canned, preserved fish were reported to be associated with reduced risk for prostate cancer. Epstein et al found that a higher omega-3 fatty acid intake predicted better survival for men who already had prostate cancer, and increased fish intake was associated with a 63% reduction in risk for aggressive prostate cancer in a case-control study by Fradet et al). So there is considerable evidence actually FAVORING an increase in fish intake for prostate cancer risk reduction.
Another piece of the picture is to compare prostate cancer rates in Japan vs the US. Here is a quote from the World Foundation of Urology:
"[Prostate cancer] incidence is really high in North America and Northern Europe (e.g., 63 X 100,000 white men and 102 X 100,000 Afro-Americans in the United States), but very low in Asia (e.g., 10 X 100,000 men in Japan).”
Since the Japanese typically eat about 8x more omega-3 fatty acids than Americans do and their blood levels are twice as high, you’d think their prostate cancer risk would be much higher... but the opposite is the case.
Omega-3 fatty acids are physiologically necessary, normalizing multiple metabolic phenomena including augmentation of parasympathetic tone, reductions of postprandial (after-meal) lipoprotein excursions, and endothelial function. It would indeed make no sense that nutrients that are necessary for life and health exert an adverse effect such as prostate cancer at such low blood levels. (Recall that an omega-3 RBC index of 6.0% or greater is associated with reduced potential for sudden cardiac death.)
I personally take 3600 mg per day of EPA + DHA in highly-purified, non-oxidized triglyceride form (Ascenta Nutrasea liquid) that yields an RBC omega-3 index of just over 10%, the level that I believe the overwhelming bulk of data suggest is the ideal level for humans.
1) Earlier studies, such as GISSI-Prevenzione, demonstrated reduction in cardiovascular events with omega-3 fatty acid supplementation, consistent with the biological and physiological benefits observed in animals, experimental preparations, and epidemiologic observations in free-living populations.
2) More recent studies (and meta-analyses) examining the effects of omega-3 fatty acids have failed to demonstrate cardiovascular benefit showing, at most, non-significant trends towards benefit.
He points out that the more recent studies were conducted post-GISSI and after agencies like the American Heart Association's advised people to consume more fish, which prompted broad increases in omega-3 intake. The populations studied therefore had increased intake of omega-3 fatty acids at the start of the studies, verified by higher levels of omega-3 RBC levels in participants.
In addition, he raises the provocative idea that the benefits of omega-3 fatty acids appear to be confined to those not taking statin agents, as suggested, for instance, in the Alpha Omega Trial. He speculates that the potential for statins to ablate the benefits of omega-3s (and vice versa) might be based on several phenomena:
--Statins increase arachidonic acid content of cell membranes, a potentially inflammatory omega-6 fatty acid that competes with omega-3 fatty acids. (Insulin provocation and greater linoleic acid/omega-6 oils do likewise.) --Statins induce impaired mitochondrial function, while omega-3s improve mitochondrial function. (Impaired mitochondrial function is evidenced, for instance, by reduced coenzyme Q10 levels, with partial relief from muscle weakness and discomfort by supplementing coenzyme Q10.) --Statins commonly provoke muscle weakness and discomfort which can, in turn, lead to reduced levels of physical activity and increased resistance to insulin. (Thus the recently reported increases in diabetes with statin drug use.)
Are the physiologic effects of omega-3 fatty acids, present and necessary for health, at odds with the non-physiologic effects of statin drugs?
I fear we don't have sufficient data to come to firm conclusions yet, but my perception is that the case against statins is building. Yes, they have benefits in specific subsets of people (none in others), but the notion that everybody needs a statin drug is, I believe, not only dead wrong, but may have effects that are distinctly negative. And I believe that the arguments in favor of omega-3 fatty acid supplementation, EPA and DHA (and perhaps DPA), make better sense.
Of the two omega-3 fatty acids that are best explored, EPA and DHA, it is likely DHA that exerts the most blood pressure- and heart rate-reducing effects. Here are the data of Mori et al in which 4000 mg of olive oil, purified EPA only, or purified DHA only were administered over 6 weeks:
In this group of 56 overweight men with normal starting blood pressures, only DHA reduced systolic BP by 5.8 mmHg, diastolic by 3.3 mmHg.
While each omega-3 fatty acid has important effects, it may be DHA that has an outsized benefit. So how can you get more DHA? Well, this observation from Schuchardt et al is important:
DHA in the triglyceride and phospholipid forms are 3-fold better absorbed, as compared to the ethyl ester form (compared by area-under-the-curve). In other words, fish oil that has been reconstituted to the naturally-occurring triglyceride form (i.e., the form found in fresh fish) provides 3-fold greater blood levels of DHA than the more common ethyl ester form found in most capsules. (The phospholipid form of DHA found in krill is also well-absorbed, but occurs in such small quantities that it is not a practical means of obtaining omega-3 fatty acids, putting aside the astaxanthin issue.)
So if the superior health effects of DHA are desired in a form that is absorbed, the ideal way to do this is either to eat fish or to supplement fish oil in the triglyceride, not ethyl ester, form. The most common and popular forms of fish oil sold are ethyl esters, including Sam's Club Triple-Strength, Costco, Nature Made, Nature's Bounty, as well as prescription Lovaza. (That's right: prescription fish oil, from this and several other perspectives, is an inferior product.)
What sources of triglyceride fish oil with greater DHA content/absorption are available to us? My favorites are, in this order:
Ascenta NutraSea CEO and founder, Marc St. Onge, is a friend. Having visited his production facility in Nova Scotia, I was impressed with the meticulous methods of preparation. At every step of the way, every effort was made to limit any potential oxidation, including packaging in a vacuum environment. The Ascenta line of triglyceride fish oils are also richer in DHA content. Their NutraSea High DHA liquid, for instance, contains 500 mg EPA and 1000 mg DHA per teaspoon, a 1:2 EPA:DHA ratio, rather than the more typical 3:2 EPA:DHA ratio of ethyl ester forms.
Pharmax (now Seroyal) also has a fine product with a 1.4:1 EPA:DHA ratio.
Nordic Naturals has a fine liquid triglyceride product, though it is 2:1 EPA:DHA.
