Replacing red and processed meat with lean or fatty fish and all-cause and cause-specific mortality in Norwegian women. The Norwegian Women and Cancer Study (NOWAC): a prospective cohort study

Nordic Nutrition Recommendations recommend reducing red and processed meat and increasing fish consumption, but the impact of this replacement on mortality is understudied. This study investigated the replacement of red and processed meat with fish in relation to mortality. Of 83 304 women in the Norwegian Women and Cancer Study (NOWAC) study, 9420 died during a median of 21·0 years of follow-up. The hazard ratios (HR) for mortality were estimated using Cox proportional hazards regression with analyses stratified on red and processed meat intake due to non-linearity. Higher processed meat (> 30 g/d), red and processed meat (> 50 g/d), and fatty fish consumption were associated with higher mortality, while red meat and lean fish consumption were neutral or beneficial. Among women with higher processed meat intake (> 30 g/d), replacing 20 g/d with lean fish was associated with lower all-cause (HR 0·92, 95 % CI 0·89, 0·96), cancer (HR 0·92, 95 % CI 0·88, 0·97) and CVD mortality (HR 0·82, 95 % CI 0·74, 0·90), while replacing with fatty fish was associated with lower CVD mortality (HR 0·87, 95 % CI 0·77, 0·97), but not with all-cause or cancer mortality. Replacing processed meat with fish among women with lower processed meat intake (≤ 30 g/d) or replacing red meat with fish was not associated with mortality. Replacing processed meat with lean or fatty fish may lower the risk of premature deaths in Norwegian women, but only in women with high intake of processed meat. These findings suggest that interventions to reduce processed meat intake should target high consumers.

Maximizing cardiovascular benefits of fish consumption within the One Health approach: Should current recommendations be revised?

AIMS

Current dietary recommendations on fish consumption for cardiovascular disease (CVD) prevention put somewhat vague emphasis on fatty fish, mainly driven by evidence on the cardioprotective effects of n-3 PUFAs. Recent data on the consumption of different types of fish in relation to hard cardiovascular endpoints suggests that fatty but not lean fish can contribute to CVD prevention. This considered, we aimed at evaluating, by an environmental perspective, fish consumption limited to the fatty type - in appropriate amounts for optimizing CVD prevention - within the European context.

DATA SYNTHESIS

Starting from the current average intake of total fish by the European population (i.e., 2 servings/week of fatty plus lean fish), we show that the shift towards the consumption of 2 servings/week of solely fatty fish - appropriate for optimizing CVD prevention - would allow a 32% saving of greenhouse gas (GHG) emissions related to fish consumption. This is due to the lower environmental impact of fatty fish globally considered, compared to lean fish. However, since the carbon footprint of different fatty fish species can vary significantly - with small blue fish (e.g., anchovies, sardines, herrings) in the lowest range, we estimated that GHG emissions due to fish consumption in Europe could be reduced by 82% by focusing on small blue fish consumption.

CONCLUSIONS

Consumption of 2 servings/week of small blue fish could represent a feasible and effective choice among the functional dietary strategies available to achieve the maximal benefits for human and environmental health.

Effect of fatty fish or nut consumption on concentrations of persistent organic pollutants in overweight or obese men and women: A randomized controlled clinical trial

BACKGROUND AND AIMS

While excess energy intake and physical inactivity constitute the obvious causes of body fat accumulation, persistent organic pollutants (POPs) are novel factors that have been linked to cardiometabolic disorders. Major sources of POPs are animal fats including fatty fish. Given the putative protective effects of fish on cardiovascular disease, we explored whether high consumption of fatty fish increased serum concentrations of POPs.

METHODS AND RESULTS

Men and women aged 35-70 years with body mass index between 25 and 38 kg/m² and at least 1 cardiometabolic component were randomized to high intakes of fatty fish (mostly farmed salmon, ∼630 g/week; n = 45), high intakes of nuts (∼200 g/week; n = 42) or a control group following their usual diet but restricting fatty fish and nuts for 6 months (n = 44). Concentrations of 15 POPs (5 organochlorinated compounds, 2 dioxin-like polychlorinated biphenyls and 8 non-dioxin-like polychlorinated biphenyls) and cardiometabolic risk factors were measured at baseline and end of the study. Results showed that changes in concentrations of individual and classes of POPs did not differ between the dietary groups and controls (p > 0.05). Among cardiometabolic risk factors HDL-cholesterol increased in the fatty fish group compared to controls (+0.10 mmol/L, CI (0.05-0.20); p = 0.005) while no changes were observed in the group consuming nuts.

