Tuesday, September 30, 2008

Globetrotters in Harlem: the case of 'ghetto' tourism

Do tourists visit Harlem merely to gawp at poor, black people? The following is an extract from an article on the Guardian's Comment is Free site by a Harlem resident, Lola Adesioye.
"I'm still struggling to get to grips with tourists' fascination with coming into a poor area, one still considered by many to be a "ghetto", just to watch black people eat, worship and generally go about their daily lives - as if deprivation is somehow interesting and the way in which black people socialise really is so different from other Americans."
Just as India has "slum tours", Brazil offers the "favela experience" and South Africa serves up township "poorism", now Harlem is the must-see place to get down with, and get photos of, people less privileged than yourself.

Or is it?

As some of the blog respondents point out, isn't the Afro-American heritage likely to be more of a draw than poverty? I think many residents would be rather unhappy slotting modern Harlem into the slum/favela/township category.

One blog respondent, Raz, says:
I intend to visit Harlem on my next visit to NYC. Not to gawp at poor people but because it's another part of the jigsaw of a fascinating city. I'm not sure that you can live in an historical neighborhood and not expect tourists. Lola, I'm sure you've visited Chinatown. How did you feel about that?
I'd have to agree with Raz. As a home of jazz music, soul-food restaurants, gospel churches, historical sites and hip-hop, Harlem has all the hallmarks of a tourist attraction.

Two years ago, I went on a hip-hop tour of Harlem (tour guide Grandmaster Caz, pictured above). Admittedly, it was a group tour on bus, which is never my favourite form of tourism, but I did it to get to know another one of the city's neighbourhoods and learn about the origins of a genre of music that became part of my own youth on the other side of the Atlantic. I certainly didn't do it to get my fix of "deprivation"; my motivations were no different from doing a Bob Dylan tour of Greenwich Village.

Back to the idea of poorism or favela tourism, it's never going to be simple right/wrong, black/white case. Each experience depends on the individual tourist's attitude, as Lola concedes. If the alternative is to visit all other neighbourhoods and ignore the so-called "black areas", I can't see that this would be preferable.

Admittedly, bus tours aren't ideal and seem to jar with something as personal as church worship (Harlem church trips are very popular among tourists), but it is up to the congregations to decide whether to accept this or not. Meanwhile, tour guides are in the ideal position to breakdown inevitable preconceptions.

The best advice from Lola comes in her parting words. "I'd encourage anyone coming to Harlem to get off the bus, sit in a bar or café and talk to some locals." Travel networking anyone?

Monday, September 29, 2008

Acne: Disease of Civilization

I often focus on the bigger facets of the disease of civilization. Things like cardiovascular disease and cancer, which are major killers and the subject of intensive research. But the disease of civilization is a spectrum of disorders that affects the body in countless ways, large and small.

I recently read an interesting paper written by an all-star cast, including Loren Cordain, Staffan Lindeberg and Boyd Eaton. It's titled "Acne Vulgaris: A Disease of Western Civilization". The paper presents data from two different groups, the Kitavans of Papua New Guinea and the Ache hunter-gatherers of Paraguay. Both were systematically examined by doctors trained to diagnose acne. Out of 1,200 Kitavans and 115 Ache of all ages, not a single case of acne was observed. Hunter-gatherers and other healthy non-industrial cultures have nice skin. I dare you to find a pimple in Nutrition and Physical Degeneration.

In Western societies, acne is a fact of life. The paper states that 79 to 95% of modern adolescents suffer from some degree of acne, along with about 50% of young adults. That's an enormous difference.

The paper presents a very Cordain-esque hypothesis to explain the high incidence of acne in Western societies. In sum, they state that the Western diet causes hyperinsulinemia, which is thought to promote acne. This is due to insulin's effects on skin cell proliferation, its interference with the retinoid (vitamin A) signaling pathway, and its effect on sebum production.

They then proceed to point the finger at the glycemic index/load of the Western diet as the culprit behind hyperinsulinemia. It's an unsatisfying explanation because the Kitavans eat a diet that has a high glycemic load due to its high carbohydrate content, low fat content, and relatively high-glycemic index foods. I think the answer is more likely to reside in the specific types of carbohydrate (processed wheat) rather than their speed of digestion, with possible contributions from refined vegetable oil and an excessive sugar intake.

Thursday, September 25, 2008

Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is milder form of NASH, in which the liver becomes enlarged and accumulates fat. Ready for a shocker? The prevalence of NAFLD is thought to be between 20 and 30 percent in the Western world, and rising. It's typically associated with insulin resistance and often with the metabolic syndrome. This has lead some researchers to believe it's caused by insulin resistance. It's a chicken and egg question, but I believe it's the other way around if anything.

There are certain animal models of human disease that are so informative I keep coming back to them again and again. One of my favorites is the LIRKO mouse, or liver-specific insulin receptor knockout mouse. The LIRKO mouse is missing its insulin receptor in the liver only, so it is a model of severe insulin resistance of the liver. It accumulates a small amount of fat in its liver in old age, but nothing that resembles NAFLD. So liver insulin resistance doesn't lead to NAFLD or NASH, at least in this model.

What else happens to the LIRKO mouse? It develops severe whole-body insulin resistance, impaired glucose tolerance, high fasting blood glucose and hyperinsulinemia (chronically elevated insulin). So insulin resistance in the liver is sufficient to cause whole-body insulin resistance, hyperinsulinemia and certain other hallmarks of the metabolic syndrome, while liver and whole-body insulin resistance are not sufficient to cause NAFLD or NASH. This is consistent with the fact that nearly everyone with NAFLD is insulin resistant, while many who are insulin resistant do not have NAFLD.

