Foods/Supplements-Vitamins: Conjugated Linoleic Acid [CLA]

The post on beef yesterday had me thinking of conjugated linoleic acid [CLA]. CLA in the meat of grass-fed cattle supposedly has anti-PCa properties. No human PCa studies, of course but see [10]. (Feedlot beef has no appreciable CLA.)

CLA is available as supplements [11] [12]. Both derived from safflower seed.

CLA is also present in the lowly white button mushroom - see [7].

There are at least 28 positional & geometric isomers of CLA. CLA is a stepping stone towards stearic acid 18:0 (18-carbon chain, fully hydrogenated & therefore with 0 double-bonds). CLA is 18:2 (18-carbon chain with two double-bonds). Each double-bond can be in the cis or trans form, & the two are separated by a single bond.

e.g. cis-9,trans-11 & trans-10,cis-12 (second number = first plus 2)

The blurb for the LEF product identifies: "two active isomers C18:2 c9,t11 and C18:2 t10,c12". This is just another way of writing it. These two are the only isomers that concern us.

Studies - oldest first:

[1] (2002 - Scotland)

"Fats have been adversely implicated in the aetiology of many forms of cancer yet evidence is accumulating that certain types of fatty acids have anticancer properties. This is well documented for fish-oil fatty acids of the n-3 family. Recently, fatty acids found to occur naturally in ruminant-derived food products were found to have anticancer properties. These fatty acids were identified as conjugated linoleic acids (CLAs) derived from the parent linoleic acid by its partial hydrogenation by rumen bacteria. Studies with tumour-bearing animals have shown that consumption of CLAs particularly with regard to breast and prostate cancer is beneficial. Studies with cancer cells have also shown that these fatty acids can inhibit cell proliferation and induce cell death."

"We have shown that CLAs specifically up-regulate cell signal systems at the level of gene expression (mRNA, protein) in human breast and prostate cancer cells which are responsible for the induction of apoptosis or programmed cell death. These findings support the anticancer effects of CLA found in animal models and indicate similar effects could occur in man."

[2] (2004 - Spain)

"Our results indicate a significant decrease in PC-3 proliferation elicited by CLA, although with high variability between isomers. The trans-10, cis-12 CLA was the most effective isomer (55% inhibition)."

"Trans-10, cis-12 seems to work preferentially through modulation of apoptosis and cell cycle control, while c9,t11 CLA isomer affects arachidonic acid metabolism."

[3] (2004 - Scotland)

"Conjugated linoleic acid inhibits proliferation and modulates protein kinase C isoforms in human prostate cancer cells."

[4] (2005 - France)

"One isomer of CLA (t9,t11-18:2) and CLA-conjugated derivatives exhibited the strongest growth-inhibitory effect against cancer cells."

[5] (2006 - Scotland)

"Only the CLA cis-9, trans-11 isomer significantly increased TNF-alpha-induced apoptosis (by 59%), which correlated with a reduction in NF-kappaB transcriptional activity (by 35% ...)"

[6] (2006 - Korea)

"The two predominant isomers of CLA are cis-9,trans-11 CLA (c9t11) and trans-10,cis-12 CLA (t10c12). The present study was performed to study the effect of the individual CLA isomers on DU145 cell growth."

"trans-10,cis-12 conjugated linoleic acid inhibits the G1-S cell cycle progression in DU145 human prostate carcinoma cells."

[7] (2008 - U.S.)

"The purpose of this research was to evaluate the effects of white button mushroom extract and its major component, conjugated linoleic acid (CLA) on prostate cancer cell lines in vitro and mushroom extract in vivo. In all cell lines tested, mushroom inhibited cell proliferation in a dose-dependent manner and induced apoptosis within 72 h of treatment. CLA inhibited proliferation in the prostate cancer cell lines in vitro. DU145 and PC3 prostate tumor size and tumor cell proliferation were decreased in nude mice treated with mushroom extract, whereas tumor cell apoptosis was increased compared to pair-fed controls."

[8] (2010 - Canada)

"The 10t,12c isomer of conjugated linoleic acid inhibits fatty acid synthase expression and enzyme activity in human breast, colon, and prostate cancer cells."

[9] (2013 - UK)

"PC3, DU145, LNCaP, VCaP and PNT2 cells were treated with 100 μM of either oleate, stearate or conjugated linoleate."

"Conjugated linoleic acid reduced cell proliferation and viability in all prostate cancer cell lines, whilst the effects of oleic and stearic acid on proliferation were found to be cell line-dependent. A reduction in gene expression of fatty acid desaturases was observed in prostate cancer cell lines compared to normal prostate cells."

{Why was CLA compared to oleate & stearate? All three have an 18-carbon backbone. CLA has 2 double-bonds (polyunsaturated), oleate has one (monounsaturated), & stearate has zero (saturated). must have seemed like a good idea. LOL.}

[10] (2012 - Canada) ... not a PCa study ...

"A cross-sectional study was designed to examine the association between c9, t11 CLA status in erythrocyte membranes (RBC) and body composition."

i.e, they looked for cis-9,trans-11 CLA in red blood cells - "a reflection of long-term (~4 months) dietary CLA intake"

"Men with RBC c9, t11 CLA status above the median had higher whole body bone mineral density (BMD) (1.359 ... vs 1.287 ... g/cm(2)"

"and whole body lean mass (WBL) percentage (78.8% ... vs 75.3% ...)"

"whereas body mass index (24.8 ... kg/m(2) vs 27.3 ... kg/m(2) ...) and whole body fat mass percentage (17.3% ... vs 21.3% ...) were lower"

-Patrick

[1] ncbi.nlm.nih.gov/pubmed/123...

[2] carcin.oxfordjournals.org/c...

[3] ncbi.nlm.nih.gov/pubmed/154...

[4] ar.iiarjournals.org/content...

[5] ncbi.nlm.nih.gov/pubmed/164...

[6] ncbi.nlm.nih.gov/pubmed/170...

[7] ncbi.nlm.nih.gov/pubmed/190...

[8] ncbi.nlm.nih.gov/pubmed/200...

[9] ncbi.nlm.nih.gov/pubmed/241...

[10] ncbi.nlm.nih.gov/pubmed/232...

[11] lifeextension.com/Vitamins-...

[12] tonalin.com/about/

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