Category: omega-3

Assorted Links

Seth Roberts4 Comments

Thanks to Dave Lull and Alex Chernavsky.

Tucker Max on Paleo: “I Started Feeling So Much Better”

Seth Roberts2 Comments

In this interview, Tucker Max talks about eating paleo.

Once I started doing this, I started feeling so much better. My brain felt like it worked better. Everything about me improved. So I kinda went down the rabbit hole, and I started reading up on diet and nutrition from alternate sources. Art De Vany, Robb Wolf, and Loren Cordain, they didn’t invent it but they kinda popularized the concept of paleo eating. I realized that if you’re just a normal person, and you have the normal ideas about diet and nutrition, everything you know is wrong.

If you ask me, Tucker’s enthusiasm/support for paleo is huge. Max Planck said progress happens funeral by funeral. I say it happens keg party by keg party — college students, more than anyone else, have open minds. A friend told me that when she was a freshman in college, her sociology professor criticized the textbook. Whoa! she thought. Textbooks can be criticized!? She had thought they were beyond criticism. As far as I can tell, American college students respect Tucker more than they respect anyone else. (My Tsinghua students may favor Nassim Taleb.) For example, this recent tweet: “ TuckerMax is my idol. and he’s on this paleodiet…so i think im going to do it too.” I found no tweets about the dietary influence of Michelle Obama (“ coolest First Lady ever“).

In spite of what the interview was shortened to say, Tucker got the idea of eating flaxseed oil from this blog, especially Tyler Cowen’s experience. He wrote to me about it at the time. I posted his comments about dental health (here and here) and sports injuries (here, here and here) under the name Anonymous.

I am pleased to announce that Tucker will be talking at the upcoming Ancestral Health Symposium at UCLA. The title of his talk is::

From Cave to Cage: Mixed Martial Arts in Ancestral Health

Sorry Tucker Max fans, symposium tickets are sold out. But after the conference you will be able to see the talk on the website.

Tucker’s latest book is Assholes Finish First.


Root Planing Cancelled

Seth Roberts15 Comments

My friend Carl Willat writes:

Last June I went to the dentist for a checkup and cleaning, fully expecting my gums to be in great shape since I had been diligently using my Braun Oral B electric toothbrush. Â To my surprise and disappointment the hygienist told me the pockets had actually become deeper and that she was seeing bleeding in many places, to the point where she was recommending I have my roots planed, a painful and expensive procedure I had undergone once before many years ago. So of course I went home and started taking the flax seed oil and ground flax seed [“a couple of tablespoons a day of oil, plus random amounts of ground flax seed”] as you had recommended. Â I also started using a Sonicare toothbrush at that point so it’s hard to figure out the degree to which either variable might be responsible, but today she said my gums were much better, and had hardly bled at all during the measurement of the pockets. All talk of root planing was forgotten.

According to this, root planing costs $400-$1600. After Tyler Cowen started drinking flaxseed oil (2 T/day), he no longer needed gum surgery.

It is hard to get well-preserved flaxseed oil in Beijing (it goes bad at room temperature) so I now take 66 g/day ground flaxseed instead of 2 T/day flaxseed oil. I add it to yogurt twice/day. I don’t know if ground flaxseed is healthier or less healthy than flaxseed oil but it is much less trouble. Preservation is no problem (flaxseeds can be stored at room temperature) and ground flaxseed requires zero willpower to eat with yogurt. I had to push myself a little to drink the oil.

Preposterous Health Claims of 2010

Seth Roberts1 Comment

Katy Steinmetz, a writer for Time, made a list called “Nutty Health Claims of 2010″ and “2010: The Year in Preposterous Health Claims.” The list of 12 includes:

Preposterous!

Marion Nestle, the New York University nutrition expert, has often said she thinks the health claims made for yogurt are bogus — at least when big companies make them. She recently called Dannon’s claims “a case study of successful marketing”.

Different Effects of Omega-3 and Omega-6 on Heart Disease

Seth Roberts5 Comments

You have probably read hundreds of recommendations to eat more polyunsaturated fatty acids (PUFAs), which in practice means omega-6 and omega-3. If you shop at Whole Foods, you may see Udo’s Blend, a blend of PUFAs which includes both omega-3 and omega-6, as if someone isn’t getting enough omega-6. It is unquestionable that omega-3 is beneficial but there is plenty of evidence that omega-6 is harmful, starting with the Israeli Paradox. Why are they lumped together?

A just-published paper in the British Journal of Nutrition makes several new points about the relation of PUFAs and heart disease. Its main point is a new look at experiments in which one group was given more PUFAs than another group. Those experiments — there are only about eight — can be divided into two groups: (a) experiments in which the treated group was given both omega-3 and omega-6 and (b) experiments in which the treated group was given only omega-6. The two groups of experiments seem to have different results. In the “both” experiments the treated group seems to benefit; in the “only omega-6″ experiments, the treated group seems to be worse off. Suggesting that omega-3 and omega-6 have different effects on heart disease. They have been lumped together because experiments have lumped them together (varied both at the same time).
Experiments that try to measure the effect of PUFAs usually say they are replacing saturated fats. More PUFAs, less butter. The paper points out that studies of the effect of PUFAs have at least sometimes confounded reduction in saturated fats with reduction in trans fats. Benefits of the change may be due to the reduction in trans fats, not the reduction in saturate fats.

The paper also makes several good points about the Finnish study, a classic in the fat/heart disease literature. Supposedly the Finnish study showed that PUFAs (replacing saturated fats) reduce heart disease. It had hundreds of subjects but they were not randomized separately. The subjects were divided by hospital. Everyone in one hospital got one diet, everyone in a second hospital got a different diet. This meant it was easy for there to be confoundings (i.e., the treatment wasn’t the only difference between the groups). Indeed, there were big differences in consumption of a certain dangerous medication and margarine between hospitals. (Margarine is high in trans fats.)

Perhaps the first author, Christopher Ramsden, who works at NIH, is responsible for the high quality of this paper.
Thanks to Susan Allport.

Flaxseed Oil vs. Fish Oil

Seth Roberts9 Comments

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

Seth Roberts6 Comments

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:

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

Seth Roberts6 Comments

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?

Seth Roberts20 Comments

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.