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Is canned tuna a good source of omega 3 fats? How much omega 3s can I expect to consume when eating canned tuna?

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I did not know that about canned tuna.

 

http://whfoods.org/genpage.php?tname=george&dbid=97

 

Examples of Tuna Fish and Their Omega 3 Fat Content Type of Fish Total Omega 3 Fat EPA (unique type of Omega 3 Fat) DHA (Unique type of Omega 3 Fat) fresh bluefin tuna, baked, 6 ounces 2.5 grams 0.6 grams 1.9 grams fresh albacore tuna, baked, 6 ounces 2.6 grams 0.5 grams 1.7 grams fresh skipjack, baked, 6 ounces 2.7 grams 0.7 grams 2.0 grams Light tuna, canned in water, 6 ounces 0.46 grams 0.08 grams 0.38 grams Light tuna, canned in oil, 6 ounces 0.34 grams 0.05 grams 0.38 grams Starkist TM Albacore tuna, canned in water, 6 ounces* 1.35 grams data not available data not available Papa George Gourmet Albacore tuna, canned in olive oil, not drained, 6 ounces 8.1 grams 2.6 grams 5.5 grams

*The brand name data is derived from Starkist's website and lab reports supplied by these two specialty tuna companies, see Sources below.

Sources: Am J Clin Nutr, January 2000 Supplement; 71:179S-188S.

USDA Nutrient Composition Database: http://www.nal.usda.gov/fnic/foodcomp/Data/index.html

Food Processor for Windows, Version 7.60, Database Version December 2000, ESHA Research, Salem, OR.

Simopoulos A, Kifer RR, and Martin RE (Eds). (1986). The Health Effects of Polyunsaturated Fatty Acids in Seafoods. Academic Press, New York. Starkist Tuna: www.Starkist.com

Papa George Gourmet Albacore, Seattle, WA. www.PapaGeorgeTuna.com Phone: 206-255-4203. Product lab analysis provided by Food Products Laboratory, Portland, OR. 

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Hi Al --

 

Sure, tuna (all species, and whether raw, canned or baked) are high in omega 3 (EPA and DHA), as are all

forms of salmon and other fatty fish (such as sardines).

 

BUT, the carnivorous fish at the top of the food chain -- especially Ahi Tuna, and also albacore tuna -- are

high in Mercury -- so I almost always avoid tuna -- especially those two species. And, since I'm a fish eater,

when I have my approximately semiannual bloodwork, I get myself tested for Mercury. My bloodwork has

consistently shown insignificant Hg.

 

I should note that all supermarket salmon -- canned, raw (sashimi), cooked (or buy raw and cook yourself)

are low mercury (no species of salmon is near the top of the food chain); and all salmon are very high

in DHA and EPA.

 

Sardines (not my personal favorite) are of course very low in the food chain -- you can ignore any fears

of mercury. And sardines are very high in the EFA's, and are cheap.

 

-- Saul

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Hi Al --

 

Sure, tuna (all species, and whether raw, canned or baked) are high in omega 3 (EPA and DHA), as are all

forms of salmon and other fatty fish (such as sardines).

 

BUT, the carnivorous fish at the top of the food chain -- especially Ahi Tuna, and also albacore tuna -- are

high in Mercury -- so I almost always avoid tuna -- especially those two species. And, since I'm a fish eater,

when I have my approximately semiannual bloodwork, I get myself tested for Mercury. My bloodwork has

consistently shown insignificant Hg.

 

I should note that all supermarket salmon -- canned, raw (sashimi), cooked (or buy raw and cook yourself)

are low mercury (no species of salmon is near the top of the food chain); and all salmon are very high

in DHA and EPA.

 

Sardines (not my personal favorite) are of course very low in the food chain -- you can ignore any fears

of mercury. And sardines are very high in the EFA's, and are cheap.

 

-- Saul

Wouldn't the EFAs in sardines be prone to oxidation and potentially quite harmful?

