Flaxseed Oil vs. Fish Oil

You can find statements like the following in a hundred places:

Both fish and flax are good sources of omega-3. Flaxseed oil is less expensive, which can be an important consideration. The main difference is that flaxseed oil contains only alpha-linoleic acid (ALA), which is the parent compound from which other omega-3 fatty acids are derived. This leaves it to your body to do the conversion to the other forms it needs, eicosapentaonoic acid (EPA) and docosahexaenoic acid (DHA). The problem is that the conversion is not always that efficient, and the body often uses the ALA for extra energy, leaving less for conversion to the other types. The body uses various enzymes to convert ALA to other omega-3s, and the process is not very efficient, especially as one gets older. Estimates of the rate of conversion range from 5% to 25%. In order to make sufficient amounts of EPA and DHA, one needs to consume 5-6 times more ALA than if one relies on fish oil alone. Fish oil, on the other hand, contains the other forms and delivers them directly to your body with no conversion necessary.

It isn’t that simple. Here are three things I rarely see mentioned:

1. The conversion rate is not fixed. It depends on the amount of the conversion enzyme, which increases with ALA exposure. The body makes the enzymes it needs and doesn’t make the enzymes it doesn’t need. You don’t have enzymes to digest food you don’t eat — but if you start to eat them you will build up the enzymes. The measurements of ALA conversion rate I have seen measured the conversion rate without giving the subjects extensive exposure to ALA before the test. (Measurements of glycemic index have the same problem.) They should be considered lower bounds of what would happen with long exposure.

2.  Time release is good not bad. When you take a dose of flax oil, its ALA is converted to DHA and EPA, which takes time, thus smoothing out the supply versus time function. If you take a dose of fish oil, the brain receives a sudden burst of DHA and EPA. It is likely that a smoother supply is better.

3. ALA (omega-3) conversion blocks AA (omega-6) conversion. Omega-3 fatty acids and omega-6 fatty acids are almost identical. The enzyme that converts short-chain omega-3 to long-chain omega-3 also converts short-chain omega-6 to long-chain omega-6. Long-chain omega-6 probably has bad effects in your brain, at least in large amounts, because it displaces long-chain omega-3. For industrial reasons, our diets are high in short-chain omega-6. Having ALA in your system, which flax oil provides but fish oil does not, slows down the conversion of short-chain omega-6 to long-chain omega-6 by occupying the conversion enzymes.

Thanks to Gary Skaleski.

Effect of Flaxseed Oil on Arithmetic

After I moved to China in September, I was surprised that my arithmetic speed went down. (That is, I got faster.) I had lowered it from about 630 msec/problem to 600 msec/problem by eating lots of butter. I had no idea how to lower it further. I didn’t deliberately change my diet in China but it was quite different. I kept some things the same: the amount and brand of butter/day, the amount and brand of flaxseed oil/day.

I failed to figure out why I had gotten faster. I reduced the amount of flaxseed oil from 3 T (tablespoons) per day to 2 T per day. It made no difference. (In the beginning of my interest in flaxseed oil, change from 2 T/day to 3 T/day had made a difference.) Perhaps because of the butter.

Surprised that the change from 3 T/day to 2 T/day hadn’t made a difference, I went down to 1 T/day for two weeks, then back to 2 T/day. Both changes made a difference:

2010-11-16 2T vs 1T flaxseed oil

Each point is a separate test. Each test had 32 arithmetic problems (e.g., 3+4, 11-3). In the beginning of the data shown in the figure I tested myself once per day. After 12 days I started doing two tests/day, one right after the other. I was curious about the repeatability of the numbers; it wasn’t hard; it was a way to get better measurements. Averaging over the tests for each day to get one value per day, combining the 19 2-T/day (before) days and the 11 2-T/day (after) days, and comparing the combination to the final 7 1-T/day days, t(38) = 6.5. If you’re not familiar with t values, t = 2 is a barely reliable difference, t = 4 is a very clear difference.

