Category: omega-3

Dry Eye and Fish Consumption

Seth Roberts17 Comments

Let’s say that dry eye is caused by lack of omega-3. If you eat enough omega-3, you’ll never get it. Here is a recently-discovered association with tuna consumption:

Tuna consumption [1 serving was 113 g (4 oz)] was inversely associated with DES [Dry Eye Syndrome] (OR: 0.81; 95% CI: 0.66, 0.99 for 2—4 servings/wk; OR: 0.32; 95% CI: 0.13, 0.79 for 5—6 servings/wk versus =< 1/wk P for trend = 0.005).

If tuna were a good source of omega-3, eating 5-6 servings per week would completely prevent dry eye. But it doesn’t. Which supports what I have come to believe for other reasons: oily fish, in the quantities most people eat it, is a mediocre source of omega-3. Even if you eat tuna almost once/day, you don’t get enough. To get enough omega-3, look elsewhere.

Thanks to Brent Pottenger.

Assorted Links

Seth Roberts4 Comments

Thanks to Casey Manion and Anne Weiss

A Month of Omega-6

Seth Roberts8 Comments

Susan Allport, having written The Queen of Fats, unsurprisingly eats a diet high in omega-3 and low in omega-6. For one month, however, she ate a diet with more omega-6 and less omega-3 and wrote about it– like Supersize Me, except far more realistic.

O magazine commissioned a story about it but didn’t run it. “My weight gain was only 0.5 pounds and they thought their readers wouldn’t see the importance of that,” says Allport. Her draft is here. There were three striking changes over the month: the omega-6/omega-3 ratio in her blood doubled (implying that this ratio is controlled by diet rather than by stored fat); her belly fat noticeably increased; and the elasticity of her arteries decreased by 20%. This supports Allport’s belief (and mine) that omega-6 is dangerous when consumed in large amounts, as it is if you eat a lot of food cooked in vegetable oil.

The American Heart Association recommends that Americans eat more omega-6. The justification of this recommendation says nothing about the Israeli Paradox, which to me is the best reason to avoid a diet high in omega-6. Allport’s experience is another reason.
Allport is also the author of Explorers of the Black Box, about neuroscience research.

Omega-3 and Dental Health (revisited)

Seth Roberts22 Comments

A few years ago I learned that flaxseed oil improved my gums and other people’s — especially Tyler Cowen’s. A few months ago I went to Beijing for two months. Toward the end of the visit my gums would bleed when I’d use a toothpick. Yet I was drinking 3 tablespoons of flaxseed oil every day, just like in Berkeley.

Well, my Beijing flaxseed oil was old. Stored in a freezer, yes, but about 9 months old. When I returned to Berkeley, I bought fresh flaxseed oil. In a week, my gums were much better. The bleeding stopped.

Last week I went to the dentist. He measured my “pockets” — the distance a probe can be inserted between the gum and the tooth. The readings were almost all 2′s (mm), with a few 3′s and one 1. Years ago, before flaxseed oil, the rear teeth were 4s and 5s. Now I floss and brush my teeth less than back then. Because of living in China, I haven’t had my teeth cleaned in more than a year (unprecedented) so I have the most plaque ever in my life. Yet my gums are the healthiest they’ve been, after just a few weeks of good flaxseed oil. (“Your gums are in good shape,” said the dentist.) This suggests that plaque doesn’t matter, the opposite of what one dentist told me and what Wikipedia appears to say (“The focus of treatment for gingivitis is removal of the [usual] etiologic (causative) agent, plaque.”). Nothing is said about too-little omega-3.

All this suggests that gingivitis, a disease of inflammation, is due to too-little omega-3. This is even more plausible because omega-3 is a precursor of an anti-inflammation signaling molecule. Here’s the sequence of events that led to this conclusion: 1. Several people wondered if they could do the Shangri-La Diet with flaxseed oil, so I tried some. It seemed to improve my balance. 2. Careful measurements of my balance confirmed this. 3. Further measurements showed that more flaxseed oil continued to improve my balance until I reached 3 tablespoons/day, which is far more than any recommended dose I’ve seen. 4. Readers of this blog and friends tried taking flaxseed oil in similar amounts. Everyone who did so, as far as I know, found their gums greatly improved. 5. One person stopped taking the flaxseed oil. His gums got worse. He resumed. They got better again. 6. The story I tell here.

Notice how important blogs (this blog) are in this story. It’s a kind of microscience — I learn something via self-experimentation, I post it, people write in with their experience — that has turned out to be surprisingly informative, given the many ways it differs from professional science (no long training, no lab, no grants, no peer review).

Assorted Links

Seth Roberts8 Comments
  • “ant tribes” near Beijing
  • What exactly is umami?
  • Is omega-3 an antidepressant? “Initial analyses failed to clearly demonstrate the effectiveness of Omega-3 for all patients taking part in the study. Other analyses, however, revealed that Omega-3 improved depression symptoms in patients diagnosed with depression unaccompanied by an anxiety disorder.” Are they fooling themselves? Maybe not. My research suggests that morning faces can reduce only depression but also anxiety disorders. So if you have depression without an anxiety disorder it may indeed have a different cause.

Thanks to Anne Weiss.

The Future of Dentistry and Experimental Psychology?

