DHA/ aging medline excerpts

[Guest guest]

I looked at the Medline's "fish oil and aging" abstracts:

Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11321-6. Epub 2003 Sep 17.

Modification by docosahexaenoic acid of age-induced alterations in geneexpression and molecular composition of rat brain phospholipids.

Advanced age is associated with reduced brain levels of long-chainpolyunsaturated fatty acids, arachidonic acid (AA) and docosahexaenoic acid(DHA). Memory impairment is also a common phenomenon in this age. Two-year-old,essential fatty acid-sufficient rats were fed with fish oil (11% DHA) for 1month, and fatty acid as well as molecular composition of the majorphospholipids, phosphatidylcholine and phosphatidylethanolamine (PE), wascompared with that of 2-month-old rats on the same diet. DHA but not AA wassignificantly reduced in brains of old rats but was restored to the level ofyoung rats when they received rat chow fortified with fish oil. This effect waspronounced with diacyl 18:0/22:6 PE species, whereas levels of 18:1/22:6 and16:0/22:6 remained unchanged in all of the three PE subclasses. Fish oil reducedthe AA in the old rat brains, diacyl and alkenylacyl 18:0/20:4 PE being mostaffected. Phosphatidylcholines gave less pronounced response. Six genes wereup-regulated, whereas no significant changes were observed in brains of old ratsreceiving fish oil for 1 month. None of them except synuclein in young ratbrains could be related to mental functions. Old rats on the fish-oil diet didnot perform better in water maze test than the control ones. A 10%increase in levels of diacyl 18:0/22:6 PE in young rat brains resulted in asignificant improvement of learning capacity. The results are interpreted interms of the roles of different phospholipid molecular species in cognitivefunctions coupled with differential responsiveness of the genetic machinery ofneurons to n-3 polyunsaturated fatty acids. PMID: 13679584

Our findings indicate that mature rats maintain a constant levelof DHA in the ROS membranes even after being directly supplemented with highdoses of DHA.PMID: 12951898

we investigated whether the supplementationof healthy elderly people with very low doses of marine oil (MO), adocosahexaenoate (DHA)- and eicosapentaenoate (EPA)-rich triacylglycerol, wasable to affect lymphocyte proliferation and biochemical markers known to bealtered with age. ...Collectively, these results demonstrate that even very low dosesof n-3 fatty acids are sufficient to affect the immune responses of elderlysubjects.PMID: 12654171

Among the fatty acids, it is the omega-3 polyunsaturated fatty acids (PUFA)which possess the most potent immunomodulatory activities, and among the omega-3PUFA, those from fish oil-eicosapentaenoic acid (EPA) and docosahexaenoic acid(DHA)--are more biologically potent than alpha-linolenic acid (ALA).

Many of the placebo-controlled trials of fish oil in chronic inflammatory diseases reveal significant benefit, including decreased disease activity and a lowered use of anti-inflammatory drugs.PMID: 12480795

These results suggest that the intake of egg-PC improves maze-learning ability in aged mice fed n-3 fattyacid-deficient diets but it does not influence the percentage of brain DHA andAA. PMID: 12378046

These experimental results suggest that the dietary intake of DHA should not be morethan 3 en% in matured rats to avoid the potentially chronic deleteriousinfluences caused by lipid peroxidation in serum and tissues, and that theamelioration of serum lipid levels is recognized in rats fed DHA at 3 en% andabove. PMID: 12378040

A significant increase in the DHA content in the brain was also observed. These results suggest that the intake of DHA-fortified Chlorella oil fraction effectively enhances working memory in maze performance. PMID: 12186415

These results suggest that in aged rats, but not youngrats, excess supplementation of DHA induces oxidative DNA damage in bone marrowand that the decrease in vitamin C synthesis in aged rats is involved in themechanisms of DNA damage. PMID: 11328678

Therefore, in AD, OD, and CIND individuals, low levels of n-3 fatty acids in the plasma may be a risk factor for cognitive impairment and/or dementia. Interestingly, a decreased level of plasma DHA was not limitedto the AD patients but appears to be common in cognitive impairment with aging. PMID: 11201991

The results suggest that oral intake of excess polyunsaturated fatty acids, i.e. EPA and DHA, in a fish oil diet can lead to acceleration of membrane lipid peroxidation resulting in RBC senescence linked to the lowering of immune response of spleen cells, and that supplementation of alpha-tocopherol as antioxidant does not always effectively prevent such oxidative degeneration as observed in spleen cells and RBC in vivo. PMID: 11004607

