Habitual fish consumption and glycated haemoglobin: the EPIC-Norfolk study

Potentially Heterogeneous Cross-Sectional Associations of Seafood Consumption with Diabetes and Glycemia in Urban South Asia

Aims: In this study, we aimed to estimate cross-sectional associations of fish or shellfish consumption with diabetes and glycemia in three South Asian mega-cities. Methods: We analyzed baseline data from 2010-2011 of a cohort (n = 16,287) representing the population ≥20 years old that was neither pregnant nor on bedrest from Karachi (unweighted n = 4017), Delhi (unweighted n = 5364), and Chennai (unweighted n = 6906). Diabetes was defined as self-reported physician-diagnosed diabetes, fasting plasma glucose ≥126 mg/dL (7.0 mmol/L), or glycated hemoglobin A1c (HbA1c) ≥6.5% (48 mmol/mol). We estimated adjusted and unadjusted odds ratios for diabetes using survey estimation logistic regression for each city, and differences in glucose and HbA1c using survey estimation linear regression for each city. Adjusted models controlled for age, gender, body mass index, waist-height ratio, sedentary lifestyle, educational attainment, tobacco use, an unhealthy diet index score, income, self-reported physician diagnosis of high blood pressure, and self-reported physician diagnosis of high cholesterol. Results: The prevalence of diabetes was 26.7% (95% confidence interval: 24.8, 28.6) in Chennai, 36.7% (32.9, 40.5) in Delhi, and 24.3% (22.0, 26.6) in Karachi. Fish and shellfish were consumed more frequently in Chennai than in the other two cities. In Chennai, the adjusted odds ratio for diabetes, comparing more than weekly vs. less than weekly fish consumption, was 0.81 (0.61, 1.08); in Delhi, it was 1.18 (0.87, 1.58), and, in Karachi, it was 1.30 (0.94, 1.80). In Chennai, the adjusted odds ratio of prevalent diabetes among persons consuming shellfish more than weekly versus less than weekly was 1.08 (95% CI: 0.90, 1.30); in Delhi, it was 1.35 (0.90, 2.01), and, in Karachi, it was 1.68 (0.98, 2.86). Conclusions: Both the direction and the magnitude of association between seafood consumption and glycemia may vary by city. Further investigation into specific locally consumed seafoods and their prospective associations with incident diabetes and related pathophysiology are warranted.

Omega-3, omega-6, and total dietary polyunsaturated fat for prevention and treatment of type 2 diabetes mellitus: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To assess effects of increasing omega-3, omega-6, and total polyunsaturated fatty acids (PUFA) on diabetes diagnosis and glucose metabolism.

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

Medline, Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and trials in relevant systematic reviews.

ELIGIBILITY CRITERIA

Randomised controlled trials of at least 24 weeks' duration assessing effects of increasing α-linolenic acid, long chain omega-3, omega-6, or total PUFA, which collected data on diabetes diagnoses, fasting glucose or insulin, glycated haemoglobin (HbA_1c), and/or homoeostatic model assessment for insulin resistance (HOMA-IR).

DATA SYNTHESIS

Statistical analysis included random effects meta-analyses using relative risk and mean difference, and sensitivity analyses. Funnel plots were examined and subgrouping assessed effects of intervention type, replacement, baseline risk of diabetes and use of antidiabetes drugs, trial duration, and dose. Risk of bias was assessed with the Cochrane tool and quality of evidence with GRADE.

RESULTS

83 randomised controlled trials (mainly assessing effects of supplementary long chain omega-3) were included; 10 were at low summary risk of bias. Long chain omega-3 had little or no effect on likelihood of diagnosis of diabetes (relative risk 1.00, 95% confidence interval 0.85 to 1.17; 58 643 participants, 3.7% developed diabetes) or measures of glucose metabolism (HbA_1c mean difference -0.02%, 95% confidence interval -0.07% to 0.04%; plasma glucose 0.04, 0.02 to 0.07, mmol/L; fasting insulin 1.02, -4.34 to 6.37, pmol/L; HOMA-IR 0.06, -0.21 to 0.33). A suggestion of negative outcomes was observed when dose of supplemental long chain omega-3 was above 4.4 g/d. Effects of α-linolenic acid, omega-6, and total PUFA on diagnosis of diabetes were unclear (as the evidence was of very low quality), but little or no effect on measures of glucose metabolism was seen, except that increasing α-linolenic acid may increase fasting insulin (by about 7%). No evidence was found that the omega-3/omega-6 ratio is important for diabetes or glucose metabolism.

