Background and aim: Serum levels of soluble cellular adhesion molecules (CAMs) and blood lipid parameters have been used as markers of inflammatory processes associated with cardiovascular disease (CVD) events. The present study evaluated the effects of the intake of n-3 polyunsaturated fatty acids (PUFAs) in fish and fish oil within energy-restricted diets, on soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular adhesion molecule-1 (sVCAM-1). Methods and results: Two hundred and seventy-five healthy European subjects aged between 20 and 40 years, were randomized to one of four hypocaloric dietary groups: control (sunflower oil capsules, no seafood), lean fish (3 × 150 g portions of cod/week), fatty fish (3 × 150 g portions of salmon/week), fish oil ((docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA) capsules, no seafood)). Diets rich in lean fish significantly decreased ICAM-1 levels, around 5% from baseline to endpoint (p < 0.05), and had no effect on VCAM-1 levels. No significant differences were observed in sICAM-1 levels after the intervention with fatty fish or fish oils. On the other hand, these two seafood based diets were responsible for a significant increase of VCAM-1 levels [fatty fish; 16.1% and fish oil; 21.9%] respectively (p < 0.05). Conclusions: CAMs as inflammatory biomarkers in young and healthy subjects are not conclusive for the evaluation of CVD risk. Hypocaloric fish diets had a different effect on CAMs, being lean fish responsible for the highest decrease in ICAM-1. On the other hand, VCAM-1 results allow speculation that a low dose of n-3 PUFA may be anti-inflammatory contrarily to a high dose which can have a pro-inflammatory effect. CAMs mechanism is complex and affected by multiple factors such as lifestyle, gender, and n-3 dose and source.
The study was a randomized 8-week intervention trial consisting on four hypo-energetic diets carried out in three European countries: Iceland, Spain and Ireland. The study is part of a large multicenter study, funded by the European Union: SEAFOODplus – A better life with seafood (see http://www.seafoodplus.org ). SEAFOODplus-YOUNG is a project in Pillar 1 of SEAFOODplus. This randomized intervention trial planned to recruit 320 subjects (140 from Iceland, 120 from Spain and 60 from Ireland) to allow detection of approximately 1 kg difference in weight loss between treatment groups, assuming a standard deviation (SD) of 3 kg, a significant p-value of 0.05 and a statistical power of 0.80.
The YOUNG study (co-ordinator Prof. Inga Thorsdottir) is part of the SEAFOODplus Integrated Project (co-ordinator Prof. Torger Børresen) which is funded by the EC through the 6th Framework Programme Contract No FOOD-CT-2004-506359.