In all fairness, there are reasons why NAFLD is believed to be caused by insulin resistance. For example, insulin-sensitizing drugs improve NAFLD. However, that doesn't mean the initial metabolic 'hit' wasn't in the liver. One could imagine a scenario in which liver insulin resistance leads to insulin resistance in other tissues, which creates a positive feedback that aggravates NAFLD. Or perhaps NAFLD requires two 'hits', one to peripheral insulin sensitivity and another directly to the liver.

In any case, I feel that the most plausible mechanism for NAFLD goes something like this: too much n-6 from polyunsaturated vegetable oil (along with insufficient n-3), plus too much fructose from sweeteners, combine to cause NAFLD. The liver becomes insulin resistant at this point, leading to whole-body insulin resistance, hyperinsulinemia, impaired glucose tolerance and general metabolic havoc.

Tuesday, September 23, 2008

Agave Syrup

Anna brought up agave syrup in a comment on the last post, so I thought I'd put up a little mini-post so everyone can benefit from what she pointed out.

Agave syrup is made from the heart of the agave plant, which is pressed to release a juice rich in inulin. Inulin is a polymer made of fructose molecules. The inulin is then broken down either by heat or by enzymatic processing. The result is a sweet syrup that is rich in fructose.

Agave syrup is marketed as a healthy, alternative sweetener. In fact, it's probably as bad or worse than high-fructose corn syrup (HFCS). They are both a refined and processed plant extract. Both are high in fructose, with agave syrup leading HFCS (estimates of agave syrup range up to 92% fructose by calories). Finally, agave syrup is expensive and inefficient to produce.

The high fructose content gives agave syrup a low glycemic index, because fructose does not raise blood glucose. Unfortunately, as some diabetics learned the hard way, using fructose as a substitute for sucrose (cane sugar) has negative long-term effects on insulin sensitivity.

In my opinion, sweeteners come with risks and there is no free lunch. The only solution is moderation.

Monday, September 22, 2008

How to Fatten Your Liver

Steatohepatitis is a condition in which the liver becomes inflamed and accumulates fat. It was formerly found almost exclusively in alcoholics. In the 1980s, a new condition was described called nonalcoholic steatohepatitis (NASH), basically steatohepatitis without the alcoholism. Today, NASH is thought to affect more than 2% of the adult American population. The liver has many important functions. It's not an organ you want to break.

This week, I've been reading about how to fatten your liver. First up: industrial vegetable oil. The study that initially sent me on this nerd safari was recently published in the Journal of Nutrition. It's titled "Increased Apoptosis in High-Fat Diet–Induced Nonalcoholic Steatohepatitis in Rats Is Associated with c-Jun NH2-Terminal Kinase Activation and Elevated Proapoptotic Bax". Quite a mouthful. The important thing for the purpose of this post is that the investigators fed rats a high-fat diet, which induced NASH.

Anytime a study mentions a "high-fat diet", I immediately look to see what they were actually feeding the animals. To my utter amazement, there was no information on the composition of the high-fat diet in the methods section, only a reference to another paper. Apparently fat composition is irrelevant. Despite the fact that a high-fat diet from coconut oil or butter does not produce NASH in rats. Fortunately, I was able to track down the reference. The only difference between the standard diet and the high-fat diet was the addition of a large amount of corn oil and the subtraction of carbohydrate (dextrin maltose).

Corn oil is one of the worst vegetable oils. You've eaten corn so you know it's not an oily seed. To concentrate the oil and make it palatable, manufacturers use organic solvents, high heat, and several rounds of chemical treatment. It's also extremely rich in n-6 linoleic acid. The consumption of corn oil and other n-6 rich oils has risen dramatically in the US in the last 30 years, making them prime suspects in NASH. They have replaced the natural (more saturated) fats we once got from meat and milk.

Next up: fructose. Feeding rats an extreme amount of fructose (60% of calories) gives them nonalcoholic fatty liver disease (NAFLD), NASH's younger sibling, even when the fat in their chow is lard. Given the upward trend of US fructose consumption (mostly from high-fructose corn syrup), and the refined sugar consumed everywhere else (50% fructose), it's also high on my list of suspects.

Here's my prescription for homemade foie gras: take one serving of soybean oil fried french fries, a basket of corn oil fried chicken nuggets, a healthy salad drenched in cottonseed oil ranch dressing, and wash it all down with a tall cup of soda. It's worked for millions of Americans!

Credit crunched? Try a home exchange

In times of hefty morgage payments, rising fuel bills and general financial doom, the Daily Telegraph has offered a solution: make your home your passport. Home exchanges are nothing new, but, as the credit crunch takes hold, the idea of living abroad rent-free has never been more appealing.

Last month, the Observer also renewed interested in such schemes with an entertaining account of a London-NYC home swap.

Juliet Kinsman writes:
Our introduction to the immediate neighbours was a hello over the fence - followed by the offer of a paddling pool loan. To parents of an infant in the sweltering city heat, this ranks with a private hotel infinity pool. Imagine our delight when they reappeared brandishing guests passes to MoMA, a mountain of toys and fresh-from-the-oven New York Times recipe cookies. We hadn't been there 48 hours and they'd already made our holiday.

It was a lovely piece and a huge success in terms of online page views. Well, who wouldn't be tempted to click on headline reading 'New York for a month without spending a dime'? (Even if this did seem to overlook living expenses and flights.)

The Daily Mail's money section has also been enthusing about home-swapping this week, while the Guardian launched its own home-exchange service, powered by Home Base Holidays, in January.