CONCLUSIONS

This is the most extensive systematic review of trials to date to assess effects of polyunsaturated fats on newly diagnosed diabetes and glucose metabolism, including previously unpublished data following contact with authors. Evidence suggests that increasing omega-3, omega-6, or total PUFA has little or no effect on prevention and treatment of type 2 diabetes mellitus.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017064110.

Persistent organic pollutants and biomarkers of diabetes risk in a cohort of Great Lakes sport caught fish consumers

BACKGROUND

Exposure to persistent organic pollutants (POPs) is associated with increased diabetes risk, although the mechanism of action is not well delineated.

METHODS

We investigated established diabetes biomarkers that could implicate potential mechanistic pathways, including C-reactive protein (CRP), a marker of systemic inflammation; gamma glutamyl transferase (GGT), a liver enzyme associated with oxidative stress; and adiponectin, an adipokine modulating glucose regulation and fatty acid oxidation. These biomarkers as well as hemoglobin A1c (HA1c), and POPs [polychlorinated biphenyls (PCBs), p,p-dichlorodiphenyldichloroethylene (DDE) and polybrominated diphenyl ethers (PBDEs)] were measured in a cohort of Great Lakes sport caught fish (GLSCF) consumers. We examined associations of POPs and fish consumption with HA1c and incident diabetes, and evaluated mediation and moderation by the diabetes biomarkers.

RESULTS

Odds of incident diabetes were elevated with exposure to DDE and PCBs. DDE and PCB 118 were positively, and fish meals were inversely, associated with HA1c. CRP was inversely associated with saltwater and total fish meals, particularly in persons with higher adiposity, but did not mediate the associations of fish meals with HA1c. There were few associations of POPs with adiponectin, CRP and GGT, with the exception of positive associations of PCB 118 with GGT, PBDEs with GGT in older persons, and PBDEs with adiponectin. Adiponectin, CRP and GGT did not mediate associations of DDE and PCBs with HA1c or incident diabetes. However, the association of DDE with HA1c was stronger in persons with higher CRP, GGT and BMI, and lower adiponectin, while the association of PCB 118 with HA1c was stronger in persons with higher GGT.

CONCLUSIONS

These findings suggest that adiponectin, CRP and GGT did not mediate effects of POPs on diabetes or HA1c. However, POPs may have stronger effects on blood glucose in persons at higher risk for diabetes.

Frequency of Food Consumption and Self-reported Diabetes among Adult Men and Women in India: A Large Scale Nationally Representative Cross-sectional Study

BACKGROUND

Recent studies have shown that the choice of foods and frequency of intake plays a role in diabetes prevention. We examined the association between frequency of consumption of specific food items and the occurrence of diabetes in adult Indian population.

METHODS

Cross sectional data of 99,574 women and 61,361 men aged 20-49 years who participated in India's third National Family Health Survey conducted during 2005-06 was used for this study. Association between frequency of food intake such as daily, weekly, occasionally and never, and prevalence of diabetes were estimated using multivariable logistic regression models after adjusting for body mass index, tobacco smoking, alcohol drinking, television watching and socio-economic and demographic characteristics, stratified by sex.

RESULTS

In men, weekly (OR:0.64; 95%CI:0.47-0.88) and occasional (OR:0.60; 95%CI:0.44-0.81) consumption of milk/curd, weekly (OR:0.48; 95%CI:0.27-0.87) and occasional (OR:0.52; 95%CI:0.28-0.99) consumption of pulses/beans and consumption of fruits (OR ranges from 0.33 to 0.39) was associated with a significantly lower likelihood of diabetes whereas daily (OR:0.55; 95%CI:0.34-0.88) or weekly (OR:0.56; 95%CI:0.35-0.90) pulses/beans consumption and fruits intake (OR ranges from 0.36 to 0.46) was associated with a lower likelihood of diabetes in women.

