Ratio of Omega 3 and Omega 6 EFAs

[mphatesmpb]

Hi Tom,

For the last several weeks, I have had one 6 oz. serving of salmon everyday in hopes of improving my omega 3-6 ratio. As you might already know, omega 3 and omega 6 fatty acids have opposing physiological functions: omega 6s generally are metabolized into pro-inflammatory prostaglandins, and omega 3s are metabolized into anti-inflammatory prostaglandins. Considering the key role played by inflammation in the pathogenesis of MPB, anyone's hair loss regimen would be improved by a diet that has a favorable n3-n6 ratio. The modern western diet contains so many foods high in omega 6 that the typical n6:n3 ratio is somewhere from 20:1 and 40:1.

Recently though I've read about the dangers of the organic form of mercury (methylmercury) which occurs in predatory fish like salmon and tuna. I've learned that while inorganic forms of mercury like the stuff released from dental amalgams accumulates in target tissues like the kidneys, liver, and CNS. The distribution of organic forms is much more diffuse, and one place where it accumulates is the skin - right in the hair follicles. Check out this bit:

Chenyang Shi*, Alfred T. Lane† and Thomas W. Clarkson*

*Environmental Health Sciences Center, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642 USA

†Department of Dermatology and Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York 14642 USA
Received 10 August 1989.
Available online 4 May 2005.

Human hair has unique advantages in monitoring environmental exposures to methylmercury. Using newborn Balb/c mice as a model system, the incorporation of methylmercury into the hair was studied and compared with methylmercury distributions in other tissues. Newborn mice were given intraperitoneal injections of 203Hg-labeled methylmercury at designated times according to hair growth stages of the mouse. Animals were sacrificed 2 days after dosing. Distribution of mercury in pelt and other tissues was measured. The level of mercury in pelt was found to correlate with hair growth. The amount of mercury in pelt peaked when hair growth was most rapid and the total amount of mercury in pelt was significantly higher than that in other tissues, constituting 40% of the whole body burden. However, when the hair ceased growing, the amount of mercury in pelt dramatically dropped to 4% of whole body burden and mercury concentrations in other tissues except brain were elevated. Autoradiographic studies with tritium-labeled methylmercury demonstrated that methylmercury concentrated in hair follicles in the skin. Within hair follicles and hairs, methylmercury accumulated in regions that are rich in high-sulfur proteins. The uptake of inorganic mercury (administered as HgCl2) by pelt was also compared with that of methylmercury. The amount of inorganic mercury found in pelt was less than one-half that of methylmercury in animals with growing hair. Cessation of hair growth did not decrease the inorganic mercury level in pelt to the same extent as in the case of methylmercury.

1Part of this study was presented at the 28th Annual Meeting of the Society of Toxicology, Atlanta, GA, February 27–March 3, 1989, and was published in an abstract form.

There is convincing evidence that if foods contaminated with mercury are accompanied by sufficient amounts of selenium (either within the food itself or through dietary supplementation), then the selenium has a protective effect against mercury toxicity. This is probably because selenium is important for the endogenous synthesis of the anti-oxident glutathione. Mercury has a high affinity for the sulfhydryl groups in thiols like glutathione and cysteine. Here's the catch: once mercury binds to glutathione or other thiols, it is not necessarily excreted from the body. In fact, evidence shows that glutathione and other thiols enhance absorption and retention of mercury. The protective effect of anti-oxidants like glutathione is probably due to the fact that it transports the mercury from critical tissues like the kidneys, liver, and CNS to less critical ones like muscle tissue and skin. Unfortunately for those of us in the MPB club, mercury accumulating in the skin is bad news for our hair follicles. And as the article above states, methylmercury accumulates in the skin and hair follicles. There is now a growing body of evidence that oxidative stress is a crucial factor in the pathology of MPB.

Thus I'm going to stop with the salmon...maybe I'll have it just a few times per month because it is such a great-tasting and healthy food containing many important nutrients. But salmon was also my major source of dietary omega-3s. There are relatively few foods that have good amounts of omega3: fatty fish, flaxseed, walnuts, and vegetables like broccoli and spinach. Of course, the DHA- and EPA-forms of omega 3 found in fatty fish have been proven to be far more beneficial for health than the omega 3s from the plant sources I listed.

