canned tuna & health risks

I

imported_flow

Guest
I eat ca. 1 can of tuna in water every day. I have heard horror stories about mercury being found in canned tuna; I also know that other kinds of fish (e. g. salmon) have been found to be contaminated with carcinogenous substances.

Is canned tuna safe? Is there an upper limit in how much you can safely consume within a given time span? Are there other, healthier kinds of fish which are neither more expensive nor less convenient to prepare?

Any answers welcome!
 
This has been discussed before in other threads. I too eat a tin of tuna every day and have the same concerns. Here's what I've found after study.

Firstly, the while thing is overblown because the studies used EPA guidelines instead of FDA guidelines. FDA allows for higher limits than EPA. Apples and oranges.

The tuna methylmercury issue is overblown. methylmercury is found in everything. Burning coal for hundreds of years has contaminated the world's water supply. To minimize risk, eat only tinned flaked and chunk light tuna. Avoid albacore (white) tuna as it has the highest mercury content. Funny how the cheapest tuna is actually the safest.

For fish in general it's better to avoid fillets and steaks. The bigger the fish, the more junk ingested. Stick with tinned fish because it's made up of smaller fish pieces.

The salmon issue is also overblown. The amount of PCB's found in farmed salmon is 10X less than animal protein and even milk. For minimal amounts, eat tinned salmon because it's made from wild sources. Don't eat the skin either because that's where contaminants tend to accumulate.

All in all I believe fish is safer than animal protein in general. Unless you eat only organic meats, it's full of anti-biotics, growth hormones, questionable water sources, full of harmful bacteria (ecoli, boch etc) and god knows what other junk they are fed.

I eat mostly tinned fish and a little organic chicken and beef for years and have had no ill health concerns. The media overblows things in order to sell eyeballs to advertisers. Don't believe everything you see. Do the research and cut through the hype to find the truth.

Sorry, I don't have the references handy. Google is your friend.
 
Another point to keep things in perspective.

Say you ingest only fish and get above the safe levels of mercury and PCB's, you have an elevated chance of cancer to 1:100000 to 1:10000 risk.

On the other hand, eating lots of animal protein high in saturated fats and bad cholesterol without any fish gives you a 1:10 to 1:5 risk of heart disease.

Clearly, I'd rather eat the salmon for the omega complex than saturated animal fats. The salmon will keep you alive longer.
 
Thanks for sharing your knowledge, ectoman. I bet I would have needed some hours of online research to find these pieces of information myself.
 
last i remember reading, the mercury is only a potential danger for fetuses - hence if ur pregnant mebe u should abstain.

personally i'm just disgusted that we even allow such substances into the oceans
 
Restless, thanks for pointing me to your former research. Phew, I didn't know that this issue is so controversial. The more important for me to come to an informed decision here (or at least to an educated guess ;) ).

The main implications of your references seem to be the following:

- High levels of mercury cause a lot of damage to your health.
- Mercury contamination can often be linked to fish consumption.
- The larger the fish, the greater the danger.

However, that doesn't answer most of my concerns:
- May the possible risks of fish consumption be outweighed by the benefits, like Aaron said (think of iodine, EFAs, low saturated fat, etc...)?
- As far as I know, tuna fish are predators, and also quite large. Ectoman said that chunky tuna is not that contaminated. Is tuna safe, or are there safer kinds of fish (salmon, trout)?
- Are there any RDAs for fish consumption, even if they're not properly based on scientific research?
 
[b said:
Quote[/b] (flow @ Feb. 24 2004,9:28)]Restless, thanks for pointing me to your former research. Phew, I didn't know that this issue is so controversial. The more important for me to come to an informed decision here (or at least to an educated guess ;) ).
Right, this is always the most important thing, in my opinion.

[b said:
Quote[/b] ]The main implications of your references seem to be the following:
- High levels of mercury cause a lot of damage to your health.

Well, yes. And since mercury has a biological half life of around one month and a half, it is very easy to get high levels of mercury by eating multiple cans of tuna a day.

[b said:
Quote[/b] ]- Mercury contamination can often be linked to fish consumption.
- The larger the fish, the greater the danger

Yes.

[b said:
Quote[/b] ]However, that doesn't answer most of my concerns:
- May the possible risks of fish consumption be outweighed by the benefits, like Aaron said (think of iodine, EFAs, low saturated fat, etc...)?

You can eat small fish with relative safety, like sardines, and still get all the benefits of fish comsumption with minor risk of PCB's and mercury exposure.