CONCLUSION

This study has confirmed findings from high income countries that diabetes among adult Indians, which is large and increasing, might be contained by regular consumption of vegetarian foods including pulses, beans, fruits and dairy products. However, this is an observational finding and uncontrolled confounding cannot be excluded as an explanation for the association. More epidemiological research with better measures of food intake and clinical measures of diabetes is needed in a developing country setting to validate the findings.

Frequency of fish intake and diabetes among adult Indians

OBJECTIVES

Recent studies have shown that the choice of foods plays a role in diabetes prevention. However, little empirical evidence on this association exists in developing countries. We aimed to examine the association between frequency of fish intake and self-reported diabetes status among adult men and women in India.

METHODS

Analysis of cross-sectional data from participants in India's third National Family Health Survey conducted during 2005-2006 was performed. Associations between fish intake, determined by frequency of consumption (daily, weekly, occasionally, and never), and self-reported diabetes were estimated using multivariable-adjusted models in 99,574 women, 56,742 men, and 39,257 couples aged 20-49 years after adjusting for frequency of consumption of other food items, body mass index (BMI) status, tobacco smoking, alcohol drinking, watching television, age, education, living standard of the household, and place of residence.

RESULTS

After adjustment for other dietary, lifestyle, and socioeconomic and demographic characteristics, odds of diabetes were 2 times higher (odds ratio [OR]: 2.02; 95% confidence interval [CI], 1.59-2.57; p < 0.0001) among those who reported consuming fish daily compared to those who never consumed fish. Weekly fish intake was also associated with a higher odds of having diabetes (OR: 1.55; 95% CI, 1.25-1.93; p < 0.0001). The adjusted effect of daily fish intake on diabetes was greater among men (OR: 2.46; 95% CI, 1.66-3.65) than among women (OR: 1.72; 95% CI, 1.26-2.33). In cross-spousal sensitivity analysis, the odds of a husband having diabetes was also associated with wife's daily/weekly consumption of fish (OR: 1.36; 95% CI, 0.92-2.01) and the odds of a wife having diabetes was also associated with husband's daily/weekly consumption of fish (OR: 1.21; 95% CI, 0.87-1.68).

CONCLUSIONS

In a large nationally representative sample of adult men and women in India, daily or weekly fish intake was positively associated with the presence of diabetes. However, this is an observational finding and uncontrolled confounding cannot be excluded as an explanation for the association. More epidemiological research with better measures of food intake and clinical measures of diabetes is needed in a developing country setting to validate the findings.

Fish intake by adolescents is related to nutrient intake but not lifestyle factors

Nutrition during adolescence influences long-term health outcomes. Consumption of fish has many health benefits, yet few studies have investigated associations between fish intake and nutrient intake and lifestyle factors in adolescents. A cross-sectional study utilizing 24-hour dietary recalls obtained by in-person interviews investigated relationships between fish intake and demographic characteristics, nutrient intake, and lifestyle factors among adolescents (mean age = 15.5 years). Height, weight, and self-administered survey data were collected from 839 high school students who took part in the 2000-2004 Hawaii Nutrition Education Needs Assessment survey. About 8.5% of the students consumed fish, based on estimated EPA (eicosapentaenoic acid) + DHA (docosahexaenoic acid) intakes. Adolescents who consumed fish had higher intake of protein, water, B vitamins, magnesium, selenium, and zinc but consumed more calories, fat, saturated fat, and sodium. Considering the school health program's potential to reach adolescents, more intensive school-based interventions can be directed to promote safe fish consumption and to encourage other positive lifestyle behaviors.

Comparison of the fatty acid composition of the serum phospholipids of controls, prediabetics and adults with type 2 diabetes

OBJECTIVE

Although abnormalities in the fatty acid composition of serum and red cell membrane phospholipids of patients with type 2 diabetes are well-documented, lacking are studies of this issue in prediabetic individuals.

MATERIALS/METHODS

For this cross-sectional study, we recruited 180 subjects (30-80 years), 56 of whom were normal with regard to glucose control (HbA1c, <5.7%), 61 who had prediabetes (HbA1c, 5.7%-6.4%) and 59 who had type 2 diabetes (HbA1c, >6.5%). Serum phospholipids were isolated and analyzed for fatty acids.