At this point I'm unsure of what to do about maintaining a good n6:n3 ratio. I guess I could up my daily dosage of krill oil to around 1.5 grams...but that still doesn't even come close to the 3-4 grams I was getting from salmon. Tom, what do you try to eat in order to maintain a good n3:n6 ratio?

Thanks,
MP

[Tom Hagerty]

Salmon is a great tasting food. I eat it maybe once a month but I wish I could eat it more often. These large fish high up on the food chain can be loaded with toxic minerals like mercury though. Mercury is a cumulative poison and there is no barrier that keeps it from reaching the brain. Sardines is perhaps a better fish to eat for the omega-3 - it's way down on the food chain and in my opinion way down on taste too. I guess we're stuck with krill oil to establish our n-3:n-6 ratio.

Here's the catch: once mercury binds to glutathione or other thiols, it is not necessarily excreted from the body.

Where did you read this? Can you give me a link to a scientific article.

Tom, what do you try to eat in order to maintain a good n3:n6 ratio?

I don't eat many foods with omega-6 fatty acids but I do take a teaspoon of cod liver oil every day for the omega-3. I'm now using Twinlab Norwegian cod liver oil that is PCB and Heavy Metal Free, if I can believe what's on the label. One teaspoon has 970 mg of total omega-3 fatty acids, 554 mg of EPA and 369 mg of DHA. I don't want to take any more than one teaspoon because of the high vitamin A content.

I eat garlic and apples almost every day. Both garlic and apple pectin detoxify and perhaps even remove mercury from the body. But if we start glowing in the dark we'll know that we're doing something wrong.

[mickey]

Tom, What meat/ foods do you eat for protein? I eat a lot of fish! may be too much!!

[Tom Hagerty]

I don't eat much red meat but I do try to have beef liver once or twice a month for the iron and the trace minerals. Other than that I occasionally eat sardines and salmon. I wish I could eat more fish because I like it but I'm concerned about the possible mercury toxicity. Sometimes I'll have a small (5 once) steak. Most of the food I eat is fresh fruit and vegetables, whole grain toast, and dairy products, including yogurt.

[mphatesmpb]

Tom,

To learn more about the relationship between selenium and toxicity, you should read through the studies cited at the bottom of this article:

http://fishscam.com/fSelenium.cfm

The article itself has many simplistic statements which make me question its credibility. For example, this is the author's explanation of why selenium protects against mercury:

In scientific jargon, selenium has an unusually high "binding affinity" for mercury. In layman's terms, this means that when the two elements are found together, they tend to connect, forming a new substance. This makes it difficult for the human body to absorb the mercury separately. So when mercury "binds" to selenium, it's no longer free to "bind" to anything else -- like brain tissue.

It's not quite this simple. There is a class of molecules called thiols which is characterized by a sulfhydryl group, and this group has very high affinity for mercury. Selenium is a co-enzyme which is important for the production of one such thiol called glutathione, which is a very important antioxidant that protects against mercury. But it's simplistic to say something like "mercury binds to glutathione, and that's the end of the story." If you read through the studies at the bottom of the page (I doubt anyone would do this), you'd see that the story behind mercury and selenium is much more complicated. At this point it's still beyond me. But from what I can tell it's just like a molecular game of hot potato: various molecules bind and unbind to mercury, and sometimes it gets distributed into the various tissues of the body. The kidneys, CNS, skin, and liver are important target sites where mercury tends to accumulate. It's all very complicated. Let me know what you think if you ever get around to reading these studies.

-MP

[Tom Hagerty]

I read through that article from the Center for Consumer Freedom, whatever that is. The whole point of the article is that you can eat most fish without too much concern about mercury toxicity. The selenium in the fish will bind to the mercury so that it is not "free" anymore to do damage in the body.

The article itself has many simplistic statements which make me question its credibility.

I question the credibility of the article too - and who is the sponsor of that Center for Consumer Freedom - perhaps the fish industry.

[mickey]

Tom, Is tinned salmon ok ?

[Tom Hagerty]

Canned salmon is mostly sockeye or pink salmon caught in Alaska. These are low in mercury and other contaminants. But even though low in mercury, I wouldn't load up on them.

[mickey]

How much salmon & how much sardines is it safe to eat a week?

[Tom Hagerty]

I wouldn't eat salmon more than once a week because of the toxicity problem. Sardines you can eat more often but who would want to.