Tuesday, 19 January 2010

Gluten, casein, running and thinking

I have stumbled upon an article "Perceptual Pleasure and the Brain" by Irving Biederman and Edward Vessel discussing the role of endorphins in cognition. It appears that our brain craves novelty, and learning is associated with pleasure via opioid receptors in the brain. This can be a mechanism for survival and for evolutionary success.

What the authors do not discuss is the possible habituation of opioid receptors by continuous stimulation. This can be the result of addiction to drug opiates, but we also know that gluten and casein break down to peptides which bind to opioid receptors in the brain. This is one reason why we crave these foods after all. Interestingly, long distance running or cycling on a regular basis also releases endorphins, leading to mild addiction (I experienced this myself).

Now, with our receptors desensitised by grains, dairy and threadmills, we might need stronger stimulation to enjoy learning or we lose interest in learning altogether.

Opium for the masses?

If indeed the dietary derived opiates have any significant impact on brain function, it would explain why Paleo people are so hungry for knowledge, as evidenced by the high calibre discussions on blogs such as WholeHealthSource, Panu or FreeTheAnimal :)

Perceptual Pleasure and the Brain
(If you Google the title you can find the full text of other sites, such as:

Regarding food and thought, I have been thinking a lot about the possible POSITIVE impact of high carbohydrate diet (even with the harmful effects of grains) after the Neolithic revolution. I imagine that glucose (though not fructose) loading can be very good for brain FUNCTION short to medium term (before the degeneration sets in). Brain thrives on glucose and can be turbo charged with more carbs in the diet. Even if that would not mean optimal HEALTH overall, it could mean more brain power for competitive advantage! The analogy would be that maximum fitness does not equal otimum health and longevity (as brilliantly laid out by John Little in Body by Science). For the same reason using stimulants, such as cocoa or coffee (and sugar too!), can translate into more effcient thinking, better strategic planning? Something that the carb lobby can consider in their PR :)

British survival expert on Paleo diet

It seems that Ray Mears approves, though cautiously, without embracing IF and wary of cholesterol:

Sunday, 17 January 2010

Progress update

Just a quick update on my N=1 experiment. The weight has been staying constant for about a month now. I is quite likely that this 90kg is what my ideal weight should be (more then the upper BMI bracket of 83kg though). I have been slimming down though, another inch, which means a bit more muscle. Two more inches waist circumference and I will have no abdominal fat left. But this is not necessarily the best and I do plan to increase carbs a little bit. Now thy are most likely under 60g/day.

But I am still burning my own fat, so still trying to limit fat in my diet. I was tempted to try dairy after a long break. The choice was organic double cream (50% fat). I ate more than 100g of if (whipped) for two days in the row. The result: respiratory mucus and metallic strange taste in my mouth. The latter probably having to do with increased ketones in my blood.

On good meat, bad meat and a bit on lipids

Paleo people know that meat is good. They also know that organic, grass-fed meat is even better. But there appears to be little discussion on futher details, which may be of critical importance if our goal is optimum health and longevity.

First, there is the lean meat versus fatty meat. Assuming that weight loss is no longer an issue (own fat deposits are no longer being burnt), there should be more fat in the diet if only to provide calories. Saturated fat no longer seems to be a problem, so going for the fattier cuts might be good if we do not want to exceed the 1g/kg daily protein and prefer to stay low carb. But is there an alternative? You say extra virgin olive oil? Perhaps, but I have a problem with EVOO: it contains a lot of phytosterols. While sitosterol in olive oil might reduce total cholesterol and/or LDL, we do not know whether that is always desirable. Here is the phytosterol content is various foods:
The real problem is for males: sitosterol inhibits 5-alpha reductase, an enzyme which converts testosterone to dihydrotestosterone (DHT). This is being advertised as good news, as DHT is supposed to be responsible for hair loss and growth of prostate cancer in men who already have it (it is unlikely to be a causative factor). But DHT is 3-4 times more active than testosterone in all aspects of virilisation, which makes men look and behave like men (or at least like Paleo men). While testosterone is responsible for muscle growth, DHT does the rest: body/facial hair, voice, mental function, libido, etc. I will do a separate post on plant-derived phytosterols and phytoestrogens (yes, turmeric and green tea do the same thing), but for now I am convinced that animal fat is better, and is definitely better for men.