CONCLUSION

Fatty fish consumption for 6 months did not increase the serum concentrations of POPs in individuals with overweight or obesity and metabolic risk. While this finding appears reassuring regarding short-term intakes of farmed salmon, long term variations in POPs in adipose stores require further study.

Effect of Weight Reduction Diets Containing Fish, Walnut or Fish plus Walnut on Cardiovascular Risk Factors in Overweight and Obese Women

BACKGROUND

This randomized controlled trial compares the effects of walnuts, fish and the combination of the two on cardiovascular risk factors among overweight or obese females who were losing their weight.

METHODS

Ninety-nine overweight and obese women were randomized to 3 weight-reducing diets: fish (300 g/week), walnut (18 walnuts/per week) or fish + walnut (150 g fish and 9 walnuts /week) for 12 weeks. Anthropometric indices, systolic & diastolic blood pressure, fasting blood glucose, inflammatory markers, serum lipids and coagulating factors were measured.

RESULTS

The reduction in systolic blood pressure (SBP) (-5.0 ± 0.3 mm Hg, P = 0.01), fasting blood glucose (FBG) (-12.4 ± 1.9 mg/ dL, P = 0.001), low-density lipoprotein (LDL) (-6.2 ± 1.3 mg/dL, P = 0.03), high-sensitivity C-reactive protein (CRP) (-0.51 ± 0.08 mg/L, P < 0.001), D-dimer (-0.45 ± 0.07 mg/dL, P < 0.001), fibrinogen (-22.4± 4.5 mg/dL, P < 0.001), alanine aminotransferase (ALT) (-6.4 ± 0.9 mg/dL, P < 0.001), aspartate aminotransferase (AST) (-6.3 ± 0.9 IU/L, P = 0.01), tumor necrosis factor-alpha (TNF-α) (-0.08 ± 0.02 ng/mL, P = 0.01), interleukin 6 (IL-6) (-1.6 ± 0.1 ng/mL, P < 0.001) and increase in high-density lipoprotein (HDL) (3.6 ± 0.2 mg/dL, P < 0.001) were significantly higher in the group randomized to the fish + walnut diet compared with either the fish group or the walnut group. A significant decrease was seen in TG (-7.3 ± 1.1 mg/dL, P < 0.001) and diastolic blood pressure (DBP) (-2.0 ± 0.06 mm Hg, P = 0.01) levels in the fish group and the walnut group compared with the fish + walnut group. The change in other risk factors was not different among groups.

CONCLUSION

The present study shows that the combination of marine and plant omega-3 together is more effective on blood pressure levels, fasting blood glucose, inflammatory markers, serum lipids and coagulating factors than the fish or walnut in isolation.

Vitamin D status in preschool children and its relations to vitamin D sources and body mass index-Fish Intervention Studies-KIDS (FINS-KIDS)

OBJECTIVES

The aims of this study were to determine vitamin D status (serum 25-hydroxyvitamin D₃ [s-25(OH)D₃]) and examine possible associations between vitamin D status and vitamin D-rich dietary sources, sun exposure, and body mass index in preschool children ages 4 to 6 y.

METHODS

This is a cross-sectional study based on baseline data (collected in January-February 2015) from the two-armed randomized controlled trial Fish Intervention Studies-KIDS (FINS-KIDS) conducted in Bergen, Norway. S-25(OH)D₃ concentration was determined by liquid chromatography-tandem mass spectrometry. Information regarding habitual dietary intake, recent sun vacations, and body mass index were assessed with questionnaires answered by the children's caregivers.