In general, as listing sites get more sophisticated, it's becoming even easier to arrange a house exchange. Although that doesn't mean swappers aren't thinking ahead: according to the Travel the Home Exchange Way blog, exchange plans are already underway for the London 2012 Olympics. Time to get on your marks? Here are the Telegraph's home-exchange tips:

  • Register with an agency, which will cost from £40 to £250, to display your home details on a professional website and give you access to details about other homes
  • Describe your home thoroughly with plenty of digital pictures, and remember that American and Australasian visitors love history
  • To start making a swap, either wait for another client to contact you or identify a place and home you like, and email the owners
  • Most agencies have checklists of details to discuss with your exchangee – cars, pets, wear-and-tear and breakages, insurance, and what’s out of bounds
  • Some agencies have pro forma contracts which can be exchanged between the two sets of home owners

  • Further advice on house exchanges on the Which website.

    Sunday, September 21, 2008

    Couch surfer: the song

    Proof that the word "couchsurfer" was around before 2004-established Couchsurfing.com. Here's an extract from Couch surfer, a Bran Van 3000 song released on their 1998 album, Glee. The band come from Montreal, which is the third most active city in the Couchsurfing.com network.

    Alongside a refrain of "I'm couch surfing, I'm a couch surfer", choice lyrics include:

    "Can I crash at your place again?
    Just one more night?"

    Plus a finale where the couchsurfer appears to have overstayed his welcome.

    "Mind if I eat those chips?
    Oh that's okay,
    I don't like salt and vinegar anyways.
    No no no, I didn't use pay-per-view.
    I figured it was free.

    Yeah, I'm going.
    I'm a couch surfer, couch surfing "

    Full lyrics here.

    Friday, September 19, 2008

    Is Couchsurfing the new Google?

    Is Couchsurfing the new Google? Not literally of course, that’d never work.

    What I mean is the word “couchsurfing” seems to have become a catch-all term for the whole hospitality movement. Today people refer to “going couchsurfing” when they may be sourcing hosts through multiple sites, while newspapers write on the “new trend of couchsurfing” when really it goes much broader than just Couchsurfing.com. (For proof, just see the list of links on the right of the Going Local Travel homepage.)

    Couchsurfing.com can’t take credit for inventing the word, it has been in the lexicon a good few before the site was established in 2004. However, Casey Fenton and co did make a very savvy move by opting for a site name that, like Google, also works as a verb (I couchsurf, you couchsurf, we all couchsurf).

    It’s certainly one of the key factors that has enabled Couchsurfing.com to pick up so much media coverage and leave its rivals in the dust. The rival conjugations don't exactly roll off your tongue: I BeWelcomed today, we are going Servasing, he has been Hospitality Clubbing.

    However, there’s one difference between Couchsurfing and Google – ok, there’s more than one, but here’s one worth noting for this discussion - whereas Couchsurfing.com has made no official statement on its service-marked buzzword, the search-engine giant has made it perfectly clear that it will sue your ass if you don’t refer to it with a capital letter (eg "I Googled it").

    In fact, the "what you are not allowed to do" section on Google's extensive permissions page is quite hilarious - in a threatening sort of way. I quote (and therefore hope not to be sued): "you can't mess around with our marks. Only we get to do that. Don’t remove, distort or alter any element of a Google Brand Feature. That includes modifying a Google trademark, for example ... Googliscious, Googlyoogly, GaGooglemania."

    Meanwhile, Couchsurfing.com have registered their term as a service mark, but don't seem to be strictly policing it. Their exclusivity rights are no doubt somewhat different as they didn't invent the name.

    The most public current use of the couchsurfing phrase includes the recent T-Mobile ad. One seemingly in-the-know member on the forum says (and this has not been confirmed):

    "Although T-mobile contacted CouchSurfers before the commercial aired, they refused to work with us before the commercial aired (...) The first thing that pops up when you google [sic] the term CouchSurfer is CS, so in the end we are still getting new members from the commercial."

    It's true that the "couchsurfer" in the advert makes no reference to using the internet to find his hosts and appears to be relying on a network of friends he contacts through his trusty mobile phone.

    Currently, there are references to couchsurfing on online dictionaries, but there’s no entry in that true bastion of language, the OED. Surely it won't be long...

    Thursday, September 18, 2008

    A New Toy

    I bought a new toy the other day: a blood glucose meter. I was curious about my post-meal blood glucose after my HbA1c reading came back higher than I was expecting. A blood glucose meter is the only way to know what your blood sugar is doing in your normal setting.

    "Glucose intolerance" is the inability to effectively control blood glucose as it enters the bloodstream from the digestive system. It results in elevated blood sugar after eating carbohydrate, which is not a good thing. In someone with normal glucose tolerance, insulin is secreted in sufficient amounts, and the tissues are sufficiently sensitive to it, that blood glucose is kept within a fairly tight range of concentrations.

    Glucose tolerance is typically the first thing to deteriorate in the process leading to type II diabetes. By the time fasting glucose is elevated, glucose intolerance is usually well established. Jenny Ruhl talks about this in her wonderful book Blood Sugar 101. Unfortunately, fasting glucose is the most commonly administered glucose test. That's because the more telling one, the oral glucose tolerance test (OGTT), is more involved and more expensive.

    An OGTT involves drinking a concentrated solution of glucose and monitoring blood glucose at one and two hours. Values of >140 mg/dL at one hour and >120 mg/dL at two hours are considered "normal". If you have access to a blood glucose meter, you can give yourself a makeshift OGTT. You eat 60-70 grams of quickly-digesting carbohydrate with no fat to slow down absorption and monitor your glucose.

    I gave myself an OGTT tonight. I ate a medium-sized boiled potato and a large slice of white bread, totaling about 60g of carbohydrate. Potatoes and bread digest very quickly, resulting in a blood glucose spike similar to drinking concentrated glucose! You can see that in the graph below. I ate at time zero. By 15 minutes, my blood glucose had reached its peak at 106 mg/dL.

