Fish consumption and coronary heart disease mortality in Finland, Italy, and The Netherlands

Fish consumption seems to protect against death from coronary heart disease (CHD). If this association is due to n-3 polyunsaturated fatty acids, especially fatty fish may be responsible for this protective effect. The association between total, lean, and fatty fish consumption and the risk of CHD mortality was examined in 1,088 Finnish, 1,097 Italian, and 553 Dutch men participants in the Seven Countries Study who were aged 50-69 years and free of CHD around 1970. After 20 years of follow-up, 242 (22.2%) men in Finland, 116 (10.6%) men in Italy, and 105 (19.0%) men in the Netherlands had died of CHD. Cox proportional hazards analysis showed no association between total fish consumption and CHD mortality. After adjustments were made for age, body mass index, smoking, energy intake, and relevant dietary variables, the pooled relative risk for the highest quartile of total fish compared with no fish consumption in the three countries was 1.08 (95% confidence interval: 0.76, 1.53). Lean fish consumption also was not associated with CHD mortality in any country. Fatty fish compared with non-fatty-fish consumption was associated with lower CHD mortality; the adjusted, pooled relative risk for fatty fish consumers was 0.66 (95% confidence interval: 0.49, 0.90). These data suggest that especially fatty fish is protective against CHD mortality.     

Intake frequency of fish and serum levels of long-chain n-3 fatty acids: a cross-sectional study within the Japan Collaborative Cohort Study

BACKGROUND: Several investigations have adopted self-reported intake frequency of fish as a surrogate for intake of long-chain n-3 fatty acids, for which protective effects against cancer have been suggested. Whether reported fish consumption reflects the fatty acid intake, however, has to be elucidated. METHODS: We examined the association between intake frequency of fish and serum long-chain n-3 fatty acids (weight percentage of total fatty acids) among 1,257 control subjects (631 men and 626 women), aged 40-79 years, in case-control studies nested in the Japan Collaborative Cohort Study. All the subjects were not fasting when blood was drawn. Serum fatty acids were determined by gas chromatography. RESULTS: In men, intake frequency of fresh fish and dried or salted fish was significantly but weakly correlated with serum levels of eicosapentaenoic (EPA), docosapentaenoic (n-3) (DPA), and docosahexaenoic (DHA) acids; the age-adjusted Spearman correlation coefficients ranged from 0.11 to 0.18. In women, fresh fish consumption was somewhat associated with serum EPA (Spearman correlation coefficient = 0.12) as was dried or salted fish consumption with serum DPA (0.11). A rising trend in geometric means of serum EPA, DPA, and DHA was found with an increasing intake frequency of fresh or dried/salted fish in both sexes. The geometric means adjusted for age and participating institution in the highest intake category were higher than those in the lowest by 7% to 40%. CONCLUSIONS: A population with high self-reported frequency of fish intake, as a group, may have higher bioavailability of long-chain n-3 fatty acids than one with low frequency.     

Adipose tissue fatty acids and risk of myocardial infarction--a case-control study

OBJECTIVES: To study the association between content in adipose tissue of very long-chain n-3 fatty acids, trans fatty acids, linoleic acid and alpha-linolenic acid and risk of a first myocardial infarction. DESIGN AND SUBJECTS: A case-control design among 100 patients and 98 population controls both men and postmenopausal women, age 45-75 y. Adipose tissue fatty acids were determined by gas-liquid chromatography. Intake data were obtained through interview using a validated food frequency questionnaire. RESULTS: Dietary intake and adipose tissue content of the fatty acids studied correlated significantly. Adipose tissue contents of eicosapentaenoic acid (20:5n-3), docosapentaenoic acid (22:5n-3) and docosahexaenoic acid (22:6n-3) were significantly lower while those of trans fatty acids, linoleic and alpha-linolenic acid were significantly higher in patients than in controls. Age and sex adjusted odds ratios (OR) were significantly reduced with increasing quintiles of very long-chain n-3 fatty acids, thus the OR in the fifth compared to the first quintile was 0.23 (95% CI 0.08-0.70). After further adjustment for waist-to-hip ratio, smoking, family history of CHD and content of trans fatty acids, the OR in the highest quintile was 0.17 (95% CI 0.04-0.76) and the P for trend 0. 016. Age and sex adjusted OR was increased in the fifth compared to the first quintile of trans fatty acids (OR 2.81, 95% CI 1.16-6.84), linoleic acid (OR 2.10, 95% CI 0.87-5.07) and alpha-linolenic acid (OR 1.96, 95% CI 0.83-4.61), and P for trend was 0.002, 0.005 and 0. 020, respectively. The trends remained significant after adjustment for waist-to-hip ratio, smoking, and family history of coronary heart disease. Trans fatty acids, linoleic acid and alpha-linolenic acid in adipose tissue were strongly correlated, indicating a common source, most likely margarine. When each of these fatty acid species were adjusted for the two others the trends were no longer significant. CONCLUSION: Intake of very long-chain n-3 fatty acids as reflected in adipose tissue content is inversely associated with risk of myocardial infarction. Trans fatty acids, linoleic and alpha-linolenic acid were intercorrelated and associated with increased risk. It is suggested that the increased risk may be connected to trans fatty acids or to some other factor associated with margarine consumption. European Journal of Clinical Nutrition 54, 618-625.     

