Seth's Blog

In nature animals must choose a healthy diet based on what tastes good. This doesn’t work for modern humans — lots of people eat poor diets — but why it fails is a mystery. There are many possible reasons. Are the wrong (“unnatural”) foods available (e.g., too much sugar, too little omega-3, not enough fermented food)? Is something besides food causing trouble (e.g., too little exercise, too little attention to food)? Are bad cultural beliefs too powerful (e.g., “low-fat”, desire for thinness)? Is advertising too powerful? Is convenience too powerful? Lab animals are intermediate between animals in nature and modern humans. They are not affected by cultural beliefs, advertising, and convenience (the foods they are offered are equally convenient). Their choice of food may be better than ours.

Nutrition researchers understand the value of studying what lab animals choose to eat. In 1915, the first research paper about “dietary self-selection” was published, followed by hundreds more. The general finding is that in laboratory or research settings, animals choose a relatively healthy diet. There are two variations:

[1.] Cafeteria experiments with chemically defined [= synthesized] diets showed that some of these animals, when offered the separate, purified nutrient components of their usual diet, eat the nutrients in a balance that more or less resynthesizes the original diet and that is often superior to it. [2.] Other animals eat two or more natural foods in proportions that yield a more favorable balance of nutrients than will any one of these foods alone.

Both findings imply that housing an animal in a lab does not destroy the mechanism that tells it what to eat.

Which is why I was fascinated to recently learn what Mr. T (pictured above), the pet rat of Alexandra Harney, the author of The China Price, and her husband, liked to eat. It wasn’t obvious. “We tried so many foods with him and always thought it made a powerful statement that even a wild rat turned his nose up at potato chips,” says Alexandra. “He hated most processed food. He also hated carrots, though.” Here are his top three foods:

1. pate
2. salmon sashimi
3. scrambled eggs

Pate = protein, animal fat, complex flavors (which in nature would have been supplied by microbe-rich, i.e., fermented, food). Salmon sashimi = protein, omega=3. Scrambled eggs = ??

He liked beer in moderation, but not yogurt. “Owners of domestic rats say they love yogurt,” says Alexandra, “but Mr T only liked it briefly and then hated it, even lunging to bite a friend who brought him some. [Curious.] He loved cheese, stored bread for future consumption (but almost never ate it). Loved pesto sauce and coconut.” Note the absence of fruits and vegetables. Alexandra and her husband have no nutritional theories that I am aware of. They did not shape this list to make some point.

For me the message is: Why scrambled eggs? I too like eggs and eat them regularly and cannot explain why.

More Alex Tabarrok’s Thanksgiving post shows the connection between libertarian ideas (economies work better when more choice is allowed) and dietary self-selection.

In response to this post, which went up three months ago, a reader named Tara has just written:

I started taking 2 TB of flax oil daily about four days ago and now my gums are barely bleeding at all after I brush and floss. My gums were red, swollen and would bleed after I brushed and flossed and are now pink and healthy looking.

I’ve had this problem for years and I could not understand why it would keep happening even though I was consistent with my dental routine. I take the berry flavored Barlean’s flax oil mainly because it tastes good and so I look forward to taking it- if it was gross I would not be consistent with taking it.

Anyhow, thanks for the information! I wish dentists would look into this but they probably won’t so I’m glad that you do.

I agree about the Barlean’s, by the way. Their Omega Swirl flaxseed oil does taste good. The Omega Swirl webpage does not list healthy gums as one of its benefits. Instead it lists a bunch of benefits, such as “Heart Health” that are nearly impossible to verify.

Someone recently told me something fascinating about flaxseed oil: It made it much easier to kneel on the floor.  Before he started taking it, his knees would hurt after a few seconds. Now they don’t. I don’t remember my knees hurting quickly but I consume 66 g/day of ground flaxseed (= about 2 T flaxseed oil) and can kneel without pain for minutes.

The tiny fact reflected in Tara’s comment — an easily-available supplement (flaxseed oil) quickly cures a common problem (bleeding gums) but hardly anyone knows this — is  a devastating comment on our health care system.

1. Dentists haven’t managed to figure this out. Flaxseed oil is not an obscure supplement. Dentists are not making money giving people much worse advice (“floss regularly”).

