Fatty acid composition of serum lipid fractions in relation to gender and quality of dietary fat

Associations of Vitamin B6 Intake and Plasma Pyridoxal 5'-Phosphate with Plasma Polyunsaturated Fatty Acids in US Older Adults: Findings from NHANES 2003-2004

Previous evidence suggests a potential dual impact of aging and vitamin B6 (B6) deficiency on polyunsaturated fatty acid (PUFA) metabolism; gender may influence PUFA biosynthesis. Perturbation of PUFA compositions during B6 deficiency could be linked to age-related health outcomes. However, little is known about the interrelationships between vitamin B6, PUFA, and gender in the older population. Therefore, we investigated whether gender-specific associations of B6 intake and plasma pyridoxal 5’-phosphate (PLP) concentration, respectively, with plasma PUFA concentrations and ratios (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, and (EPA + DHA)/AA) existed in older adults. We further examined the relationships of adequate B6 status (PLP ≥ 20 nmol/L) with high (above median) plasma PUFA relative to deficient B6 status. This cross-sectional study analyzed 461 participants aged ≥60 years from NHANES 2003−2004. Nutrient intakes were assessed using two 24-h recalls and supplement questionnaires. PLP and PUFA concentrations were measured. Multivariate linear regression assessed the association of B6 intake and PLP with PUFA; multivariate logistic regression evaluated the relationship of adequate B6 status with high plasma PUFA, adjusting for demographic, socioeconomic, and dietary factors; physical activity; smoking; alcohol; medication; and BMI. There were interactions between gender and B6 intake on EPA (P-interaction = 0.008) and AA (P-interaction = 0.004) only, whereas no interaction existed between gender and PLP on PUFA. PLP was directly associated with EPA (β = 0.181, P = 0.002), DHA (β = 0.109, P = 0.005), EPA + DHA (β = 0.14, P = 0.002), EPA/AA (β = 0.186, P = 0.004), and (EPA + DHA)/AA (β = 0.13, P = 0.026). The odds of having high plasma EPA (adjusted (a) OR: 2.03, P = 0.049) and EPA/AA (aOR: 3.83, P < 0.0001) were greater in those with adequate B6 status compared to those with deficient B6 status. In conclusion, in US older adults, a higher PLP level was associated with a greater level of EPA, DHA, EPA + DHA, EPA/AA, and (EPA + DHA)/AA. Adequate B6 status was associated with high EPA and EPA/AA status. These findings suggest that sufficient vitamin B6 status may positively influence PUFA metabolism in older adults.

Impact of Dietary Palmitic Acid on Lipid Metabolism

Palmitic acid (PA) is ubiquitously present in dietary fat guaranteeing an average intake of about 20 g/d. The relative high requirement and relative content in the human body, which accounts for 20–30% of total fatty acids (FAs), is justified by its relevant nutritional role. In particular physiological conditions, such as in the fetal stage or in the developing brain, the respectively inefficient placental and brain blood–barrier transfer of PA strongly induces its endogenous biosynthesis from glucose via de novo lipogenesis (DNL) to secure a tight homeostatic control of PA tissue concentration required to exert its multiple physiological activities. However, pathophysiological conditions (insulin resistance) are characterized by a sustained DNL in the liver and aimed at preventing the excess accumulation of glucose, which result in increased tissue content of PA and disrupted homeostatic control of its tissue concentration. This leads to an overaccumulation of tissue PA, which results in dyslipidemia, increased ectopic fat accumulation, and inflammatory tone via toll-like receptor 4. Any change in dietary saturated FAs (SFAs) usually reflects a complementary change in polyunsaturated FA (PUFA) intake. Since PUFA particularly n-3 highly PUFA, suppress lipogenic gene expression, their reduction in intake rather than excess of dietary SFA may promote endogenous PA production via DNL. Thereby, the increase in tissue PA and its deleterious consequences from dysregulated DNL can be mistakenly attributed to dietary intake of PA.

The microbiome affects liver sphingolipids and plasma fatty acids in a murine model of the Western diet based on soybean oil

Studies in mice using germfree animals as controls for microbial colonization have shown that the gut microbiome mediates diet-induced obesity. Such studies use diets rich in saturated fat, however, Western diets in the United States America are enriched in soybean oil, composed of unsaturated fatty acids, either linoleic or oleic acid. Here, we addressed whether the microbiome is a variable in fat metabolism in mice on a soybean oil diet. We used conventionally-raised, low-germ, and germfree mice fed for 10 weeks diets either high or low in high-linoleic-acid soybean oil as the sole source of fat. Conventional and germfree mice gained relative fat weight and all mice consumed more calories on the high fat vs. low fat soybean oil diet. Plasma fatty acid levels were generally dependent on diet, with microbial colonization status affecting iso-C18:0, C20:3n-6, C14:0, and C15:0 levels. Colonization status, but not diet, impacted levels of liver sphingolipids including ceramides, sphingomyelins, and sphinganine. Our results confirm that absorbed fatty acids are mainly a reflection of the diet and that microbial colonization influences liver sphingolipid pools regardless of diet.

Baseline omega-3 level is associated with nerve regeneration following 12-months of omega-3 nutrition therapy in patients with type 1 diabetes

AIM

Omega-3 (n-3) polyunsaturated fatty-acids are essential for the development and maintenance of nerve function, but the relationship of plasma n-3 to the presence of diabetic distal-symmetric-polyneuropathy (DSP) and the effect of n-3 therapy on plasma levels and small nerve fibre morphology in T1D are unknown.

