Health effects of lean fish consumption in overweight and obese young adults following an energy-restricted diet for eight weeks

In the cross-European study SEAFOODplus YOUNG it was recently shown that consumption of lean fish increases weight loss in men and has other positive health effects. The aims of this thesis were to investigate whether lean fish consumption increases weight loss and improves cardiovascular risk factors in a dose-dependent manner during an eight-week energy restriction in young overweight or mildly obese healthy adults. A total of 126 Icelandic individuals were grouped into three isocaloric diets, energyrestricted by 30%, which consisted of different amounts of cod; diet group 1 (control group)receiving no seafood, diet group 2 receiving 150 g cod three times a week and diet group 3 receiving 150 g cod five times a week. All subjects were 20-40 years of age and had a BMI of 27.5-32.5 kg/m2. Participants followed a detailed individual-based meal plan and no changes were made in their physical activity level. Anthropometric measurements and cardiovascular risk factors were assessed at baseline and endpoint. One hundred subjects completed the trial. During the eight-week trial, body weight decreased on average by 5.0 kg and significant reductions were also seen in other anthropometric measurements. According to multivariate analysis weight loss was 1.7 kg greater among subjects consuming the highest amount of cod compared to the control group. Trend analysis supported a dose-response relationship between cod consumption and weight loss, although these effects were mainly seen in women. Systolic and diastolic blood pressure, serum triglycerides and insulin concentration also decreased during the intervention and the prevalence of the metabolic syndrome dropped from 29% to 21%. Changes of other measured cardiovascular risk factors were similar between the diet groups and mainly thought to be attributed to weight loss and not cod consumption. The present study indicates weight loss effects of lean fish consumption in a dosedependent manner in young overweight or mildly obese adults, especially women, although further studies are needed on this mechanism.

Samevrópska rannsóknin SEAFOODplus YOUNG sýndi nýverið fram á að neysla magurs fisks eykur þyngdartap hjá karlmönnum auk þess að hafa ýmis önnur jákvæð heilsufarsleg áhrif. Markmið þessarar ritgerðar var að kanna hvort skammtaáhrif séu af neyslu magurs fisks, sem hluti af orkuskertu átta vikna mataræði, á þyngdartap og áhættuþætti hjarta- og æðasjúkdóma meðal ungra heilbrigðra fullorðinna í ofþyngd eða vægri offitu. Í heildina var 126 íslenskum einstaklingum skipt niður í þrjá rannsóknarhópa sem innihéldu 30% orkuskerðingu en sama orkumagn. Rannsóknarhóparnir samanstóðu af mismiklu magni þorsks; rannsóknarhópur 1 (viðmiðunarhópur) innihélt enga fiskneyslu, rannsóknarhópur 2 innihélt 150 g þorsk þrisvar í viku og rannsóknarhópur 3 innihélt 150 g þorsk fimm sinnum í viku. Allir þátttakendur voru á aldrinum 20-40 ára og með líkamsþyngdarstuðul á bilinu 27.5-32.5 kg/m2. Þátttakendur fylgdu ítarlegum einstaklingsmiðuðum matseðli en engar breytingar voru gerðar á hreyfingu þeirra. Líkamsmál og áhættuþættir hjarta- og æðasjúkdóma voru metin í upphafi og lok rannsóknar. Hundrað þátttakendur kláruðu íhlutunina. Á þessum átta vikum höfðu þátttakendur að meðaltali lést um 5.0 kg auk þess sem marktæk minnkun varð á öðrum líkamsmálum. Samkvæmt fjölþátta greiningu léttust þeir þátttakendur sem neyttu mesta magn þorsks um 1.7 kg meira en viðmiðunarhópurinn. Skammtaáhrif reyndust vera til staðar, þ.e. aukin fiskneysla leiddi til meira þyngdartaps, þó svo þessara áhrifa hafi aðallega gætt meðal kvenna. Slag- og hlébils blóðþrýstingur, styrkur þríglýseríða og insúlínstyrkur lækkuðu einnig meðan á rannsókninni stóð og tíðni efnaskiptavillu lækkaði úr 29% í 21%. Breytingar á öðrum blóðgildum voru svipaðar milli rannsóknarhópa og voru aðallega taldar vera vegna þyngdartaps en ekki þorsksneyslu. Núverandi rannsókn gefur til kynna skammtaáhrif af neyslu magurs fisks á þyngdartap meðal ungra fullorðinna í ofþyngd eða vægri offitu, sérstaklega kvenna, en þörf er á frekari rannsóknum á þessu ferli.