Omega-3 and omega-6 fatty acid intakes and endometrial cancer risk in a population-based case–control study

Purpose

Animal and laboratory studies suggest that long-chain omega-3 (n-3) fatty acids, a type of polyunsaturated fat found in fatty fish, may protect against carcinogenesis, but human studies on dietary intake of polyunsaturated fats and fish with endometrial cancer risk show mixed results.

Methods

We evaluated the associations between endometrial cancer risk and intake of fatty acids and fish in a population-based sample of 556 incident cancer cases and 533 age-matched controls using multivariate unconditional logistic regression methods.

Results

Although total n-3 fatty acid intake was not associated with endometrial cancer risk, higher intakes of eicosapentaenoic (EPA 20:5) and docosahexaenoic (DHA 22:6) fatty acids were significantly associated with lower risks (OR = 0.57, 95 % CI: 0.39–0.84; OR = 0.64, 95 % CI: 0.44–0.94; respectively) comparing extreme quartiles. The ratio of n-3:n-6 fatty acids was inversely associated with risk only on a continuous scale (OR = 0.84, 95 % CI: 0.71–0.99), while total fish intake was not associated with risk. Fish oil supplement use was significantly associated with reduced risk of endometrial cancer: OR = 0.63 (95 % CI: 0.45–0.88).

Conclusions

Our results suggest that dietary intake of the long-chain polyunsaturated fatty acids EPA and DHA in foods and supplements may have protective associations against the development of endometrial cancer.     

Intakes of long-chain n-3 polyunsaturated fatty acids and fish in relation to measurements of subclinical atherosclerosis

BACKGROUND: Data on the relations of different types of fish meals and long-chain n-3 polyunsaturated fatty acids (PUFAs) to measures of atherosclerosis are sparse. OBJECTIVE: We examined intakes of long-chain n-3 PUFAs and fish in relation to clinical measures of subclinical atherosclerosis. DESIGN: A cross-sectional study was conducted in a multiethnic group of 5,488 adults aged 45-84 y and free of clinical cardiovascular disease. Diet was assessed by using self-administered food-frequency questionnaires. Subclinical atherosclerosis was determined by measurements of common carotid intima-media thickness (cCIMT, >80th percentile), internal CIMT (iCIMT, >80th percentile), coronary artery calcium score (CAC score, >0), or ankle-brachial index (ABI, <0.90). RESULTS: After adjustment for potential confounders, intakes of long-chain n-3 PUFAs and nonfried (broiled, steamed, baked, or raw) fish were inversely related to subclinical atherosclerosis determined by cCIMT but not by iCIMT, CAC score, or ABI. The multivariate odds ratio comparing the highest to the lowest quartile of dietary exposures in relation to subclinical atherosclerosis determined by cCIMT was 0.69 (95% CI: 0.55, 0.86; P for trend < 0.01) for n-3 PUFA intake; 0.80 (95% CI: 0.64, 1.01; P = 0.054) for nonfried fish consumption; and 0.90 (95% CI: 0.73, 1.11; P = 0.38) for fried fish consumption. CONCLUSIONS: This study indicates that the dietary intake of long-chain n-3 PUFAs or nonfried fish is associated with a lower prevalence of subclinical atherosclerosis classified by cCIMT, although significant changes in iCIMT, CAC score, and ABI were not observed. Our findings also suggest that the association of fish and atherosclerosis may vary depending on the type of fish meal consumed and the measures of atherosclerosis.     