METHODS

Participants with T1D (n = 40, 53% female, aged (mean ± SD) 48 ± 14 years, BMI 28.1 ± 5.8 kg/m², diabetes duration 27 ± 18 years), 23 of whom had DSP, took seal-oil (10 mL/day; 750 mg eicosapentaenoic acid (EPA), 560 mg docosapentaenoic acid (DPAn-3), and 1020 mg docosahexaenoic acid (DHA)) for 12-months in a single-arm open-label study. The improvement in corneal nerve fibre length (CNFL) (primary outcome) was previously reported. In this secondary analysis, plasma n-3s were measured at baseline, 4, 8 and 12-months.

RESULTS

At baseline, participants with DSP had lower DHA than those without (1.73 ± 0.89 vs. 2.27 ± 0.70%, p = 0.049). Twelve-months seal-oil therapy increased mean plasma EPA by 185%, DPA by 29%, DHA by 79% (p < 0.001) and CNFL by 29% (p = 0.001). Change in CNFL was positively associated with higher baseline total n-3 (Spearman's correlation coefficient r = 0.41, p = 0.013), DPA (r = 0.33, p = 0.047) and DHA (r = 0.42, p = 0.012).

CONCLUSION

In conclusion, low plasma DHA was associated with prevalent DSP, n-3 therapy increased blood n-3 levels and higher baseline n-3s were associated with greater nerve regeneration.

Gender Differences in the Associations of Plasma Pyridoxal 5'-Phosphate with Plasma Polyunsaturated Fatty Acids among US Young and Middle-Aged Adults: NHANES 2003-2004

Vitamin B6-restricted diets and low plasma pyridoxal 5'-phosphate (PLP) status altered plasma polyunsaturated fatty acids (PUFA) compositions. Evidence suggests the role of gender in the metabolism of vitamin B6 and PUFA. However, no epidemiologic study examined the impact of gender on the relationship between vitamin B6 and PUFA status in adults. Thus, we investigated whether there were gender differences in the association of vitamin B6 intake and plasma PLP concentration with plasma PUFA concentrations and ratios (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (AA), EPA + DHA, EPA/AA, (EPA + DHA)/AA) in US young/middle-aged adults. In total, 864 participants (20-59 years; 484 men, 380 women) from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 were used for this cross-sectional study. Nutrient intakes were estimated from two 24 h recalls and supplement questionnaires; plasma PLP and PUFA were measured. Multivariate linear regression was utilized to obtain unstandardized (b) and standardized (β) coefficients. Covariates included demographic, socioeconomic, dietary variables, physical activity level, cigarette smoking status, alcohol consumption, prescription medication use, and BMI. There were significant interactions between gender and PLP on EPA (P-interaction = 0.004), DHA (P-interaction = 0.020), EPA + DHA (P-interaction = 0.010), EPA/AA (P-interaction = 0.002), (EPA + DHA)/AA (P-interaction = 0.004), whereas no interaction between gender and B6 intake existed. In gender-stratified analyses, in men, PLP was positively associated with EPA (β = 0.138, b = 0.104, p = 0.0004), DHA (β = 0.101, b = 0.058, p = 0.036), EPA + DHA (β = 0.125, b = 0.073, p = 0.005), EPA/AA (β = 0.144, b = 0.099, p = 0.0002), (EPA + DHA)/AA (β = 0.123, b = 0.068, p = 0.005). However, no associations between PLP and PUFA existed in women. In conclusion, gender differences were found in the relationships between plasma PLP and plasma EPA, DHA, EPA + DHA, EPA/AA, and (EPA + DHA)/AA, with significant direct associations in men only among US young/middle-aged adults.

Plasma Phospholipid n-3/n-6 Polyunsaturated Fatty Acids and Desaturase Activities in Relation to Moderate-to-Vigorous Physical Activity through Pregnancy: A Longitudinal Study within the NICHD Fetal Growth Studies

Maternal plasma phospholipid polyunsaturated fatty acids (PUFAs) play critical roles in maternal health and fetal development. Beyond dietary factors, maternal moderate-to-vigorous physical activity (MVPA) has been linked to multiple health benefits for both the mother and offspring, but studies investigating the influence of maternal MVPA on maternal PUFA profile are scarce. The objective of present study was to examine the time-specific and prospective associations of MVPA with plasma PUFA profile among pregnant women. This study included 321 participants from the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies–Singletons cohort. Maternal plasma phospholipid PUFAs and MPVA were measured at four visits during pregnancy (10–14, 15–26, 23–31, and 33–39 gestational weeks (GW)). Associations of maternal MVPA with individual plasma PUFAs and desaturase activity were examined using generalized linear models. Maternal MVPA was associated inversely with plasma phospholipid linoleic acid, gamma-linolenic acid, and Δ6-desaturase in late pregnancy (23–31 or 33–39 GW), independent of maternal age, race, education, parity, pre-pregnancy body mass index, and dietary factors. Findings from this longitudinal study indicate that maternal habitual MVPA may play a role on PUFAs metabolism, particular by alerting plasma n-6 subclass and desaturase activity in late pregnancy. These associations are novel and merit confirmation in future studies.