Seth Roberts4 Comments

Rereading an old post, I found this:

Today I had my teeth cleaned and was told my gums were in excellent shape, better than ever before [due to flaxseed oil]. They were less inflamed than usual. “What causes inflammation?” I asked. “Tartar,” I was told.

I believe that reddish gums are a great sign (so easy to see) that overall your body has too much inflammation, putting you at higher risk for many common diseases. (Perhaps due to too little omega-3, which the body uses to make an anti-inflammation hormone.) Every day my dentist measured, or at least saw, a great correlate of health (the redness of his patients’ gums) and failed to notice. It’s like failing to notice an oil field under your property. If dentists became experts in measuring gum redness and helped their patients lower overall inflammation, the public health contribution would be great. (Writing this makes me wonder why I haven’t become skilled at measuring the redness of my gums.)
Experimental psychologists are in a similar position. I believe brain health is closely correlated with health of the rest of the body. In other words, the foods that make the brain work better make the rest of the body work better. I discovered the anti-inflammatory effects of flaxseed oil because it improved my balance. The brain is much easier to study (via behavior) than the rest of the body — it’s a model system for the rest of the body. Experimental psychologists are as unaware of their good fortune as dentists. By using their skills to figure out how to have the healthiest possible brain, they could make a great contribution to human welfare.

Omega-3 Correlations in Eskimos Support Anti-Inflammation Effect

Seth Roberts8 Comments

A problem with much nutritional epidemiology, as I blogged earlier, is “the narrow range of intakes within a given population”. For this reason Ernst Wynder thought it better to make between-country comparisons. Of course different countries differ in many ways other than the ones you care about. A solution to both problems is to study an unusual country — a country with a wide range of intakes of the nutrient you care about — in depth.

This is what a new paper about omega-3 has done. The researchers measured the blood of about 400 Eskimos, who had a much larger range of omega-3 levels in their blood than Americans or Europeans. The results aren’t easy to sum up because there were plenty of non-linear associations. Here’s what I think is their most interesting result:

Associations of EPA and DHA with C-reactive protein were inverse and nonlinear: for EPA, the association appeared stronger at concentrations >3% of total fatty acids; for DHA, it was observed only at concentrations >7% of total fatty acids.

C-reactive protein is a marker of inflammation. Notice that, due to the details, the combination of (a) high intakes and (b) a wide range of intakes makes this correlation much easier to see. This result suggests that EPA and DHA (or something correlated with them) indeed reduce inflammation, as is often proposed. Perfectly consistent with my dentist’s observation that my gums looked a lot better (less inflamed) right after I started drinking 4 T/day flaxseed oil. Plus a reader’s observation that his sports injuries healed much faster after he started drinking 4 T/day flaxseed oil. (And here.)

Previous epidemiology had had a hard time detecting the anti-inflammatory correlation of omega-3s. My self-experimentation plus other people’s observations made it obvious there was something to it (and provided experimental evidence for causality: more omega-3, less inflammation). Better epidemiology has now supported this.

Thanks to Dave Lull.

Dangerous Fish Oil

Seth Roberts13 Comments

Many people take fish oil to get omega-3. (I get mine from flaxseed oil.) Fish contain PCBs, therefore fish oil does. How much? More than we’re told. A lawsuit has been filed about this:

Mateel Justice Foundation, in conjunction with two individual plaintiffs, brought a lawsuit against six fish oil manufacturers and two retailers for labeling violations of the California Safe Drinking Water and Toxic Enforcement Act, also known as Proposition 65. Filed March 2 in Superior Court of San Francisco, the suit alleges several fish oil products sold in California failed to include label warnings for levels of PCBs (polychlorinated biphenyl compounds) found in the products by testing initiated by the plaintiffs . . . Named as defendants in the suit were two retailers—CVS Pharmacy Inc. and Rite Aid Corp.””and six manufacturers—General Nutrition Corp. (GNC); NOW Health Group Inc.; Omega Protein Inc.; Pharmavite LLC (Nature Made brand); Solgar Inc.; and Twinlab Corp. . . . The plaintiffs conducted testing on 10 products produced or sold by the defendants, looking at all 209 known PCB compounds . . . Many fish oil companies test for as few as seven such compounds. [emphasis added]

The plaintiffs plan to post testing results here (I have been unable to reach this site).

Assorted Links

Seth Roberts5 Comments
  • LA Times article about omega-3 health effects
  • Sanity about CO2 emissions. “When and where did the climate alarmists tell you about CO2 levels that were up to 20 times current levels when dinosaurs roamed the earth? When and where did alarmists tell you that the conditions they openly worry about have repeatedly happened without turning the earth into an oven?”

Thanks to Dave Lull.

Assorted Links

Seth Roberts2 Comments
  • Vision therapy
  • Omega-3 and brain health. “Participants were 280 community volunteers between 35 and 54 y of age, free of major neuropsychiatric disorders, and not taking fish oil supplements. . . Five major dimensions of cognitive functioning were assessed . . . Among the 3 key (n-3) [poly-unsaturated fatty acids], only DHA [was] associated with major aspects of cognitive performance.”
  • The rise and fall of Beijing restaurants

Thanks to Steve Hansen, Tim Lundeen, and Eric Meltzer.