The decline in structural and functional integrity of this tissue appears to correlate with loss in membrane DHA concentrations. Arachidonic acid, also predominant in this tissue, is a major precursor for the synthesis of eicosanoids, that serve as intracellular or extracellular signals.With aging comes a likely increase in reactive oxygen species and hence a concomitant decline in membrane PUFA concentrations, and with it, cognitive impairment. Neurodegenerative disorders such as Parkinson's and Alzheimer's disease also appear to exhibit membrane loss of PUFAs. Thus it may be that an optimal diet with a balance of n-6 and n-3 fatty acids may help to delay their onset or reduce the insult to brain functions which these diseases elicit. PMID: 10817922

Fish oil decreases the proliferation of tumour cells, whereas arachidonic acid, a longchain n-6 fatty acid, increases their proliferation. These opposite effects are also seen with inflammation, particularly with rheumatoid arthritis, and with asthma. DHA has a positive effect on diseases such as hypertension, arthritis, atherosclerosis, depression, adult-onset diabetes mellitus, myocardial infarction, thrombosis, and some cancers. PMID: 10479465

These results suggest that in aged rats, supplementation with DHA alters the membrane fatty acid composition as well as the amount of ATP released from vascular endothelial cells and decreasesplasma noradrenaline, and that these factors may ameliorate the rise in blood pressure normally associated with advancing age. PMID: 9915878

The blood pressure of DHA-treated SHRSP was significantly lower than that of non-treated SHRSP. A positive correlation existed between blood pressure and blood viscosity. These findings suggest that decreased blood viscosity induced by DHA appears to be associated with the reduction of thrombosis formation and hypotensive action in SHRSP. PMID: 9730013

The results are discussed with respect to the rapid accumulation of retinal DHA in early lifeand the avid retention of this fatty acid by the adult retina. PMID: 9313833

It was concluded that dietary DHA suppresses the development of hypertension and stroke-related behavioral changes, resulting in prolongation of the SHRSP's life span. PMID: 9378247

The experiments reported here indicate that incorporation of long-chain polyunsaturated n-3 fatty acids into mitochondrial membranes does not appear likely to reverse the effects of age on mitochondrial function. PMID: 9168456

Docosahexaenoic acid at a dose of less than 2 g/d did not change serum lipid concentrations of normolipidemic subjects. The effects of DHA in hyperlipidemic patients remain to be investigated in a double-blind study. PMID: 8914949

These findings suggest that both functional and morphological changes occur with aging. DHA- and EPA-induced responses are not altered by aging in intact rings; however, removal of the endothelium enhances their vasorelaxant properties in all three age groups. This may be related to the direct actions of DHA and EPA on vascular smooth muscle, rather than on mechanisms associated with generation of endothelium-derived relaxing factor. PMID: 8641598

Essential fatty acids (EFA), which are not synthesized in animal and human tissues, belong to the n-6 and n-3 families of polyunsaturated fatty acids (PUFA), derived from linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (LNA, 18:3n-3). Optimal requirements are 3-6% of ingested energy for LA and 0.5-1% for LNA in adults. ...Dietary fatty acids exert a great influence and are often inhibitory. Dietary LNA inhibits delta 6 desaturation of LA. The desaturation products AA, EPA, and DHA inhibit delta 6 desaturation of LA and delta 5 desaturation of DGLA (dihomo-gamma-linolenic acid). With regard to hormones, insulin and thyroxin are necessary to delta 6 and delta 5 desaturation activities, whereas other hormones (glucagon, epinephrine, ACTH, glucocorticoids) inhibit desaturation. ...Just after birth, in animals, the delta 6 desaturation activity increases in the liver and decreases in the brain. In aging, the capacity of the whole liver to desaturate LA and DGLA is equal at 1.5 and 25 months of age in rats fed a balanced diet throughout their life and the AA and DHA content of tissue phospholipids is unchanged in aging. PMID: 7840871

Mortality due to ventricular fibrillation (VF) was highest in rats fed corn oil with the highest ratio of AA/DHA. Sudden cardiac death in man was frequently associated with a higher ratio of AA/DHA than observed in people of the same age who died in accidents. The balance between n-6 and n-3 fatty acids in cellular phospholipids seems to play an important role in stress tolerance and survival. PMID: 2730548

Regards.

----- Original Message -----

From: Dowling

Sent: Wednesday, August 25, 2004 12:16 PM

Subject: Re: [ ] Re: Fat Guru Udo Erasmus' take on ALA, etc.and Prostate CA

Dunno if it's cost effective to get pure EPA. I'm also not entirely sold on going without DHA, at this point, anyway.....>From: "jwwright" <jwwright@...>>Reply- >< >>Subject: Re: [ ] Re: Fat Guru Udo Erasmus' take on ALA, >etc.and Prostate CA>Date: Wed, 25 Aug 2004 11:57:53 -0500>>Thanks, ,>I guess it's not reasonable to look for EPA without the DHA? {in light of >MR's concern over DHA accelerated aging hypothesis}.>