RESULTS

Most importantly, the fatty acid compositions of the controls and prediabetic subjects were not different for 19 fatty acids. However, the fatty acid profile of the phospholipids of the patients with diabetes differed from the other two groups; the 14 to 18-carbon saturated fatty acids were decreased by 12%-26% whereas the unsaturated fatty acids 16:1n-7, 18:1n-9, 18:2n-6, 20:3n-6 and 20:4n-6 were increased by 45%-64%. Of note, the docosahexaenoic acid (DHA) status of individuals in all three study groups was remarkably low compared with international values, as indicated by DHA proportions in the 1.62%-2.07% range, and there were no differences between groups. The mean melting point of the phospholipid fatty acids of the diabetic patients (32.2°C) was significantly lower (p < 0.001) than that of the prediabetic subjects (38.1°C) and the controls (39.9°C) which were not different from each other.

CONCLUSION

These observations indicate that the fatty acid changes associated with type 2 diabetes follow the onset of the disease as opposed to being a causative factor of poor glucose control and insulin insensitivity.

Association of fish and n-3 fatty acid intake with the risk of type 2 diabetes: a meta-analysis of prospective studies

Results from observational studies on the association of fish and n-3 fatty acid consumption with type 2 diabetes mellitus (T2DM) risk are conflicting. Hence, a meta-analysis was performed to investigate this association from cohort studies. A comprehensive search was then conducted to identify cohort studies on the association of fish and/or n-3 fatty acid intake with T2DM risk. In the highest v. lowest categorical analyses, the fixed or random-effect model was selected based on the homogeneity test among studies. Linear and non-linear dose-response relationships were also assessed by univariate and bivariate random-effect meta-regression with restricted maximum likelihood estimation. In the highest v. lowest categorical analyses, the pooled relative risk (RR) of T2DM for intake of fish and n-3 fatty acid was 1·146 (95 % CI 0·975, 1·346) and 1·076 (95 % CI 0·955, 1·213), respectively. In the linear dose-response relationship, the pooled RR for an increment of one time (about 105 g)/week of fish intake (four times/month) and of 0·1 g/d of n-3 fatty acid intake was 1·042 (95 % CI 1·026, 1·058) and 1·057 (95 % CI 1·042, 1·073), respectively. The significant non-linear dose-response associations of fish and n-3 fatty acid intake with T2DM risk were not observed. The present evidence from observational studies suggests that the intake of both fish and n-3 fatty acids might be weakly positively associated with the T2DM risk. Further studies are needed to confirm these results.

Prevalence and risk factors for self-reported diabetes among adult men and women in India: findings from a national cross-sectional survey

OBJECTIVE

We examined the distribution of diabetes and modifiable risk factors to provide data to aid diabetes prevention programmes in India.

DESIGN

Population-based cross-sectional survey of men and women included in India's third National Family Health Survey (NFHS-3, 2005-2006).

SETTING

The sample is a multistage cluster sample with an overall response rate of 98 %. All states of India are represented in the sample (except the small Union Territories), covering more than 99 % of the country's population.

SUBJECTS

Women (n 99 574) and men (n 56 742) aged 20-49 years residing in the sample households.

RESULTS

Prevalence of diabetes was 1598/100 000 (95 % CI 1462, 1735) among men and 1054/100 000 (95 % CI 974, 1134) among women in India. Rural-urban and marked geographic variation were found with higher rates in south and north-eastern India. Weekly and daily fish intake contributed to a significantly higher risk of diabetes among both women and men. Risks of diabetes increased with increased BMI, age and wealth status of both women and men, but no effects of the consumption of milk/curd, vegetables, eggs, television watching, alcohol consumption or smoking were found. Daily consumption of pulse/beans or fruits was associated with a significantly reduced risk of diabetes among women, whereas non-significant inverse associations were observed in the case of men.

CONCLUSIONS

Prevalence was underestimated using self-reports. The wide variation in self-reported diabetes is unlikely to be due entirely to reporting biases or access to health care, and indicates that modifiable risk factors exist. Prevention of diabetes should focus on obesity and target specific socio-economic groups in India.

Fish, shellfish, and long-chain n-3 fatty acid consumption and risk of incident type 2 diabetes in middle-aged Chinese men and women

BACKGROUND

Long-chain polyunsaturated n-3 (omega-3) fatty acids, found mainly in fish, have been postulated to reduce type 2 diabetes (T2D) risk. However, the role of long-chain n-3 fatty acids and fish intake in the development of T2D remains unresolved.