The Distribution of Fatty Acid Biomarkers of Dairy Intake across Serum Lipid Fractions: The Prospective Metabolism and Islet Cell Evaluation (PROMISE) Cohort

Circulating fatty acids (FA) derived largely from dairy consumption have most commonly been measured in total human serum or phospholipid (PL) fractions, and have been used as validated biomarkers of dairy intake in a growing number of epidemiological studies. Nevertheless, measurement and characterization of a wider spectrum of FA biomarkers of dairy across the four major serum lipid fractions is lacking. This study aimed to (1) quantify FA biomarkers of dairy in PL, triacylglycerol (TAG), cholesteryl ester (CE), and unesterified fatty acid (FFA) serum lipid fractions; and (2) identify potential demographic and metabolic factors that may modify the proportions of these FA across serum fractions. Baseline data from 444 adults in the PROMISE cohort were analyzed. FA biomarkers, 15:0, t16:1n-7, 18:2-c9,t11, and t18:1n-7 were quantified from serum. Dairy intake was estimated using the validated Canadian Diet History Questionnaire. Our results show that t18:1n-7 was the most abundant FA biomarker in all fractions except CE, where 18:2-c9,t11 was the most abundant. Positive correlations within fractions, and across FA in the PL, CE, and FFA fractions were found, however, TAG FA were negatively correlated with the other fractions. PL and CE FA were positively associated with dairy intake, and negatively associated with markers of dysmetabolism while, in contrast, these markers were predictors of higher TAG dairy FA. This study is the first to demonstrate distinct proportions of dairy FA in different serum lipid fractions. PL and CE FA marked dairy intake in this cohort, while TAG FA appeared to be markers of dysmetabolism.

Sex hormones and n-3 fatty acid metabolism

α-Linolenic acid (ALA) is an n-3 fatty acid found in plant-derived foods such as linseeds and linseed oil. Mammals can convert this essential fatty acid into longer-chain fatty acids including EPA, docosapentaenoic acid (DPA) and DHA. Women demonstrate greater increases in the EPA status after ALA supplementation than men, and a growing body of animal model research identifies mechanisms by which sex hormones such as oestrogen and progesterone interact with the synthesis of EPA and DHA. Alternatively, EPA, DPA and DHA can be consumed directly, with oily fish being a rich dietary source of these nutrients. However, current National Diet and Nutrition Data reveals a median oily fish intake of 0 g daily across all age ranges and in both sexes. As longer-chain n-3 fatty acids have a crucial role in fetal and neonatal brain development, advice to consume dietary ALA could prove to be a pragmatic and acceptable alternative to advice to consume fish during pregnancy, if benefits upon tissue composition and functional outcomes can be demonstrated. Further research is required to understand the effects of increasing dietary ALA during pregnancy, and will need to simultaneously address conflicts with current dietary advice to only eat 'small amounts' of vegetable oils during pregnancy. Improving our understanding of sex-specific differences in fatty acid metabolism and interactions with pregnancy has the potential to inform both personalised nutrition advice and public health policy.

Sex Differences in Omega-3 and -6 Fatty Acids and Health Status Among Young Adults With Acute Myocardial Infarction: Results From the VIRGO Study

BACKGROUND

Young women (aged ≤55 years) with acute myocardial infarction (AMI) have poorer health status outcomes than similarly aged men. Low omega-3 fatty acids (FAs) have been implicated as risk factors for cardiovascular outcomes in AMI patients, but it is not clear whether young women have similar or different post-AMI omega-3 FA profiles compared with young men.

METHODS AND RESULTS

We assessed the sex differences in post-AMI omega-3 FAs and the associations of these biomarkers with patient-reported outcomes (symptom, functioning status, and quality of life) at 12-month follow-up, using data from 2985 US adults with AMI aged 18 to 55 years enrolled in the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young Acute Myocardial Infarction Patients) study. Biomarkers including eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid (AA), eicosapentaenoic acid/AA ratio, omega-3/omega-6 ratio, and omega-3 index were measured 1 month after AMI. Overall, the omega-3 FAs and AA were similar in young men and women with AMI. In both unadjusted and adjusted analysis (controlling for age, sex, race, smoking, hypertension, diabetes mellitus, body mass index, and health status score at 1 month), omega-3 FAs and AA were not significantly associated with 12-month health status scores using the Bonferroni corrected statistical threshold.

CONCLUSIONS

We found no evidence of sex differences in omega-3 FAs and AA in young men and women 1 month after AMI. Omega-3 FAs and AA at 1-month after AMI were generally not associated with 12-month patient-reported health status after adjusting for patient demographic, clinical characteristics, and the corresponding 1-month health status score.

Fatty acid components in Asian female patients with irritable bowel syndrome

Abdominal pain is one of the key symptoms of irritable bowel syndrome (IBS). Studies have indicated an increase in the incidence of IBS in Asia. However, yet the pathophysiology of this disease remains unknown. Women are more likely to develop the condition than men, especially the constipation-predominant type. Essential fatty acid (EFA) malnutrition is one of several theories discussing the mechanism of IBS.The authors hypothesized that significant EFA deficiency may cause abdominal pain in patients with IBS. However, because patterns in the oral intake of EFAs differ between cultures, the authors narrowed this study to examine the nutritional status of Asian female patients with IBSThe authors investigated Asian female patients with IBS and compared them with a group of healthy controls. Thirty patients with IBS and 39 healthy individuals were included in this study. The participants' age, height, weight, and waist size were recorded. The 24-item Hamilton Depression Rating Scale was documented. Both erythrocyte and plasma fatty acid content were analyzed through gas-liquid chromatography.The authors found that patients with IBS exhibited significantly higher scores for depression, higher proportions of plasma saturated fatty acids and monounsaturated fatty acids, and lower proportions of docosahexaenoic acid and total omega-3 polyunsaturated fatty acids in plasma are associated with IBS in Asian female patients. Further study is indicated to confirm the causality of this association.

