Short chain omega-3 good, long chain bad for prostate cancer?

[John Kennerson]

Contrary to this study:
http://www.ncbi.nlm.nih.gov/pubmed/24824038
which highlighted the beneficial effect of EPA on prostate cancer, this other one:
http://www.ncbi.nlm.nih.gov/pubmed/25787237

seems to point out that while alpha-linolenic acid is inversely associated with prostate cancer risk, blood eicosapentaenoic acid concentration and blood docosahexaenoic acid concentration are positively associated with aggressive prostate cancer risk and non aggressive prostate cancer risk.

Abstract follows:

J Epidemiol. 2015 Mar 14. [Epub ahead of print]

Effect of Individual Omega-3 Fatty Acids on the Risk of Prostate Cancer: A
Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies.

Fu YQ(1), Zheng JS, Yang B, Li D.

Author information:
(1)Department of Food Science and Nutrition, Zhejiang University.

Epidemiological studies have suggested inconsistent associations between omega-3
polyunsaturated fatty acids (n-3 PUFAs) and prostate cancer (PCa) risk. We
performed a dose-response meta-analysis of prospective observational studies
investigating both dietary intake and circulating n-3 PUFAs and PCa risk. PubMed
and EMBASE prior to February 2014 were searched, and 16 publications were
eligible. Blood concentration of docosahexaenoic acid, but not alpha-linolenic
acid or eicosapentaenoic acid, showed marginal positive association with PCa risk
(relative risk for 1% increase in blood docosahexaenoic acid concentration: 1.02;
95% confidence interval, 1.00-1.05; I(2) = 26%; P = 0.05 for linear trend), while
dietary docosahexaenoic acid intake showed a non-linear positive association with
PCa risk (P < 0.01). Dietary alpha-linolenic acid was inversely associated with
PCa risk (relative risk for 0.5 g/day increase in alpha-linolenic acid intake:
0.99; 95% confidence interval, 0.98-1.00; I(2) = 0%; P = 0.04 for linear trend),
which was dominated by a single study. Subgroup analyses indicated that blood
eicosapentaenoic acid concentration and blood docosahexaenoic acid concentration
were positively associated with aggressive PCa risk and nonaggressive PCa risk,
respectively. Among studies with nested case-control study designs, a 0.2%
increase in blood docosapentaenoic acid concentration was associated with a 3%
reduced risk of PCa (relative risk 0.97; 95% confidence interval, 0.94-1.00; I(2)
= 44%; P = 0.05 for linear trend). In conclusion, different individual n-3 PUFA
exposures may exhibit different or even opposite associations with PCa risk, and
more prospective studies, especially those examining dietary n-3 PUFAs and PCa
risk stratified by severity of cancer, are needed to confirm the results.

PMID: 25787237 [PubMed - as supplied by publisher]

[John H. Gohde]

Post by John Kennerson
http://www.ncbi.nlm.nih.gov/pubmed/24824038
http://www.ncbi.nlm.nih.gov/pubmed/25787237
seems to point out that while alpha-linolenic acid is inversely associated with prostate cancer risk, blood eicosapentaenoic acid concentration and blood docosahexaenoic acid concentration are positively associated with aggressive prostate cancer risk and non aggressive prostate cancer risk.

Can you say magnesium?

Now, wasn't that simple?

Now, how about the following?

http://tinyurl.com/lbjkzp4

Je suis Moi, posted from Mint.

[Taka]

Used to be the other way around:

"studies have found that fish and fish oil may protect against prostate cancer, but a few studies have seemed to show that alpha-linolenic acid was associated with an increased risk for prostate cancer."

SOURCE: http://umm.edu/Health/Medical/AltMed/Supplement/Alphalinolenic-acid

"Alpha-linolenic acid was associated with a strong positive association (fourth quartile of intake odds ratio, 3.91; 95% confidence interval, 1.50-10.1) after controlling for total calorie intake and for the other types of fat. The effect was similar when alpha-linolenic acid was analyzed by its sources of origin (odds ratio for vegetable linolenic acid, 2.03; 95% confidence interval, 1.01-4.07). Including this report, five of six studies that have examined the relationship between alpha-linolenic acid and prostate cancer yielded a positive association, which was significant in four studies. Thus, there appears to be evidence of a role of alpha-linolenic acid in prostate carcinogenesis."

PMID: 10750674

"the association between high intake of ALA and prostate cancer is of concern and warrants further study."

PMID: 15051847

"RESULTS: The combined estimate showed an increased risk of prostate cancer in men with a high intake or blood level of alpha-linolenic acid (ALA) (combined relative risk (RR) 1.36; 95% CI 1.08-1.70). The association is stronger in the case-control studies (RR 1.84; 95% CI 1.04-3.25) than in the prospective studies (RR 1.10; 0.91-1.32). Ecosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were not significantly associated with prostate cancer."

PMID: 18951003