    My numbers were 97 mg/dL at one hour, and 80 mg/dL at two hours; far below the cutoff for impaired glucose tolerance. I completely cleared the glucose by an hour and 45 minutes. My maximum value was 106 mg/dL, also quite good. That's despite the fact that I used more carbohydrate for the OGTT than I would typically eat in a sitting. I hope you like the graph; I had to prick my fingers 10 times to make it! I thought it would look good with a lot of data points.

    I'm going to have fun with this glucose meter. I've already gotten some valuable information. For example, just as I suspected, fast-digesting carbohydrate is not a problem for someone with a well-functioning pancreas and insulin-sensitive tissues. This is consistent with what we see in the Kitavans, who eat a high-carbohydrate, high glycemic load diet, yet are extremely healthy. Of course, for someone with impaired glucose tolerance (very common in industrial societies), fast-digesting carbohydrates could be the kiss of death. The big question is, what causes the pancreas to deteriorate and the tissues to become insulin resistant? Considering certain non-industrial societies were eating plenty of carbohydrate with no problems, it must be something about the modern lifestyle: industrially processed grains (particularly wheat), industrial vegetable oils, refined sugar, lack of fat-soluble vitamins, toxic pollutants and inactivity come to mind. One could make a case for any of those factors contributing to the problem.

    Monday, September 15, 2008

    Staying with weirdos and murderers

    Couchsurfing: an idea for weirdos and full of potential axe murderers. Discuss.

    This was basically the tone of the Richard Bacon Show on Radio Five Live, which I appeared on as a guest on Thursday night.

    It wasn't the approach I was expecting, or could have predicted following chats with enthusiastic researchers who had heard I was speaking about Couchsurfing across South America at the TNT Winter Travel Show. But that's tabloid radio, I guess. They were bound to be provocative.

    "I'm not offering my house to anyone!" cried out a melodramatic Bacon (pictured above) within seconds.

    "I'm sensing the plot of a very scary slasher movie," added comedian Steve Punt, a fellow guest on the show.

    I gave them both a telling off for being such cynics and, by the end, I think they were coming round to the idea.

    "Actually, I can see that having a personal introduction to a strange city would be good," said Punt. "You know how in a hotel reception, you go to the concierge and it all feels really impersonal? I really like the idea of having someone who knows the place being able to show you around."

    "I'm warming to it," admitted Bacon finally.

    It was a pity that such an interesting debate had to be condensed to such as short segement, but we had to make way for the breaking news of the XL travel collapse.

    Given more time I would have shared a recommendation with Punt, who mentioned he'd draw the line if his 18-year-old daughter wanted to go and stay with "complete strangers" on her gap year.

    The Punts should try YourSafePlanet.com, a site that, for a small fee, could put their daughter in touch with an in-country contact who has been fully vetted and could be on-hand if she had any problems. Not only that, she'd also have her first "friend" already set up in advance. Surely any father would be happier with this than knowing she was boarding a plane to a place where she didn't know a soul, as many gappers do.

    "Really, it's a terrible comment on the world that we both heard this idea and thought 'serial killers'," said Punt to Bacon at one point. And, on this, I couldn't agree more.

    Friday, September 12, 2008

    Inactivity and Weight Gain

    Most of the papers I read in the field pay lip-service to some familiar stories: thrifty genes; calories in, calories out; energy density; fat intake; gluttony and sloth.

    It may sound counterintuitive, but how do we know that inactivity causes overweight and not the other way around?  In other words, isn't it possible that metabolic deregulation could cause both overweight and a reduced activity level? The answer is clearly yes. There are a number of hormones and other factors that influence activity level in animals and humans. For example, the "Zucker fatty" rat, a genetic model of severe leptin resistance, is obese and hypoactive (I wrote about it here). It's actually a remarkable facsimile of the metabolic syndrome. Since leptin resistance typically comes before insulin resistance and predicts the metabolic syndrome, modern humans may be going through a process similar to the Zucker rat.

    Back to the paper. Dr. Nicholas Wareham and his group followed 393 healthy white men for 5.6 years. They took baseline measurements of body composition (weight, BMI and waist circumference) and activity level, and then measured the same things after 5.6 years. In a nutshell, here's what they found:
    • Sedentary time associates with overweight at any given timepoint. This is consistent with other studies.

    • Overweight at the beginning of the study predicted inactivity after 5.6 years.

    • Inactivity at the beginning of the study was not associated with overweight at the end.

    In other words, overweight predicts inactivity but inactivity does not predict overweight. With the usual caveat that these are just associations, this is not consistent with the idea that inactivity causes overweight. It is consistent with the idea that overweight causes inactivity, or they are both caused by something else.

    Wednesday, September 10, 2008

    Unlit on the road

    The Unlit boys have gone up in the world. No crashing on couches for them anymore. They've bagged themselves a spanking new tour bus.

    With T-Mobile having pounced on Couchsurfing, it seems mobile companies can't get enough of hip, new social-networking projects. Orange are the latest to jump aboard, sponsoring the new Unlit tour round the UK.

    Nonetheless, the lads' concept remains as down to earth as ever. They travel around, putting on gigs in the homes of people they've found online, mainly through MySpace and, this time, through the Orange website.

    At the helm of the online series are two of my superbly talented friends Jont (singer-songwriter) and Dave Depares (filmmaker). They first took the road together back in 2006, travelling across the US and creating a series of films en route.

    Catch them if you can, or catch up with the movies online.

    Couchsurfing goes mainstream

    Wanna Couchsurf? You'll be "outta luck" without a mobile phone.

    Says who?

    Says mobile phone giant T-Mobile, which has used the concept in its recent US ad campaign.