Prospective study of dietary fat and risk of cataract extraction among US women

The authors examined prospectively the association between dietary fat intake and cataract extraction in adult women from the Nurses' Health Study. A total of 71,083 women were followed prospectively for up to 16 years between 1984 and 2000. Dietary fat was assessed by repeated food frequency questionnaires. Incident cases of cataract extraction were determined by a biennial questionnaire. The multivariate-adjusted relative risk for the highest compared with the lowest quintile of total fat intake was 1.10 (95% confidence interval (CI): 0.99, 1.22; p(trend) = 0.01). Women in the highest quintile of long-chain omega-3 fatty acid had a 12% lower risk of cataract extraction compared with those in the lowest quintile (relative risk = 0.88, 95% CI: 0.79, 0.98; p(trend) = 0.02). Total fish intake was inversely associated with cataract (for intake of > or = 3/week vs. <1/month: relative risk = 0.89, 95% CI: 0.81, 0.98; p(trend) = 0.01). The authors' findings suggest that higher intake of long-chain omega-3 fatty acid (eicosapentaenoic acid and docosahexaenoic acid) and consumption of fish may modestly reduce the risk of cataract.     

Blood concentrations of individual long-chain n-3 fatty acids and risk of nonfatal myocardial infarction

BACKGROUND: Whereas dietary intake of long-chain n-3 fatty acids has been associated with risk of nonfatal myocardial infarction (MI), few studies have examined the relation for blood concentrations. OBJECTIVE: We aimed to investigate the effect of long-chain n-3 fatty acids in blood on the risk of nonfatal MI. DESIGN: Baseline blood samples were collected from 32 826 participants of the Nurses' Health Study in 1989-1990, among whom 146 incident cases of nonfatal MI were ascertained during 6 y of follow-up and matched with 288 controls. RESULTS: After multivariate adjustment, the relative risks (95% CI) comparing the highest with the lowest quartiles in plasma were 0.23 (0.09, 0.55; P for trend = 0.001) for eicosapentaenoic acid (EPA), 0.40 (0.20, 0.82; P for trend = 0.004) for docosapentaenoic acid (DPA), and 0.46 (0.18, 1.16; P for trend = 0.07) for docosahexaenoic acid (DHA). The associations for these fatty acids in erythrocytes were generally weaker and nonsignificant. In contrast to EPA and DHA, blood concentrations of DPA were not correlated with dietary consumption of n-3 fatty acids. Higher plasma concentrations of EPA, DPA, and DHA were associated with higher plasma concentrations of HDL cholesterol and lower concentrations of triacylglycerol and inflammatory markers. CONCLUSIONS: Higher plasma concentrations of EPA and DPA are associated with a lower risk of nonfatal MI among women. These findings may partly reflect dietary consumption but, particularly for DPA, may indicate important risk differences based on metabolism of long-chain n-3 fatty acids.     

The use of novel foods enriched with long-chain n-3 fatty acids to increase dietary intake: a comparison of methodologies assessing nutrient intake

OBJECTIVE: To evaluate the effect of consuming a variety of foods enriched in long-chain n-3 fatty acids in low fish eaters. DESIGN: Evaluation of reported dietary intakes in a 6-month, double-blind, randomized, controlled parallel design trial. SUBJECTS/SETTING: Eighty-five men and women with overweight and mildly elevated triglyceride levels who have a low habitual intake of fish. INTERVENTION: Subjects were randomized to consume foods either enriched in long-chain n-3 fats or control foods (not enriched). Subjects were asked to consume eight portions per day (equivalent to approximately 1 g/day long-chain n-3 fatty acid if randomized to the intervention). MAIN OUTCOME MEASURE: Reported energy, macronutrient, and fatty acid intakes were measured by diet history, 3-day food records, and body weight. STATISTICAL ANALYSES: Repeated measures analysis of variance, Kruskall-Wallis test, Pearson's correlation coefficient, and Bland-Altman plots were conducted. RESULTS: The two groups did not differ in mean dietary intake of long-chain n-3 fatty acid intake at baseline (258 mg and 313 mg for the intervention and control groups, respectively). At 6 months the intervention group members increased their intake of long-chain n-3 fats 4.5-fold compared with baseline and with the control group (P<.001). The data from the diet histories correlated well with the food records for all reported macronutrient and fatty acid values. Food pattern analysis showed that milk (13.8%), cereal (12.1%), and bread (11.3%) contributed the most to the overall long-chain n-3 fatty acid intake in the intervention group. CONCLUSIONS: This long-term study in free-living subjects indicates that population intakes of long-chain n-3 fatty acids could be substantially increased through the availability of a variety of n-3 fatty acid-enriched processed foods.     

