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Wednesday, June 09, 2010

Best sources of DHA omega-3 essential fatty acid

Axolotl by Ethan Hein from flickr (CC-NC-SA)

This is surprisingly difficult to find out, so I decided to share the results with everyone. But first, background:
  • Animals need omega-3 and omega-6 essential fatty acids
  • The same enzymes are used for omega-3 and omega-6 processing, so too much of one will interfere with the other. People used to have diets with about 1:1 omega-3:omega-6. Today ratio is more like 1:20, and that little omega-3 we eat is mostly ALA.
  • Three most important omega-3 are ALA (18 carbons), EPA (20 carbons), and DHA (22 carbons).
  • Brains are made largely out of DHA.
  • Land plants produce no EPA / DHA. None whatsoever. Zero.
  • Some land plants produce adequate amounts of ALA, but even this is uncommon.
  • Algae produce quite a lot of EPA / DHA.
  • Animals including humans can convert ALA to EPA, and then DHA, but this is a painfully slow and inefficient process; and over-saturation of omega-6 and many conditions interfere with even that much.
Based on this some people believe it would be wise to try to increase amount of omega-3 fatty acids in diets. Hard evidence is rather lacking, this is however to be expected as hard evidence of anything about diet is essentially nil. It's almost only short term studies of crappy proxies, and there are millions of reasons why this is just wrong. Anyway, concerning supplementation:
  • All mixed omega-3/omega-6/omega-9 supplements are waste of money - you're eating too much omega-6 already, and you can make as much omega-9 as you wish yourself.
  • You don't want generic "omega-3" supplements - most of these are ALA, which is of very limited use. You want DHA. At worst EPA. ALA is little more than filler, it's not bad for you but it's less relevant, and much easier to get via normal diet anyway.
  • If you're surprised why it's so hard to get DHA, this is possibly highly relevant.
Hopefully now you see why I'm measuring DHA, not anything else. And to keep science proper what I'm interested in is "% of calories coming from DHA", not "grams of DHA per portion" or anything like it. Portions are whatever manufacturer says they are, "per 100g" measures mostly tell you how much water foods have, and only "% of calories from" measures the right thing.

Escher Symmetry by Pieter Musterd from flickr (CC-NC-ND)

Best Sources of DHA

I digged through USDA National Nutrient Database, and this is what I found.
  • The data only contains "food" not supplement pills and such. These will of course contain highest concentrations. Rarely eaten foods like dolphin meat are not in the database, so I have no idea how nutritious dolphin sashimi would be.
  • The best source of DHA is unsurprisingly - fish oil. Salmon oil is 18.2% DHA and 34.2% omega-3 altogether; other fish oils are pretty good too, but not so much. Other oils like cod liver, sardine, and menhaden are 8.5%-10.9% DHA, 18.8%-26.6% total omega-3. Herring oil is less impressive 4.2%/11.1%. Fish oil also contains most mercury and other poisoning, so enjoy that. Once ultra-refined you won't need to worry about poisoning but it's more supplementation than food.
  • The second best source is caviar/roe, with 7.7%-13.6% DHA, and 13.7%-24.2% total omega-3. Might be expensive to turn it into a major part of your diet.
  • The third best source is seal oil with 6.5-12% DHA, 14.0-27.7% omega-3. Let's see if you can buy some legally outside Canada. So far we're totally out of luck.
  • Finally something more useful. The fourth best source is salmon. There's wide range of nutritious value from 2%/4% to 8.9%/13.7% - depending on where they're caught and what's their diet. Fortunately there doesn't seem to be a big difference between wild and farmed salmon, so either will work. Unfortunately the same mercury poisoning problem applies as to fish oil - poisonous substances are stored in oil so the oilier (and more useful for us) the fish the more toxic, and there is no way to escape that.
  • Fifth best source is mackerel. Like salmon, it can have as little as 1.5%/2.8% or as much as 8.7%/14.7%.
USDA says the next best source is dried parsley leaves at 7.3%/9.9% - which is most likely a massive measurement error, as there are no other plants anywhere, and it really makes little sense.

