|Image 1: Farmed Atlantic salmon - raised with & fried in soy *yummy*|
We are what that what we eat ate!
In a soon to be published study in the British Journal of Nutrition, Anita R. Alvheim and her colleagues from the National Institute of Nutrition and Seafood Research, the Department of Biomedicine at the University of Bergen in Norway, the National Institute on Alcohol Abuse and Alcoholism in Rockville, USA, and the Department of Biology at the University of Copenhagen in Denmark, report which astonishing (or should I say frightening?) downstream effects it can have when the fish farmer who supplies your local fish monger with salmon wants to save a couple of bucks and replaces the fish oil in the diet of his farm-raised Atlantic salmon with some cheap (and hip / at least among vegans ;-) soybean oil.
|Table 1: Fatty acid composition of rodent chow (top) and change in fa content of salmon due to soy oil feeding (rel. fish oil fed salmon, bottom; Alvheim. 2012)|
As the data in figure 1 goes to show the rodents on the "soy-salmon" diet had a significantly elevated hepatic alpha linoleic acid and arachidonic acid (AA) content in the hepatic phospholipids. After 9 weeks on the diet, there was a trend towards increased body weight gains that reached statistical significance in week 15 - and that in the absence of statistically significant differences in energy intake.
|Figure 1: Linoleic acid, Arachidonic acid and Arachidonoylglycerol (endocannaboid) content of liver phospholipids (left, data expressed relative to fish oil diet group), body weight development (right; Alvheim. 2012)|
|Figure 2: I must admit I did not check if AP got the data in this chart right, but if they did, the increase in AA and AA-related endocannaboids is only part of the problem and you better stick to grass-fed beef if you can't afford wild salmon.|
With the study at hand, Alvheim et al. show pretty conclusively that the effect of certain foods, specifically oils, can be "handed down" in the food chain an effect that is hitherto largely ignored by scientists and nutritionists. In conjunction with reports that show that the DHA and EPA content of Atlantic salmon is already on the decline, while the linolic acid content has increased from 1.1 g/100 g in 2005 to 1.6 g/100 g in 2010 (NIFES. 2011), this raises the question of whether salmon, which is still considered to be the go-to protein and fat source for health-conscious customers, has not already been turned into another Frankenfood and puts another emphasis on the importance of knowing not just what you eat, but also what whatever you eat ate or grew on... but the latter is, I guess a topic for another blogpost ;-)
- Alvheim AR, Torstensen BE, Lin YH, Lillefosse HH, Lock EJ, Madsen L, Hibbeln JR, Malde MK. Dietary linoleic acid elevates endogenous 2-arachidonoylglycerol and anandamide in Atlantic salmon (Salmo salar L.) and mice, and induces weight gain and inflammation in mice. Br J Nutr. 2012 Aug 10:1-10.
- Blasbalg TL, Hibbeln JR, Ramsden CE, Majchrzak SF, Rawlings RR. Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century. Am J Clin Nutr. 2011 May;93(5):950-62. Epub 2011 Mar 2.
- Bremer AA, Devaraj S, Afify A, Jialal I. Adipose tissue dysregulation in patients with metabolic syndrome. J Clin Endocrinol Metab. 2011 Nov;96(11):E1782-8. Epub 2011 Aug 24.
- Massiera F, Saint-Marc P, Seydoux J, Murata T, Kobayashi T, Narumiya S, Guesnet P, Amri EZ, Negrel R, Ailhaud G. Arachidonic acid and prostacyclin signaling promote adipose tissue development: a human health concern? J Lipid Res. 2003 Feb;44(2):271-9.
- NIFES. National Institute of Nutrition and Seafood Research. Research on nutrition;
feed for fish and fish as food. < www.nifes.no/sjomatdata > retrieved Aug 14, 2012.