Low levels of linoleic acid and α-linolenic acid and high levels of arachidonic acid in plasma phospholipids are associated with hypertension

Dietary fat is an important determinant in the development and progression of high blood pressure (BP), a major risk factor for cardiovascular diseases and mortality. The aim of the present study was to determine the association between plasma phospholipid fatty acids and hypertension in Japanese men. The plasma level of linoleic acid (LA) in the subjects with hypertension (systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg) was identified to be significantly higher than that in the healthy controls. Following adjustment for age, body mass index, physical activity, smoking status, alcohol consumption, salt intake, and serum levels of glucose and hemoglobin A1c, higher plasma levels of LA and α-linolenic acid (ALA), and lower levels of arachidonic acid (AA) were significantly associated with a lower prevalence of hypertension. The odds ratio (OR) for the highest quartile (Q4) versus the lowest quartile (Q1) of LA was 0.17 (P=0.003), the OR for Q4 versus Q1 of ALA was 0.26 (P=0.042) and the OR for Q4 versus Q1 of AA was 2.04 (P=0.047). These results indicate that elevated levels of LA and ALA, and reduced levels of AA in the plasma prevent hypertension.

Modulation of Ras/ERK and Phosphoinositide Signaling by Long-Chain n-3 PUFA in Breast Cancer and Their Potential Complementary Role in Combination with Targeted Drugs

A potential complementary role of the dietary long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFA) in combination with innovative mono-targeted therapies has recently been proposed. These compounds are thought to act pleiotropically to prevent the development and progression of a variety of cancers, including breast cancer. We hereinafter critically analyze the reports investigating the ability of LCn-3 PUFA to modulate the Ras/ERK and the phosphoinositide survival signaling pathways often aberrantly activated in breast cancer and representing the main targets of innovative therapies. The in vitro or in vivo animal and human interventional studies published up to January 2017 investigating the effects of LCn-3 PUFA on these pathways in normal and cancerous breast cells or tissues were identified through a systematic search of literature in the PubMed database. We found that, in most cases, both the in vitro and in vivo studies demonstrated the ability of LCn-3 PUFA to inhibit the activation of these pro-survival pathways. Altogether, the analyzed results strongly suggest a potential role of LCn-3 PUFA as complementary agents in combination with mono-targeted therapies. Moreover, the results indicate the need for further in vitro and human interventional studies designed to unequivocally prove the potential adjuvant role of these fatty acids.

Effect of a 2-y dietary and physical activity intervention on plasma fatty acid composition and estimated desaturase and elongase activities in children: the Physical Activity and Nutrition in Children Study

BACKGROUND

Evidence on the effects of lifestyle interventions on plasma fatty acid composition in children is limited.

OBJECTIVE

We investigated the effects of a dietary and physical activity intervention on plasma fatty acid composition of cholesteryl esters (CEs) and phospholipids and estimated desaturase and elongase activities in children.

DESIGN

We conducted a 2-y controlled dietary and physical activity intervention based on Finnish nutrition and physical activity recommendations in a population sample of 506 children aged 6-8 y. We assessed plasma fatty acid composition by gas chromatography and estimated desaturase and elongase activities as the ratio of product fatty acids to precursor fatty acids. We analyzed data by using linear mixed models adjusted for age and sex.

RESULTS

The proportion of total polyunsaturated fatty acids (PUFAs) in CEs tended to increase in the intervention group compared with the control group (P = 0.007 for group × time interaction). The proportion of total PUFAs in phospholipids (P = 0.019 for group × time interaction) and the proportion of linoleic acid in CEs (P = 0.038 for group × time interaction) decreased in the control group. The proportion of α-linolenic acid in CEs (P < 0.001 for group × time interaction) increased and in phospholipids (P = 0.015 for group × time interaction) tended to increase in the intervention group. The proportion of stearic acid in CEs decreased in the intervention group (P = 0.001 for group × time interaction). The proportion of oleic acid in CEs (P = 0.002 for group × time interaction) increased and in phospholipids (P = 0.023 for group × time interaction) tended to increase in the control group. Estimated elongase activity in CEs decreased in the control group (P = 0.050 for group × time interaction). Intervention had no effect on estimated desaturase activities.

CONCLUSIONS

Dietary and physical activity intervention had a beneficial effect on plasma fatty acid composition in children by preventing the decrease in the proportion of total PUFAs and linoleic acid and by increasing the proportion of α-linolenic acid. This study was registered at clinicaltrials.gov as NCT01803776.

Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults

Studies reporting blood levels of the omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were systematically identified in order to create a global map identifying countries and regions with different blood levels. Included studies were those of healthy adults, published in 1980 or later. A total of 298 studies met all inclusion criteria. Studies reported fatty acids in various blood fractions including plasma total lipids (33%), plasma phospholipid (32%), erythrocytes (32%) and whole blood (3.0%). Fatty acid data from each blood fraction were converted to relative weight percentages (wt.%) and then assigned to one of four discrete ranges (high, moderate, low, very low) corresponding to wt.% EPA+DHA in erythrocyte equivalents. Regions with high EPA+DHA blood levels (>8%) included the Sea of Japan, Scandinavia, and areas with indigenous populations or populations not fully adapted to Westernized food habits. Very low blood levels (≤4%) were observed in North America, Central and South America, Europe, the Middle East, Southeast Asia, and Africa. The present review reveals considerable variability in blood levels of EPA+DHA and the very low to low range of blood EPA+DHA for most of the world may increase global risk for chronic disease.

