After cessation, blood levels quickly dropped to normal. When the monkeys were tested at 13 years of age they displayed clumsiness and loss of fine motor skills as well as decreased sensitivity to touch. Humans are exposed to mercury for decades and have longer to develop overt signs of mercury toxicity.
One of the problems with the studies from the Seychelles and the Faroe Islands on the effect of methylmercury on neurodevelopment is that they rely on hair testing of mercury levels. This is often accurate, but does not take into account the fact that mercury disrupts cellular transport due to its affinity for sulfhydryl molecules. These molecules often form the active site in cellular transport proteins. Mercury binds to these active sites, altering mineral transport. This can result in hair readings for mercury and other toxic elements that are artificially low. Thus children with high exposure may actually be classed as having low exposure. Hair analysis actually provides a measure of how much mercury is being excreted. The most important factor is how much mercury is being retained in the body – but that is difficult to measure.
Amy Holmes found that autistic children, even though they had higher exposures to mercury through their mothers’ dental amalgams and Rhogam injections, had lower levels of mercury in their hair, implying a reduced ability to excrete mercury5. The following hair test illustrates the ability of mercury to disrupt mineral transport in a child with ADHD and a weak immune system – http://www.livingnetwork.co.za/files/hairtest_564.pdf
This is clearly an abnormal distribution of elements (all except one of the essential elements are below the 50th percentile) associated with a low reading for mercury.
It may be safe for some individuals with optimal antioxidant and metallothionein status to consume tuna and other high mercury fish, but I think for many it would be safer to stick to fish such as sardines and salmon, which have high levels of omega 3s, but much lower levels of mercury.
Thanks,
David Hammond
author – Mercury Poisoning: The Undiagnosed Epidemic.
References
1 Chang, L. W., & Yamaguchi, S. (1974). Ultrastructural changes in the liver after long-term diet of mercury-contaminated tuna. Environmental Research, 7(2), 133-148.
2 Raymond, L. J., & Ralston, N. V. (2004). Mercury: selenium interactions and health implications. Seychelles Medical and Dental Journal, 7(1), 72-77.
3 Rowland, I. R., Robinson, R. D., & Doherty, R. A. (1984). Effects of diet on mercury metabolism and excretion in mice given methylmercury: role of gut flora. Archives of Environmental Health: An International Journal, 39(6), 401-408.
4 Rice DC. Delayed neurotoxicity in monkeys exposed developmentally to methylmercury. Neurotoxicology. 1989 Winter; 10(4):6450-50.
I agree that some people should limit their consumption of fish and avoid those with higher mercury content. There’s plenty of anecdotal and clinical evidence of people becoming mercury toxic from eating fish. I question selenium binding to mercury in the fish, making the mercury no longer free to bind to anything else. Can this ‘new substance’ [what is this substance?] be cleaved apart in the gut? Are there other things in the body which mercury has a greater affinity for causing it to release this new substance and bind to other things? People with systemic illnesses that have low glutathione (GSH) among other things, have less GSH available to make glutathione peroxidase (GPx). The presence of adequate selenium does not mean there will be enough GPx to deal with the mercury. Often people with low GSH will have polymorphisms which reduce their bodies ability to make GSH. Often GSH is depleted because of a higher demand for GSH to detox products from systemic infection. Often there is a blockage in GSH production that has happened over time. Non-denatured cysteine is usually low in such people. Cysteine is considered a rate limiting factor in GSH production. Cysteine is also needed to metabolise most forms of selenium to selenocysteine so that the body can use it to make GPx. So the bodies of people who are low in GSH will usually be unable to utilise the selenium as much as those with enough non- denatured cysteine. People with low GSH should avoid fish higher in mercury, and limit their intake of most fish.
Thank you for the science-based information. Also thanks to Chris.
Thank you for taking the time to add to the discussion so relevantly.
Thanks for the detailed info. I ,as a layman, also wondered that it could be considered ‘healthy’ to use up our selenine intake just to bind with mercury. The other issue is that there are many of us who eat fish as others might eat meat, and so the low intakes mentioned in the article, don’t really help. I’ve started to find mackerel and salmon unappetising, so I may follow my gut and stick more to white fish, and less of it at that.
