2 replies to this topic

[yoyo]

Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice

Abstract
Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while at the same time live shorter lives. These relationships have been combined in the ‘membrane pacemaker hypothesis of aging’. It suggests that membrane PUFA content might determine an animal’s life span. PUFAs in general and certain long-chain PUFAs in particular, are highly prone to lipid peroxidation which brings about a high rate of reactive oxygen species (ROS) production. We hypothesized that dietary supplementation of either n-3 or n-6 PUFAs might affect (1) membrane phospholipid composition of heart and liver tissues and (2) life span of the animals due to the altered membrane composition, and subsequent effects on lipid peroxidation. Therefore, we kept female laboratory mice from the C57BL/6 strain on three diets (n-3 PUFA rich, n-6 PUFA rich, control) and assessed body weights, life span, heart, and liver phospholipid composition after the animals had died. We found that while membrane phospholipid composition clearly differed between feeding groups, life span was not directly affected. However, we were able to observe a positive correlation between monounsaturated fatty acids in cardiac muscle and life span.

free fulltext http://www.ncbi.nlm....MC3022160/#Sec2

Unfortunately, ALL diets were high in w-6, so this doesn't show w-6 restriction not to be helpful

One thing i noticed was the apparent stability of total PUFA in the membranes, despite w-6 vs w-3 changed ratio. but this might be because dietary PUFA was constant in the diets...
 360_2010_520_Fig2_HTML.jpg   54.68KB   12 downloads

which is similar to the study showing more w-3 kept membrane w-6 down
 Lands HUFA.jpg   40.24KB   14 downloads

second image from source: http://wholehealthso...art-diseas.html

Edited by Michael, 22 May 2011 - 12:29 PM.

[niner]

Unfortunately, ALL diets were high in w-6, so this doesn't show w-6 restriction not to be helpful

I just read this paper, and at first that's what I thought, too. It turns out, however, that their presentation of the composition of the three diet groups is stupid. Sometimes I wish I could reach out through the internet and slap the authors... They mixed units in their chart; the control diet was only 2% fat, while the intervention groups were a lot higher. Where they reported the breakdown of the individual fatty acids, those were expressed as percent of fat, rather than percent of diet. It's still the case that the ratios of the different fatty acids in the control diet were very similar to the ratios in the n-6 intervention diet.

[Sillewater]

What I find interesting is that their survival curves look similiar and pretty good. Considering as MR always says well-kept mice average LS = 900d with MLSP = 1200d while the calculated UI and PI was increased in the higher PUFA diets.

Edited by Sillewater, 22 December 2011 - 05:38 AM.