[b said:
Quote[/b] ]- As far as I know, tuna fish are predators, and also quite large. Ectoman said that chunky tuna is not that contaminated. Is tuna safe, or are there safer kinds of fish (salmon, trout)?

Canned tuna is usually small baby tuna, that couldn't be used to make the more expensive tuna steaks (spelling?), so it should be safer and have lower levels of mercury. What people don't seem to realise, especially those who don't bother to research the facts, is that it's all a matter of how large your intake is. Like I said, methylmercury has a biological half life of around 44 days. This means that 44 days after you eat one can of tuna, there will be half of the mercury in that can still active in your body. Now, if you have eaten one can of tuna per day since, you'll have to add up all the other mercury still active in your body from all the other cans you ate since. It is very easy to build up significant levels of it in the blood.

I know people that have been forbidden to eat fish by doctors, and they only ate two servings a day of it, due to dangerous levels of mercury in the blood. And he was eating a fraction of what many bodybuilders eat per day.


Farmed salmon has been linked to higher risks of some cancers, so I would avoid that completely.

[b said:
Quote[/b] ]- Are there any RDAs for fish consumption, even if they're not properly based on scientific research?

There is a one pound per week upper limit, but don't quote me on this since this is from memory. And memory ain't what it used to be....
 
On a related note:

is there any way, accessible to the common fella, of accurately measuring how much mercury is in your system?
 
[b said:
Quote[/b] ([xeno]Julios @ Feb. 24 2004,3:21)]On a related note:
is there any way, accessible to the common fella, of accurately measuring how much mercury is in your system?
You'd have to take the specific blood test for it in a laboratory.
 
I hope I don't come across meaning that all you can eat fish is fine. Absolutely not. As with anything, moderation is the key.

The mercury risk is a major concern for children and pregnant women. Less so for adults. Restless is right when saying there's not much study on long term, low level mercury exposure to adults. We just don't know for certain what the effects are. It's a balance of fish species, concentrations and your body weight to make assumptions of safe levels.

The FDA mercury limit is 1 ppm per week. The mean non-albacore canned tuna dose is 0.17 ppm. So, using FDA data you can eat 5 cans of non-albacore tuna a week and remain under the limit. Even better would be to alternate daily between canned tuna and canned salmon. If you did that, you could be sure of staying well below FDA limits.

I would not personally risk eating more than 1 can of tuna/salmon a day. As restless mentioned, sardines are an excellent safe alternative. Wish I could stomach them myself.

As I stated before, PCB levels in salmon are less than beef, chicken and milk. I'm firmly convinced that the benefits of salmon outweigh the risks. Period. As long as you moderate fish intake at FDA levels. Frankly, as I've said before, the real concern should be focused on animal proteins and dairy products. There are WAY more dangers lurking there.

Risk is all relative here. Your risk of Type II Diabetes and heart disease is hundreds of times greater from animal fats than cancer from canned salmon.

*All my data is from the FDA website. Sorry, I have misplaced all my direct links. Grrrrrrrr.
 
[b said:
Quote[/b] (flow @ Feb. 24 2004,2:28)]Restless, thanks for pointing me to your former research. Phew, I didn't know that this issue is so controversial. The more important for me to come to an informed decision here (or at least to an educated guess ;) ).
The main implications of your references seem to be the following:
- High levels of mercury cause a lot of damage to your health.
- Mercury contamination can often be linked to fish consumption.
- The larger the fish, the greater the danger.
However, that doesn't answer most of my concerns:
- May the possible risks of fish consumption be outweighed by the benefits, like Aaron said (think of iodine, EFAs, low saturated fat, etc...)?
- As far as I know, tuna fish are predators, and also quite large. Ectoman said that chunky tuna is not that contaminated. Is tuna safe, or are there safer kinds of fish (salmon, trout)?
- Are there any RDAs for fish consumption, even if they're not properly based on scientific research?
AFAIK there is no convincing evidence that wild fish are safer than farm raised. Some wild fish have had ridiculous evels of mercury due to the waters they swim in. There isn't stringent water regulation throughout the world.
 
Thanks for all the replies, guys (especially because all of this has probably already been mentioned, as Stevie said).

Now I have the one can per day rule, which is more than I usually eat (ca. 3-5 cans per week). Still, next time I go grocery shopping, I'll have a closer look at the alternatives.

Thanks again!!!
worship.gif
 
Back
Top