 

Fish oil has been shown to be high in peroxidized polyunsaturated fats a majority of the time, and that's when you're supplying EFAs fresh from a laboratory with a CoA stored under refrigeration in an amber nitrogen-purged glass bottle with several potent antioxidants.  I can only imagine that some smelly sardines that have been cooked / smoked and stored in a plastic-lined tin for several months (over a year?) with a bunch of warm water off some warm grocery store shelf would look fairly oxidized?

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Hi Sirtuin!

 

A canned fish (sardine, tuna or salmon) can't get any more oxidized then when it was canned -- there's no oxygen in the can.

 

:)xyz

 

  --  Saul

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Hi Sirtuin!

 

A canned fish (sardine, tuna or salmon) can't get any more oxidized then when it was canned -- there's no oxygen in the can.

 

:)xyz

 

  --  Saul

By the same logic, then fish oil should be remarkably unoxidized, since it cannot get any more oxidized than when it was bottled at low temperatures with antioxidants?  Although with canned fish, you're also cooking the oils before you can them and storing with water and without antioxidants.

Edited by sirtuin

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The fish oil is capsules is remarkably unoxidized (but as with every food should be refrigerated).

 

The bottled fish oil is a different matter:  You open the bottle from time to time to make use of it.  (Still, you're probably worrying too much -- remember Al Pater's wise post about hormesis and radiation -- a little radiation appears to be beneficial; too much obviously isn't).

 

  --  Saul

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Interesting:  Just noted here at the University of Rochester.   Omega-3 Fatty Acids May Reduce Infections for COPD Patients

United Press International, March 16

"We never really knew why diets high in omega fatty acids seemed good, but now we know it's because they provide the precursors for molecules that help shut down excessive inflammation," Richard Phipps, professor of environmental medicine who holds the Wright Family Research Professorship.

 
BTW. I remember a very wise post that was on the old CR mailing list, way back:  The subject was exactly, "what is the best way to store fish oil"?  The final answer:
 
"The best container for fish oil is a fish".
 
:)xyz
 
  --  Saul

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Saul wrote:

"The best container for fish oil is a fish".

 

to which I'll append:

 

And the best container for a fish is the ocean, not your belly.

 

Fish are friends not food:

 

 

RIP Kyle and Comet...

 

Ah - the joys and freedom of the Chit Chat forum 

 

--Dean

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All,

 

Saul and several other people on this thread and elsewhere have suggested sardines are a good choice for anyone seeking long-chain Omega-3 DHA/EPA. The idea is that sardines, unlike tuna, are low on the food chain and therefore shouldn't bioaccumulate harmful heavy metals. Anyone with this impression might want to reconsider, after watching today's Dr. Greger video (embedded below) and checking out the studies he references, especially [1].

 

The video is mostly about the dangers of lead contamination in one of Paleo dieter's favorite foods, bone broth. But during his introduction, at 0:43, he flashes up a table from [1] showing the levels of heavy metal contamination in various raw and cooked foods. Here is the table from the full text of [1]:

 

Z0NuqQW.png

 

Notice that tuna and especially sardines are high in arsenic, Saul's poison of choice.

 

Sardines are also nearly as high as tuna in lead (Pb) content, the serious toxicity of which is the focus of Dr. Greger's video.

 

So people thinking they are doing themselves a favor by eating low-on-the-food-chain sardines to get their Omega-3s while avoiding heavy metal contamination appear to be kidding themselves. Stick to plants, and go with an algae-based Omega-3 supplement if you are looking for a contaminant-free source of DHA/EPA.

 

--Dean

 

 

-----------

[1] J Agric Food Chem. 2008 Dec 10;56(23):11262-9. doi: 10.1021/jf802411q.

 
Effects of various cooking processes on the concentrations of arsenic, cadmium,
mercury, and lead in foods.
 
Perelló G(1), Martí-Cid R, Llobet JM, Domingo JL.
 
Author information: 
(1)"Rovira i Virgili" University, San Lorenzo, Reus, Spain.
 