OBJECTIVE

We examined associations between fish, shellfish, and long-chain n-3 fatty acids and the risk of T2D in a middle-aged Chinese population.

DESIGN

This was a prospective population-based cohort study in 51,963 men and 64,193 women free of T2D, cardiovascular disease, and cancer at baseline with valid dietary information. Dietary intake, physical activity, and anthropometric measurements were collected. A Cox regression model was used to evaluate the association of fish, shellfish, and long-chain n-3 fatty acid (in g/d) with risk of T2D.

RESULTS

Fish, shellfish, and long-chain n-3 fatty acid intakes were inversely associated with T2D in women. The relative risks [RRs (95% CI)] for quintiles of fish intake were 1.00, 0.96 (0.86, 1.06), 0.84 (0.75, 0.94), 0.80 (0.71, 0.90), and 0.89 (0.78, 1.01) (P for trend = 0.003) and for shellfish were 1.00, 0.91 (0.82, 1.01), 0.79 (0.71, 0.89), 0.80 (0.71, 0.91), and 0.86 (0.76, 0.99) (P for trend = 0.006). In men, only the association between shellfish intake and T2D was significant. The RRs (95% CI) for quintiles of fish intake were 1.00, 0.92 (0.75, 1.13), 0.80 (0.65, 1.00), 0.89 (0.72, 1.11), and 0.94 (0.74, 1.17) (P for trend = 0.50) and for shellfish intake were 1.00, 0.93 (0.76, 1.12), 0.70 (0.56, 086), 0.66 (0.53, 0.82), and 0.82 (0.65, 1.02) (P for trend = 0.003).

CONCLUSIONS

An inverse association between fish and shellfish intake and T2D in women was found. No evidence of a detrimental effect of fish intake in this population was observed.

Eating fish and risk of type 2 diabetes: A population-based, prospective follow-up study

OBJECTIVE

To investigate the relation between total fish, type of fish (lean and fatty), and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake and risk of type 2 diabetes in a population-based cohort.

RESEARCH DESIGN AND METHODS

The analysis included 4,472 Dutch participants aged >or=55 years without diabetes at baseline. Dietary intake was assessed with a semiquantitative food frequency questionnaire. Hazard ratios (relative risk [RR]) with 95% CIs were used to examine risk associations adjusted for age, sex, lifestyle, and nutritional factors.

RESULTS

After 15 years of follow-up, 463 participants developed type 2 diabetes. Median fish intake, mainly lean fish (81%), was 10 g/day. Total fish intake was associated positively with risk of type 2 diabetes; the RR was 1.32 (95% CI 1.02-1.70) in the highest total fish group (>or=28 g/day) compared with that for non-fish eaters (P(trend) = 0.04). Correspondingly, lean fish intake tended to be associated positively with type 2 diabetes (RR highest group [>or=23 g/day] 1.30 [95% CI 1.01-1.68]; P(trend) = 0.06), but fatty fish was not. No association was observed between EPA and DHA intake and type 2 diabetes (RR highest group [>or=149.4 mg/day] 1.22 [0.97-1.53]). With additional adjustment for intake of selenium, cholesterol, and vitamin D, this RR decreased to 1.05 (0.80-1.38; P(trend) = 0.77).

CONCLUSIONS

The findings do not support a beneficial effect of total fish, type of fish, or EPA and DHA intake on the risk of type 2 diabetes. Alternatively, other dietary components, such as selenium, and unmeasured contaminants present in fish might explain our results.

Association between type of dietary fish and seafood intake and the risk of incident type 2 diabetes: the European prospective investigation of cancer (EPIC)-Norfolk cohort study

OBJECTIVE

To investigate the association between fish and seafood intake and new-onset type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a population-based prospective cohort (European Prospective Investigation of Cancer [EPIC]-Norfolk) study of men and women aged 40-79 years at baseline (1993-1997). Habitual fish and seafood intake (white fish, oily fish, fried fish, and shellfish) was assessed using a semiquantitative food frequency questionnaire and categorized as less than one or one or more portions/week. During a median (interquartile range) follow-up of 10.2 (9.1-11.2) years, there were 725 incident diabetes cases among 21,984 eligible participants.

