In a New Yorker article titled “The Way We Age Now,” Atul Gawande writes:
With age . . . the gums tend to become inflamed.
As I posted a few weeks ago, my gums have recently become less inflamed — no doubt because of more omega-3 from flaxseed oil. For the first time in memory they are not inflamed at all. (My dentist was surprised. Hardly anybody improves, he said.) Could Gawande’s “with age” effect be due to not enough omega-3?
As I’ve described in previous posts, flaxseed oil (high in omega-3) seems to improve my balance. As I increased the daily dose, I found that 4 tablespoons (T)/day had almost the same effect as 3 T/day. To measure the effects of omega-3, I plan to use 3 or 4 T/day flaxseed oil — which presumably produces near-optimal omega-3 levels — as a baseline for measuring the effect of other things.
For my first comparison I chose olive oil: widely believed healthy, but low in omega-3. (And recommended by me in The Shangri-La Diet.) I used an ABA design: several days flaxseed oil, several days olive oil, several days flaxseed oil. In all conditions, I took 2 tablespoons of the oil at about 10 am and 2 tablespoons at about 10 pm each day. I measured my balance at about 8 am the next day. Each daily test consisted of 30 trials. Each trial consisted of balancing on one foot on a board atop a metal cylinder (pictures). The score was how long before I lost my balance and put the other foot down.
Here are the results.
While drinking the olive oil, my balance slowly got worse. When I returned to flaxseed oil, my balance quickly returned to its previous level. Very clear difference between the oils, F (2,40) = 18, which corresponds to a tiny p value and t about 5.
A possible explanation is that when the concentration of omega-3 in the blood is low, the omega-3 in cell membranes slowly “evaporates” into the blood. When a cell’s membranes lose omega-3, it doesn’t work as well.
A reader (Josh Mangum) writes:
The flavorless calorie diet lets me drop weight whenever I need to. I was usually 10-15 lbs overweight and up to 25 lbs when under stress. Both my parents are overweight so I was worried that I would put on weight under stress and not take it off. My dad especially has followed the pattern of gaining a few pounds a year his whole adult life and is now about 75 lbs overweight. Besides the obvious advantages of losing weight now it’s really nice that I don’t have to worry about being very overweight in the future.
Flax oil is more subtle. I think it’s improving my sleep and mental ability. For sleep I’ve noticed being rested and having more vivid dreams. There seems to be a dosage effect. One night I tried 6 tbls of flax oil, had very vivid dreams and felt very rested the next day. The other thing that seems consistent with it working is that I can go back to sleep for a couple hours after waking at 7 am if I’m still tired. Previously I was never able to go back to sleep whether I woke at 2 am or 7 am.
I write software and notice that it seems easier while I’ve been using flax oil. It seems to be easier to hold large problems in my head and work though them than previously. I don’t notice much effect on how often I’m “insightful” or “clever” though. So rather than being smarter it seems like being adequately smart more often. This is subtle though and it could be the phase of the project or my outlook or just better sleep. Maybe the effects are just the result of coming out of the shorter foggier San Francisco winter days.
I think could read the New York Times for a hundred years and not come across anything as well-written as this gem of a blog post by Joyce Cohen, who writes The Hunt column in the Times. I love her column — but this is better. It’s about something I don’t even care about, New York real estate.
By incredible coincidence, Nicholas Kristof’ s most recent blog entry (April 17, 2007) is also better, in my opinion, than essentially everything that appears in the Times (or any other paper). Kristof reprints a letter to him from a student that makes an extremely important point about Africa coverage in the Times (and, probably, all other Western newspapers): It is unceasingly focussed on failure. I wonder why.
In his blog a few days ago, as I mentioned earlier, Nicholas Kristof printed a letter from a University of North Carolina graduate student about why she was not going to enter Kristof’s contest to go to Africa with him. Kristof wrote too much about failure, she said:
[Quoting Kristof:]“I’m hoping that you’ll be changed when you see a boy dying of malaria because his parents couldn’t afford a $5 mosquito net, or when you talk to a smart girl who is at the top of her class but is forced to drop out of school because she can’t afford a school uniform.” . . . The story of Africa in turmoil is the African narrative that many Americans – and certainly those who read The New York Times – already know. It is virtually the only type of reporting that Western news outlets broadcast about the continent. . . Americans don’t need any more stories of a dying Africa. Instead, we should learn of a living one. Kristof and his winners should investigate how it is that Botswana had the highest per-capita growth of any country in the world for the last 30 years of the twenty-first century.