This is more evidence that flaxseed oil improves brain function. It interests me because it implies the optimum dose is close to 2 T/day. It cost about $20 and took 1 person-month. In contrast, the DHA-Alzheimer’s study I mentioned two days ago cost about $1 million and took about 7000 person-months. And used (a) a cruder something-versus-nothing comparison, b) a less-sensitive between-subjects comparison, and (c) a more ethically-problematic placebo-controlled design.

Periodontitis and Omega-3

A few years ago, after I started taking about 3 tablespoons/day of flaxseed oil, my dentist told me my gums were much healthier. They were less red, more pink. Friends and blog readers who took flaxseed oil in similar amounts noticed the same thing. Tyler Cowen’s gums improved so much he no longer needed gum surgery.

An epidemiological study in the November Journal of the American Dietetic Association reports correlations between omega-3 intake and periodontitis (an extreme form of inflamed gums). The more omega-3, the less periodontitis. I’m sure that sufficient omega-3 intake cures periodontitis so this study has methodological interest for me. One interesting point is that the study reached a correct conclusion — contrary to the nihilism of John Ioannidis. Another is that the correlations were weak. The risk of periodontitis was only 20% lower in the group (quintile?) with the highest omega-3 intake. Although there were 9000 subjects, there was no significant correlation with linolenic acid, the form of omega-3 found in flaxseed oil.

Thanks to Sean Curley.

Walnuts: Brain Food?

At a Mr. Lee’s restaurant (a Chinese chain), I started chatting with a girl sitting near me. I told her I was a psychology professor. “You know what people are thinking,” she said. I lamely said, no, I study what foods make the brain work best.

“I don’t know the English word for it,” she said. She drew a walnut.  Good for your brain, her parents had told her. I was astonished. When I got to China, my arithmetic scores mysteriously improved. I had expected them to get worse, if anything. I tried to duplicate my American diet in Beijing but it is hard to duplicate the flaxseed oil. (Chinese flaxseed oil is worthless. I can bring it from America but not easily, and it’s impossible to keep it cold the whole way.) I had tested various explanations of the improvement but none held up.

I was starting to believe the reason for the improvement was walnuts. I have two servings/day of yogurt, each time with walnuts. I ate a lot of yogurt with walnuts in Berkeley, too; this was not a dramatic change. But maybe I eat more walnuts in China, and maybe the walnuts have more omega-3.  Maybe the walnuts are fresher. In Berkeley I put ground flaxseed in my yogurt (in addition to walnuts), without obvious improvement. Walnuts are lower in omega-3 than flaxseeds.

A Chinese friend of mine had told me the same thing — that her parents had said that walnuts are good for the brain. This is a common Chinese belief, mingled with the curious idea that they are good for the brain because they look like a brain. The Wikipedia entry for walnut, which includes its use in Chinese medicine, says nothing about improving brain function. This long article about the benefits of walnuts doesn’t connect them directly with better brain function. It does say they are considered “brain food” because of high omega-3 content and links to a page that says 1/4 cup of walnuts (25 g) has 2.3 g of omega-3. I am now consuming 2 tablespoons/day of flaxseed oil, which contains 14 g of omega-3. I have sometimes consumed 3 or 4 tablespoons/day (with 21 or 28 g omega-3). You can see why 2 g doesn’t impress me, especially when added to 14 g. I thought I was getting the optimal amount of omega-3 from flaxseed oil. Adding a small amount to the optimal amount shouldn’t have a noticeable effect. This article says walnuts are brain food because of their lecithin content. Lecithin is used to make acetylcholine, a neurotransmitter.

Miraculously I can gather better evidence by myself, in a month, than all the evidence I’ve found. I simply vary how much walnuts I eat and see what happens to my arithmetic score. The experiment is worth doing because of the common Chinese belief and my puzzlingly good scores. Maybe walnuts help a brain that is already getting plenty of omega-3. Maybe not.