The effects of cooking processes commonly used by the population of Catalonia
(Spain) on total arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb)
concentrations in various foodstuffs were investigated. All food samples were
randomly acquired in local markets, big supermarkets, and grocery stores of Reus 
(Catalonia). Foods included fish (sardine, hake, and tuna), meat (veal steak,
loin of pork, breast and thigh of chicken, and steak and rib of lamb), string
bean, potato, rice, and olive oil. For each food item, two composite samples were
prepared for metal analyses, whose levels in raw and cooked (fried, grilled,
roasted, and boiled) samples were determined by inductively coupled plasma-mass
spectrometry (ICP-MS). The highest concentrations of As, Hg, and Pb (raw and
cooked samples) were mainly found in fish, with a clear tendency, in general, to 
increase metal concentrations after cooking. However, in these samples, Cd levels
were very close to their detection limit. In turn, the concentrations of metals
in raw and cooked meat samples were detected in all samples (As) or only in a
very few samples (Cd, Hg, and Pb). A similar finding corresponded to string
beans, rice, and olive oil, while in potatoes, Hg could not be detected and Pb
only was detected in the raw samples. In summary, the results of the present
study show that, in general terms, the cooking process is only of a very limited 
value as a means of reducing metal concentrations. This hypothetical reduction
depends upon cooking conditions (time, temperature, and medium of cooking).
 
PMID: 18986150

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A big proportion of the folks from New Hampshire got their arsenic from rice and water.  There are suggestions that arsenic from seafoods may be less risky.

 

 
These 5 Foods Can Be High In ArsenicThough you might not want to or be able to cut them out entirely, the toxins will build up so you shouldn't eat them all the time.
by EMILY MAIN 
NOVEMBER 25, 2013
 
Whether it's the legacy of toxic arsenic-based pesticides used on apple orchards and cotton fields or the naturally occurring arsenic in irrigation water and soil, this heavy metal has become pervasive in our diets. And a new study from Dartmouth University researchers has concluded that foods that contain arsenic could easily be your primary exposure sources for this harmful metal.
 
After comparing arsenic levels found in about 850 people's toenails (over time, arsenic concentrates in the keratin your body uses to create nails) with food questionnaires, Dartmouth researchers concluded that "diet can be an important contributor to total arsenic exposure in U.S. populations, regardless of arsenic concentrations in drinking water." Although the Environmental Protection Agency has set limits for arsenic in municipal water supplies, the metal isn't regulated in private wells used for drinking and irrigation. and its presence has always been an issue for people who survive off well water.
 
"After we accounted for exposures via water, we still saw high levels of exposure from food," says lead author Kathryn Cottingham, PhD, professor of biological sciences at Dartmouth. However, she adds, "We can't say much about the potential for harm because we don't know the health risks yet for the levels we found."
 
Although it's fatal at high doses, the low levels of arsenic in food don't cause immediate health problems for the average person, but with chronic exposures, their dangers can be serious. Long-term exposure to the metal is known to cause lung, kidney, skin, and bladder cancers, and it interferes with estrogen and testosterone, as well as with the hormones that regulate your metabolism and immune system. The Food and Drug Administration (FDA) has been trying to decide how to cope with foods that contain arsenic ever since independent tests by Consumer Reports magazine and others revealed high levels of arsenic in rice, apple juice, and other processed foods. The agency has never set a limit on how much of the metal can be allowed in food.
 
"My advice," says Cottingham, "if there are foods that are high in arsenic, just don't eat them all the time." Based on the Dartmouth study results, here are 5 foods that shouldn't make regular appearances in your daily diet:
 
Brussels Sprouts
Despite the fact that these vegetables are among the healthiest you can eat, Cottingham's research, along with others studies, note that inorganic arsenic that exists in soil is highly attracted to sulfur compounds in brussels sprouts, along with other "super-veggies" in the cruciferous family, including kale, broccoli, and cauliflower. The arsenic could also come from contaminated irrigation water, or even your own cooking water if you happen to draw your water from a private well. Arsenic levels in regular sprout eaters were 10.4 percent higher than in people who never ate them or ate them less than once a month.
 