Impact of foods enriched with n-3 long-chain polyunsaturated fatty acids on erythrocyte n-3 levels and cardiovascular risk factors

Consumption of fish or fish oils rich in the n-3 long chain PUFA EPA and DHA may improve multiple risk factors for CVD. The objective of this study was to determine whether regular consumption of foods enriched with n-3 long-chain PUFA can improve n-3 long-chain PUFA status (erythrocytes) and cardiovascular health. Overweight volunteers with high levels of triacylglycerols (TG; >1.6 mmol/l) were enrolled in a 6-month dietary intervention trial conducted in Adelaide (n 47) and Perth (n 39), and randomised to consume control foods or n-3-enriched foods to achieve an EPA + DHA intake of 1 g/d. Test foods were substituted for equivalent foods in their regular diet. Erythrocyte fatty acids, plasma TG and other CVD risk factors were monitored at 0, 3 and 6 months. There were no significant differences between groups for blood pressure, arterial compliance, glucose, insulin, lipids, C-reactive protein (CRP) or urinary 11-dehydro-thromboxane B2 (TXB2) over 6 months, even though regular consumption of n-3-enriched foods increased EPA + DHA intake from 0.2 to 1.0 g/d. However, the n-3 long-chain PUFA content of erythrocytes increased by 35 and 53 % at 3 and 6 months, respectively, in subjects consuming the n-3-enriched foods. These increases were positively associated with measures of arterial compliance and negatively associated with serum CRP and urinary 11-dehydro-TXB2 excretion. Sustainable increases in dietary intakes and erythrocyte levels of n-3 long-chain PUFA can be achieved through regular consumption of suitably enriched processed foods. Such increases may be associated with reduced CV risk.     

Dietary intakes of arachidonic acid and alpha-linolenic acid are associated with reduced risk of hip fracture in older adults

PUFA are hypothesized to influence bone health, but longitudinal studies on hip fracture risk are lacking. We examined associations between intakes of PUFA and fish, and hip fracture risk among older adults (n = 904) in the Framingham Osteoporosis Study. Participants (mean age ~75 y at baseline) were followed for incident hip fracture from the time they completed the baseline exam (1988-1989) until December 31, 2005. HR and 95% CI were estimated for energy-adjusted dietary fatty acid exposure variables [(n-3) fatty acids: α-linolenic acid (ALA), EPA, DHA, EPA+DHA; (n-6) fatty acids: linoleic acid, arachidonic acid (AA); and the (n-6):(n-3) ratio] and fish intake categories, adjusting for potential confounders and covariates. Protective associations were observed between intakes of ALA (P-trend = 0.02) and hip fracture risk in a combined sample of women and men and between intakes of AA (P-trend = 0.05) and hip fracture risk in men only. Participants in the highest quartile of ALA intake had a 54% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.46; 95% CI = 0.26-0.83). Men in the highest quartile of AA intake had an 80% lower risk of hip fracture than those in the lowest quartile (Q4 vs. Q1: HR = 0.20; 95% CI = 0.04-0.96). No significant associations were observed among intakes of EPA, DHA, EPA+DHA, or fish. These findings suggest dietary ALA may reduce hip fracture risk in women and men and dietary AA may reduce hip fracture risk in men.     

Fish intake, mercury, long-chain n-3 polyunsaturated fatty acids and risk of stroke in northern Sweden

Results of previous studies on fish intake and stroke risk have been inconclusive. Different stroke types have often not been separated. Our aim was to elucidate whether intake of fish, Hg or the sum of proportions of fatty acids EPA (20 : 5n-3) and DHA (22 : 6n-3) influence the risk of haemorrhagic or ischaemic stroke. Within a population-based cohort from a community intervention programme, 369 stroke cases and 738 matched controls were identified and included in the present nested case-control study. Information on fish intake had been recorded at recruitment, i.e. before diagnosis. Hg levels were determined in erythrocyte membranes, also collected at recruitment, and the relative content of fatty acids was measured in erythrocyte membranes or plasma phospholipids. The results showed that in women there was a non-significant decrease in stroke risk with increasing fish intake (OR 0.90 (95 % CI 0.73, 1.11) per meal per week). The risk in women differed significantly (P = 0.03) from that in men, in whom the OR for stroke rose with increasing fish intake (OR 1.24 (95 % CI 1.01, 1.51) per meal per week). The corresponding risk in men for Hg was 0.99 (95 % CI 0.93, 1.06), and for the sum of proportions of EPA and DHA 1.08 (95 % CI 0.92, 1.28). We conclude that the relationship between stroke risk and fish intake seems to be different in men and women. Increased levels of EPA and DHA do not decrease the risk for stroke and there is no association between stroke risk and Hg at these low levels.     

