Sunday, 17 January 2010

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:
http://www.dietaryfiberfood.com/cholesterol-low.php
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.

5 comments:

  1. One minor caveat re meat. I've read that the cost/hurdles of officially getting a designation of "organic" can be prohibitive for smaller farms. Locally-sourced grass-fed meat may be as good, possibly better, than "organic" from an industrial source.

    I'm curious why you didn't mention coconut oil? Seems to be all the rage in some cross-fit/paleo circles.

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  2. I am starting to look at coconut oil, although so far just eating grated coconut, perhaps mixed with hazelnut butter, has been a very good exerience. With minimum frying there is little need for isolated fat, so I might as well eat coconuts along with the carbs and protein that come with the oils. The oil is fresh and it works out cheaper too :)

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  3. Wow, you're full of good news ;-)

    If budget is a concern, what would you recommend? Right now for me it has to be cheap cuts of pork, mince, supermarket eggs and cream; would I really be better off sticking to (cheaper) organic porridge?

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  4. I saw organic, grass-fed brisket for £7/kg and also discovered muntjac deer hunch for about the same price at the local farmers (hunters?) market. Organs a only slightly cheaper. Mince is really bad due to oxidation of cholesterol, better to eat organs (though not previously frozen lambs liver from New Zealand) or non organic lean but never mince. Fish can be chaper too, go fresh herring for £2/kg, same for sprats (not fried though, better baked).
    And if you go for the porridge, soak it for 24h before cooking. But I would stay away to save on the dentist.
    Bon apetit!

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  5. I doubt that anyone manufactures a wig big enough to fit over my hair. Or that a woman wearing something will help make it acceptable for a man. What is needed for this Warhol trend is for some cool young guys to start wearing it. Then it's all about getting to the "tipping point."

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