Exploratory serum fatty acid patterns associated with blood pressure in community-dwelling middle-aged and elderly Chinese

Background

Epidemiological studies have assessed relationships between circulating levels of fatty acid (FA) and blood pressure (BP), and their results remain controversial. Nevertheless, data are sparse on serum FA as biomarker and BP in China. The aim of the study was to investigate the association between serum FA and BP in Chinese populations.

Methods

We conducted a cross-sectional study nested within a community-based cohort of 2447 Chinese participants aged 35–79 years who completed a baseline assessment between October 2012 and April 2013. Baseline assessment included the collection of fasting blood samples, anthropometric measurements and a personal interview using a validated questionnaire. Serum FA was determined by gas-liquid chromatography. Exploratory factor analyses were employed to identify FA-factor as a reflection of serum FA pattern. A multiple regression model was conducted to estimate adjusted mean of BP with 95 % confidence interval (CI) by tertile groups of the generated FA-factor scores.

Results

Hypertensive patients have significantly higher serum 14:0, 16:0, 16:1n-7, 18:3n-6, 20:3n-6 and Δ⁶-desaturase index (18:3n-6/18:2n-6) as well as lower 18:2n-6, 22:6n-3 and Δ⁵-desaturase index (20:4n-6/20:3n-6) compared with normotensive participants. Factor 1 (low linoleic acid/high saturated FA pattern: 14:0, 16:0, 16:1n-7, 18:2n-6, 18:3n-6, 20:3n-6) and Factor 2 (n-3 PUFA pattern: 20:5n-3, 22:5n-3, 22:6n-3, 18:1n-9) were identified as indicators of the serum FA pattern. After adjustment for age, gender, body mass index, hypertension treatment, smoking, alcohol intake, education, profession, exercise habit, salt intake, family history of hypertension, heart rate, blood lipids and fasting blood-glucose levels, per a standard deviation (SD) increment of Factor 1 scores was associated with an increment of 2.44 (95 % CI: 1.73, 3.15) mm Hg for systolic BP, whereas per a SD increment of Factor 2 scores was associated with a reduction of 1.40 (95 % CI: 0.80, 2.04) mm Hg for diastolic BP.

Conclusions

The serum FA pattern characterized by low proportions of 14:0, 16:0, 16:1n-7 and 18:3n-6 as well as high 18:2n-6 and 22:6n-3 was beneficially associated with BP levels in this Chinese population. This evidence well supports the current dietary recommendations in the communities to replace saturated fat with polyunsaturated fat.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-016-0226-3) contains supplementary material, which is available to authorized users.

Cross-sectional relationships between dietary fat intake and serum cholesterol fatty acids in a Swedish cohort of 60-year-old men and women

BACKGROUND

The present study aimed to describe the relationship between self-reported dietary intake and serum cholesterol fatty acids (FAs) in a Swedish population of 60-year-old men and women.

METHODS

Cross-sectional data collected in 1997-1998 from 4232 individuals residing in Stockholm County were used. Five diet scores were created to reflect the intake of saturated fats in general, as well as fats from dairy, fish, processed meat and vegetable oils and margarines. Gas chromatography was used to assess 13 FAs in serum cholesterol esters. The association between each diet score and specific FAs was assessed by percentile differences (PD) with 95% confidence intervals (CI) at the 10th, 25th, 50th, 75th and 90th percentile of each FA across levels of diet scores using quantile regression.

RESULTS

Fish intake was associated with high proportions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). For each point increase in fish score, the 50th PD in EPA and DHA was 32.78% (95% CI = 29.22% to 36.35%) and 10.63% (95% CI = 9.52% to 11.74%), respectively. Vegetable fat intake was associated with a high proportion of linoleic acid and total polyunsaturated fatty acids (PUFA) and a low proportion of total saturated fatty acids (SFA). The intake of saturated fats in general and dairy fat was slightly associated with specific SFA, although the intake of fat from meat was not.

CONCLUSIONS

In the present study population, using a rather simple dietary assessment method, the intake of fish and vegetable fats was clearly associated with serum PUFA, whereas foods rich in saturated fats in general showed a weak relationship with serum SFA. Our results may contribute to increased knowledge about underlying biology in diet-cardiovascular disease associations.

Serum long-chain omega-3 polyunsaturated Fatty acids and future blood pressure in an ageing population

OBJECTIVES

To investigate the associations of serum long-chain omega-3 polyunsaturated fatty acids (PUFA) and hair mercury with future blood pressure in an ageing population.

DESIGN

Prospective study with baseline measurements in 1998-2001 and follow-up measurements in 2005-2008. The linear relationships (β) of baseline serum fatty acids and hair mercury with future systolic and diastolic blood pressure and pulse pressure were analyzed with multiple linear regression models, using log-transformed values.

PARTICIPANTS

181 men and 200 women aged 53-73 y from the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD) population in Eastern Finland, who were free of cardiovascular disease, diabetes or hypertension at baseline.

MEASUREMENTS

Total serum esterified and nonesterified fatty acids and pubic hair mercury were used as markers for exposure. Anthropometric and other lifestyle and health-related data were collected.