    "Guess it was just a matter of time before mainstream marketers hitched to the buzz and good will of Couchsurfing," sighs World Hum.

    The girl who filmed this rather shaky YouTube clip is far more impressed. "Oh my God, that is like the coolest thing I have seen all week," she gushes.

    Go local, get laid

    “Meet the locals, get laid,” announces a Sydney Morning Herald travel blog about Couchsurfing.

    "Mate, it's sensational," Brian, an Aussie enthusiast, told the blogger. "It's a shag-fest. I stayed with this French girl in Paris, and she barely let me put down my pack before she jumped me. I'm doing it every time I travel now. You should get on there."

    Is Brian really that irresistible? Probably not, but that’s why Couchsurfing dating appeals. Suddenly - much to his own surprise - average old Brian has morphed into a exotic foreigner with a sexy accent and no strings attached. Let’s face it with all these random encounters (646,877 at last count) – sex is going to happen.

    “Couchsurfing is not a dating agency,” the site insists. However, what annoyed devotees most about the SMH blog (and caused them to complain in droves) was not that they implied sex happens, but the implication that this should be the predominant reason for joining.

    As an India-based member of the Couchsurfing forum explains: “We were pissed off by … the insinuation that CS has no other dimensions than young people hooking up for sex... The piece says clearly that no one but single people who do this... which in itself was quite a strong and untrue judgement.”

    Indeed, families and couples are just as likely to be Couchsurfing these days.

    The question is: can all these different groups coexist on one site?

    Monday, September 8, 2008

    A Practical Approach to Omega Fats

    Hunter-gatherers and healthy non-industrial cultures didn't know what omega-6 and omega-3 fats were. They didn't balance nutrients precisely; they stayed healthy by eating foods that they knew were available and nourishing. Therefore, I don't think it's necessary to bean count omega fats, and I don't think there's likely to be a single ideal ratio of n-6 to n-3. However, I do think there's evidence for an optimal range. To find out what it is, let's look at what's been done by healthy cultures in the past:
    • Hunter-gatherers living mostly on land animals: 2:1 to 4:1

    • Pacific islanders getting most of their fat from coconut and fish: 1:2

    • Inuit and other Pacific coast Americans: 1:4 or less

    • Dairy-based cultures: 1:1 to 2:1

    • Cultures eating fish and grains: 1:2 or less

    It looks like a healthy ratio is between 4:1 and 1:4 n-6 to n-3. Some of these cultures ate a good amount of n-3 polyunsaturated fat, but none of them ate much n-6 [One rare exception is the !Kung. SJG 2011]. There are three basic patterns that I've seen: 1) low fat with low total n-6 and n-3, and a ratio of less than 2:1; 2) high fat with low total n-6 and n-3 and a ratio of 2:1 or less; 3) high fat with low n-6 and high n-3, and a low carbohydrate intake.

    I think there's a simple way to interpret all this. Number one, don't eat vegetable oils high in n-6 fats. They are mostly industrial creations that have never supported human health. Number two, find a source of n-3 fats that can approximately balance your n-6 intake. In practical terms, this means minimizing sources of n-6 and eating modest amounts of n-3 to balance it. Some foods are naturally balanced, such as grass-fed dairy and pastured lamb. Others, like coconut oil, have so little n-6 it doesn't take much n-3 to create a proper balance.

    Animal sources of n-3 are the best because they provide pre-formed long-chain fats like DHA, which some people have difficulty producing themselves. Flax oil may have some benefits as well. Fish oil and cod liver oil can be a convenient source of n-3; take them in doses of one teaspoon or less. As usual, whole foods are probably better than isolated oils. Weston Price noted that cultures throughout the world went to great lengths to obtain fresh and dried marine foods. Choose shellfish and wild fish that are low on the food chain so they aren't excessively polluted.

    I don't think adding gobs of fish oil on top of the standard American diet to correct a poor n-6:n-3 ratio is optimal. It may be better than no fish oil, but it's probably not the best approach. I just read a study, hot off the presses, that examines this very issue in young pigs. Pigs are similar to humans in many ways, including aspects of their fat metabolism. They were fed three diets: a "deficient" diet containing some n-6 but very little n-3; a "contemporary" diet containing a lot of n-6 and some n-3; an "evolutionary" diet containing a modest, balanced amount of n-6 and n-3; and a "supplemented" diet, which is the contemporary diet plus DHA and arachidonic acid (AA).

    Using the evolutionary diet as a benchmark, none of the other diets were able to achieve the same fatty acid profile in the young pigs' brains, blood, liver or heart. They also showed that neurons in culture require DHA for proper development, and excess n-6 interferes with the process.

    With that said, here are a few graphs of the proportion of n-6 in common foods. These numbers all come from nutrition data. They reflect the percentage n-6 out of the total fat content. First, animal fats:

    Except salmon oil, these are traditional fats suitable for cooking. Except schmaltz (chicken fat), they are relatively low in n-6. Next, vegetable oils:

    These range from very low in n-6 to very high. Most of the modern, industrially processed oils are on the right, while most traditional oils are on the left. I don't recommend using anything to the right of olive oil on a regular basis. "HO" sunflower oil is high-oleic, which means it has been bred for a high monounsaturated fat content at the expense of n-6. Here are the meats and eggs:

    n-3 eggs are from hens fed flax or seaweed, while the other bar refers to conventional eggs.

    A few of these foods are good sources of n-3. At the top of the list is fish oil, followed by n-3 eggs, grass-fed butter, and the fat of grass-fed ruminants. It is possible to keep a good balance without seafood, it just requires keeping n-6 fats to an absolute minimum. It's also possible to overdo n-3 fats. The traditional Inuit, despite their good overall health, did not clot well. They commonly developed nosebleeds that would last for three days, for example. This is thought to be due to the effect of n-3 on blood clotting. But keep in mind that their n-3 intake was so high it would be difficult to achieve today without drinking wine glasses full of fish oil.