Old friend by JennyHuang from flickr (CC-BY)

Other than that, it's fish, fish, fish, mollusks, jellyfish, crustaceans, and more fish. My hopes for finding something that's not fish are getting slimmer and slimmer, so I'm just going to skip all of them now (you can probably see the pattern), and only focus on things which are not fish/seafood.
  • Brains. Beef/lamb/pork brains have 3%-5.4% DHA and 4.4%-7.7% total omega-3. Not surprisingly, as that's what animals primary need DHA for. And we simply throw away this most nutritious part.
  • Whale oil - 3.9%/8.3%. Whale meat on the other hand is pretty useless at 0.2%/0.5%. Not that you'll find much of either at the nearest supermarket. It's technically not a fish. Anyway, between brains and ocean creatures we pretty much ran out of good sources, the next source is:
  • Roasted squirrel - and that at mere 0.5%/0.6%
  • Chicken can be anywhere from 0.1%/0.2% to 0.5%/0.8%
  • Egg yolk - 0.3%-0.4% DHA, 0.4%-0.7% total.
  • Whole egg - 0.2%-0.3% DHA, 0.2%-0.8% total. Pretty much all of that in yolk.
  • We're long past useful concentrations anyway, so I won't be listing them. Next on the list are caribou, green turtles, turkeys, lamb kidneys, frog legs, guineahen, lamb hearts, squab/pigeon, pork livers, bear, raccoon, pork lung (and other beef/lamb/pork offal), and emu. Pork/beef/lamb meat doesn't register other than as rounding error.
So to summarize:
  • Get supplements;
  • Or eat a lot of fish and other seafood;
  • Or eat ridiculous amount of poultry, eggs, and game meat;
  • Or you're fucked.
There's no way to get enough DHA in anything resembling standard Western diet. Simply no way. Fruits and vegetables contain none, even "organic" ones. Actually fast food contains more as it often uses eggs and poultry as ingredients, but that's still not that useful.

One more long-term option would be to genetically engineer some common oily plants like soy or canola to produce some EPA/DHA - even if humans wouldn't eat them, if they're used as animal feed, we'd benefit indirectly quite a lot.

Actually someone already genetically engineered pigs to produce 4x omega-3 fatty acids, including 2x DHA, which sounds like the most urgent reminder that we need GMO now, and Luddites should not be in charge of policy.

EDIT: GM soybeans with more omega-3 (this most likely means ALA) and higher stability so they don't need partial hydrogenation has just been approved in US. If people moved from usual partially hydrogenated soybean oil to that it would be a massive health benefit. Of course our Euro-Luddites + CAP-paid farmer lobby coalition will probably ban it until long after "America vs Europe" picture get reversed. It's already much closer than you think.

Wednesday, June 02, 2010

What is Internet good for?

im in ur tube, blockin ur internets by the boy on the bike from flickr (CC-NC-SA)

Here a quick poll, pick the most fitting answer:
  • I spend too much time on the Internet, and I'm aware of this
  • I spend too much time on the Internet, I'm deluding myself about it
There's no need to bother with the third option, as people who don't use too much Internet are extremely unlikely to ever read this blog.

But in the spirit of "What have the Romans ever done for us?" - what good is Internet really for? Is it worth all the time we spend on it?

For the last two weeks in the spirit of Alicorn's luminosity - by the way definitely read that linked article, her first attempt was at that was a major tl;dr but these "seven shiny stories" are so short and insightful you're probably better off spending some time reading them than whatever else you're typically wasting your time on Internet, and it promoted her to my second favourite lesswrong writer after Eliezer.

So as I was saying before I interrupted myself, for the last two weeks I've been making a log of my daily activities and how much satisfaction I actually got from a given day.

Now many people who have learned economics 101 and are treating it too seriously think that whatever we're doing must by definition be the things we most enjoy, our claims to the contrary notwithstanding - so people who say the want to get thinner, but eat fuckloads of pizza actually prefer eating pizza and being fat to not eating pizza and being thin. This point of view is usually something worth considering - people usually say they want things they feel they're "supposed to want". On the other hand, the amount of evidence that we don't do what's best for us is ridiculously overwhelming.

A very very short list of such examples would include:
  • hyperbolic discounting - there's only one "mathematically consistent" way of treating values over time (exponential discounting), and the evidence is completely unambiguous that we're not doing so.
  • rodent experiments show also rather unambiguously that brains have separate systems for "wanting something" and "liking something". They are of course connected, so other things being equal if we like something more we will probably want it more - but this influence is far far less than total identity assumed by economics 101. Once you're aware that people might "want" things they don't really "like", and "not want" things they "like" (by the way - I'm using the words "want" and "like" rather vaguely - natural languages are spectacularly bad when analyzing humans - quite surprising actually as they seem to have been originally developed largely for social use) the entire utilitarian / consequentialist framework of analysis collapses.
  • Happiness research in spite of all its ambiguity at least shows that simple models of happiness are plain wrong. If you have time to waste on the Internet - TED is filled with good talks about happiness, not just the one linked.
  • Even disregarding these, you'd need to have ridiculously good information on yourself to decide what's the best thing to do. And it would be a massive understatement to say that we don't have it. And it's really really difficult to measure yourself. The idea behind "living luminously" is that increasing your self-awareness of your own mental state even somewhat might lead to highly positive results.
  • and many many more

