Grass-Fed Pork? Not Really. Still the Difference in Fatty Acid Composition & Micronutrient Content Are Profound & Not Accounted for by Food Databases - Let Alone Epidemiology
|You often hear that pigs are pretty closely related to us humans, but "are all pigs created equal"? Or what may be a more appropriate question for the SuppVersity: Is all pork really created equal?|
If pizza salami equals pork...
... in epidemiological studies, how can these studies on the fallacies and advantages of eating red meat, which usually get a hell lo of media attention, be accurate, given the fact that the amount of unquestionably beneficial coQ10, for example, would differ by 60 percent, even if you would only ignore the difference between loin that was cut from the trapezius (= high coQ10 content) and the longissimus dorsi (=low coQ10 content)?
Let's get to the obvious: Grass-fed is... ah, wait a minute
"Grass fed is best" as you will people say about beef obviously won't be the case for pork, because pigs, just like humans, by the way, are omnivores. The simple formula, grass-fed = most beneficial fatty acid and micronutrient profile that may (in general) be valid for beef doesn't apply and we will have to take a closer look at the actual data first to decide what would be the "best" feed for pigs, if the goal was not a maximal yield of lean meat (in that case adding some clenbuterol, like the Chinese like to do it would be the least you should do; cf. The China Post. 2011), but rather to produce the meat with the most beneficial fatty acid composition.
- more food (yet no excess) can produce overall leaner muscle meat in the type II fibers, while the total body fat is increasing
- aside from local desaturation and elongination effects, the overall muscular fatty acid pattern does (much like in humans, by the way) mirror the dietary intake
- canola or linseed oils produce a substantial increase in the content of linolenic acid (C 18:3), and slightly increase the eicosapentaenoic (EPA, C 22:5) and docosahexaenoic (DHA, C 22:6) acid contents in pork mea
- soy, peanut, corn, and sunflower increase the content of linoleic acid (C 18:2; omega-6), increase the n-6:n-3 ratio and reduce the content of mono-unsaturated fats (MUFAs)
- fish oils or algae added to the feed substantially increases the content of EPA and DHA and thus reduce the n-6:n-3 ratio
- a high saturated fat content as in tallow (see figure 2) increases the levels of palmitic, palmitoleic, stearic and oleic acids in pork meat and reduces the PUFA:SFA ratio
- CLA supplementation can increase the CLA content of the fatty portion of the meats (1% CLA results in 5.5 mg CLA/100g) and the adipose tissue (2% CLA yields 1,490mg CLA/100g fatty acids).
Do you notice a pattern? I guess even based on the data in figure 2 you will already have noticed that the "grainier" the diet, or in other words, the more corn and soy there is in the diet of the swine the less favorable is the fatty acid composition of their meats going to be. Now, I am asking an outrageous question: If swine are such a good model for human metabolism, what do you believe your belly was going to be made of, if you copied the pigs' diets and lived on "healthy grains", their oils and the uber-healthy soy beans for the (probably pretty short) rest of your life?
Wallowing, roaming, routing: Work out like a pig
Since pigs make a pretty decent model of human metabolism and in view of the fact that - aside from our diets - the amount of exercise we get is one of the fundamental determinants of the total and relative levels of body fat, it should not be forgotten that "exercise" or rather the ability to range freely and be as active as any swine should be, is another determinant of the quality of the meat you are buying at the supermarket, grocery store, butcher or your local farmer. In this context, Reig et al. point out that
And if you really intend to overcomplicate things, you would also have to ask your butcher, whether the sausages you are about to buy were made of the meat of male of female pigs. After all, meat from barrows typically contain more fat and marbling and a thicker subcutaneous fat layer than meat from gilts (Armero. 1999). But let's face it: If you start stressing about things like this, the quality of your meat is probably your least problem.
"[i]t has been reported that pigs maintained in free-range conditions in the Mediterranean forest had subcutaneous and intramuscular fats with higher monounsaturated fatty acids and lower saturated fatty acids than those pigs housed individually and receiving acorns as feed. The subcutaneous fat depth increases with exercise being 15.9 mm for exercised pigs in comparison to 11.5 mm depth for those kept in confinement. The same applies for the intramuscular fat content where 3.36% for extensive vs 1.44% for intensive raised pigs have been reported in the semimembranosus muscle." (Reig. 2012)
If you have no idea of the different cuts and location of the individual muscle, I suggest you download the "Meat Cuts Manual" from the website of the Canadian Food Agency. It's free and bilingual.
|If you want to know read more about epidemiological overgeneralization andthe effects of "pork" and red meat on your health (spec. the prostate) I suggest you go back to the Meat-Ology post.|
In fact, the real significance of these results lies elsewhere. It concerns the way epidemiological studies are conducted (I may remind you of the metaphorical pizza salami being red meat or pork), their over-generalizing interpretations and the conclusions on what the optimal human diet should look like. So, once the next study is telling you "red meat" or "pork" is bad for you - you may want to remind yourself of some of the things you have learned in today's blogpost and ask yourself (and if you incidentally have the chance, the researchers as well): What kind of "pork" are we talking about?
- Abebe W, Mozaffari MS. Role of taurine in the vasculature: an overview of experimental and human studies. Am J Cardiovasc Dis. 2011;1(3):293-311.
- Armero E, Flores M, Toldrá F, Barbosa JA, Olivet J, Pla M, Baselga M.Effects of pig sire types and sex on carcass traits, meat quality and sensory quality of dry-cured ham. Journal of the Science of Food and Agriculture. 1999; 79:1147-1154.
- Enser M, Hallett K, Hewitt B, Fursey GA, Wood JD. Fatty acid content and composition of english beef, lamb and pork at retail. Meat Sci. 1996 Apr;42(4):443-56.
- Reig M, Aristoy MC, Toldra.Variability in the contents of pork meat nutrients and how it may affect food composition databases. Food Chemistry. 2012 [ahead of print]
- The China Post. Clenbuterol-tainted pork latest China food scandal. March 18, 2011. < http://www.chinapost.com.tw/china/national-news/2011/03/18/295146/Clenbuterol-tainted-pork.htm > retrieved Dec 06, 2012.