    Travel networking: the rules

    Want to start surfing couches round the world? Here are some tips on how to do it the right way.

    Keep it personal
    Contacting someone saying simply "Hello. Can I stay at your house for a week?" is unlikely to elicit a positive response. Introduce yourself and your plans. Where possible make the person feel you've chosen them for a reason.

    Always reply
    If you request to meet someone and they send a personal response to say they won't be able to make it, return the courtesy with a reply rather than just moving straight on to the next person.

    Keep to your plans. Don't leave your host waiting for you. Don't pull out at the last minute.

    Give a little
    If you're staying at someone's house, bring a gift (maybe something typical from your own country). If they're showing you around town, buy lunch or drinks if you can, and always pay your way. Many guests offer to cook their hosts dinner; cleaning up after yourself should go without saying.

    Be courteous
    If staying at someone's home, do not use it as a base to party with other people. Fit in with host's schedule. Don't sleep in for hours. Don't overstay your welcome.

    Make sure you spend time getting to know your host. If you're just after free accommodation or a tour guide, you've got the wrong idea.

    Consider a skill swap
    One way to give something back is through a skill exchange. Offering a dance lesson or DIY expertise can enhance the travel-networking experience and increase the chances of being hosted.

    Keep in touch
    Lots of hosts don't travel themselves, but open their homes in order to make friends around the world. Don't disappear off into the sunset when you leave. Drop an email every now and again. If they've got on a travel-networking site, it's highly likely they're on Facebook, MySpace or the like.

    Sunday, September 7, 2008

    Is sofa surfing safe?

    Safety. It’s everyone’s first thought when you mention couchsurfing. And rightly so. No one should enter into meeting “strangers” completely blindly.

    However, blind panic isn’t the answer either.

    A while ago I was contacted by a journalist from Sky News who was writing a piece about the safety issues of travel networking and staying at the homes of people you have met through websites.

    Oddly the readers’ comments don’t seem to be visible anymore, but here’s one I made a note of at the time. "Stupidest thing I have heard of,” it began. “I am a young male and I wouldn’t risk it, especially in places like South America and most certainly not in Austria. Imagine couch surfing at the Fritzl household. There is no level of safety you can maintain when you are sound asleep in a stranger’s house."

    Now, although I totally understand people concerns, and would always advise employing caution before embarking on any face-to-face meets, this view seems extreme, close-minded and rather sad. He appears to be writing off an entire country (a nation of Fritzls) and one of the world’s biggest continents (just full of drug dealers and pickpockets, right?)

    People have much more control over the risks they take through these sites than they think. After all, you could meet someone for a coffee in a public place in the middle of the day.

    As I said in my first Going Local column, any sort of independent travel relies on the kindness of strangers and you often find yourself hanging out with people you don't know, even if it's just another backpacker in a bar.

    Neither travel networking or straightforward backpacking ever 100% guarantees your safety, but I for one wouldn't pick the alternative: staying at home.

    Here are my tips for staying safe when travel networking:

    · Take advantage of the sites' own safety precautions. Couchsurfing.com offers members a security grading — from 0 (ie anyone who signs up) to 3 (name and address verified by a small credit card payment) — along with the chance to be vouched for by a high-level, "trusted" member. Other sites, such as globalfreeloaders.com and hospitalityclub.org, require users to exchange passport numbers and advise people to check identity documents when they meet. Most sites also store all email exchanges for at least a year.

    · Always meet in a public place and tell people who you are meeting.

    · Check references left by other travellers. Most social network profiles include testimonials from people who have previously met the person via the site.

    · Attend an event in your hometown first (Couchsurfing.com has loads). Get to meet some active members and they can recommend some of hosts/guests that they know personally. This way it is more of a friend-of-a-friend situation rather than complete strangers.

    · Suggest talking on the phone or via Skype or instant messenger before you meet up. Perhaps check out their MySpace, Facebook or Bebo page. If it’s your first time, tell the person. They’ll understand your nerves.

    · Consider parting with a small amount of cash to use vetted contacts who have undergone police checks and provide official references, like those on yoursafeplanet.com or Servas.

    · Don't be afraid to pull out of a meeting if it doesn't feel right and, above all, use common sense.

    Saturday, September 6, 2008

    Omega Fats and Cardiovascular Disease

    I noticed something strange when I was poring over data about the Inuit last month. Modern Inuit who have adopted Western food habits get fat, they get diabetes... but they don't get heart attacks. This was a paradox to me at the time, because heart disease mortality typically comes along with the cluster of modern, non-communicable diseases I call the "diseases of civilization".

    One of the interesting things about the modern Inuit diet is it's most often a combination of Western and traditional foods. For example, they typically use white flour and sugar, but continue to eat seal oil and fish. Both seal oil and fish are a concentrated source of long-chain omega-3 (n-3) fatty acids.The 'paradox' makes much more sense to me now that I've seen

    It's from the same paper as the graphs in the last post. Note that it doesn't take much n-3 to get you to the asymptote. Here's another one that might interest you:

    The finding in this graph is supported by the Lyon diet heart study, which I'll describe below. One more graph from a presentation by Dr. Lands, since I began by talking about the Inuit:

    Cardiovascular disease mortality tracks well with the n-6 content of blood plasma, both across populations and within them. You can see modern Quebec Inuit have the same low rate of CVD mortality as the Japanese. The five red triangles are from
    MRFIT, a large American intervention trial. They represent the study participants divided into five groups based on their plasma n-6. Note that the average percentage of n-6 fatty acids is very high, even though the trial occurred in the 1970s! Since n-3 and n-6 fats compete for space in human tissue, it makes sense that the Inuit are protected from CVD by their high n-3 intake.  [Update: I don't read too much into this graph because there are so may confounding variables.  It's an interesting observation, but take it with a grain of salt.. SJG 2011].