RESULTS

The mean serum concentrations were 1.67% (SD 0.92) for eicosapentaenoic acid (EPA), 0.79% (SD 0.16) for docosapentaenoic acid (DPA) and 2.78 (SD 0.92) for docosahexaenoic acid (DHA), of all serum fatty acids. The mean hair mercury concentration was 1.5 µg/g (SD 1.6). We did not find statistically significant associations between the baseline serum long-chain omega-3 PUFA concentrations or hair mercury content and future blood pressure. Hair mercury did not modify the associations with the long-chain omega-3 PUFAs, either.

CONCLUSIONS

Higher serum long-chain omega-3 PUFA concentration, a biomarker of fish or fish oil consumption, may not have an impact on future blood pressure in an ageing population.

Cross-sectional associations of food consumption with plasma fatty acid composition and estimated desaturase activities in Finnish children

Plasma fatty acid (FA) composition is known to be an indicator of dietary fat quality, but the associations of other dietary factors with plasma FA composition remain unknown in children. We investigated the cross-sectional associations of food consumption with the proportions of FA and estimated desaturase activities in plasma cholesteryl esters (CE) and phospholipids (PL) among children. The subjects were a population sample of 423 children aged 6–8 years examined at baseline of The Physical Activity and Nutrition in Children (PANIC) Study. We assessed food consumption by food records and plasma FA composition by gas chromatography. We used linear regression models adjusted for age, sex, physical activity and total energy intake to analyze the associations. A higher consumption of vegetable oil-based margarine (fat 60–80 %) was associated with a higher proportion of linoleic and α-linolenic acids in plasma CE and PL. A higher consumption of high-fiber grain products was related to a lower proportion of oleic acid in CE and PL. The consumption of candy was directly associated with the proportion of palmitoleic and oleic acid in plasma CE. The consumption of vegetable oil-based margarine was inversely associated with estimated stearoyl-CoA-desaturase activity in plasma CE and PL and the consumption of candy was directly related to it in plasma CE. The results of our study suggest that plasma FA composition is not only a biomarker for dietary fat quality but also reflects the consumption of high-fiber grain products and foods high in sugar among children.

The lipid profile of brown adipose tissue is sex-specific in mice

Brown adipose tissue (BAT) is a thermogenic organ with a vital function in small mammals and potential as metabolic drug target in humans. By using high-resolution LC-tandem-mass spectrometry, we quantified 329 lipid species from 17 (sub)classes and identified the fatty acid composition of all phospholipids from BAT and subcutaneous and gonadal white adipose tissue (WAT) from female and male mice. Phospholipids and free fatty acids were higher in BAT, while DAG and TAG levels were higher in WAT. A set of phospholipids dominated by the residue docosahexaenoic acid, which influences membrane fluidity, showed the highest specificity for BAT. We additionally detected major sex-specific differences between the BAT lipid profiles, while samples from the different WAT depots were comparatively similar. Female BAT contained less triacylglycerol and more phospholipids rich in arachidonic and stearic acid whereas another set of fatty acid residues that included linoleic and palmitic acid prevailed in males. These differences in phospholipid fatty acid composition could greatly affect mitochondrial membranes and other cellular organelles and thereby regulate the function of BAT in a sex-specific manner.

Age and sex differences in the incorporation of EPA and DHA into plasma fractions, cells and adipose tissue in humans

The aim of the present study was to determine whether age and sex influence both the status and incorporation of EPA and DHA into blood plasma, cells and tissues. The study was a double-blind, randomised, controlled intervention trial, providing EPA plus DHA equivalent to 0, 1, 2 or 4 portions of oily fish per week for 12 months. The participants were stratified by age and sex. A linear regression model was used to analyse baseline outcomes, with covariates for age or sex groups and by adjusting for BMI. The change in outcomes from baseline to 12 months was analysed with additional adjustment for treatment and average compliance. Fatty acid profiles in plasma phosphatidylcholine, cholesteryl esters, NEFA and TAG, mononuclear cells (MNC), erythrocyte membranes, platelets, buccal cells (BU) and adipose tissue (AT) were determined. At baseline, EPA concentrations in plasma NEFA and DHA concentrations in MNC, BU and AT were higher in females than in males (all P< 0·05). The concentrations of EPA in AT (P= 0·003) and those of DHA in plasma TAG (P< 0·01) and AT (P< 0·001) were higher with increasing age. Following 12-month supplementation with EPA plus DHA, adjusted mean difference for change in EPA concentrations in plasma TAG was significantly higher in females than in males (P< 0·05) and was greater with increasing age (P= 0·02). Adjusted mean difference for change in DHA concentrations in AT was significantly smaller with increasing age (P= 0·02). Although small differences in incorporation with age and sex were identified, these were not of sufficient magnitude to warrant a move away from population-level diet recommendations for n-3 PUFA.

