Posted by Larry Hoover on February 25, 2007, at 18:19:39
In reply to Little Evidence Omega-3 Fights Depression: Study, posted by Joe Bloe on February 22, 2007, at 1:39:54
> Along with their conclusion that omega-3 has little or no effect on depression, the authors said there is evidence that fish oil supplements contain environmental toxins, which may be especially concentrated in supplements made from fish livers.
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> This means that people should not exceed the maximum recommended doses of these supplements, the authors said. They also noted that pregnant women should take only low doses of fish oil supplements, which contain vitamin A. High levels of vitamin A can harm a developing fetus.Hogwash. That's my reaction to this article. I'd like to see the actual published version, but I can't yet find it. Anyway....
I'm an environmental toxicologist, and these toxicants that were inferred are the dioxins, PCBs, PCDDs, and similar cyclic hydrocarbons. They are fat-soluble, so they do partition into fatty tissues, or oils. The thing is, recent studies have shown that fish and fish oil are no more contaminated than meat or dairy. Belgian and Norwegian studies have those three groups at about 30% each as dietary sources, with the rest made up by grain products. In Egypt, 90% of these toxicants are dairy-sourced. I don't hear anyone saying butter is contaminated (or beef), do I?
Any risk-benefit analysis I've ever read has concluded that fish oil intake is better for you than the effect of trying to avoid the contaminants it contains. And I agree with them. However, that's not to say that spending a little more and getting a certified pure product isn't worth the money. Peace of mind is priceless. The findings of toxic substances at these ppt (part per trillion) levels is really a result of better instrumentation. Twenty years ago, these toxins were undetectable. Do what you can to reduce the burden, but don't lose any sleep over it.
I've grabbed a couple of recent abstracts to make two points. The first is that fish oil is almost totally accepted as an augmentative treatment strategy in mood disorders. Look at the names of the authors, below. Second point: Whole fish is better for you than is fish oil, even at equivalent fatty acid intake levels. For unexplained reasons, the fat from whole fish is better absorbed. It's possible (but unproven) that my admonishment to take fish oil with your fattiest meal of the day might minimize that poor uptake, but I'm just speculating.
Best,
LarJ Clin Psychiatry. 2006 Dec;67(12):1954-67.
Omega-3 fatty acids: evidence basis for treatment and future research in psychiatry.
Freeman MP, Hibbeln JR, Wisner KL, Davis JM, Mischoulon D, Peet M, Keck PE Jr, Marangell LB, Richardson AJ, Lake J, Stoll AL.
Women's Mental Health Program, Department of Psychiatry, University of Arizona College of Medicine, Tucson 85724-5002, USA. marlenef@email.arizona.eduOBJECTIVE: To determine if the available data support the use of omega-3 essential fatty acids (EFA) for clinical use in the prevention and/or treatment of psychiatric disorders. PARTICIPANTS: The authors of this article were invited participants in the Omega-3 Fatty Acids Subcommittee, assembled by the Committee on Research on Psychiatric Treatments of the American Psychiatric Association (APA). EVIDENCE: Published literature and data presented at scientific meetings were reviewed. Specific disorders reviewed included major depressive disorder, bipolar disorder, schizophrenia, dementia, borderline personality disorder and impulsivity, and attention-deficit/hyperactivity disorder. Meta-analyses were conducted in major depressive and bipolar disorders and schizophrenia, as sufficient data were available to conduct such analyses in these areas of interest. CONSENSUS PROCESS: The subcommittee prepared the manuscript, which was reviewed and approved by the following APA committees: the Committee on Research on Psychiatric Treatments, the Council on Research, and the Joint Reference Committee. CONCLUSIONS: The preponderance of epidemiologic and tissue compositional studies supports a protective effect of omega-3 EFA intake, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in mood disorders. Meta-analyses of randomized controlled trials demonstrate a statistically significant benefit in unipolar and bipolar depression (p = .02). The results were highly heterogeneous, indicating that it is important to examine the characteristics of each individual study to note the differences in design and execution. There is less evidence of benefit in schizophrenia. EPA and DHA appear to have negligible risks and some potential benefit in major depressive disorder and bipolar disorder, but results remain inconclusive in most areas of interest in psychiatry. Treatment recommendations and directions for future research are described. Health benefits of omega-3 EFA may be especially important in patients with psychiatric disorders, due to high prevalence rates of smoking and obesity and the metabolic side effects of some psychotropic medications.
Lipids. 2006 Dec;41(12):1109-14.
Enhanced incorporation of n-3 fatty acids from fish compared with fish oils.
Elvevoll EO, Barstad H, Breimo ES, Brox J, Eilertsen KE, Lund T, Olsen JO, Osterud B.
Norwegian College of Fishery Science, Department of Marine Biotechnology, University of Tromso, Norway. edel.elvevoll@nfh.uit.noThis work was undertaken to study the impact of the source of n-3 FA on their incorporation in serum, on blood lipid composition, and on cellular activation. A clinical trial comprising 71 volunteers, divided into five groups, was performed. Three groups were given 400 g smoked salmon (n = 14), cooked salmon (n = 15), or cooked cod (n = 13) per week for 8 wk. A fourth group was given 15 mL/d of cod liver oil (CLO) (n = 15), and a fifth group served as control (n = 14) without supplementation. The serum content of EPA and DHA before and after intervention revealed a higher rise in EPA and DHA in the cooked salmon group (129% rise in EPA and 45% rise in DHA) as compared with CLO (106 and 25%, respectively) despite an intake of EPA and DHA in the CLO group of 3.0 g/d compared with 1.2 g/d in the cooked salmon group. No significant changes were observed in blood lipids, fibrinogen, fibrinolysis, or lipopolysaccharide (LPS)-induced tissue factor (TF) activity, tumor necrosis factor-alpha (TNFalpha), interleukin-8 (IL-8), leukotriene B4 (LTB4), and thromboxane B2 (TxB2) in whole blood. EPA and DHA were negatively correlated with LPS-induced TNFalpha, IL-8, LTB4, TxB2, and TF in whole blood. In conclusion, fish consumption is more effective in increasing serum EPA and DHA than supplementing the diet with fish oil. Since the n-3 FA are predominantly in TAG in fish as well as CLO, it is suggested that the larger uptake from fish than CLO is due to differences in physiochemical structure of the lipids.
poster:Larry Hoover
thread:735013
URL: http://www.dr-bob.org/babble/alter/20070201/msgs/736197.html