Fish Oils, Health and Cognition

acupuncture

Headlines and news stories regarding diet often misinterpret what a research article is stating. This is especially true regarding fish oils because of poorly designed studies. Fish contain long chain fatty acids eicosapentaenoic acid (EPA), and docosahexanoic acid (DHA) that create cellular fluidity which is important for brain health. For all the positive studies on fish oils there are negative studies that grab headlines because they are in opposition of accepted prior evidence.

For example a study concluding that there was no benefit of fish oil after 8 months of a randomized control trial will read “Fish Oil No Benefit for the Brain”. Do you think 8 months is long enough to conclude no lifetime benefit?  Likely not. How did they measure cognitive health as it seems a simple test may show little significance improvement over short term. Poor study designs can grab headlines and confuse consumers.

Another example is one study will show that fish oils are beneficial for prostate cancer while another grabs headlines that fish oils increase prostate cancer risk. Why is that? There are many issues with the methodologies used in the latter headline grabbing study as can be seen from the number of comments. The authors conclude that increasing omega-6: omega-3 fatty acid ratio is preferred for preventing prostate cancer flies in the face of previous studies.

That brings me to the motivation for this post which is another positive conclusion drawn between cognition and fish oils:

April 27, 2014
Source:
Federation of American Societies for Experimental Biology (FASEB)

 

The importance of long-chain polyunsaturated fatty acids (PUFAs) to brain health has been demonstrated in multiple studies. To assess whether lower dietary intake of alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexanoic acid (DHA) were risk factors for cognitive decline, Tammy Scott, PhD, a scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University recently conducted a longitudinal, observational study using the Boston Puerto Rican Health Study cohort. Alice Lichtenstein, DSc, also from the USDA HNRCA at Tufts University, and Katherine Tucker, PhD, the cohort director from the University of Massachusetts-Lowell, were co-authors of the study, which has been published as an abstract.

 

“The participants were put through an intensive series of cognitive tests such as memory tests using a list of words, an attention test to repeat lists of numbers forward and backward, and a test of organization and planning involving copying complex figures,” said Dr. Scott. To determine the participants’ intake of PUFAs they were given a questionnaire. The results were determined after comparing baseline test numbers with a 2 year follow up.

 

The researchers found that the intake of omega-3 PUFAs in the study sample of 895 participants was low. The 2010 U.S. Dietary Guidelines recommended an intake of 8 or more ounces of seafood per week (less for young children) to ensure an adequate intake of the very long chain omega-3 fatty acids (EPA and DHA). This translates to about 1,750 mg of EPA and DHA per week, which averages to 250 mg per day. Scott’s group reported that only 27% of the participants in their study met or exceeded that recommendation. The major source of EPA and DHA in their diets appeared to be from canned tuna. Based on the scientists’ findings, being in the lowest four quintiles of EPA and DHA intake was predictive of cognitive decline over 2 years.

 

What is the takeaway from this research? There is growing evidence that very long chain omega-3 fatty acids are beneficial for maintaining cognitive health, and many Americans do not have an adequate intake of these nutrients. “While more research is needed to determine whether intake of fatty fish such as salmon, tuna and trout can help prevent against cognitive decline, our preliminary data support previous research showing that intake of these types of fish have health benefits,” Scott said.

It is also important that if one is supplementing with fish oils they use a good quality oil.   You get what you pay for with supplements and an inexpensive fish oil is probably not as good quality as professional grade supplements where each batch is tested.   Nordic Naturals is one retail company that seems to test well.   Also there is the Blue Ice fermented Cod Liver oil that is revered by the Weston Price foundation.  Consumer Labs tested fish oils for metals, labeling, cost:benefit and other metrics and is worth the price of membership.

In Good Health
George Mandler
Licensed Dietitian
Licensed Acupuncturist

References

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Lund EK1, Harvey LJ, Ladha S, Clark DC, Johnson IT. Effects of dietary fish oil supplementation on the phospholipid composition and fluidity of cell membranes from human volunteers. Ann Nutr Metab. 1999;43(5):290-300. PMID: 10749029. [PubMed] [Read by QxMD]

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Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002 Oct;56(8):365-79. PMID: 12442909. [PubMed] [Read by QxMD]

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