2. Nutrition professors haven’t managed to figure this out. Omega-3 is not an obscure nutrient. Nevertheless, the 2010 USDA Dietary Guidelines says omega-3 fats are “essential” but says nothing about how much you need. Inflammation is believed to be the cause of many diseases, including heart disease. By getting this one thing  (minimum omega-3 intake you need to be healthy) right, the USDA could do a world of good. Instead they tell people to eat less animal fat (“consume less than 10 percent of calories from saturated fatty acids”).

To be fair, professional researchers are starting to figure this out.  A 2010 study of 9000 people found that “participants in the middle and upper third for omega-3 fatty acid consumption were between 23 percent and 30 percent less likely to have gum disease than those who consumed the least amount of omega-3 fatty acids.” With the right dose, I believe gum disease becomes 100% less likely. But at least they noticed a connection.

For the last four years or so I have daily measured how well my brain is working by means of balance measurements and mental tests. For three years  I have used a test of simple arithmetic (e.g, 7 * 8, 2 + 5). I try to answer as fast as possible. I take faster answers to indicate a better-functioning brain.

Yesterday my score was much better than usual. This shows what happened.

My usual average is about 550 msec or more; my score yesterday was 525 msec. An unexplained improvement of 25 msec.

What caused the improvement? I came up with a list of ways that yesterday was much different than usual, that is, was an outlier in other ways. These are possible causes. From more to less plausible:

1. I had 33 g extra flaxseed last night. (By mistake. I’m not sure about this.)

2. The test came at the perfect time after I had my afternoon yogurt with 33 g flaxseed. When I took flaxseed oil (now I eat ground flaxseed), it was clear that there was a short-term improvement for a few hours.

3. Many afternoons I eat 33 g ground flaxseed with yogurt. Yesterday I ground the afternoon flaxseed an unusually long time, making made the omega-3 more digestible.

4. I did kettlebells swings and a kettlebell walk about 2 hours before the test. These exercises are not new but usually I do them on different days. Yesterday was the first time I’ve done them on the same day. I’m sure ordinary walking improves performance for perhaps 30 minutes after I stop walking.

5. I had duck and miso soup a half-hour before the test. Almost never eat this.

6. I had a fermented egg (“thousand-year-old egg”) at noon. I rarely eat them.

7. I had peanuts with my yogurt and ground flaxseed. Peanuts alone seem to have no effect. Perhaps something in the peanuts improves digestion of the omega-3 in the flaxseed.

8. I started watching faces at 7 am that morning instead of 6:30 am or earlier.

Here are eight ideas to test. Perhaps one or two will turn out to be important. Perhaps none will.

After I made this list, I read student papers. The assignment was to comment on a research article. One of the articles was about the effect of holding a warm versus cold coffee cup. Holding a warm coffee cup makes you act “warmer,” said the article. Commenting on this, a student said she thought it was ridiculous until she remembered going to the barber. She sees the person who washes her hair (in warm water) as friendly, the barber as cold. Maybe this is due to the warm water used to wash her hair, she noted. This made me realize another unusual feature of yesterday: I had washed my hair in warm water longer than usual. I think I did it at least 30 minutes before the arithmetic test but I’m not sure. In any case, here is another idea to test. I found earlier that cold showers slowed down my arithmetic speed.

This illustrates a big advantage of personal science (science done for personal gain) over professional science (science done because it’s your job): The random variation in my life may suggest plausible new ideas. As far as I can tell, professional scientists have learned almost nothing about practical ways to make your brain work better. You can find many lists of “brain food” on the internet. Inevitably the evidence is weak. I’d be surprised if any of them helped more than a tiny amount (in my test, a few msec). The real brain foods, in my experience, are butter and omega-3. Perhaps my tests will merely confirm the value of omega-3 (Explanations 1-3). But perhaps not (Explanations 4-8 and head heating).

• Edward Jay Epstein’s Adweek columns. Epstein on James Angleton, the spy.
• Indigenous fermented foods (1st 8 pages of chapter)
• Did McDonald’s cause a decline in violence in America?

Thanks to Navanit Arakeri and Casey Manion.

I used to get my omega-3 from flaxseed oil. Then I encountered problems with the flaxseed oil going bad, in the sense of losing potency. (It did not smell bad.) I switched to flax seeds, which I grind and eat with yogurt. This is more difficult than drinking flaxseed oil.

From Peter Spero I have learned of a possible new source of omega-3: camelina oil. Camelina oil, unlike flaxseed oil, contains high levels of anti-oxidants, which protect it from going bad. Camelina is cheap to grow and can be grown where other crops cannot.