Dr. Klaper writes: In recent years, I have been taking DHA, a long-chain, omega-3 fatty acid, as a supplement form in the hopes of preventing dementia and have been recommending others do the same, largely on the basis of reports in the medical journals, such as these:
J Nutr. 2010 Apr; 140(4): 869-874.
DHA May Prevent Age-Related Dementia
Greg M. Cole* and Sally A. Frautschy
Monday, October 28, 2019
News & Perspective Drugs & Diseases CME & Education Academy Consult Video
From Medscape Family Medicine
DHA and Dementia: Preserving Cognition in the Aging Patient
Authors: Sally A Frautschy, MS, PhD; Greg M Cole, PhD
The reports like those above are filled with suggestions that DHA *MIGHT* be of some value in brain function, but none present ironclad research proving a solid connection between DHA deficiency and dementia in vegans. Very importantly, no study conclusively demonstrates that DHA supplementation will prevent or reverse dementia in vegans. Several authors of these reports, like Greg Cole, PhD cited above, have received money from companies that make DHA supplements and cannot be regarded as unbiased researchers.
As you will see in this brief video, I have changed my thinking about taking this supplement due to (1) the lack of solid scientific evidence of dementia prevention in vegans through DHA supplementation and (2) concern over increased cancer risk.
The most worrisome reason that I have stopped taking DHA supplements and no longer recommend that others ingest this substance is that researchers at the Fred Hutchinson Cancer Research Center and others have found, in a subset of men, a strong link between high levels of DHA in their blood and tissues and the development an aggressive form of prostate cancer:
From these studies, I conclude that, although loading up the tissues with pre-formed DHA from supplements may superficially seem to make some sense, apparently “leapfrogging” over the body’s natural enzymatic processes that normally make EPA and DHA from alpha-linolenic acid in our food, and just saturating the prostate cells with pre-formed DHA through supplementation may make the prostate cells unstable and start the cascade towards prostate cancer development in some men.
Whether there is any adverse effects of DHA supplementation upon women is not known at this time, but because “Do no harm” applies to dietary advice, as well, in view of the concerning evidence above, I can no longer recommend that people - especially men - take DHA supplements.
The safest course is to regularly consume walnuts, ground flax and chia seeds and dark green leafy vegetables in smoothies, salads and porridge - while avoiding omega-6 heavy vegetable oils and processed foods - and to let our body make our own DHA.
Science dictates that when newer knowledge is gained that make old concepts obsolete, the previous beliefs must be left behind. My thinking on DHA has certainly evolved on this subject and, as a result, (and with my uncle dying of prostate cancer), I am leaving the algae-derived DHA capsules behind.