Dark-Meat Fish
Arsenic exists naturally in seawater and, as a result, it exists naturally in fish. However, the forms of arsenic usually detected in seafood are organic, which are presumed to be relatively harmless. They usually clear your body a few days after they're consumed. But this study found inorganic forms of arsenic were 7.4 percent higher in people eating dark-meat fish (tuna, mackerel, salmon, sardines, bluefish, and swordfish) once a week, compared to people who ate them less than once a month. And that's concerning, Cottingham says. It suggests that the body can metabolize organic arsenic into the inorganic forms that cause cancer and other health problems, or that the organic forms of arsenic are as harmful as the inorganic forms. "That's part of the reason the FDA has had such a hard time acting on arsenic in rice," she says. "It's not just inorganic arsenic that we need to be concerned about. Some forms of organic arsenic are toxic, too." The problem, she adds, is that scientists don't know enough about the various organic forms to determine which are harmful and which aren't. Since all seafood tends to be high in arsenic, Cottingham says, make it an occasional meal.
 
Rice
Cottingham's study didn't show a significant association between rice consumption and arsenic levels, but that's likely due to the fact that her study participants weren't big rice eaters. They reported eating one to three cups of white rice a month, whereas arsenic is found in much higher levels in brown rice. Other studies, though, are "pretty compelling," she says, showing that people who eat rice closer to the amount the average American does (about half a cup per day) have consistently high arsenic levels. Consumer Reports suggests restricting your rice intake to two servings per week.
 
Chicken + Other Poultry
Like rice, chicken and other poultry weren't a big hit with this population, but Cottingham says these meats are still concerning. Poultry birds are regularly given feed containing with arsenic-based drugs, which studies have shown, lead to an elevated level of arsenic in their meat. Thankfully, the FDA recently revoked approvals for three out of four of these toxic feed additives, but industry experts estimate that it'll be at least a year before producers run through the remaining supplies of their arsenic-laced feed. Continue to opt for organic poultry, which is raised without the use of arsenic feed additives.
 
Beer + Wine
Call it the contaminant that killed your happy hour: In the Dartmouth study, men who had 2.5 beers per day had arsenic levels over 30 percent higher than nonconsumers, and women who drank five to six glasses of wine per week had levels 20 percent higher than nonconsumers. The arsenic may be coming from the water used to brew these beverages, but beer and wine producers also use a filtration material, diatomaceous earth, that's know to harbor arsenic; it's made up of ground fossils collected from ocean and lake floors. The good news is that some producers are moving away from using diatomaceous earth since it can pose inhalation problems for workers, but there's really no way to know whether your favorite producer uses it unless you ask.
 
 
Rice consumption contributes to arsenic exposure in US women.
Gilbert-Diamond D, Cottingham KL, Gruber JF, Punshon T, Sayarath V, Gandolfi AJ, Baker ER, Jackson BP, Folt CL, Karagas MR.
Proc Natl Acad Sci U S A. 2011 Dec 20;108(51):20656-60. doi: 10.1073/pnas.1109127108. Epub 2011 Dec 5.
PMID: 22143778 Free PMC Article
 
Abstract
 
Emerging data indicate that rice consumption may lead to potentially harmful arsenic exposure. However, few human data are available, and virtually none exist for vulnerable periods such as pregnancy. Here we document a positive association between rice consumption and urinary arsenic excretion, a biomarker of recent arsenic exposure, in 229 pregnant women. At a 6-mo prenatal visit, we collected a urine sample and 3-d dietary record for water, fish/seafood, and rice. We also tested women's home tap water for arsenic, which we combined with tap water consumption to estimate arsenic exposure through water. Women who reported rice intake (n = 73) consumed a median of 28.3 g/d, which is ∼0.5 cup of cooked rice each day. In general linear models adjusted for age and urinary dilution, both rice consumption (g, dry mass/d) and arsenic exposure through water (μg/d) were significantly associated with natural log-transformed total urinary arsenic (βrice = 0.009, βwater = 0.028, both P < 0.0001), as well as inorganic arsenic, monomethylarsonic acid, and dimethylarsinic acid (each P < 0.005). Based on total arsenic, consumption of 0.56 cup/d of cooked rice was comparable to drinking 1 L/d of 10 μg As/L water, the current US maximum contaminant limit. US rice consumption varies, averaging ∼0.5 cup/d, with Asian Americans consuming an average of >2 cups/d. Rice arsenic content and speciation also vary, with some strains predominated by dimethylarsinic acid, particularly those grown in the United States. Our findings along with others indicate that rice consumption should be considered when designing arsenic reduction strategies in the United States.
 

