mardi 9 juin 2020

Fishes recommended during pregnancy, salmon and others

https://www.nordicnaturals.com/healthy-science/dha-and-pregnancy/



Table 1

Fish Consumption During Pregnancy
Fish to Consume*Fish to Avoid
ShrimpShark
SalmonSwordfish
PollockKing mackerel
CatfishTilefish
Scallops
Sardines
Light tuna
*Have less than 0.05 ppb of mercury per 6-oz serving, except light tuna, which has < 0.12 µg/g.15

Use caution for fish caught in local rivers and streams that may have high mercury content; check with local authorities before consuming fish from these waters.

This recommendation is about mercury content.

Coletta JM, Bell SJ, Roman AS. Omega-3 Fatty acids and pregnancy. Rev Obstet Gynecol. 2010;3(4):163‐171.

Another document gives us the mercury content. it is from the USA (FDA) because there no resources on this matter from the EU...
https://www.fda.gov/food/metals-and-your-food/mercury-levels-commercial-fish-and-shellfish-1990-2012
In a paper published in 2015 (https://www.researchgate.net/publication/268038456_Contaminant_levels_in_Norwegian_farmed_Atlantic_salmon_Salmo_salar_in_the_13-year_period_from_1999_to_2011) it seems that that the xenobiotic content of farmed salmon in Norway is decreasing. Unfortunately, they didn't measure in the same area the xenobiotic content of wild salmon.
Finally, the FDA releases all the results of mercury measures in fishes, a true example of transparency.
https://www.fda.gov/media/101237/download

In this setting, it is difficult to find this same information in the EU, so news media fall short of evidence and speculated about the studies of the association of risks which are observational studies completely disqualified (https://www.nouvelobs.com/rue89/rue89-planete/20130619.RUE7117/la-norvege-reconnait-que-son-saumon-peut-etre-dangereux-pour-la-sante.html?fbclid=IwAR3L92KoRXM0mq6vdHRiCTxO-gv01MBumjcbvhIRO49IyMLFScquWu3i6iw). 

In this RCT the fat content of salmon fillets and the blood profiles of cardiac patients was studied and the results are stunning. Farmed salmon should be fed with fishes or fish oil in order to improve the lipid and inflammatory profile of cardiac patients. This study should also be used for pregnant women in order to assess the improvement of blood DHA which is important for the fetus.
2/ Xenobiotics and especially POPs must be monitored and maintained at a very low level in meat, but significant effect in humans is not backed by evidence
There is no solid evidence of significant effect in humans at the concentrations we observed and at the consumption level of farmed salmon in European populations. Studies like this one (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0025170#pone.0025170.s006) are of poor value as it is by feeding mice with a very high-fat diet containing salmon during 8 weeks that a difference in insulin resistance is observed... Those mice are known to develop a T2D when fed with high-fat diet (Burcelin M, Crivelli V, Dacosta A, Roy-Tirelli A, Thorens B (2002) Heterogeneous metabolic adaptation of C57BL/6J mice to high-fat diet. Am J Physio Endocrinol Metab 282: E834–E842.) so this is a huge bias in the model...
In this review (http://archive.foundationalmedicinereview.com/publications/16/4/301.pdf) the author reported only association studies and correlations which are of no value as biases are obvious and numerous. 
3/ Farmed or wild? Organic or conventional?
Due to regulations and strong improvement control of marine water and feeding process and products, the content in POP in farmed salmon is lower than wild ones (https://www.sciencedirect.com/science/article/pii/S0013935116311811?via%3Dihub). However, the ratio of W3/W6 is lower in farmed salmon. So you have to make a trade-off between those data.
4/ Finally a RCT about POP and insulin resistance in men
"This randomized controlled clinical trial found no change in circulating concentrations of 15 POPs during 6 months of high dietary intakes of fatty fish compared to avoidance of fatty fish in the diet among persons at risk of cardiometabolic disorders. In addition to comparison with a control group avoiding fatty fish, we included a group consuming nuts and avoiding fatty fish. Likewise no differences were found between the group consuming fatty fish compared to nuts group (data not shown). Cardiometabolic risk markers did not change in the groups consuming fatty fish or nuts compared to the group asked to avoid both food groups, with the exception of concentrations of HDL-cholesterol that increased in the group consuming fatty fish."

In this setting, I recommend wild pacific salmon or farmed salmon fed with fishes or fish oil (check the content in DHA and the W3/W6 ratio). Organic farmed salmon has not at this time produce significant evidence of superiority on conventional farmed salmon. Check the content of the meat on the label.

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