RESULTS

The children (n = 212) had a mean (standard deviation) s-25(OH)D₃ of 60.7 (13.8) nmol/L; 18.9% had s-25(OH)D₃ ≤50 nmol/L. In logistic regression models, non-overweight versus overweight status was inversely associated with s-25(OH)D₃ ≤50 nmol/L (odds ratio: 0.41; 95% confidence interval, 0.18-0.95; P = 0.037). Non-sun versus sun vacations were associated with s-25(OH)D₃ ≤75 nmol/L (odds ratio: 5.33; 95% confidence interval, 1.93-14.77; P = 0.001).

CONCLUSIONS

The majority of the preschool children (81%) had s-25(OH)D₃ >50 nmol/L. Children with overweight status had an increased risk of s-25(OH)D₃ ≤50 nmol/L, and children who had not been on sun vacations were at a greater risk of s-25(OH)D₃ ≤75 nmol/L.

The effect of Atlantic salmon consumption on the cognitive performance of preschool children - A randomized controlled trial

BACKGROUND AND AIMS

Long chain polyunsaturated n-3 fatty acids (LC-PUFA) are of functional and structural importance for brain development. Observational studies have shown positive relations between fatty fish consumption and cognitive performance in children, but Results from intervention studies using supplementary n-3 LC-PUFA are conflicting. Salmon is a good source of n-3 LC-PUFA, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We tested the hypothesis that an increased dietary salmon intake results in better cognitive outcomes than a meat based diet.

METHODS

Children (n = 205, age 4-6 years) in this trial were individually randomized to eating meals containing farmed Atlantic salmon or meat three times weekly for 16 weeks. Pre- and post-intervention a cognitive test (Wechsler Preschool and Primary Scale of Intelligence, 3rd edition, WPPSI-III) and a fine-motor coordination test (Nine Hole Peg Test, 9-HPT) were performed. Biochemical analyses included glycerophospholipid fatty acid profiles in plasma and cheek cells, serum 25-hydroxyvitamin D, and urinary iodine concentration. Dietary intake before and during the study were determined using food frequency questionnaires.

RESULTS

Intakes of EPA, DHA, vitamin D and iodine were higher in the salmon than the meat group, but on biomarker level only EPA and DHA increased significantly in the salmon group compared to the meat group (p < 0.001). In general linear models no significant differences between the intervention groups were found in the scale scores of the WPPSI-III tests and the 9-HPT. In analyses of the raw scores, the salmon group showed significantly better improvement in two of the eight raw scores compared to the meat group (symbol search p = 0.038, picture concepts p = 0.047).

CONCLUSIONS

Intake of farmed Atlantic salmon led to a greater increase of the raw scores of the picture concept and symbol search subtests, while in the six other subtests raw scores were not different between the groups. This might indicate a modest positive association of salmon intake with the performance of preschool children in some subtests evaluating fluid intelligence but does not suggest an influence on global IQ development.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

ClinicalTrials.gov registration number: NCT01951937.

Effects of fatty and lean fish intake on stroke risk: a meta-analysis of prospective cohort studies

BACKGROUND

Fish intake has been postulated to reduce the risk of stroke. However, whether the beneficial effect of fish are mainly linked to fat content, as a source of omega-3 polyunsaturated fatty acids, remains unclear. We conducted a meta-analysis to compare the effect of fatty and lean fish intake on stroke risk.

METHODS

We performed a literature search on four database (PubMed, Embase, Scopus, and Cochrane Library) through February 1, 2018 to identify prospective studies of fatty and lean fish in relation to stroke risk. A random-effects model was used to calculate the summary estimates.

RESULTS

We identified five prospective studies, including 7 comparisons for fatty fish intake and 5 comparisons for lean fish intake. Compared with the highest category of intake with lowest category, the summary relative risk was 0.88 [95% confidence interval (CI), 0.74-1.04] for fatty fish intake and 0.81 (95% CI, 0.67-0.99) for lean fish intake. No heterogeneity across studies and publication bias were observed.

CONCLUSION

Our findings demonstrated that fatty and lean fish intake has beneficial effects on stroke risk, especially lean fish intake. Additional prospective studies are necessary to confirm these observations.

Total and lean fish intake is positively associated with bone mineral density in older women in the community-based Hordaland Health Study

PURPOSE

Fish is a source of various nutrients beneficial for bone health, but few studies have investigated the association between bone mineral density (BMD) and fish consumption. Thus, the aim was to investigate the relationship between total fish intake and BMD and between both lean and fatty fish intake and BMD.