‘Selenium’
They fed the kittens a diet of nothing but tuna, nutrients and vitamins. Do you think any of us would want to exist on just that? A well rounded diet includes lots of variety. If we ate just one thing over and over we wouldn’t be healthy either. This study doesn’t prove anything!
If any human was fed just tuna they would be unhealthy because they are not getting any of the other many things that we need to make a well rounded diet.
fantastic comment! Thank you for clarifying this so well!
Well, I eat 5-6 cans of fish a day. With oats for breakfast and salad for lunch. Over the past 12 months I have lost 115lbs in weight and have managed to come off my BP and cholesterol meds. And I am in great shape. So I pay my money and takes my chances…
I too, am wondering about the issue of radiation and other toxins in the fish besides mercury. Also, what is the best source for Tuna?
I’m almost 18 years old and I consume fish 3 or 4 times a week, mostly wild sustainable alaskan salmon. Is this fine?
Is it safe to eat Crustaceans during pregnancy? I am thinking yes, since they are at the bottom of the food chain and have less methylmercury compared to other fish. But I would like some clarification. Thanks!
FYI Brazil nuts are the highest in selenium also an easy way to increase selenium levels just 2-3 of them is enough a day…..
Hi, Unless I’ve missed it, with all this talk of mercury, no one has mentioned chlorella. It is one of if not the best methods of ridding the body of mercury. I started taking it 10 years ago after finding my mercury fillings were almost killing me. Had them all removed and have never looked back. I have to say though, the side effects of mercury being removed from the system are truly horrendous, but it has been worth it.
Don’t forget that this doesn’t apply to pregnant and lactating women. For them the only solution is still to eat fish low in mercury.
Chlorella is awesome! You do have to be very careful about where you get it from. Organic standards allow cow manure to be used as the fertilizer for the Chlorella…. then that means you need clean manure to provide for the Chlorella… seems we just have to get this planet and its environment back in balance in general (including ourselves). Check out Spirulina as well!
Thanks–saved me researching for selenium!!
Hi Chris,
You do amazing work, and I appreciate you approach! I find your articles and podcasts very informative and have already changed the way I eat. I was wondering what suggestions you have regarding avoiding or reducing radiation while increasing fish consumption in light of the ongoing Fukushima situation. Also, do the risks of eating regular canned sardines (bpa, etc) outweigh the benefits. I’m on a budget and the “organic” canned sardines are 3.5X the price. Thank you!
Hi. Sardines are wild caught, so anyone labelling some of them ‘organic’ would be breaking the law in Europe, since they are not farmed organically. They are the same, unless someone has started farming them ,which i doubt would make sense.
My biggest issue with any fish consumption is sustainability. Most of our oceans have been depleted of large fish (“fishing down the food web”), and marine ecosystems in general are pretty trashed worldwide (with the exception of the Ross Sea, Antarctica, which we are just starting to fish more extensively). Certification and watchdog programs like the MSC (Marine Stewardship Council) and SeafoodWatch are not necessarily relying on science to make their recommendations. The MSC is notorious for being highly influenced by the fishing industry, and SeafoodWatch just green-listed Chilean Sea Bass, which no scientist who studies this species or its ecosystem would ever recommend fishing commercially (they are long lived, slow to reproduce, and have already shown a huge population crash in the Southern Ocean). Furthermore, farmed fish is almost completely unsustainable by definition, because you still have to fish the small fish to make the pellets that feed the farmed fish (the entire anchovy and sardine fishery off the coast of western South America is in peril because of farmed salmon). Pellets are also often mixed with GMO corn or soy, which I’m sure isn’t ideal from a nutritional perspective.
Chris, I would be delighted if you could address this topic in the context of recommending fish consumption, and stress the importance of obtaining sustainable fish. I think it can be done, but relying on SeafoodWatch and the MSC is not enough. In the San Francisco Bay Area we can join seafood “CSAs” like Siren SeaSA or Fair Share of Sea Forager who purchase directly from small boats, which are by definition fishing more sustainably than most, but how does one obtain sustainable fish in places where there is little access to this kind of program?