Dry Eye and Fish Consumption

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

Thanks to Casey Manion and Anne Weiss

A Month of Omega-6

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)

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. Continue reading “Omega-3 and Dental Health (revisited)”

Assorted Links

  • “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?

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

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

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

  • 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.

Grass-Fed vs. Grain-Fed Beef

A new review article compares them. Here is most important info, as far as I’m concerned:

A healthy diet should consist of roughly one to four times more omega-6 fatty acids than omega-3 fatty acids. The typical American diet tends to contain 11 to 30 times more omega -6 fatty acids than omega -3, a phenomenon that has been hypothesized as a significant factor in the rising rate of inflammatory disorders in the United States[40]. Table 2 shows significant differences in n-6:n-3 ratios between grass-fed and grain-fed beef, with and overall average of 1.53 and 7.65 for grass-fed and grain-fed, respectively, for all studies reported in this review.

Grass-fed really is better.

Schizophrenia Prevented By Fish Oil

A new study in the Archives of General Psychiatry, summarized in the Wall Street Journal:

Researchers in the new study identified 81 people, ages 13 to 25, with warning signs of psychosis, including sleeping much more or less than usual, growing suspicious of others, believing someone is putting thoughts in their head or believing they have magical powers. Forty-one were randomly assigned to take four fish oil pills a day for three months. The other patients took dummy pills.

After a year of monitoring, 2 of the 41 patients in the fish oil group, or about 5%, had become psychotic, or completely out of touch with reality. In the placebo group, 11 of 40 became psychotic, about 28%.

The study is impressive not only because it uses ordinary food (fish oil) rather than  dangerous drugs (such as Prozac) but also because it studies prevention. Just as the ketogenic diet suggests a widespread animal-fat deficiency, so this study suggests a widespread omega-3 deficiency, which won’t surprise any reader of this blog. Completing the picture — I believe most Americans eat far too little animal fat, omega-3, and fermented food — baker’s yeast is being studied as a cure for cancer.

Thanks to Oskar Pearson and Chris.

“The 11 Best Foods You Aren’t Eating”

There isn’t one fermented food on a list of “the 11 best foods you aren’t eating” compiled by Tara Parker-Pope, author of the world’s most visible health blog. Nor do any of the listed foods contain animal fat. One of them (sardines) is high in omega-3, so the list gets a D instead of an F. Fermented foods and animal fat (in sufficient quantity) have easily-noticed benefits, in contrast to every food on the list. Parker-Pope and the nutritionist she consulted (Jenny Bowden) have large gaps in their understanding of nutrition.

Are We Running Out of Omega-3?

Apparently. The obvious source is fish but we are running out of fish:

In 2006, aquaculture production was 51.7 million metric tons, and about 20 million metric tons of wild fish were harvested for the production of fishmeal. “It can take up to 5 pounds of wild fish to produce 1 pound of salmon, and we eat a lot of salmon,” said Naylor, the William Wrigley Senior Fellow at Stanford’s Woods Institute for the Environment and Freeman Spogli Institute for International Studies. [via Future Pundit]

This is why Jared Diamond’s Collapse is so unfortunate. Diamond is a good writer and the question he tried to answer in that book is extremely important. But he whiffed. Suppose I write a book about obesity. I give a list of ten reasons people are fat: 1. Too much Food X. 2. Too much Food Y. And so on. (Just as Diamond gave a list of eight-odd reasons societies collapse.) Such a book would be far less helpful than a book with a correct theory about obesity, a theory that explains why Foods X, Y, etc. cause obesity. The theory could be used to find new, better, flexible ways of avoiding obesity. The list of foods to avoid cannot. In The Economy of Cities, Jane Jacobs (whom Diamond doesn’t mention) said that collapse happens for one overarching reason: The society is too resistant to new ways of doing things. The crucial struggle in any society, said Jacobs, isn’t between the rich and the poor or between owners and labor; it’s between those who benefit from the status quo and those who benefit from change.

Thanks to Peter Spero.