Serum omega-3 polyunsaturated fatty acids and risk of incident type 2 diabetes in men: the Kuopio Ischemic Heart Disease Risk Factor study

OBJECTIVE The relationship between fish or omega-3 polyunsaturated fatty acids (PUFAs) and type 2 diabetes is inconclusive. Even contaminants in fish, such as mercury, may modify the effects. We investigated the associations between serum omega-3 PUFAs eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), α-linolenic acid (ALA), hair mercury, and risk of incident type 2 diabetes in middle-aged and older Finnish men. RESEARCH DESIGN AND METHODS A total of 2,212 men from the prospective, population-based Kuopio Ischemic Heart Disease Risk Factor study, aged 42-60 years and free of type 2 diabetes at baseline in 1984-1989, were investigated. Serum PUFA and hair mercury were used as biomarkers for exposure. Dietary intakes were assessed with 4-day food recording. Type 2 diabetes was assessed by self-administered questionnaires and fasting and 2-h oral glucose tolerance test blood glucose measurement at re-examination rounds 4, 11, and 20 years after the baseline and by record linkage to hospital discharge registry and reimbursement register on diabetes medication expenses. Cox proportional hazards models were used to analyze associations. RESULTS During the average follow-up of 19.3 years, 422 men developed type 2 diabetes. Men in the highest versus the lowest serum EPA + DPA + DHA quartile had 33% lower multivariate-adjusted risk for type 2 diabetes (95% CI 13-49; P trend 0.01). No statistically significant associations were observed with serum or dietary ALA, dietary fish or EPA + DHA, or hair mercury. CONCLUSIONS Serum long-chain omega-3 PUFA concentration, an objective biomarker for fish intake, was associated with long-term lower risk of type 2 diabetes.

Delta-6-desaturase gene polymorphism is associated with lipoprotein oxidation in vitro

Background

Oxidative modification of low-density lipoprotein (LDL) is a key event in the oxidation hypothesis of atherogenesis. We have previously shown that HDL does not protect LDL from oxidation in vitro, but is in fact oxidized fastest of all lipoproteins due to its rich polyunsaturated fatty acid (PUFA) composition, which is oxidation promoting. Evidence has accumulated to show that in addition to diet, common polymorphisms in the fatty acid desaturase (FADS) gene cluster have very marked effects on human PUFA status. There is a deletion [T/-] in the promoter region of the Δ⁶ –desaturase gene (FADS2, rs 3834458), which has a direct inhibitory influence on production of PUFA from linoleic and alpha-linolenic acid. To investigate the possible role of rs 3834458 in lipoprotein modification, oxidation of LDL with HDL₂ or HDL₃ were analyzed from plasma of 58 free-living individuals.

Results

Total eicosapentaenoic acid and arachidonic acid were significantly decreased in plasma from the 10 subjects homozygous for the deletion in FADS2 rs 3834458. When the isolated LDL and HDL₂ were subjected to Cu²⁺-induced oxidation, these subjects showed decreased rate of appearance (p = 0.027) and the final concentration of conjugated dienes (p = 0.033) compared to the other genotypes. For oxidation of LDL with HDL₃, the final concentration of conjugated dienes was also significantly decreased in subjects with [−/−] compared with [T/T] and [T/-] (p = 0.034).

Conclusion

We conclude that FADS2 genotype may play a role in peroxidation susceptibility of lipoproteins.

Gender differences in the long-chain polyunsaturated fatty acid status: systematic review of 51 publications

BACKGROUND/AIMS

Sex hormones may influence the activity of enzymes which are involved in the synthesis of long-chain polyunsaturated fatty acids. The objective of this review was to assess the role of gender in determining the fatty acid composition of human samples, like plasma and erythrocyte membrane lipids, and adipose tissue.

METHODS

The method included a structured search strategy on MEDLINE, Scopus and the Cochrane databases, with formal inclusion/exclusion criteria, data extraction procedure and meta-analysis.

RESULTS

We evaluated 51 publications, dated from 1975 to 2011. Meta-analysis showed significantly lower values of both arachidonic acid (AA) and docosahexaenoic acid (DHA) in total plasma lipids (32 and 33 studies) and in plasma phospholipids (PL; 21 and 23 studies) in men than in women. Primary analysis of the phospholipid fraction showed the mean difference in AA to be 0.42% weight/weight (95% CI: 0.18-0.65, n = 7,769) and in DHA 0.37% weight/weight (95% CI: 0.24-0.51, n = 8,541), while there was no gender difference in the values of linoleic acid and α-linolenic acid.

CONCLUSIONS

This systematic review based on 51 publications showed significantly lower contribution of AA and DHA to plasma total lipids and plasma PL in men than in women. Gender distribution should be regarded as a significant potential confounding factor in every study assessing data on fatty acid composition.

Genetic variation at the FADS1-FADS2 gene locus influences delta-5 desaturase activity and LC-PUFA proportions after fish oil supplement

Delta-5 and delta-6 desaturases (D5D and D6D) are key enzymes in endogenous synthesis of long-chain PUFAs. In this sample of healthy subjects (n = 310), genotypes of single nucleotide polymorphisms (SNPs) rs174537, rs174561, and rs3834458 in the FADS1-FADS2 gene cluster were strongly associated with proportions of LC-PUFAs and desaturase activities estimated in plasma and erythrocytes. Minor allele carriage associated with decreased activities of D5D (FADS1) (5.84 × 10(-19) ≤ P ≤ 4.5 × 10(-18)) and D6D (FADS2) (6.05 × 10(-8) ≤ P ≤ 4.20 × 10(-7)) was accompanied by increased substrate and decreased product proportions (0.05 ≤ P ≤ 2.49 × 10(-16)). The significance of haplotype association with D5D activity (P = 2.19 × 10(-17)) was comparable to that of single SNPs, but haplotype association with D6D activity (P = 3.39 × 10(-28)) was much stronger. In a randomized controlled dietary intervention, increasing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) intake significantly increased D5D (P = 4.0 × 10(-9)) and decreased D6D activity (P = 9.16 × 10(-6)) after doses of 0.45, 0.9, and 1.8 g/day for six months. Interaction of rs174537 genotype with treatment was a determinant of D5D activity estimated in plasma (P = 0.05). In conclusion, different sites at the FADS1-FADS2 locus appear to influence D5D and D6D activity, and rs174537 genotype interacts with dietary EPA+DHA to modulate D5D.