Intake of n-6 and n-3 fatty acids and fish and risk of community-acquired pneumonia in US men

BACKGROUND: Essential fatty acids modulate inflammation and glucose metabolism and may alter infection risk. OBJECTIVE: We examined the association between intakes of n-6 and n-3 fatty acids and fish and the risk of community-acquired pneumonia. DESIGN: We prospectively evaluated 38,378 male US health professionals aged 44-79 y at the outset. We updated medical and lifestyle information biennially through questionnaires and diet every 4 y with the use of a validated food-frequency questionnaire. We excluded men who reported pneumonia, myocardial infarction, stroke, other heart disease, arterial surgery, cancer, or asthma before 1990 or those with incomplete dietary data. Community-acquired pneumonia was determined by blinded medical record review of chest radiographs. RESULTS: During 10 y of follow-up, there were 441 new cases of nonfatal community-acquired pneumonia. Pneumonia risk was lower in men in the highest energy-adjusted quintiles of intake than in men in the lowest quintiles of intake of linoleic acid [multivariate relative risk (RR): 0.70; 95% CI: 0.51, 0.96; P for trend = 0.01] and alpha-linolenic acid (multivariate RR: 0.68; 95% CI: 0.50, 0.93; P for trend = 0.01). Pneumonia risk decreased 4% for every 1-g/d increase in linoleic acid intake (multivariate RR: 0.96; 95% CI: 0.93, 0.99). Pneumonia risk was reduced by 31% for every 1-g/d increase in alpha-linolenic acid intake (multivariate RR: 0.69; 95% CI: 0.51, 0.93). Intakes of eicosapentaenoic acid and docosahexaenoic acid were not significantly related to pneumonia risk. CONCLUSION: Higher intakes of alpha-linolenic and linoleic acids and possibly of fish may reduce the risk of pneumonia.     

Fish consumption and breast cancer risk

The omega-3 fatty acids, especially long-chain eicosapentaenoic acid (20:5n-3) and docosahexaenoic (22:6n-3) contained in "fatty" fish, have consistently been shown to retard the growth of breast cancer in vitro and in animal experiments. In contrast, studies of the association between fish consumption and breast cancer risk in human populations have not consistently shown inverse associations. However, previous studies have not considered the specific types of fish consumed. Using data from a large, nationwide case-control study conducted in Sweden, we examined the association between consumption of fatty and lean fish and breast cancer risk. Odds ratios (OR) and 95% confidence intervals were computed from unconditional logistic regression models. High consumption of fish was weakly associated with reduced breast cancer risk, and the association was not statistically significant. With multivariate adjustment, the OR for women with the highest consumption (> or =3.5 servings/wk) compared with women with the lowest (virtually none) was 0.88 (95% confidence interval = 0.60-1.29, P for trend = 0.15). When type of fish was examined separately, the association was similar for fatty and lean fish.     

Fat intake and risk of squamous cell carcinoma of the skin

The varied effects of different classes of dietary fatty acids on carcinogenesis suggest that fatty acid composition is an important determining factor in tumor development. In the present study, we investigated the association between dietary n-3 and n-6 fatty acid intake and risk of squamous cell carcinoma of the skin (SCC). Data were taken from a population-based case-control study of skin SCC in Southeastern Arizona. Our data show a consistent tendency for a lower risk of SCC with higher intakes of n-3 fatty acids [p (for trend) = 0.055]. The adjusted odds ratios for increasing levels of n-3 fatty acids were 0.85 [95% confidence interval (CI) = 0.56-1.27] and 0.71 (95% CI = 0.49-1.00) compared with the lower level as the referent. For the ratio of n-3 to n-6 fatty acids, the odds ratios in successively higher levels were 0.88 (95% CI = 0.59-1.32) and 0.74 (95% CI = 0.51-1.05), suggesting a tendency toward decreased risk of SCC with increased intake of diets with high ratio of n-3 to n-6 fatty acid. More studies are clearly needed to elucidate the function of dietary fatty acids so that recommendations can be made to alter the human diet for cancer prevention, particularly in light of the increasing incidence of SCC of the skin.     