Table 2.

Median {interquartile range} of creatinine and urinary arsenic metabolites for all subjects, then rice eaters and non-rice eaters separately

---------------------------------------------------------
Variable Total (n = 229) Rice eaters* (n = 73) Non-rice eaters (n = 156) P
---------------------------------------------------------
Creatinine (mg/dL) 54.85 {27.69–101.05} 51.81 {29.02–89.73} 57.65 {26.68–107.10} 0.69
Arsenobetaine (μg/L) 0.67 {0.07–5.47} 0.57 {0.07–3.66} 0.69 {0.09–7.74} 0.33
iAS (μg/L) 0.24 {0.13–0.40} 0.28 {0.13–0.51} 0.21 {0.13–0.36} 0.03
MMA (μg/L) 0.30 {0.14–0.50} 0.41 {0.18–0.63} 0.23 {0.13–0.43} <0.01
DMA (μg/L) 3.25 {1.51–5.53} 4.09 {2.42–7.20} 2.84 {1.34–4.40} <0.001 
Total arsenic (μg/L) 3.78 {1.80–6.10} 5.27 {2.86–8.72} 3.38 {1.64–5.39} <0.001
MMA/iAs (μg/L) 1.07 {0.70–1.52} 1.16 {0.76–1.70} 1.01 {0.68–1.41} 0.11
DMA/MMA (μg/L) 9.86 {8.05–13.14} 9.86 {7.89–15.21} 9.83 {8.17–12.65} 0.63
---------------------------------------------------------
Urinary creatinine was measured using Cayman's Creatinine Assay, and urinary arsenic metabolites were measured via HPLC. Total urinary arsenic is the sum of inorganic arsenic, monomethylarsonic acid, and dimethylarsinic acid; arsenobetaine was not included in this total.

*Women who reported any rice consumption during the 2 d before urine collection were categorized as “rice eaters.”

P from the Wilcoxon rank-sum test comparing the median urinary concentration of different variables in rice eaters and non-rice eaters.

Sample sizes for creatinine measurements are 64 for rice eaters and 134 for non-rice eaters, respectively.

Edited by AlPater

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Fabulous. Of course, Brussels sprouts, kale, broccoli, cauliflower and cruciferous vegetables we've all been eating nearly daily for years.

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I'd say no, there probably is nothing we can eat that doesn't have a downside. This is probably why CR helps prolong healthspan -- eat less and the body damages itself less frequently? Eat nothing, fast, and the body begins consuming parts of itself, but this is no longterm solution either. Honestly I'd eat nothing if I could maintain a constant weight and not suffer from weakness. Eventually we'll have better tools to advance personalized medicine -- we're just in this teasing-the-health-seeking people long phase of frustration. Eating kale is healthier than most alternatives, at least from an RDA perspective... What else we got?!

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Mike,

 

Is there anything we can eat that has no downside?

 

It would be hard to find fault with consuming good old H2O, as long as it is in moderate quantities, and either the distilled or reverse-osmosis varieties :-). Oh yeah - and avoid Flynt...

 

Seriously - my approach as I've discussed on several occasions is to eat as diverse a diet of whole (plant) foods as possible. That way you don't put too many eggs in one basket when it comes to food choices.

 

--Dean

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Seriously - my approach as I've discussed on several occasions is to eat as diverse a diet of whole (plant) foods as possible. That way you don't put too many eggs in one basket when it comes to food choices.

 
--Dean

That I totally agree with Dean! I eat very small amount of fish and a 1/2 cup of kefir and the rest is vegan and lots of variety.

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