Table 2 Characteristics of studies on fish consumption and metabolic syndrome (MetS), organized by study design (intervention, prospective, cross-sectional)

Ramel et al., 2009[10]

Iceland RCT, part of SEAFOODplus YOUNG study 8w parallel intervention

Investigate whether cod consumption increases weight loss and CVD risk factors

n = 126, 20–40 y, overweight healthy, no gender distribution given

Energy-restricted diets (−30%), identical macronutrient composition, different amounts of cod (control group: no seafood, group 1: 150 g cod 3x/w, group 2: 150 g cod 5x/w)

In linear model with waist (baseline anthropometric measure, gender, diet group), and with blood variables (baseline anthropometric measure, weight loss, gender, diet group)

No association

Baik et al., 2010[11]

Korea 3 y follow up Korean Genome Epidemiology Study

Investigate effect of fish and n-3 fatty acid intake on incidence of MetS

n = 3504, 40–69 y 52% men, free of MetS and CVD at baseline

FFQ Average fish intake was grouped (<1/week, 1-4/week, 5-6/week and daily)

Age, BMI, income, occupation, marital status, education, smoking, alcohol, physical activity, dietary intake (energy, fat, fibre, red meat, dairy products, sweetened carbonated beverage, multivitamin), health (diabetes, hypertension, menopausal status, postmenopausal hormone use)

Men: Average daily intake of fish (40–70 g) reduced the risk of having MetS, compared with eating fish less than once a week OR 0.43 (0.23-0.83) Women: No associations

Kouki et al., 2011[12]

Finland Cross-sectional, DR’s EXTRAStudy

Studie associations between food items and nutrients versus the risk of having MetS

n = 1 334, 57–78 y 50% men Representative population sample

4-day food record Consumption of fish divided into tertiles (<18.5, 18.5–59.5, (>59.5 g/day)

a, Age, alcohol consumption, smoking b, Further for education, VO₂max

Men: the middle and highest tertile had almost half the risk of having MetS, compared to lowest tertile. a, t2: 0.51 (0.33–0.77) t3: 0.53 (0.35–0.81)b, t2: 0.52 (0.32–0.83) t3: 0.63 (0.40–1.00)Women: No association

Lai et al., 2013[13]

Cross-sectional National Heart, Lung, and Blood Institute Family Heart Study

Assess association between dietary omega-3 fatty acids and MetS prevalence

n = 4941, mean age (SD) 52.1 (13.9) y 46% men

FFQ (fish consumption classified as 0, 1, 2, ≥3 servings/ week)

Age, gender, race, alcohol intake, smoking, exercise, TV watching, energy intake, multivitamin use, fruits/vegetables intake, fibre intake, risk group

No association

Pasalic et al. 2011[14]

Croatia Cross-sectional

Investigate prevalence of MetS, and influence of lifestyle habits between continental and Mediterranean–Adriatic centres

n = 320, 70–90 y, 44% men

FFQ Consumption of fish grouped into never/rarely or monthly

Centres

No association

Ruidavets et al., 2007[15]

France Cross-sectional

Analyse relation between food groups and frequency of IRS

n = 912, 100% men 45–64 years randomly selected

3-day food record fish consumption divided into tertiles

Age, centre, physical activity, education, smoking habits, alcohol consumption, drugs (hypertension, dyslipidaemia), energy intake (without alcohol), dieting, and diet quality index

A negative association between fish intake and prevalence of MetS OR 0.57 (0.38-0.86), when comparing highest tertile to lowest

Zaribaf et al., 2014[16]

Iran Cross-sectional

Association between fish consumption and metabolic syndrome and its components

n = 420, 100% women, >30 y

FFQ fish consumption divided into tertiles

Age, energy intake, physical activity, socioeconomic status, medication use, marital, menopausal status, dietary intake (red meat, grains, fruits, vegetables, legume, nuts, dairy products, fibre, oils), BMI

Individuals in the highest tertile of fish intake were less likely to have MetS, compared to those in the lowest tertile OR 0.04 (0.004–0.61)