RESULTS

Higher total fish intake (one or more versus less than one portions/week) was associated with a significantly lower risk of diabetes (odds ratio [OR] 0.75 [95% CI 0.58-0.96]), in analyses adjusted for age, sex, family history of diabetes, education, smoking, physical activity, dietary factors (total energy intake, alcohol intake, and plasma vitamin C) and obesity (BMI and waist circumference). White fish and oily fish intakes were similarly inversely associated with diabetes risk, but the associations were not significant after adjustment for dietary factors (oily fish) or obesity (white fish). Fried fish was not significantly associated with diabetes risk. Consuming one or more portions/week of shellfish was associated with an increased risk of diabetes (OR 1.36 [1.02-1.81]) in adjusted analyses.

CONCLUSIONS

Total, white, and oily fish consumption may be beneficial for reducing risk of diabetes, reinforcing the public health message to consume fish regularly. Greater shellfish intake seems to be associated with an increased risk of diabetes, warranting further investigation into cooking methods and mechanisms.

Diet and glycosylated haemoglobin in the 1946 British birth cohort

OBJECTIVES

Raised glycosylated haemoglobin (HbA(1c)) concentration is a recognized risk factor for diabetes, the incidence of which is rising worldwide. The intake of certain foods has been related to HbA(1c) concentration. The aim of this study was to investigate whether nutrient intake, sourced by these foods, was predictive of raised glycosylated haemoglobin (HbA(1c)) concentration in a British cohort.

SUBJECTS

The subjects were 495 men and 570 women who were members of the Medical Research Council National Survey of Health and Development, 1946 birth cohort.Diet was assessed from 5-day records in 1982, 1989 and 1999. HbA(1c) was measured in blood samples collected in 1999. Individuals in whom concentration of HbA(1c) was > or =6.3% were identified as being 'at risk' and their nutrient intake was compared with those whose concentration of HbA(1c) was within the normal range (< or =6.2%).

RESULTS

Lower intakes of protein, carbohydrate, non-starch polysaccharide, iron, folate, vitamin B(12) and a higher percentage energy from fat in 1989 were significantly predictive of high HbA(1c) status in 1999. In 1999, there were no nutrient intakes that were predictive of HbA(1c) status. Global tests of whether the intakes of energy, carbohydrate, sodium, iron, riboflavin and vitamin B(12) at all three time points were related to HbA(1c) status in 1999, were significant.

CONCLUSION

An increased intake of energy, carbohydrate, sodium, iron, riboflavin and vitamin B(12) over 10 years was predictive of raised HbA(1c) status. Increased energy intake may have resulted in increase in body weight, which is a risk factor for diabetes.

Cross-sectional association between fish consumption and albuminuria: the European Prospective Investigation of Cancer-Norfolk Study

BACKGROUND

Studies have shown a potential beneficial role for fish and fish oil consumption in the management of diabetes and its complications. The aim of this study is to examine the association between fish consumption and albuminuria in individuals with and without diabetes.

STUDY DESIGN

A cross-sectional analysis conducted in the European Prospective Investigation of Cancer-Norfolk population-based cohort study.

SETTING & PARTICIPANTS

22,384 men and women from general practices in the city of Norwich and vicinity, of whom 517 had diabetes by self-report and 21,867 did not report diabetes.

PREDICTORS

Fish consumption was measured in a validated semiquantitative food frequency questionnaire and categorized as less than 1, 1 to 2, and more than 2 portions/wk. Interaction between fish intake and diabetes status was hypothesized a priori.

OUTCOMES & MEASUREMENTS

Microalbuminuria and macroalbuminuria were defined as urinary albumin-creatinine ratio of 2.5 or greater to 24.9 and 25 mg/mmol or greater, respectively. Log-transformed albumin-creatinine ratio was used as a continuous variable.

RESULTS

Prevalences of microalbuminuria were 22.6% in participants with diabetes and 11.4% in participants without diabetes. Prevalences of macroalbuminuria were 8.3% and 0.6%, respectively. Fish consumption was associated with a lower risk of macroalbuminuria in participants with diabetes (odds ratio, 0.22, >2 versus <1 portion/wk; 95% confidence interval, 0.07 to 0.70; P for trend = 0.009) after adjustment for confounding. This association was not observed in participants with diabetes with microalbuminuria or in the nondiabetic population. There was a significant interaction between diabetes status and fish consumption of 1 to 2 portions/wk (P = 0.03) and more than 2 portions/wk (P = 0.007) for risk of macroalbuminuria.