Thank you for this comment. I agree, sustainability is a really important issue here.
Also, what of the relative toxicity of farmed fish?
It depends! Some fish farms produce little in the way of toxic byproducts, but most farmed fish are heavily contaminated. There is one trout farm in California that raises fish very sustainably, but it’s a rare case. Trout, incidentally, happen to be vegetarian, so farm feeding them has a smaller environmental impact than raising, say, a salmon.
Hi Chris
This article brings up the issue of fermented cod liver oil again. Many nutritionists now recognise that FCLO is rancid and wont use it. I know you value it for the fat soluble vitamin content, but I still don’t understand why you would recommend it when it’s oxidized?
Cancer estimates also assumed lifetime salmon consumption of 1,000 mg/d of EPA & DHA (four 6-oz servings of wild salmon every week for 70 years). Of course virtually nobody in the U.S. currently eats this much salmon.”of course virtually no on in the US currently eats this much salmon in a week”
I easily eat this much wild salmon in a week. Considering a lot of people eat about 21 meals a week, four meals of salmon doesn’t seem unreasonable.
What about the radioactive waste being spewed out of Fukushima. It gets diluted, I agree, but long term consumption will have an effect. Go with Atlantic Fishes only!
JMHO
Exactly what I’ve been doing…sticking with Atlantic fish…at least until the next Big Spill on the Eastern Seaboard……
Chris,
Great article.
But I post to request that you date all your articles on your website and elsewhere. It’s important for us, even professionals like me, to know when something was written.
Thanks.
~~~
Can you review the research on overfishing and the state of the World’s ocean. I’ve read research that overfishing is causing more harm to our oceans, specifically coral reefs, than oil spills. This seems to never get main stream media attention. For environmental reasons, I lowered my intake of Omega 6’s, increased flax seed to improve the balance which is more important.
This article is quite misleading. Fish are in fact a significant source of PCB’s, dioxins, and heavy metals. You shouldn’t write articles that could effect peoples health if you don’t know what your talking about. People need to be aware that you shouldn’t eat top predator fish like swordfish. Vegetables are not a significant source of toxins typically speaking. The comment by Daniel is very good, sure fish are good for you, but you need to be smart about what types of you eat and how often. You can’t just advocate fish as being a care free healthy choice. I disagree that it is all hype – I have measured mercury in fish and the levels would astound you. Be smart people, don’t believe everything you read, especially in this article.
Hi there, a new study came out half a year ago, showing that seemingly the protective effect of Selenium found for rats in the study you cite, does not protect childbearing women as the IQ of there offspring significantly dropped with the amount of fish consumed:
http://www.sciencedirect.com/science/article/pii/S027869151100576X
adding the problems concerning the PCBs, as noted above by Daniel, I would not advise to rely on fish during pregancy but rather taking algeal DHA supplements.
Kind regards,
Frank
“The following chart illustrates the relative levels of selenium and mercury in commonly eaten ocean fish:”
I do wish people would put relevant units on stats graphics!
Good article, but you forgot to mention that some people don’t have the ability to detoxify. Heavy metal detoxifications are much more complex than binding minerals like mercury and selenium, it involves lots of pathways. If you have something like GI issues, metabolic imbalances, a stressed liver, or a weak immune system, just to name a few, your body might not be able to excrete that mercury.
Seafood is just right for a healthy life style.
Environmentalist left wing nut and New York Times are part of the head of lies when it allows the publication of distorted information.
I love seafood and its so healthy
Hi there,
Are there any reliable charts that categorise fish and seafood in terms of their levels of mercury?
Thanks
gotmercury.org
Chris, this line:
“The highest dietary sources of PCBs and dioxins are not fish, but beef, chicken and pork (34%), dairy products (30%) and vegetables (22%). Fish constitute only 9% of our dietary intake of these chemicals” is misleading.
is misleading. If you look at the original source, which is called “INTAKE OF DIOXINS AND RELATED COMPOUNDS FROM FOOD IN THE U.S. POPULATION,” the authors state that fish only contributes 9% of total dioxin intake because Americans tend not to consume a lot of fish. There are two graphs in this same paper showing that freshwater fish and butter have staggering levels of dioxins.