    Now for a little mechanism. Dr. Lands' hypothesis is that a high n-6 intake promotes a general state of inflammation in the body. The term 'inflammation' refers to the chronic activation of the innate immune system. The reason is that n-3 and n-6 fats are precursors to longer-chain signaling molecules called eicosanoids. In a nutshell, eicosanoids produced from n-6 fatty acids are more inflammatory and promote thrombosis (clotting) more than those produced from n-3 fatty acids. Dr. Lands is in a position to know this, since he was one of the main researchers involved in discovering these mechanisms. He points out that taking aspirin to 'thin' the blood and reduce inflammation (by inhibiting inflammatory eicosanoids) basically puts a band-aid over the problem caused by excess n-6 fats to begin with.
      [Update- this mechanism turns out not to be so straightforward. SJG 2011]

    Lyon Diet Heart Study assessed the effect of n-3 fat supplementation on CVD risk. The four-year intervention involved a number of diet changes designed to mimic the American Heart Association's concept of a "Mediterranean diet". The participants were counseled to eat a special margarine that was high in n-3 from alpha-linolenic acid. Overall PUFA intake decreased, mostly due to n-6 reduction, and n-3 intake increased relative to controls. The intervention caused a 70% reduction in cardiac mortality and a large reduction in all-cause mortality, a smashing success by any measure.

    In a large five-year intervention trial in Japan,
    JELIS, patients who took EPA (a long-chain n-3 fatty acid) plus statins had 19% fewer cardiac events than patients taking statins alone. I don't know why you would give EPA by itself when it occurs with DHA and alpha-linolenic acid in nature, but it did nevertheless have a significant effect. Keep in mind that this trial was in Japan, where they already have a much better n-6/n-3 ratio than in Western nations.

    In my opinion, what all the data
    (including a lot that I haven't included) point to is that a good n-6 to n-3 ratio may be important for vibrant health and proper development. In the next post, I'll talk about practical considerations for achieving a good ratio.

    It’s not such A Small World after all

    Is it the end of ASmallWorld.net? This week the Guardian predicted the demise of the exclusive, invite-only travel networking site. "Did you manage to get into the site?” sneered a well-to-do member at the reporter, as if this illustrated its downfall.

    I'm sure the same member would turn his nose up at me. Not typically moving in the same circles as other members, which include Naomi Campbell and Ivana Trump, I managed to wangle an invite to ASW through a very vague contact.

    I've dipped in from time to time, curious to how travel networking functions at the other end of the spectrum. However, when I mentioned the site within my weekly travel-networking column in the Guardian, it sparked a couple of reader emails.

    One wanted to know if I could hook him up. (Sadly no, I'm a low-level member without invite privileges). Another said it was wrong of me to include it when it was clear out of bounds to most readers. (Although perhaps not anymore, if this week's article is anything to go by.)

    I'd argue that ASW - even if you can't or won't join - is fascinating. Not just because of the outlandish snobery found in its forums, but it is also an interesting illustration of how the travel-networking movement is forming "niche" offshoots and how it is motivated by the idea of “belonging” to a likeminded group. Whether you’re a member of ASW or BeWelcome.org, people trust each other based on a presumed mutual understanding.

    The Guardian has recently reported on how the future of social networks lies in niche sites. I also predicted this when I started out on my trip.

    However, achieving a small-club feel on worldwide web must have its limits. Have some already reached their peak? ASW has now grown to 325,000 users. Far behind Facebook’s 90 million, but almost matching the 328,000 of Hospitality Club, a site that is open to all and sundry.

    I've always thought that ASW and HospitalityClub/Couchsurfing – although based on the same principles of bringing travellers together – share no overlap. But it seems this is changing too. One of the other big hitters in the ASW forum recently was a thread suggesting ASW members start accommodating each other in their own homes ("Couchsurfing on ASW" was its heading).

    What surprised me the most was finding there is already such a big cross over of members from the two sites. It seems many ASW members are also part of the exceedingly down-to-earth and non-elitist Couchsurfing.com. It’s something that must horrify the core elite. An old-school member (since 2004) replied to say he didn't believe the two networks are compatible: "Everyone is satisfyingly rich on aSmallWorld. Every ASW member I know stays in the Belle Etoile Suite at Le Meurice when they visit me.” He was soon shot down by the Small World Couchsurfers for totally missing the point.

    It seems ASWers aren’t as likeminded as they once were. Perhaps the original members will set up their own offshoot where people have to provide proof-of-funds before signing up.

    Meanwhile, the ‘Death of ASW’ thread (9,000 views) is nothing if not entertaining. One London member said the day they knew it really was all over was when a Foxtons estate agent told him he’d “discovered cool new website for chatting up girls and all his mates were on it”.

    A London/Dubai member added: "This used to be a playground for the jet set, the good looking, the creative and business powers that be. now i feel like a slimebag when i log in." Something tells me his inner slimebag has been waiting to get out for sometime.

    Thursday, September 4, 2008

    Omega-3 Fats and Brain Development

    Another interesting study that Dr. Hibbeln sent me is about the link between maternal seafood consumption and neurodevelopmental outcomes in children. The study is about as powerful as epidemiology gets, with an enrollment of 11,875 mothers.

    The bottom line is short and sweet: compared to the children of mothers who ate 340 grams or more of fish per week, children whose mothers ate very little fish had an increased risk of low verbal intelligence, poor social behavior, poor motor skills, poor communication skills, and poor social development. These associations remained after adjusting for 28 potential confounders, including social status, level of education, stressful life events, smoking, alcohol, and several others.