METHOD

These cross-sectional analyses include 4656 participants in the Hordaland Health Study, a community-based study conducted in 1997-1999. The study includes two birth cohorts of men and women from Hordaland county (Norway) born in 1950-1951 and 1925-1927. BMD was measured by dual-energy X-ray absorptiometry and dietary intake was obtained from a semi-quantitative food-frequency questionnaire.

RESULTS

The average total fish intake was 33 ± 18 g/1000 kcal and was primarily lean fish. Older women had significantly lower BMD than older men and middle-aged men and women. In older women, total and lean fish intake (50 g/1000 kcal) was significantly and positively associated with BMD also after multivariate adjustments (β-coefficient 0.018, p = 0.017 and 0.026, p = 0.021).

CONCLUSION

A high intake of fish, in particular lean fish, was positively associated with BMD in older women. No association between intake of fatty fish and BMD was found in either of the age and sex groups.

Fatty fish intake and cognitive function: FINS-KIDS, a randomized controlled trial in preschool children

BACKGROUND

Marine resources including fatty fish are important sources of n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs), which are important for brain development. To our knowledge, this is the first randomized controlled trial (RCT) investigating the impact of fatty fish on cognition in preschool children. The purpose of the trial was to investigate whether an increased intake of fatty fish compared to meat improves cognitive function in children 4-6 years old.

METHODS

The children (n = 232) in this two-armed RCT, Fish Intervention Studies-KIDS (FINS-KIDS) were recruited from 13 kindergartens in Bergen, Norway. They were randomly assigned to lunch meals with fatty fish (herring/mackerel) or meat (chicken/lamb/beef) three times a week for 16 weeks. The fish and meat were weighed before and after the meals to record the exact consumption (dietary compliance). The primary outcome was cognitive function measured by the Wechsler Preschool and Primary Scale of Intelligence, 3rd edition (WPPSI-III) and fine-motor coordination measured by the 9-Hole Peg Test (9-HPT) at pre- and post-intervention. Biological samples (blood, urine, hair), and questionnaires to the caregivers were included at both time points. Linear mixed effect models with a random intercept for kindergarten were used to analyze changes from pre- to post-intervention in the primary outcome variables.

RESULTS

There were 218 children included in the trial (105 in the fish, and 113 in the meat group). The children consumed a mean (standard deviation) of 2070 (978) g fish or 2675 (850) g meat from the study meals (p < 0.0001). The fish group had a significant increase of red blood cell n-3 LC-PUFAs. The intervention had no effect on the WPPSI-III scores (mean change total raw score; fish group 17.7, 95% confidence interval (CI) 14.8-20.7 vs meat group 17.8, 95% CI 15.0-20.6, p = 0.97) in the main analyses. In the sub-analyses, adjusting for dietary compliance, the fish group showed a higher improvement on total raw score (20.4, 95% CI 17.5-23.3) compared to the meat group (15.2, 95% CI 12.4-18.0, p = 0.0060); docosahexaenoic acid mediated this effect.

CONCLUSIONS

There was no beneficial effect of fatty fish compared to meat on cognitive functioning in the preschool children. When considering dietary compliance, we found a beneficial effect of fatty fish on cognitive scores.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02331667 December 17, 2014.

The effects of fatty fish intake on adolescents' nutritional status and associations with attention performance: results from the FINS-TEENS randomized controlled trial

Background

Adolescence involves changes in dietary habits that may induce imbalances in the intake of different nutrients. Fish is an important dietary source of omega-3 (n-3) long-chain polyunsaturated fatty acids (LCPUFAs), vitamin D, several minerals and high-quality protein. By using secondary outcomes and exploratory analyses, the aims of this paper were to evaluate if nutritional biomarkers (red blood cell fatty acids, serum (s)-25(OH)D, s-ferritin and urinary iodine concentration (UIC)) were altered during a dietary intervention, and if they mediated previously reported changes in attention performance. In addition, to examine the status of the biomarkers and explore associations between dietary pattern, biomarkers and attention performance cross-sectionally at baseline.