Economics 101

By the way - and if you don't enjoy how I keep straying away from whatever is my main subject all the time, you probably shouldn't be reading this blog - I'm in no way disparaging "economics 101" thinking. I find it really sad that virtually every single person in the world pretty much belongs to these two classes:
  • People who don't understand Economics 101. They fail to get even such basic notions like comparative advantage or externalities.
  • People who get Economics 101 - and take it far too seriously. If you even briefly look at assumptions behind all its theorems, none of them is even approximately true in the real world. Very often you get lucky and this toolkit lets you predict things about the real world decently enough, but this is about as often not the case.

This is not to say Economics 101 should be thrown away. All models are wrong, some are useful. Or from a closely related perspective - all abstractions leak. If you don't perform sanity checks, and blindly trust everything the models tell you, they will lead you far astray (you could always argue that it's not models' fault, it's fault of the way you're applying them - but this is a purely theoretical distinction).

So for example in theory economics 101 models say that laissez-faire international trade policy should outperform any kind of intervention, but in practice countries which practice export subsidies by currency manipulation like the East Asia are better off than those with less laissez-faire trade policy like Europe, which in turn are better off than those that try to follow the route of import substitution via high tariffs like Latin America.

By the way if you find this curious, the standard answer to this puzzle is that benefits of economy of scale overwhelm loses due to comparative advantage - pumping subsidies into narrow range of related industries lets your country specialize in those, and import everything else - while limiting imports of wide range of products to protect diverse local industries means they will all be small and weak. As economics 101 completely ignores the dominant factor of scale advantages, focusing on an undoubtedly real but less important factor instead.

Similar misapplication of economics 101 says that minimum wage laws invariably increase unemployment. This was universally believed by nearly all economists a few decades ago according to some surveys cited by Wikipedia, and holding such belief became almost the canonical way of signaling that you're "economically savvy". And not surprisingly it turned out to be false, all research showing either no effect whatsoever, or effect that is really tiny compared to the huge increase in well-being of the working poor. The economists have finally figured that out, and they're more or less evenly divided on the question - even those standing against the minimum wage laws typically holding much more nuanced views - and yet some naive hard-liners still hold this as a measure of "economic enlightenment".
I'm in your PC, stealing your internets by the boy on the bike from flickr (CC-NC-SA)

My logs

Getting back to the subject, for each day in a bit over the last two weeks I recorded my activities, and some measures of satisfaction. The logs weren't terribly detailed, and "recording one's satisfaction" is exactly the kind of thing which would never get published in any reputable peer-reviewed journal. That's not to say that it's useless - "the official way of doing science" has led to many important discoveries, but it's for many questions it's been rather impotent, and it's important that people try different ways of finding things out too, if for nothing else then to fill in the blind spots of the mainstream science.

So my logs, of however dubious methodology they are, seem to point to the following correlations. I won't even bother pretending to have any "statistical significance" in all that of course, even forgetting about small sample of just two weeks measuring "statistical significance" necessarily assumes that samples are essentially independent, and they're nothing like that. The list is:
  • Physical exercise of all kinds - definitely positive - this isn't really surprising, as this is something that's highly enjoyable once started, but it takes effort to begin, so the hyperbolic discounting excuse applies
  • With video games it's mixed. First person shooter games like online Modern Warfare 2 have positive correlations, but Total War games negatively correlate with my end-of-the-day satisfaction, even though they're not really frustrating or anything most of the time.
  • Cleaning up my GTD system - definitely positive
  • Being productive at work, and in general getting done things I want to get done, especially the long postponed ones - definitely positive
  • Reduction in caffeine consumption - mildly negative, but that doesn't really imply anything about long term effects of different levels of caffeine, and it wasn't even as bad as I expected
  • Watching TV series, and reading books - mildly negative; this might be a false result, or the effect might be real but minor, in any case - there's no reason to do much more of those
  • And the largest and rather surprising correlation - spending more time online has a huge negative correlation with my satisfaction levels
Now there standard economics 101 disclaimer applies - these measures are necessarily marginal - so finding out that I'm better off exercising more and Internetting less implies only that I would be better off exercising a bit more than now, and Internetting a bit less than now, and it's more likely than at some point increasing amount of exercise and decreasing Internet use will make me worse off.