LIMITATIONS

Cross-sectional nature of study. Self-report of fish intake and diabetes status.

CONCLUSIONS

Greater fish intake was associated with a lower risk of macroalbuminuria in a self-defined diabetic population. These findings merit confirmation in prospective studies and intervention trials and suggest that fish intake may be beneficial for albuminuria in people with diabetes.

The Pro12Ala polymorphism of the PPAR-gamma2 gene affects associations of fish intake and marine n-3 fatty acids with glucose metabolism

BACKGROUND/OBJECTIVES

Data on associations between marine n-3 fatty acids and glucose metabolism are inconsistent. Therefore, we explored effects of the Pro12Ala polymorphism in peroxisome proliferator-activated receptor (PPAR)-gamma2 gene on associations of fish intake and dietary and plasma eicosapentaenoic and docosahexaenoic acid with glucose metabolism. The design comprises of the cross-sectional analysis.

SUBJECTS/METHODS

The Pro12Ala variant in the PPAR-gamma2 (PPARG) gene was genotyped in 571 non-diabetic relatives of subjects with type II diabetes. The dietary intake was measured by a 3-day food record, and the plasma cholesterol ester fatty acid composition was analysed with gas chromatography. Associations of dietary and plasma variables with insulin resistance and fasting and 2-h glucose and free fatty acid concentrations were analysed with multiple linear regression analysis.

RESULTS

In men, there was a significant interaction between PPARG polymorphism and plasma docosahexaenoic acid on fasting free fatty acid concentration (P=0.036), and genotype-stratified models showed an inverse association in Pro homozygotes only (P=0.028). In women, the proportion of plasma eicosapentaenoic acid was higher in Ala-allele carriers compared to Pro homozygotes (1.67 vs 1.44% respectively, P=0.006). A significant interaction between PPARG polymorphism and fish intake on 2-h glucose was found in women (P=0.021), and genotype-stratified models suggested an inverse association in Ala-allele carriers only (P=0.039).

CONCLUSIONS

The findings suggest that PPARG polymorphism might affect the plasma proportion of eicosapentaenoic acid and modulate the associations of fish intake and marine n-3 fatty acids with glucose metabolism and fasting free fatty acids.

Oily fish reduces plasma triacylglycerols: a primary prevention study in overweight men and women

OBJECTIVE

Previous studies have demonstrated benefits of high-dose long-chain omega-3 polyunsaturated fatty acid (LC omega-3 PUFA) supplements on metabolic risk. Effects of increased dietary omega-3 PUFA, via oily fish and/or plant-derived omega-3 PUFAs, are less clear and may be modulated by the omega-6:omega-3 PUFA of the habitual diet. This study examined the effect on cardiovascular disease risk markers of reducing dietary omega-6:omega-3 PUFA by changes in linoleic acid:alpha-linolenic acid (LA:LNA) and/or increasing LC omega-3 PUFA. It tested whether decreases in LA:LNA modulate effects of LC omega-3 PUFA.

METHODS

One hundred forty-two subjects, recruited to a 24-wk randomized study, were assigned to a control group or one of four interventions. Intervention groups received two portions of oily fish (4.5 g eicosapentaenoic acid + docosahexanoic acid) or white fish (0.7 g eicosapentaenoic acid + docosahexanoic acid) per week, and replaced habitual household fats with ones high in sunflower (high LA:LNA) or rapeseed (low LA:LNA) oil.

RESULTS

Modest dietary manipulations of omega-6 and omega-3 PUFAs resulted in significant group x time interactions for serum triacylglycerols (TAGs; P = 0.05); at 24 wk the control and two oily fish groups showed lower TAG than did the white fish/sunflower group (P = 0.05). Reductions in TAG, associated with increased oily fish intakes, were maximized when combined with lower dietary LA:LNA. There were no significant changes in several other cardiovascular disease risk markers.

CONCLUSIONS

Two portions of oily fish per week led to significant reductions in TAG relative to consumption of two portions of white fish per week. Changes in TAG were maximized when combined with lower LA:LNA.