Hans, you have been talking about your parents and the pre-vegetable oil era people having Mead acid in their cells. Novadays people and farmed animals are fed vegetable oils so they are loaded with AA instead. But how about the wild animals, they are still eating like they were thousands of years ago so there should be some Mead acid in them. Here is one example study looking at lipids in 42 mammalian species and all they are finding are n-3 to n-6 PUFAs. I don't have access to the full text but it's unlikely they used only animals kept in ZOO and fed vegetable oils. I have yet to find some report of Mead acid in game meat or wild species (except the elongated Mead acid derivative in Turkeys I posted on the other thread). Does it mean that the wild animals are getting enough Omega-3 and Omega-6 PUFAs in their natural diet to prevent the synthesis of Mead acid?
Aging Cell. 2007 Feb;6(1):15-25. Epub 2006 Dec 5.
N-3 polyunsaturated fatty acids impair lifespan but have no role for metabolism.
Valencak TG, Ruf T.
Research Institute of Wildlife Ecology, University of Veterinary Medicine, Savoyenstrasse 1, A-1160 Vienna, Austria. teresa.valencak[at]vu-wien.ac.at
Although generally considered as beneficial components of dietary fats, polyunsaturated fatty acids (PUFA) have been suspected to compromise maximum lifespan (MLSP) in mammals. Specifically, high amounts of phospholipid PUFAs are thought to impair lifespan due to an increase in the susceptibility of membranes to lipid peroxidation and its damaging effect on cellular molecules. Also, there is evidence from in vitro studies suggesting that highly unsaturated PUFAs elevate basal metabolic rate (BMR). Previous comparative studies in this context were based on small sample sizes, however, and, except for one study, failed to address possible confounding influences of body weight and taxonomic relations between species. Therefore, we determined phospholipid membrane composition in skeletal muscle from 42 mammalian species to test for a relation with published data on MLSP, and with literature data on BMR (30 species). Using statistical models that adjust for the effects of body weight and phylogeny, we found that among mammals, MLSP indeed decreases as the ratio of n-3 to n-6 PUFAs increases. In contrast to previous studies, we found, however, no relation between MLSP and either membrane unsaturation (i.e. PUFA content or number of double bonds) or to the very long-chain, highly unsaturated docosahexaenoic acid (DHA). Similarly, our data set gave no evidence for any notable relation between muscle phospholipid fatty acid composition and BMR, or MLSP and BMR in mammals. These results contradict the 'membrane pacemaker theory of aging', that is, the concept of a direct link between high amounts of membrane PUFAs, elevated BMR, and thus, impaired longevity.
PMID: 17156083 |
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