I believe she is correct. The Times and — I’ll take her word for it — “Western news outlets” in general have made a serious mistake in their Africa coverage: Far too much coverage of failure relative to success. An especially curious misjudgment because generally journalists like feel-good stories.
Could an entire well-respected profession do the wrong thing for a long time? Well, Jane Jacobs thinks so. In a 2000 interview, she said this about economists:
One place where past economic theory has gone wrong in a subtle way is that it has always been called upon for explanations of breakdowns and trouble. Look how foreign aid, even today, is all about poverty and where things are not working. There is no focus on trying to learn how things are working when they work. And if you are going to get a good theory about how things work, you have to focus on how they work, not on how they break down. You can look forever at a broken down wagon or airplane and not learn what it did when it was working.
Maybe you say Jacobs wasn’t a real economist (because she didn’t write mainstream academic papers). Well, consider this. In the 1960s, Saul Sternberg changed the face of experimental psychology when he showed what could be done with reaction-time experiments, which are set up so that the subject almost always gets the right answer. Before Sternberg, memory and perception were usually studied via percent-correct experiments, set up so that subjects were often wrong.
Sternberg’s reaction-time research was so much more revealing than the percent-correct research that preceded it that almost everyone switched to using reaction time. The profession of experimental psychologists had done the wrong thing for a long time.
I think very highly of Philip Weiss and rarely disagree with him. But I certainly disagree with this:
My first feeling seeing the crapulous tape on the news last night was, Burn it. What more are we going to learn about this sick monster [the Virginia Tech shooter] from his first-person maunderings? O.K., archive it, let criminologists study it, but why give him the attention he so craved? Wipe his name from history. Did you notice he honored Dylan Klebold and Eric Harris of Columbine in his statement? Why not erase their names too.
I have not yet found the interview in which Jane Jacobs says something like “It’s a funny thing. You can’t change something unless you love it.” But I did find an interview in which she said:
You can’t prescribe decently for something you hate. It will always come out wrong.
The longer you hate the Virginia Tech shooter, as Mr. Weiss and many others do, the longer it will be till you understand what to do about him — how to prevent such things in the future. It was a fundamentally decent thing that the shooter did by sending that stuff to NBC. Like everyone, he wants to be listened to. As I blogged earlier, one of my students did a project that involved visiting homeless people in People’s Park. He was surprised by how much they wanted to talk to him. The solution to homelessness, he was pretty sure, would involve a lot of listening.
Addendum: A forensic psychiatrist named Michael Weiner argues the opposite (that showing the videos does no good and lots of bad) here. Jacobs’ view is supported by a wealth of evidence. I can’t tell if any evidence supports Weiner’s view.
When I read an empirical scientific paper I ask four main questions:
1. How clear is the effect or correlation? Generally measured by p values.
2. How clear is the cause of the effect?
3. How much can we generalize from this?
4. Assuming we can generalize, how much will this change what anyone does?
The overall value is something like the product of the answers. Most research gets a modest score on #1 (because a high score would be overkill and, anyway, the low-hanging fruit has been picked) and a low score on #4. Experiments get a high score on #2, surveys a low score.
Tim Lundeen’s little experiment that I described a few days ago, in which he found that a higher dose of DHA improved his arithmetic ability, gets a very high score:
1. The effect is very clear.
2. It’s an experiment. Because the variation was between two plausible doses of a food supplement, I doubt it’s a placebo effect.
3. The subject, the treatment, and the test are “ordinary” — e.g., Tim does not fall into a special group that might make him more likely to respond to the treatment.
4. Who wouldn’t want to improve how well their brain works?
From the point of view of a nutrition scientist, I’d guess, the effect is shockingly clear and direct. Experimental nutrition with humans almost always measures correlates of disease (e.g., correlates of heart disease) rather than disease. To me, an experimental psychologist, the results are shockingly useful. Practically all experimental psychology results (including mine) have little use to most people. The clarity of the effect does not quite shock me but I’m very impressed.