Methods

The Fish Intervention Studies-TEENS (FINS-TEENS) was a three-armed intervention trial, including adolescents from eight secondary schools (n = 415; age: 14–15y) in Bergen, Norway. Participants were individually randomized to receive either fish meals, meat meals or n-3 LCPUFA supplements, three times a week for a total of 12 weeks. Blood and urine samples were collected pre and post intervention and attention performance was assessed with the d2 test of attention. Analyses of covariance (ANCOVA) assessed differences between groups in changes of biomarkers and linear mixed models were applied in analyses of attention performance and biomarkers. The trial is registered in ClinicalTrials.gov (NCT02350322).

Results

At baseline, the mean omega-3 index was 5.8 ± 1.3% and deficient status were identified for s-25(OH)D (54%), s-ferritin (10%) and UIC (40%). The intervention resulted in an increase in DHA and the omega-3 index which was larger in the supplement group compared to the fish and meat group (P < 0.01), and in the fish group compared to the meat group (P < 0.01). No differences between the groups were observed for changes in 25(OH)D, s-ferritin or UIC. None of the biomarkers mediated performance in the d2 test. The intake of fatty fish and a healthy dietary pattern was associated with scores in processing speed at baseline.

Conclusions

These results show that Norwegian adolescents have insufficient status of important nutrients, which may be improved with fatty fish consumption or n-3 LCPUFA supplements. However, nutritional status was not associated with scores in the d2 test of attention.

Fatty fish intake and attention performance in 14-15 year old adolescents: FINS-TEENS - a randomized controlled trial

Background

Fatty fish is the dominant dietary source of n-3 LCPUFAs but it also contains other micronutrients considered important for brain development and function. To our knowledge, the effect of fatty fish intake on cognitive function in adolescents has not been investigated in randomized controlled trials (RCTs) previously. The aim of the present trial was to investigate whether consumption of fatty fish meals three times per week for 12 weeks could alter attention performance in adolescents compared to similar meals with meat or n-3 LCPUFA supplements.

Methods

In the Fish Intervention Studies-TEENS (FINS-TEENS), adolescents from eight secondary schools (n = 426; age: 14-15y) were individually randomized. Attention performance was assessed with the d2 test of attention. Differences between groups from pre to post intervention were assessed with linear mixed effect models and general estimates equation. The fish group was set as reference. Dietary compliance was recorded for each meal throughout the trial and controlled for in the adjusted analyses.

Results

The improvement in processing speed was significantly lower in the meat (−11.8; 95% CI: -23.3, −0.4) and supplement (−13.4; 95% CI: -24.9, −1.8) group compared to the fish group (reference). The supplement group also showed inferior improvement in total performance (−10.4; 95% CI: -20.0, −0.7) compared to the fish group (reference). The results were slightly affected when controlling for dietary compliance. Omission errors decreased in the meat group compared to the fish group (Incidence rate ratio = 0.85; 95% CI: 0.74, 0.98), but the difference disappeared when controlling for dietary compliance.

Conclusions

We observed a small beneficial effect of fatty fish, compared to meat meals and supplements on processing speed. However, these results are difficult to interpret due to low dietary compliance. This study shows that different taste preferences among participants is challenging in intervention trials with food. A prospective cohort design may be a better alternative when studying diet in the future.

Trial registration number

ClinicalTrials.gov registration number: NCT02350322.

Electronic supplementary material

The online version of this article (10.1186/s12937-017-0287-9) contains supplementary material, which is available to authorized users.

Fish intake is associated with lower cardiovascular risk in a Mediterranean population: Prospective results from the Moli-sani study

BACKGROUND AND AIMS

Fish consumption reportedly reduces the risk of heart disease, but the evidence of cardiovascular advantages associated with fish intake within Mediterranean cohorts is limited. The aim of this study was to test the association between fish intake and risk of composite coronary heart disease (CHD) and stroke in a large population-based cohort adhering to Mediterranean Diet.

