View Full Version : AA Levels and Grass-Fed Meats
10-13-2009, 07:02 PM
This is a topic that I've been wondering about for quite some time, and finally decided to do some research on.
My thought is that foods which are identified by Dr. Sears as high in arachidonic acid such as egg yolks and red meat may have those levels determined by the diet which those animals have been fed.
Considering that industrialized hens and cattle are fed a pro-inflammatory diet consisting mostly of grains and animal fats, I think it's a rather safe assumption that those inflamed animals would produce eggs and meat that are also highly inflammatory and contain high levels of arachidonic (or its precursor, linoleic) acid.
My thought then is that those same products should have acceptable AA levels when fed a grass (anti-inflammatory) diet. I haven't found any research specifically related to this, but here's what little I have found. All links are wfs.
This is a post by one of the heads of nutritiondata.com relating the high inflammation index of farmed salmon as compared to wild-caught. Farmed salmon, of course, are fed a grain diet. The poster makes brief mentions of the differing levels of omega-3 and omega-6 fatty acids in grain fed and grass fed beef.
A rather detailed comparison of grain vs grass fed beef. A comparison chart at the bottom of the page states that grass fed has lower levels of omega 6 and higher levels of omega 3. I haven't yet, but will definitely be reading the provided references.
My impression here is that foods which Dr. Sears pins as pro-inflammatory such as red meat and eggs are actually only pro-inflammatory in their industrialized form and are actually anti-inflammatory when acquired from pastured animals.
Thoughts or better resources?
10-13-2009, 10:24 PM
Some data from Kraft et al. 2008 (http://www.ncbi.nlm.nih.gov/pubmed/18491911) attached below. They examined the lipid content from four beef breeds (2 grass-fed, and 2 grain-fed). The relevant data is in the bottom left of the table, where the arachidonic acid content (20-4 n-6) is shown to be practically similar between the breeds.
It's probably not as simple as labeling a food "pro-inflammatory" based on the AA content. A recent commentary (http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1304756&fulltextType=AC&fileId=S0007114507761779) on this paper (http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1304684&fulltextType=RA&fileId=S0007114507734566) raises some interesting points:
In contrast to what might be predicted, studies assessing a range of immune functions and inflammatory markers in healthy adults in response to increased intake of arachidonic acid (up to 1·5 g/d) have not identified any major effects. Taken together with the studies on blood lipids, platelet reactivity and bleeding time, including this latest study, it seems appropriate to conclude that a significant increase in arachidonic acid intake by healthy adults, up to an intake of, say, 1·5 g/d appears unlikely to have any adverse effect. However, the earlier study by Seyberth et al. suggests that higher intakes of arachidonic acid should be approached with caution. Furthermore, there is no information on the impact of increased arachidonic acid supply in disease. It is possible that inflammatory processes that already exist within an individual could be exacerbated by providing exogenous arachidonic acid. However, the discovery of novel anti-inflammatory mediators produced from arachidonic acid and the identification of hitherto unknown anti-inflammatory actions of mediators previously considered to be pro-inflammatory in nature indicate first, the complexity of this system and, second, that predicting the effect that increased arachidonic acid supply might have is difficult. Nevertheless, it is important to keep in mind that, just because there is little biological impact of an increase in arachidonic acid intake or status, there may still be significant benefit from a decrease in its intake or status.
It is important to note that a role for arachidonic acid in neurological development has been identified, that arachidonic acid-derived eicosanoids are not confined to pathology but have many physiological roles, that human breast milk contains arachidonic acid, that infant formulas, which include arachidonic acid (and DHA), are associated with improved growth and development and that formula containing arachidonic acid (and DHA) has been shown to enable preterm infants to achieve immune development similar to that seen with breast-milk feeding and to lower the risk of necrotising enterocolitis in preterm boys. These observations suggest an important role for arachidonic acid in the normal growth and development of infants and demonstrate that harmful actions are not seen as a consequence to its provision, at least when given in combination with DHA.
In conclusion, this new study by Katsumoto et al. adds valuable new information to our knowledge about the impact of increased dietary intake of arachidonic acid. Taken together with earlier studies, this study suggests that, rather than being harmful, moderately increased arachidonic acid intake is probably harmless in healthy adults, although the effect of intakes above 1·5 g/d are not known and the effect of increased intake in diseased individuals is not known. Furthermore, arachidonic acid appears to be an important constituent of infant formulas and in this setting may be helpful in growth, development and health.
10-14-2009, 07:10 AM
Interesting, and very detailed, but why the hell didnt they use the same breeds for both feeding methods for a direct comparison?? That looks like what happened.
CLA looks much hight in the GF cows;
The n3 to n6 ratio also looks much better;
cant see the total fat % though..
SFAs look higher in the GF heffers also oddly..
10-14-2009, 07:30 AM
Many primary research papers can be found in PDF form here (including the Kraft paper mentioned previously):
10-14-2009, 08:52 AM
AA being labeled "bad" is a complete result of conventional medicine/nutrition needing to have everything in black & white.
Recall that only recently did U.S. baby formula manufacturers start adding AA to formula because it is absolutely necessary for truly proper brain development (another blow to veganism).
More to read on AA: http://www.bodybio.com/BodyBio/docs/BodyBioBulletin-4to1Oil.pdf
This should not be interpreted as being pro-feedlot beef at all, however. Just putting AA in proper perspective.
10-16-2009, 06:59 AM
I dont shy away from eggs(AA), but i dont think i'll take up the bodybio oil, i would think that most folks get enough O6 in their diets without trying, let along by taking 6 table spoons of mostly O6 oil. Ill chow down on some more walnuts.
10-21-2009, 10:22 AM
I agree with Tony here. LA is rightfully classified as an essential fatty acid, but I think it's pretty safe to say that there's no shortage of it in the typical western diet and such a diet undoubtedly contains very high levels of LA and AA.
My impression from the Kraft summary is that, as one would expect in any balanced homeostatic system (including pro and anti inflammatory) too little or too much AA or LA is damaging and it is likely that there is an appropriate level. The real question would be, just what is that level?
I really appreciated the flashback to o-chem and biochem in the pdf. I thought I'd successfully repressed that year of my life. ;)
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