Thursday, October 25, 2012

Wheat Belly

I was disappointed by this book.
It falls pretty squarely in the standard genre of "Do this one special thing PS Don't eat junk food"-diet books / programs that American doctors seem so fond of. And the diet he recommends people is pretty much lacto-paleo, primal diet - which is okay by me but if he had just mentioned that then all his readers would have a much easier time finding more recipes.
Apparently his reading of various studies was superficial enough for him to get several things wrong. Especially about going gluten-free and losing weight. You can find a critique here.

Okay, with that out of the way there were things I found interesting. For example I thought celiac disease was always accompanied by intestinal distress but apparently that's not the case. Good to know. But while 1-2% of the population being celiac is a lot (apparently about 1 in 10 are undiagnosed) that still leaves 98-99% of the population without celiac. Reading the book I get confused about what has to do with gluten grains in general and what has to do with celiac disease specifically.

There are things about this book I just don't get. When discussing whole grain vs refined grain he fails to mention that the epidemiological data that shows benefits from whole grain is based on populations that either ate one or the other - there's no comparison between grain and no grain - and the whole grain products available back then were oats and rye. Probably rolled oats and whole, soaked, sourdough rye black bread (not what Americans usually call rye which is a white, wheat bread with miniscule rye amounts). There wasn't any whole grain pasta and fake, whole grain, wheat bread. And even if you could have found some back then, not enough people were eating it for it to have impact on the hypotheses drawn from the epidemiological data. So he fails to point out the most damning evidence against wheat. At least he does mention Denise Minger and I think he must reference what she found in the China Study data: that wheat was the greatest predictor of disease and mortality of all the foods recorded in the China Study. And when people in China didn't eat wheat they replaced it with rice. So while the energy density is lower in cooked rice than in bread it probably isn't the tiny difference in carbohydrate intake that changed the statistics dramatically.
There are studies that can't find much difference between refined and whole grain. I should probably link more than one study here but I'm tired and can't be arsed.

William Davies means well but he comes off as narcissistic and unoriginal. The books is a bit boring at times, confusing at others (not that my writing is amazing but it's free and it hasn't been through an editor - heck I barely remember to edit it myself). Do not want.

Sunday, October 21, 2012

What do I want with this?

Kinda forgot what I wrote in the introduction that I wanted with this blog and I can't be bothered to go back and look, but I think I might actually be most interested in figuring out why paleo works for people. I'm a scientist. I like taking things apart. And figuring out how and why they work of course - I totally don't like breaking things just to break them (cuz that would be childish).

Mice and also at some point asthma to come (I'm completely lost comma-wise).

Saturday, October 13, 2012

Food composition databases

I forgot to mention and link to the USDA's database for food composition in my post on how much omega-6 you need to eat to get enough. Here you go:
USDA National Nutrient Database for Standard Reference
Here are a couple of more official databases to help you get all the high-quality information you want.
The official Danish Food Composition Database
Canadian Nutrient File
Australian Food Composition Program has NUTTAB and AUSNUT.


Wednesday, October 10, 2012

Omega-6: Obesity and addiction

So Derek Lowe recently wrote in his medicinal chemistry blog 'In the Pipeline' about a new interest from pharmaceutical companies in cannabinoid receptor 1 (CB1). CB1 was the target of the (successful) obesity drug rimonabant. Successful until it was withdrawn from the european market for the side effects of depression and suicidal thoughts. Now people are however trying to make drugs that also target CB1 but without the ability to enter the brain from the blood. And it will of course be interesting to see how that plays out.
Why is this interesting? Well, rimonabant is an inverse agonist of CB1 which means that it blocks the action of the agonist as well as removes the spontaneous signalling through CB1 that occurs even without an agonist. And the agonists of CB1 are THC from cannabis (of course) and the neurotransmitters anandamide and 2-arachidonoylglycerol (2-AG). And those two agonists produced naturally by the body are made from omega-6 fatty acids. I actually got to the point, hurray!
So what do these agonists and inverse agonists do? Well, THC increases appetite and decreases short-term memory. It also makes mice more sensitive to reward from sugar water. Inverse agonists however decrease appetite, improves memory in mice, and makes giving up cigarettes easier. And cause depression, anxiety, and make you want to kill yourself. In addition the cannabinoid system is involved in a shitload of other things as well - I think it's better to leave that whole bag of rats alone (on the other hand a drug is definitely preferable to the current standard of care - a ridiculously dangerous operation that permanently changes the gastrointestinal layout and still isn't effective without lifestyle changes). However, I don't see why you would take a drug to reduce this signalling without first trying to reduce your amounts of the signalling molecule. Unfortunately, it would be quite hard to figure out if a lifestyle change to reduce the intake of omega-6 would be effective against obesity because of the elimination of excess omega-6 or because of the necessary reduction in junk food intake to reach that goal.

tl;dr The human equivalent to pot is made from omega-6 fatty acids. It is better for you to eat an amount of omega-6 that is natural (not much actually). I don't care if you get high, I just think it's fucking stupid to do the equivalent of taking just enough to not get high every single day of your life.