Now, this estrogenic (anti-androgenic) aspect is also essential when choosing meat. Non-organic meat (grass-fed or not) is likely to have higher content of pesticides which act as hormonal disruptors making men less virile. I would say, better be vegetarian than eat pesticide loaded meat. And more fat in the meat means more pesticide, because that is where those chemicals are stored. Perhaps if it is not organic, it would have to be nearly 100% lean. (BTW wild game can be loaded with pesticides, as there is little control of what the animals eat when they have uncontrolled access to fields. I used to eat wild pigeons, not anymore).

So, we are left with fatty meat but organic. Grass-fed is also very important, not only because of the obvious omega-3 content, but also because of more antioxidants and lower content of oxidised cholesterol. Lipid oxidation is thought to be one of the major contributors to atherosclerosis, therefore the less oxidised cholesterol, the better. This probably matters less if you are going to eat the meat straight after slaughter, but this is typically not the case. Meat is aged, transported, salted, smoked, sometimes frozen, sometimes irradiated, minced (this is probably the worst). All of this increases oxidation of cholesterol (as well as those omega-3 and 6). This leaves us with organic, grass-fed, fresh, minimally cut meat.

Packaging is also important. Smaller pieces with more surface exposed to air oxidise quicker. Also, sometimes meat is kept in high oxygen atmosphere which protects the pink colour of oxyhaemoglobin, but which also speeds oxidation of cholesterol. In addition, packaging in plastics will add more of the nasty hormone disrupting chemicals.

Then you bring the bacon home and what to you do? The next step is high heat processing, which further increases cholesterol and fatty acid oxidation (BTW, cooking often also means Maillard reaction). Often you do not eat it all up but keep in the fridge for a few days, sometimes you even freeze. Then you reheat it. Now, the more of those oxidised lipids in the food, the more will end up in your LDL, increasing the risk of atherosclerosis.

If you heat process your meat, another factor contributing to lipid oxidation is iron. I suggest not using cast iron pans. Also acidity: if you heat process meat, do not use lemon juice, vinegar etc, as low pH helps heme iron react with lipids. Eating as Paleo as possible really does make sense.

Of course, if you do not eat your meat with fresh leafy vegetables you might contribute not only to greater acidity, but to more oxidation of endogenous lipids. All this can make you realise that vegetarians have a point: the kind of meat people eat and the way they eat it is better avoided. If the choice is between standard ground beef, kept on supermarket shelves for days, then fried, I would say lentils are much better choice. The same applies to dairy, if you decide to opt for this non-paleo food: commercially available dairy is loaded with oxidised cholesterol, salt, Maillard compounds, hormones, as well as hormone disrupting chemicals, so here even vegans may have a point.

As I wrote before, I had been vegetarian for nearly 15 years, but if the only alternative had been diet loaded with unhealthy, high heat processed meat, I think I chose the lesser evil.

It appears that a lot of people compromise of meat quality. They belive that any meat is better than no meat. I disagree. But I believe that there is nothing better than best quality fresh meat, either raw (as in steak tartare), rare or boiled. If you compromise, you might as well eat bread. Bad meat and little antioxidants is probably where Atkins and Kwasniewski followers have gone wrong. Future epidemiologist might disciver that meat was the cause of their atherosclerosos, while it would have been oxidation and glycation end products.

Now, the ideal organic, grass-fed fresh meat is expensive. If money is an issue, I suggest sticking to organs, fat and marrow, if possible, and do not fry it. It seems though that geeting cheap fatty pieces of organic meat is not easy: those who can afford it buy organic lean, those who eat cheaper cuts, do not think organic.