Introducing the comment of Dr. Barnard, with the addition of more and more comments by Dr. Luciana Baroni, President of the Scientific Society of vegetarian nutrition.
Omega-3 fatty acids associated with prostate cancer risk
Thanks to a new study published in the American Journal of Epidemiology (Brasky,2011), people there now think twice before taking fish oil capsules-or eating fish. It is apparent that men with higher blood levels of DHA are at greater risk of developing prostate cancer.
The researchers examined the 3,461 participants in the Prostate Cancer Prevention Trial, a study on the prevention of prostate cancer, and found that those with the highest levels of DHA in their blood had a chance to develop an aggressive form of prostate cancer twice and a half higher than those with the lowest blood levels.
Many recent studies have shown that advertising promises of fish oil have never been kept. Specifically, it is not help heart patients, does not serve against Alzheimer's disease, not prevent depression, and, at least so far, does not make children smarter.
In 2005 a study published in the Journal of the American Medical Association (JAMA)showed how, despite the supposed anti aritmiche properties of fish oil supplementation actually with this kind of dietary supplement could increase the risk of cardiac arrhythmias in some patients (Raitt, 2005). A year later, the same magazine published a systematic review of 38 studies that have evaluated the effects of consumption of omega-3 fatty acids on cancer risk, from which it emerged that fish oils ineffective in preventing cancer (MacLean, 2006).
In the same year, also appeared in the British Medical Journal a systematic review with the same purpose, which, in keeping with the foregoing, confirmed not only that there was evidence of a protective effect of supplementation with supplements of omega-3long chain on the risk of cancer, but not even that these are able to reduce total mortality and cardiovascular events (Hooper, 2006).
Later studies confirmed the absence of a clear beneficial effect of these fatty acids on cardiovascular health: in 2009 the analysis of over 5,000 persons in the context of the Rotterdam Study led researchers to conclude that taking fish or supplements of EPA and DHA is not protective against the development of heart failure (Dijkstra, 2009). In2010 the New England Journal of Medicine reported the results of a study conducted on fewer than 5,000 patients who had already suffered myocardial infarction, from which emerged the absence of significant differences in the incidence of cardiovascular events among those who consumed omega-3 supplements and the control group who received a placebo, in addition to standard drug therapy(Kromhout, 2010).
Also, surprisingly, a study conducted by researchers from the Harvard School of Medicine has found a correlation between fish intake and supplements containing omega-3 fatty acids long-chain and type 2 diabetes. Following 195,204 adults over a period of 14-18 years, researchers showed that a higher consumption of fish and supplements of omega-3 fatty acids long-chain matched to a greater risk of developing diabetes mellitus (Kaushik, 2009).
Meanwhile, producers of fish oil have banked all their hopes on brain function. Perhaps fish oil will make you more intelligent, they thought. But last year, research in this field of application has destroyed this hope. A group of elderly 867 and was assigned, at random, a fish oil supplement containing high amounts of DHA and EPA or a placebo (a pill with no supposed active content) based on olive oil. After two years, seniors who consumed the supplements of omega-3 fatty acids long-chain did not show any added benefit, on cognitive function, compared to subjects taking olive oil (Dangour, 2010).
A subsequent study published in JAMA confirmed that omega-3 supplements (in this case, DHA) are not able to slow the progression of mental decline and brain atrophy in Alzheimer's patients (Quinn, 2010). Nor, on the other side of the spectrum of age, infants seem to get benefits. In fact, another study published in JAMA on showed that consumption of fish oil rich in DHA in pregnant women does not improve subsequent cognitive development of unborn children throughout childhood and even the incidence of postpartum depression by his mother (Makrides, 2010).
These data are then to consider fish oil as the false elixir of life of hucksters of the past. The new, yet another report that links the blood levels of DHA to prostate cancer is another reason to avoid fish and fish oil supplements.
Our body can indeed produce the fatty acids omega-3 long chain, i.e. those found in fish, starting from their natural, the precursor to alpha-linolenic acid, the only omega-3fatty acid essential, which was derived from vegetable source (flaxseed, walnuts, soy).This mechanism allows the body to regulate the amount of short-chain fatty acids longer, namely DHA and EPA, on the basis of its needs, thus avoiding having to engage with large amounts of these fats that derives from this brief comment, are, if not harmful to health, certainly ineffective and harmful to the portfolio, however, not only consumers but also of the National Health System since they are provided free of charge in the form of medication to certain categories of patients.