A valid food frequency questionnaire for measuring dietary fish intake

There is considerable interest in the potentially protective effects of high fish consumption on many chronic diseases. Many epidemiological studies use food frequency questionnaires (FFQ) to quantify usual dietary fish intake, so it is important to validate this assessment against objective markers. The objective of this study was to determine the relationship between plasma percentage fatty acids and dietary fish intake as assessed by a FFQ. A semiquantitative FFQ was completed by 174 adults from the community (aged 26-49 years) who also had venous blood analysed for plasma percentage fatty acids. Following linear regression modelling, total non-fried fish intake was a significant predictor of n-3 (regression coefficient, B = 0.94; 95% CI = 0.60-1.28), docosahexaenoic acid (DHA; B = 0.73; 95% CI = 0.47-0.99) and the ratio of n-6: n-3 fatty acids (B = -1.0; 95% CI = - 1.35- -0.65). Steamed, grilled or baked fish was a small but significant predictor of eicosapentaenoic acid (EPA) levels (B = 0.13; 95% CI = 0.05-0.21) while total fish intake was a predictor of n-6 fatty acids (B = -0.88; 95% CI = -1.41- -0.36). This semiquantitative FFQ could be useful for ranking subjects according to their likely plasma n-3, DHA, and n-6 fatty acid intake and the ratio of n-6: n-3 fatty acids, when the available resources may simply not permit biological markers to be used.     

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.     

Intake of Fish and n-3 Fatty Acids and Future Risk of Metabolic Syndrome

Background

Whether or not fish and n-3 fatty acid intake is associated with the metabolic syndrome risk has not been carefully evaluated. This study investigated the effect of fish and n-3 fatty acid intake on the incidence of metabolic syndrome and on the individual risk factors for the syndrome.

Methods

A population-based prospective cohort study included 3,504 male and female Koreans aged 40 to 69 years from the Korean Genome Epidemiology Study. At the beginning of follow-up, all individuals were free of metabolic syndrome and known cardiovascular disease. Each participant completed a food frequency questionnaire. Incident cases of metabolic syndrome were identified by biennial health examinations during a follow-up period between April 17, 2003, and November 17, 2006. Pooled logistic regression analysis was applied to obtain an odds ratio (OR) of metabolic syndrome with its 95% confidence interval (CI) for fish or n-3 fatty acid intake.

Results

After controlling for potential cardiovascular risk factors, multivariate OR for metabolic syndrome was 0.43 (95% CI 0.23 to 0.83) for men who ate fish daily when compared with those eating fish less than once a week. Similarly, metabolic syndrome risk was halved for men in the top decile of n-3 fatty acid intake when compared with those in the bottom decile (OR 0.53, 95% CI 0.28 to 0.99). In particular, fish intake was significantly associated with triglyceride level and high-density lipoprotein cholesterol level among the metabolic syndrome components. For women, apparent associations were not observed between fish intake or n-3 fatty acid intake and metabolic syndrome risk.

Conclusions

In a prospective study, high consumption of fish and n-3 fatty acids was significantly associated with a lower risk of metabolic syndrome among men, but not among women. Whether or not encouraging fish intake can help prevent the development of metabolic syndrome warrants further studies.     

Marine fatty acid intake is associated with breast cancer prognosis

EPA and DHA, long-chain (n-3) PUFA largely obtained from fish, inhibit the proliferation of breast cancer cells in vitro and reduce the initiation and progression of breast tumors in laboratory animals. Our purpose in this analysis was to examine whether intake of these marine fatty acids (EPA and DHA) were associated with prognosis in a cohort of women who had been diagnosed and treated for early stage breast cancer (n = 3,081). Median follow-up was 7.3 y. Dietary intake was assessed using 24-h recalls (~4 recalls per dietary assessment obtained at 7 time points over 6 y). Survival models with time-dependent covariates were used to examine the association of repeated measures of dietary intake of EPA and DHA from food (i.e., marine sources) and supplements with disease-free survival and overall survival. Women with higher intakes of EPA and DHA from food had an approximate 25% reduced risk of additional breast cancer events [tertile 2: HR = 0.74 (95% CI = 0.58-0.94); tertile 3: HR = 0.72 (95% CI = 0.57-0.90)] compared with the lowest tertile of intake. Women with higher intakes of EPA and DHA from food had a dose-dependent reduced risk of all-cause mortality [tertile 2: HR = 0.75 (95% CI = 0.55-1.04); tertile 3: HR = 0.59 (95% CI = 0.43-0.82)]. EPA and DHA intake from fish oil supplements was not associated with breast cancer outcomes. The investigation indicates that marine fatty acids from food are associated with reduced risk of additional breast cancer events and all-cause mortality.     