METHODS AND RESULTS

Prospective analysis on 20,969 subjects free from cardiovascular disease at baseline, enrolled in the Moli-sani study (2005-2010). Food intake was recorded by the Italian version of the EPIC food frequency questionnaire. Hazard ratios were calculated by using multivariable Cox-proportional hazard models. During a median follow-up of 4.3 years, a total of 352 events occurred (n of CHD = 287 and n of stroke = 66). After adjustment for a large panel of covariates, fish intake ≥4 times per week was associated with 40% reduced risk of composite CHD and stroke (HR = 0.60; 95%CI 0.40-0.90), and with 40% lower risk of CHD (HR = 0.60; 95%CI 0.38-0.94) as compared with subjects in the lowest category of intake (<2 times/week). A similar trend of protection was found for stroke risk although results were not significant (HR = 0.62; 95%CI 0.26-1.51). When fish types were considered, protection against the composite outcome and CHD was confined to fatty fish intake.

CONCLUSIONS

Fish intake was associated with reduced risk of composite fatal and non-fatal CHD and stroke in a general Mediterranean population. The favourable association was likely to be driven by fatty fish.

Lean fish consumption is associated with lower risk of metabolic syndrome: a Norwegian cross sectional study

Background

Fish consumption may have a role in reducing the prevalence of metabolic syndrome (MetS). The aim of this study was to identify associations between fish consumption and MetS and its components, especially regarding differences concerning consumption of fatty and lean fish.

Methods

This cross sectional study uses data from the Tromsø 6 survey (2007–08), where a sample of 12 981 adults, aged 30–87 years (47 % men) from the Norwegian general population was included. Fish consumption was assessed using food frequency questionnaires (FFQ). Blood sample assessments, anthropometric and blood pressure measurements were carried out according to standard protocols. MetS was defined using the Joint Interim Societies (JIS) definition. All tests were two-sided. Analyses were performed using IBM SPSS Statistics 22 (Pearson’s correlation, Chi-Square tests, analysis of variance (ANOVA), linear and logistic regression models).

Results

Mean age was 57.5, and the prevalence of MetS was 22.6 %. Fish consumption once a week or more was associated with lower risk of having MetS among men (OR 0.85, CI 95 % 0.74 to 0.98, P = 0.03). In the adjusted models, lean fish consumption was associated with a decreased risk of having MetS, whereas fatty fish consumption was not associated with a decreased risk of having MetS. Both an increased fatty and lean fish consumption (0–1 times per month, 2–3 times per month, 1–3 times per week, 4–6 times per week, 1–2 times per day) were associated with decreased serum triglyceride (TG), and increased high-density lipoprotein cholesterol (HDL-C).

Conclusions

Fish consumption may be associated with a lower risk of having MetS and consumption of lean fish seems to be driving the association. Further investigation is warranted to establish associations between fish consumption and MetS.

Associations between fish consumption and metabolic syndrome. A large cross-sectional study from the Norwegian Tromsø Study: Tromsø 4

BACKGROUND

Fish consumption may prevent or improve metabolic health. The aim of this study was to identify associations between fish consumption, both fatty and lean, and metabolic syndrome and its components.

METHODS

Associations between fish consumption and metabolic syndrome and its components were studied in a large sample from a Norwegian population (N = 23,907), using cross-sectional data from the Tromsø 4 survey (1994-1995). Metabolic syndrome was defined using the JIS definition, and dietary data was collected using food frequency questionnaires (FFQ). Blood samples were taken for biochemical assessments, and anthropometric and blood pressure measurements were carried out according to standard protocols.

RESULTS

In this sample from an adult population (aged 26-70 years, mean age 44 years, SD 11.69, 48 % men), a higher fish consumption (≥1/week) was associated with a healthier lipid profile with increased HDL-C and decreased TG. Participants aged 60-70 years consuming fish once a week or more had significantly lower risk of having MetS, compared to those consuming fish less than once a week (OR 0.64, CI 0.45-0.91). When investigating fatty and lean fish separately, only lean fish consumption was associated with a reduced the risk of having MetS. Participants aged 60-70 years consuming lean fish once a week or more, had lower risk of having MetS compared to those consuming lean fish less than once a week (OR 0.65, CI 0.48-0.87). No association was found for consumption of fatty fish, or for lean fish in the age groups <45 or 45-59 years.

CONCLUSIONS

These results indicates that fatty and lean fish consumption influences MetS risk differently, possibly also related to age. However, further investigation is needed to establish how various fish consumption may influence MetS and its components, particularly when stratified by fatty and lean fish.