T Nation

tuna is killing you

I eat around 3 cans of tuna a day so I was kind of disillusioned when I heard that the mercury levels in tuna are deadly over time. I heard that the mercury sits in your body and builds up over time. After years over exposure, it could kill you. A study said not to eat more than one can of tuna per week. Any thoguhts?

I will get you guys the study soon. I have to have someone send it to me first.

I remember reading that you have to eat a whole lot of fish to get mercury poisoning. Most of the mercury in tuna is naturally occurring and not solely from pollution. Tuna as a species usually are caught at least 20-100 miles offshore in water depths over 1000 feet sometimes. I think some of this information is biased that is out there.

in case you want to read the article, it is in Health magazine(june 2003) on page 120.

If you have access to a computer to enable your message here, you also have access to the “study”. Look it up on Medline, Pubmed, National Library of Medicine, etc. etc. I’m eager to see this research and the data that you are basing your conclusions on.

Thanks for the nutrition tip though. It’s intelligent comments such as “Tuna is killing you” that have forced my diet into nothing but cottage cheese and T-vixens. Just don’t tell me that licking a Vixen will cause LSD-like symptoms. Or maybe that would be a good thing. Whatever. I’m going to go see if “carrots cause blindness” or “Flax-seed is the cause of Mad Cow disease”.

"I know people who had. A while ago we where having a discussion on this at the HST forum and when I and others talked about the concerns one poster was very quick to state that he was on a tuna and rice only diet for one year and nothing wrong happened to him. Curiously, after we started talking about possible symptoms of chronic mercury poisoning the guy actually came out and said that during that year he developed a constant shaking in his hands that he couldn’t find what the case was. Guess what’s one of the symptoms we where talking about? Mercury functions as a very potent neurotoxin, it’s no joke. The study I referenced in cats showed that they became letargic after a few months on a tuna only diet, lost energy, and lost motor skills, including coordination. Other more serious symptoms at a further stage will be muscle wastying, loss of strenght, memory, etc…

The mother of a friend of mine also developed a very weird nervous disease, kind of like Parkinsons, after years of only eating fish and not meat. Two serving a day she had. A friend of this same friend who is a fisherman was ordered by his doctor to completely avoid fish after he developed symptoms of poisoning. Again, two or three servings per day.

Obviously they weren’t eating only tuna.

So if your only concern is dying a fulminant death, then fear not and eat at will. If you’re somewhat scared of developing a neural disease latter and life that will make you lose your hability to function as a normal human been by your own, then maybe there’s reason for concern. Like I said before, there’s no research proving that a steady long term low level intake of mercury is safe so in this particular case I think the benefit of doubt is in the side of the cautious faction."

Also, The tuna that is used in cans are to young and small to contain harmful amounts of mecury in it.

No need to mock me smilecreator, i posted this thread because i have heard that that mercury in tuna is harmful and i wanted to find out if other people have heard the same.
I just heard that from someone else too rank, do you know the reason for it. Do they accumulate mercury throughout their lifetime?

Minomata disease is the result of mercury poisoning. High levels of mercury, while extremely toxic, have been mainly found in fish found in limited regions of the globe (“Minomata” is a city in Japan, where a high population of people had neurological disorders later linked to mercury poisoning.)
I’d be more concerned about the high levels of chlorine found in Tuna, than mercury. It is generally chlorine that is cause for concern for pregnant women and young children. A can a day has been found to be healthy (sorry can’t remember the report).

JB posted something on this in one of his appetite articles

bob2624, I didn’t mean it like that, and I apologize.

It is important to discuss things like this. For every study saying there is a health benefit to something, there is also one or more saying the opposite. We all have to weigh the evidence and make our own decisions regarding the risks and benefits.
Again, I’m sorry for offending you.

JB said that the levels of toxins in tuna are 1/10 of what it would take to harm a human. Cats are another matter.

Three cans a day everyday is quite a bit, and long term you could run into some problems. I seeriously doubt that it would killl you though. I would try varying your protein choices a little more.

There was a case where a lady was eating 6 oz of swordfish everyday, and after 6 weeks, she began showing early symptoms of mercury poisoning. She quit eating swordfish, and the symptoms went away after a month.

The occurrence of mercury poisoning iin Minomata, was due to an industrial accident. The mercury level in fish there were way above normal.

I think the main issue is not that tuna will kill you in 2 years due to mercury poisoning but the long term effects. By long term I mean 20 years. (What you don’t think that far ahead?) I think over a few years you probably won’t notice anything. I myself used to eat a ton of tuna for years…and I don’t think I noticed any symptoms of mercury poisoning. But according to some, mercury over many years is the cause of elzhimers and other neurological afflictions. So you may want to think of it that way. Ciao. :slight_smile:

3 cans a day is a bit much. Although there haven’t been many conclusive studies done on this as of yet, high mercury levels could give you trouble down the road.
Moderation is the key here.
Try getting some variety and maybe lower your consumption down to 1/day.
There are many other quality sources of protein out there that should not be neglected.

Cottage cheese
Wild Salmon
Eye of round steaks

Just a few to keep on your grocery list :slight_smile:

I am not limiting myself really, but while i am in school, tuna in those pouches is most convenient at lunch so I usually eat 3 of them. The rest of the day I eat steak, eggs, and chicken… I can’t take the look or what i assume will be the taste of cottage cheese.

I didn’t mean like if you eat 6 cans of tuna, tomorrow you will be sleeping with the fishes… HAHAHAHAHAHAHAHAHAHA… yea, anyway, you guys get the idea. I was wondering also, is the murcury in all fish or just some, or just tuna?

Tuna, swordfish, shark, etc…

basically, my understanding(which is mostly un-informed, so take it for what it’s worth) is that the higher up the food chain, the higher the mercury danger.

No, it isn’t. Think for a moment how such a comment sounds… preferably before mashing submit.


I was under the impression that heavy metals in fish is more of a problem in areas where the water is polluted. For example, I grew up in an area where, for many years, steel mills dumped heavy metals into the rivers. It is still a problem years after the mills have closed down, and people do not eat the fish in these waters because of this.

There are conspiracy theories out there based on anecdotal evidence. For example, we know that the neurological disease multiple sclerosis occurs much more frequently in northern latitudes and is almost nonexistent in equatorial regions. I’ve read studies that suggest MS is linked to sunlight/vitamin D deficiency, aspartame, and EFA deficient diets. Another speculation with regards to MS involves mercury exposure, and studies have been done trying to link this to living near steel mills or having amalgam tooth fillings with mercury. Others have sought to isolate a virus responsible, but there really has been no established cause.

While it’s not a good idea to go on anecdotal evidence, these theories are often what lead to studies being performed in order to prove or disprove these theories. This is a good thread and I’m interested in this because tuna and fish oils are staples of my diet, so keep the info coming.

I think I read the same thing, although probably in a different place.

Fresh tuna actually has more mercury then canned tuna, if I remember correctly. Also, you’d have to eat something like 3lbs of tuna a day, or some insane amount, to do anything truly harmful.

No doubt, mercury = bad. But is it as bad as french fries from McDonalds? I doubt it!

I hope tuna isn’t killing me. I am still in high school and my parents aren’t the biggest advocates of my bodybuilding lifestyle, so I buy all my food and supplements on my own. Having very little money, I don’t buy very much chicken or red meat. Tuna is the core of my protein intake and I eat 3 or more cans a day. This could be bad…mabye worse than McD’s fries.