Dietary (n-3)/(n-6) fatty acid ratio: possible relationship to premenopausal but not postmenopausal breast cancer risk in U.S. women

Recent research has suggested that an increased (n-3) fatty acid intake and/or increased (n-3)/(n-6) polyunsaturated fatty acid (PUFA) ratio in the diet is associated with a lower breast cancer risk. This case-control study investigated the association between intake of (n-3) and other fatty acids and the (n-3)/(n-6) PUFA ratio and breast cancer risk. After combining data from two related case-control studies in Connecticut, we had information available on a total of 1119 women (565 cases and 554 controls). Cases were all histologically confirmed, incident breast carcinoma patients. Controls were hospital-based (Yale-New Haven Hospital study site) and population-based (Tolland County study site). Information on dietary intake was obtained through a validated food-frequency questionnaire. Standard multivariate methods were used to address the independent effects of specific fatty acids, fat classes and macronutrients on breast cancer risk. In the full study population, there were no significant trends for any macronutrient/fatty acid when comparing the highest to the lowest quartile of intake. When the analysis was restricted to premenopausal women, consumption of the highest compared with the lowest quartile of the (n-3)/(n-6) PUFA ratio was associated with a nonsignificant 41% lower risk of breast cancer [odds ratio (OR) = 0.59, 95% confidence interval (CI) 0.29, 1.19, P for trend = 0.09]. A higher (n-3)/(n-6) PUFA ratio was significantly associated with a lower risk of breast cancer when the data were restricted to the Tolland County (population-based) study site; OR = 0.50, 95% CI 0.27, 0.95, P for trend = 0.02. These results are consistent with the hypothesis that a higher (n-3)/(n-6) PUFA ratio may reduce the risk of breast cancer, especially in premenopausal women.     

Fish and fat intake and prevalence of allergic rhinitis in Japanese females: the Osaka Maternal and Child Health Study

OBJECTIVE: It remains uncertain whether intake of fish or n-3 polyunsaturated fatty acids is preventive against allergic disorders. This cross-sectional study investigated the association of intake of selected high-fat foods and specific types of fatty acids with the prevalence of allergic rhinitis in Japan where intake of fish is high. METHODS: Study subjects were 1002 Japanese pregnant females. Allergic rhinitis (including cedar pollinosis) was defined as present if subjects had received drug treatment at some point during the previous 12 months. Information on dietary factors was collected using a validated self-administered diet history questionnaire. Adjustment was made for age, gestation, parity, cigarette smoking, passive smoking at home and at work, indoor domestic pets, family history of asthma, atopic eczema, and allergic rhinitis, family income, education, mite antigen level in house dust, changes in diet in the previous month, season when data were collected, and body mass index. RESULTS: There was a tendency for an inverse dose-response association between fish intake and allergic rhinitis although the adjusted odds ratio for comparison of the highest with the lowest quartile was not statistically significant (p for trend = 0.09). Intake of eicosapentaenoic and docosahexaenoic acids was independently associated with a decreased prevalence of allergic rhinitis: the multivariate odds ratio for the highest quartile was 0.56 (95% confidence interval: 0.32-0.96, p for trend = 0.03). Intake of n-6 polyunsaturated fatty acids in the third quartile but not the second and fourth quartiles showed a tendency for an inverse association with the prevalence of allergic rhinitis. No measurable relationship was found between consumption of meat, eggs, dairy products, total fat, saturated, monounsaturated, and n-3 polyunsaturated fatty acids, and cholesterol or the ratio of n-3 to n-6 polyunsaturated fatty acids and allergic rhinitis. CONCLUSION: Our findings suggest that the intake of eicosapentaenoic and docosahexaenoic acids may be associated with a reduced prevalence of allergic rhinitis.