In a recent post I described Tim Lundeen’s arithmetic data. He found that increasing his daily dose of DHA seemed to increase the speed at which he did simple arithmetic. Here is the graph:
I didn’t bother to do any statistical tests because I thought the DHA effect was obvious. However, someone in the comments said it wasn’t obvious to them. Fair enough.
If DHA has no effect, then the scores with more DHA should be the same as the just-preceding scores with less DHA. There are practice effects, of course, so I analyzed the data after practice stopped having an effect: After about Day 40. (And I left out days preceded by a gap in testing — e.g., a day preceded by a week off.) Thousands of learning experiments have found that practice makes a difference at first and then the effect goes away — additional practice doesn’t change behavior.
If I do a t-test comparing low-DHA days (after Day 40) with high-DHA days, I get a huge t value — about 9. If you’re familiar with real-life t values, I’m sure you’ll agree that’s a staggeringly high value for a non-trivial effect. The model corresponding to this test is indicated by the lines in this figure:
The red (”more DHA”) points don’t fit the line very well, which suggests doing an analysis where the slopes can vary:
There is still a huge effect of DHA, now split between two terms in the model — a difference-in-level term (t = 4) and a difference-in-slope term (t = 3).
But this analysis can be improved because based on thousands of experiments I don’t believe that the less-DHA line could have a positive slope, as it does in the model. Or at least I believe that is very unlikely. So I will constrain the less-DHA line to have a slope of zero:
Now I get t = 8 for the difference in slopes and t = 4 for the difference in level. This is interesting because it implies that more DHA not only caused immediate improvement but also opened the door to more gradual improvement (indicated by the slope difference). DHA changed something that allowed practice to have more effect.
That’s a new way of thinking about the effects of omega-3 — actually, I have never seen any data with the feature that a treatment caused a practice effect to resume — so I have to thank the person who claimed the difference wasn’t obvious.
Several months ago I got this email from someone at the Seed Media Group:
Thank you for your interest in being hosted by ScienceBlogs. In the last couple of months, we have received well over a hundred queries from bloggers representing an impressive breadth and depth of science
expertise. However, as we are trying to maintain a sense of community at ScienceBlogs, we are able to extend only a small number of invitations at a time. . . . In light of the very limited number of spaces we have to offer, we regret to inform you that we cannot extend you an invitation at this time.
This was sent to about 50 people. Their email addresses were visible. One of the recipients thought that we, the rejectees, could form our own umbrella website and wrote to us about this. I replied:
I love the idea of a form rejection letter leading to the founding of a competitive website — count me in!
Four months later I got an invitation to join the result, www.scientificblogging.com. It is now a well-functioning website with lots of interesting stuff.
During the recent PBS special on obesity Fat: What No One is Telling You, a segment about surgery included this voiceover:
Until recently it was believed that the tiny stomach [that the surgery produces] is what forces the patient to eat less and lose weight. The surprise came when researchers learned that what makes surgery work so well is the cutting of some nerves in the bowel, which changes signals which flow between the gut and the brain.
I’m not surprised the researchers were surprised. The obvious function of nerves from gut to brain is to tell the brain food is present in the gut; and when enough food is present, to cause satiety. If this view of what the nerves do is correct, you would think that cutting those nerves reduces satiety signals and thus increases how much people eat at each meal — and thus causes weight gain. But the opposite is what happened.
The theory behind the Shangri-La Diet, however, easily explains the weight loss: Cutting the nerves reduced the calorie signal from food, thus reduced the strength of the flavor-calorie association. (After nerves are cut, your brain thinks that a 300-calorie food only has 150 calories. So the flavor-calorie association becomes weaker.) The weaker the flavor-calorie associations of your food, the lower your set point. The observation supports the theory so well that I will try to track it down to include in a revision of my paper.
The implication is that weight-loss surgery could consist of cutting some of those calorie-signalling nerves and nothing more. It would be relatively painless: Food would still taste good, especially in the beginning. (Because cutting the nerves does not change the memory stored in the brain.) Food would gradually taste less good as the flavor-calorie association become weaker. As flavor-calorie associations become weaker, your set point goes down. Causing weight loss without effort.