It's an interesting find that I seem to actually enjoy my work - I should probably put that one in my CV for future reference. And it's nice to get some insight on what kinds of recreational activities work better for me than others (due to small sample size less repeatable events like those involving interaction with other people not included). But the big find is that Internet is bad for me, and let's focus on that.

What is Internet good for?

Do you remember what life was before the Internet? It was horrible! We had to copy games from friends on stacks of floppies instead of just bittorrenting them! But really, what good is Internet for?
  • Email and IM are always far superior means of communication than phone calls (I really hate those, they should all die in fire); and are so much faster and easier than driving all the way to meet someone in person that they usually win, even if the throughput is somewhat less.
  • There's shopping - at which Internet really excels, most of the time. At least when you know exactly what you want, otherwise not so much.
  • There is information - but I'm far from happy about it. For some kinds of thing that you want to find, if they follow "keyword keyword of keyword" pattern, you can usually google or bing it out in seconds. Otherwise, all search engines become nearly useless, even if this information is somewhere. And it requires a lot of knowledge to turn a problem into unique keywords - very often you know little more than "X doesn't work", or "I'm not happy about Y", and search engines won't help you with those at all. This assumes information is even online in the first place - as very often it's not - it's really sad how nearly all research papers have been successfully pay-walled. It seems that "information wants to be free" only when the information in question is something on the top 100 bestsellers list of one kind or another, and not to the long tail which contains most of the real value.
  • There's Google Maps and similar sites, which are far superior to paper maps.
  • There are some funny things online - but they're swamped by such amounts of unfunny repetitive material that I really doubt Internet is even good for that. I dare you, go to let's say /r/funny on reddit - which is supposedly about the most recent funny stuff online (or at least reddittors seem to believe they find stuff first, and everyone else copies stuff from them) - and how many things you'll find there that will make you laugh, and are not nearly ancient? And it's the same on nearly every other place which is supposedly filled with funny stuff. People keep going there because occasionally something good turns out, but it's so rare it's probably not worth it.
  • There are news - and again the flood problem applies. I'm yet to find any RSS feed with only important news. Everyone seems to believe the right way to do news online is to just throw 10+ trivia items a day - Obama said something, one minor celebrity divorced another minor celebrity, stock prices decreased somewhere, IDF shot a few unarmed civilians somewhere else - as if knowing things like these made you better off in any way. The choice is to either get ridiculous amount of political trivia, or just ignore the news altogether.
  • There are all kinds of social networking sites - and I'm increasingly doubting their value. I have a Facebook account (and accounts on some other sites) and I might even use it occasionally, but I don't see that my life would be that much worse if Facebook and the rest didn't exist.
  • There are blogs, wikis, and similar places where you can contribute your knowledge, which can give tremendous amount of satisfaction to the contributor. If you add them all up, they provide a lot of value for readers as long as search engines manage to find a relevant blog post or wiki article, which is always in doubt. On the other hand, I have serious doubts about reading everything on a blog, or unfocused browsing on wikis. I haven't yet seen a blog which had consistently good posts - much less consistently good and relevant to my interests.
  • There are online video games, for some things playing with people is more fun than playing against computer.

These seem to cover the main points. And what's obvious is that the most valuable online activities - email, highly focused search, shopping, maps - take rather little time. On the other hand, the ones that take a lot of time - like all the reddits, forums, social sites, wikis, blogs, etc. - don't provide that terribly much value per time spent.

Unless you actually measure how you use internet, it's really easy to overestimate how much value spending time on it gives you - as you're far more likely to remember the high points which didn't really take long - as opposed to relatively pointless activities which took most of your online time. Human memory just works like that.

This distinction would be pointless if it was impossible to make a distinction between the two - if reduction in the bad kind of internet use required essentially proportional reduction in the good kind. Fortunately it seems to me that this is fairly straightforward - good things like email (this of course assuming you have a working spam filter / and all mailing lists etc. go somewhere else than your inbox), shopping, maps, directed search - have different entry points than less useful things like social sites, wikis, news, and funnies etc. Sometime you'll look for something specific and in the process accidentally fall into a wiki trap, but this shouldn't be too common with some self-awareness. Much more often you waste a ridiculous amount of time by wanting to "quickly check if there's anything good on X" and having hyperbolic discounting ("just one more link") turn that into a disaster.

It doesn't mean reducing your lolcat consumption to zero - only that you should force yourself to make an up-front decision "I'm start looking at funnies now, even though I know well enough it will probably take the next few hours" and having a realistic idea how good this time will be; instead of fooling yourself it will be quick and only filled with the good stuff, as seems typical now.

tl;dr - using internet only when you have clear goal, and not for vague "maybe there's something good" is good for you.