    In support of this association, in another study the four-year-old children of mothers who were given DHA and arachidonic acid supplements had higher IQs than those given "placebo" (corn oil). There have been a number of trials of varying quality that have shown varying results with n-3 supplementation, so I'll leave you to decide what you think of this. A 2007 review I found on n-3 supplementation and brain development states that "the evidence for potential benefits of LCPUFA [long-chain polyunsaturated fatty acid] supplementation is promising but yet inconclusive".

    I do think it's interesting to note that the brain has the highest concentration of long-chain n-3 fats of any organ, and eating n-3 fats in the form of fish, fish oil or cod liver oil increases the amount in tissues. Eating too much n-6 depletes the brain of DHA and adversely affects neuron development in piglets. n-3 deficiency affects the release of serotonin (a neurotransmitter) in rat brains.

    Put it all together, including the data from the last two posts, and I think there's some evidence that a good balance of n-3 to n-6 fatty acids is important for optimal brain function and perhaps development.

    Tuesday, September 2, 2008

    The Omega Ratio

    The theory advanced by Dr. Lands and Hibbeln is that the ratio of omega-6 to omega-3 fatty acids in the diet is the crucial factor for mental and physical health, rather than the absolute amount of each. Omega-6 and -3 fats are essential long-chain polyunsaturated fatty acids. The number refers to the position of the double bond near the methyl end of the carbon chain.

    The ratio of omega-6 to omega-3 (hereafter, n-6 and n-3) in the diet determines the ratio in tissues. Since these molecules have many cellular roles, it doesn't stretch the imagination that they could have an effect on health. Hunter-gatherer and healthy non-industrial cultures typically have a favorable ratio of n-6 to n-3, 2:1 or less. In the US, the ratio is currently about 17:1 due to modern vegetable oils.

    DHA, a long-chain n-3 fatty acid, is concentrated in neuronal synapses (the connections between neurons) and is required for the normal functioning of neurons. n-6 fats compete with n-3 fats for space in cellular membranes (which have a fixed amount of total polyunsaturated fat), so a high intake of n-6 fats, particularly linoleic acid, displaces n-3 fatty acids. Lower tissue levels of DHA and total n-3 correlate with measures of hostility in cocaine addicts. Feeding mice a diet high in linoleic acid increases aggressive behavior, and increses the likelihood of rats to kill mice.

    If the ratio of n-6 to n-3 in the diet predicts psychiatric problems, we'd expect to see an association with n-3 intake as well. Let's take a look:

    This is homicide mortality vs. n-3 intake for 24 countries, published here. The association is significant (p> 0.001) even without correcting for n-6 intake. Of course, one could see this as a cloud of points with a few well-placed outliers. Here are some closer associations from the same paper:

    It's clear that both a high n-6 intake and a low n-3 intake correlate with negative psychiatric outcomes. Together, the data are consistent with the hypothesis that the ratio of n-6 to n-3 impacts brain function. Dr. Hibbeln and Dr. Lands do not claim that this ratio is the sole determinant of psychiatric problems, only that it is a factor.

    Now to address the big criticism that was brought up by very astute readers of the last post, namely, that the data were purely correlative. Believe me, I wouldn't even have posted on this topic if I didn't have intervention data to back it up. In addition to the animal data I mentioned above, here are more studies that support a causal role of fatty acid balance in psychiatric problems:
    Most of those were placebo-controlled trials. If we can see a significant effect of n-3 supplementation in short-term trials, imagine how well it would work as a long-term preventive measure.

    Monday, September 1, 2008

    Vegetable Oil and Homicide

    One of the major dietary changes that has accompanied the downward slide of American health is the replacement of animal fats with industrially processed vegetable oils. Soybean oil, corn oil, cottonseed oil and other industrial creations have replaced milk and meat fat in our diet, while total fat consumption has remained relatively constant. The result is that we're eating a lot more polyunsaturated fat than we were just 30 years ago, most of it linoleic acid (omega-6). Corn oil may taste so bad it inspires you to violence, but its insidiousness goes beyond the flavor. Take a look:

    This figure is from a paper that Dr. Joe Hibbeln sent me recently, of which he is the first author. This followed an interesting e-mail conversation with Robert Brown, author of Omega Six: the Devil's Fat. He put me in touch with Dr. Hibbeln and Dr. William Lands (NIH, NIAAA), both of whom warn of the dangers of excessive linoleic acid consumption from modern vegetable oils. Dr. Lands has been researching the relationship between dietary fat and inflammation since the 1970s, and has been a critic of modern vegetable oils for just as long. Both Dr. Hibbeln and Dr. Lands were very generous in sending me a number of their papers. The figure above shows the homicide rate vs. linoleic acid consumption of five countries over the course of 40 years. Each point represents one year in one country. The U.S. has the distinction of being in the upper right.

    I asked Dr. Hibbeln how he selected the five countries, and he told me the selection criteria were 1) available homicide and linoleic acid consumption statistics, 2) "first world" countries, and 3) countries representing a diversity of linoleic acid intakes. I'm satisfied that there was probably not a significant selection bias.

    What's interesting about the graph is that not only does the homicide rate track with linoleic acid consumption across countries, but it also tracks within countries over time. For example, here is the same graph of the US alone:

    And here is the UK, which doesn't suffer as much from the confounding factor of firearm availability:

    I don't think we can draw any solid conclusions from this, but it is worth noting that epidemiological associations don't get much better. In the next few posts, I'll explore the data from intervention trials that support the hypothesis that excessive omega-6 consumption, and insufficient omega-3 consumption, cause serious problems for psychiatric and physical health.