Monday,21 February,2011 10:26:40
The constant misuse and misunderstanding of science as it pertains to aquaculture is not only simply too bad but in many respects it is deplorable. The FDA recently pronounced that we should be eating more seafood than we are. Regular consumption of seafood should be part of a healthy well balanced diet. In countries where widespread consumption of seafood is the norm, there is strong evidence to support the practice as being healthful.
There are few that would disagree that this is not true as the science clearly supports that the benefits from consuming seafood far outweigh any potential negatives that have been occasionally associated with particular types of seafood. This is not to say that there are not potential problems with any food. Whether it is mercury in high niche marine carnivores or the dark brown coating on a grilled hamburger, eating food will always carry some risk.
As the internet has increasingly become a part of our lives, I, like many others, have focused much less effort on getting my news from the printed word and more from electronic sources. This is facilitated by Wi-Fi and an iPad and I often spend the first few moments of my day wandering through various news providers’ web sources to see what is happening in the world today.
Recently, I ran across a health-oriented website that listed the “10 best foods for your heart”. Having reached the time in my life where I typically think about issues such as this before the fork enters my mouth, I visited the website. The first item was oatmeal. This certainly made sense, enough so that I clicked onto the next item. The second item was salmon. Salmon is known to be high in essential fatty acids and this certainly made sense as well. Then I noted that they quoted the dogmatic misrepresentation that farmed salmon is not a suitable choice as farm-raised fish may be packed with insecticides, pesticides and heavy metals.
As soon as one sees statements like this, one should wonder how such a broad generalization could be true. Can all farmed salmon be bad while only wild salmon is good? A thorough review of what has been published on this says otherwise. Not all science is good science and not all scientists who publish articles in peer reviewed journals are non-biased. Sorting the good from the bad is not an easy task and requires an understanding of the complexities of the science and analytical methodologies involved that few of us have. We have to rely on a common consensus and many look to various organizations, some of whom have clear anti-aquaculture biases, for meaningful interpretation.
As with many things in life, we are really dealing with shades of gray. Some farmed salmon will have levels of contaminants in them, the excessive consumption of which (whatever this means) will possibly increase the potential health risks beyond purported benefits. There is no doubt that the same thing can be said of some wild sources as well. As the point of this blog is not to review what we know about this, I will not cite specifics. I would be glad to refer any questions to the sources that I have.
The point in all of this is that making broad generalizations that all farmed salmon is not good for you and that all wild salmon is good for you is polarizing remarks. They are simply not true and not supported by any reputable science. There is data to support the claim that some sources have higher levels of some types of chemical pollutants (for lack of a more appropriate term) in them than others. We only see what we look for and often what we find is universally labeled as bad. In the case of salmon, it has been observed that diet composition has a significant impact on the levels of these “bad actors”. Salmon that consume aquaculture feeds high in marine oils that have been contaminated with toxins will have higher levels of toxins in them. Wild salmon that eat wild feeds that have originated in areas where environmental levels of certain toxins are elevated will also have higher tissue levels of toxic materials of concern.
Typically the focus is on compounds such as PCBs (Poly chlorinated biphenyls, a class of environmentally persistent organochlorines that are widely distributed in the human food chain), pesticides that also bio-accumulate as well as certain types of heavy metals. Globally the overall level of PCBs in foods has dropped considerably in the last decade and there are signs that it will continue to do so. Levels in farmed salmon have dropped as well, primarily as a result of progressive feeding strategies that lessen the use of marine oils that heretofore were sources of PCBs. This has also impacted the presence of other compounds that most of wish were not in any food we ate.
While workers often report risk in terms of an increased risk of cancers these are at the very best controversial calculations and cannot take into account individual life styles, genetic and cultural factors and the impact of overall carcinogen loads. The mere fact that a substance is purported to cause cancer at some level does not mean that it will always cause cancer or for that matter that it actually will in human beings. It is a common scare tactic to label something as a carcinogen and tell everyone how bad it is to eat.
Carcinogens are ubiquitous in the environment and there is virtually no way one can eat anything without being exposed. In fact, the vast majority of them are naturally occurring substances. Establishing carcinogenicity is typically done with very high doses. If a compound is found to cause cancer in lab animals at high dosages, it does not mean that a much lower level will also cause cancer. The individual risk is calculated using statistical manipulations.
They say that the odds of any one of us dying in a motor vehicle accident in our lives is 1:87 yet when questionable science methodology states that eating something will increase your risk of getting cancer by 1:100000 this causes alarm and is cited as justification for labeling all farmed fish as bad to eat? Since the odds of one getting cancer whether you eat these things or not is widely stated as a one in seven risk, if this risk is actually real then this additional risk is negligible. Eating farmed salmon, even if it does contain low levels of purported carcinogens or toxins is not likely to cause you any more harm than eating the wild equivalent with slightly lower (or in some cases higher) levels of these compounds.
These scare tactics are irresponsible and simply do not belong as any part of a discussion about the relative health merits of consuming certain kinds of seafood. The benefits that are derived by the consumption of the HUFAs present in the flesh of salmon, whether farmed or wild, far outweigh any risks of getting cancer from levels of compounds that are in reality far below any legal action level. So the next time you read something like this, think about it. The internet can be a great resource and a little bit of research can go a long way towards sorting out whether statements have a great likelihood of being true or are more than likely convenient exaggerations.
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