Wednesday, October 3, 2012

Omega-6: How much is enough?

As so many of my posts, this one will start with a disclaimer.
Disclaimer: I am a firm believer of "the dose makes the poison" and "we all have to die from something". But I'd like the dose to be low enough to not be poison and I also want to be healthy and sexy in the time that comes before dying. I definitely don't think there's a single dietary component that's hurting everybody's health and sexiness as some seem to do. Fat! Saturated fat! Carbs! Fructose! Alcohol! Meat! Gluten! Wheat! Omega-6 fatty acids! (but it is way easier to focus on one thing at a time so that's what I'm doing)

tl;dr You will never become deficient in omega-6. Never.

I dug up a 2010 paper by the American Heart Association (AHA) where they review whether there might be cardiovascular benefits to reap from limiting omega-6 fatty acid intake (spoiler: they find that the experiments reported in the literature are poorly designed but that there appears to be a protective effect from increasing polyunsaturated fat intake but it's quite modest and only when replacing carbohydrates or saturated fat - and I didn't go through the papers they looked at). What was really useful though is the estimates for how much omega-6 humans need. 0.5-2% of the energy intake (okay, based on babies and stuff but still useful). For a 2000 kcal diet that comes out to about 1-4.5 grams. And somehow the AHA got 14.6 grams when they calculated the average daily omega-6 intake for Americans. So that seems like the average American gets about 3-14 times as much as they minimally need (I don't want to be average though). In addition it seems a reasonable assumption that the AHA estimate is low - read on to find out why I think so. I could however not find any reports of omega-6 deficiency in humans. I found a paper on rats where some of the rats were restricted to 0.01% of their energy from omega-6 in the form of linoleic acid but were otherwise provided omega-3s (in the form of alpha-linolenic acid), monounsaturated, and saturated fatty acids - the control group got 2% of their energy from linoleic acid. The restricted rats developed slightly scaly front paws, weighed about 15% less (not necessarily a good thing), and a few of them lost some hair. At the end of the experiment they were fed some omega-6 and they only metabolised 1% whereas the control rats metabolised 34%. So the group with too little omega-6 reduced the amount of omega-6 they used for energy but were otherwise quite alive and doing fairly well.

Back to the real world. Where might one find approximately 15 grams of omega-6? Most easily from junk food.

15.6 grams if you go to McDonalds and get 6 McNuggets, a 22 g / 0.78 oz tiny tub of Creamy Ranch Sauce, and a medium fries.

14.0 grams if you eat half a can of Pringles (but once you pop you can't stop).

19.0 grams if you eat a standard 3 oz bag of microwave popcorn. Though the metric standard bags seem to be 100 g in which case you get 22.4 grams.

12.7 grams if we make sure to get the most important meal of the day and go past Starbucks and get a medium blueberry muffin and a medium, sorry grande, soy latte (this is not breakfast! This is not an improvement on not eating breakfast!).

Or if you are sucking it down straight from the source the daily average intake is the equivalent of approx. 2 tablespoons of soybean or corn oil, or 3 tablespoons of peanut oil, or 4 tablespoons of canola oil, or 1 1/2 tablespoon of grape seed oil, or 11 tablespoons of olive oil. But then you would have to not eat anything else that contained any fat to not ingest more than 15 grams.
These values are pulled from and of course I pulled the things with the highest values for shock value (for the soy latte I used a 1 to 7 ratio of omega-3 to -6 to calculate the omega-6 content). But I'm still missing things like margarine, mayo, cookies, crackers and puff pastries (totally ruined your day there, didn't I?). Take-home message is that an average American (sorry again but it's always easiest to find numbers for the Americans) eats at least 3-14 times as much omega-6 as the AHA estimates that they need and eating more than those 15g/day is really really easy.

"What about people who don't eat junk? You paleo people are going to keel over from lack of omega-6, right? Ha!"
Urgh, my own storytelling device (or whatever it's called) is so stupid that I'm giving myself a headache.
Let's go with 4.5 grams of omega-6. It was the higher bound requirement on a diet of only 2000kcal but since even paleo eaters are going to be eating more than 4.5 grams it doesn't really matter. To get ~4.5 grams of omega-6 you would eat:
8 eggs, or 37 almonds, or 2 pork chops (loin), or 2 small avocados (California), or 1 large avocado (Florida), or 3 tablespoons olive oil. Or said in another way, if we skip the almonds we could get 4.5 gram omega-6 covered with 2 eggs, ½ pork chop, ½ small avo, and 2 teaspoons olive oil. Or our weekly (maximum) requirement could be covered by a 250g bag of almonds.

I'm not saying there isn't a place for seed oils in the modern world. I just think that place is in biodiesel and bioplastics.

PS I was going to add a table with omega-6 and omega-3 content of various fats but I just can't be bothered right now. Just know that
seed oils and things made from seed oils: bad
fruit oils, nut oils, and animal fats: fine

Extra reading:

EDIT 21.11.2012 Just fell over this paper, in Poultry Science of all places, which has omega-6 requirement at 4.4g for a 2000kcal diet and an upper limit of 6.6g.