Serum long-chain n-3 polyunsaturated fatty acids, mercury, and risk of sudden cardiac death in men: a prospective population-based study

Objectives

Fish consumption has been associated with reduced risk of cardiovascular diseases (CVD), especially sudden cardiac death (SCD). Fish is the major source of long-chain n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid and docosahexaenoic acid. It is also a major source of methylmercury, which was associated with increased risk of CVD in this study population. Impact of interaction between long-chain n-3 PUFA and methylmercury on the SCD risk is unknown.

Methods

A total of 1857 men from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor study, aged 42–60 years and free of CVD at baseline in 1984–1989, were studied. Serum long-chain n-3 PUFA was used as the marker for long-chain n-3 PUFA intake and hair mercury as the marker for mercury exposure.

Results

During the mean follow-up of 20.1 years, 91 SCD events occurred. In the multivariate Cox proportional hazards regression models, serum long-chain n-3 PUFA concentration was not associated with the risk of SCD until hair mercury was accounted for; then the hazard ratio (HR) in the highest vs. lowest tertile was 0.54 [95% confidence interval (CI) 0.32 to 0.91, p for trend  = 0.046]. When the analyses were stratified by hair mercury content, among those with lower hair mercury, each 0.5 percentage unit increase in the serum long-chain n-3 PUFA was associated with HR of 0.77 (95% CI 0.64 to 0.93), whereas no association was seen among those with higher hair mercury (p for interaction  = 0.01). Among the individual long-chain n-3 PUFA, docosahexaenoic acid was most strongly associated with the risk.

Conclusion

High exposure to mercury may reduce the benefits of long-chain n-3 PUFA on SCD.

Serum long-chain n-3 polyunsaturated fatty acids, methylmercury and blood pressure in an older population

Fish or fish oil consumption has been associated with lower blood pressure. Fish may also contain methylmercury, which has been associated with cardiovascular diseases and higher blood pressure. Our aim was to study the associations of serum long-chain n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), mainly reflecting fish or fish oil intake, and hair mercury concentration with blood pressure. Data were available for 848 men and 909 women from the Kuopio Ischaemic Heart Disease Risk Factor Study, aged 53-73 years. We excluded participants with ischemic heart disease, stroke, diabetes or hypertension treatment, leaving 396 men and 372 women. Log-transformed values were used to study the associations. The mean serum concentrations were 1.63% (s.d. 0.91) for EPA, 0.77% (s.d. 0.16) for DPA and 2.73% (s.d. 0.90) for DHA of all serum fatty acids. Multivariate-adjusted serum EPA+DPA+DHA was associated with lower systolic blood pressure (β = -4.50, 95% confidence interval (CI) -8.02 - -0.99) and pulse pressure (β = -4.41, 95% CI -6.95 - -1.87), but not with diastolic blood pressure (β = -0.45, 95% CI -2.31-1.52). The associations were similar with EPA, DPA and DHA evaluated individually. The mean hair mercury concentration was 1.42 μg g(-1) (s.d. 1.54). Hair mercury was not associated with blood pressure and it did not modify the association between PUFA and blood pressure. These results suggest that higher serum long-chain n-3 PUFA concentration has a modest inverse association with blood pressure in older men and women.

Childhood serum cholesterol ester fatty acids are associated with blood pressure 27 y later in the Cardiovascular Risk in Young Finns Study

BACKGROUND

In adults, dietary fatty acids (FAs) modify blood pressure (BP), but it is not known whether childhood FA quality is associated with adulthood BP.

OBJECTIVE

The purpose of the study was to investigate links between childhood serum cholesterol ester fatty acid (CEFA) proportions and adulthood systolic blood pressure (SBP) and diastolic blood pressure (DBP).

DESIGN

We examined a cohort of 803 boys and girls (aged 3-18 y at baseline in 1980 and followed for 27 y) by using regression models adjusted for the known risk factors of BP. CEFAs were analyzed as markers of dietary FA intake.

RESULTS

In men, serum SFA (B = 2.97, P < 0.001 for SBP; B = 1.48, P = 0.015 for DBP), MUFA (B = 0.61, P = 0.001 for SBP; B = 0.27, P = 0.078 for DBP), and omega-3 (n-3) PUFA (B = 5.50, P < 0.001 for SBP; B = 2.47, P = 0.015 for DBP) proportions, which were derived mainly from animal fats in this population, were positively associated with BP, whereas the omega-6 (n-6) PUFA proportion, which was derived mainly from vegetable oils and margarines, was negatively associated with BP (B = -0.56, P < 0.001 for SBP; B = -0.27, P < 0.018 for DBP). Serum cholesterol ester SFA and PUFA associations were supported by dietary intake data. In women, the associations between CEFA proportions and BP were weaker [for SBP: B = 0.36, P = 0.638 (NS) for SFA; B = 0.44, P = 0.019 for MUFA; B = 1.18, P = 0.376 (NS) for n-3 PUFA; and B = -0.33, P = 0.023 for n-6 PUFA].

CONCLUSION

Our findings suggest that fat quality as reflected in the serum cholesterol ester fraction in childhood is independently associated with adulthood BP particularly in men but also, to some extent, in women.

Changes in rat n-3 and n-6 fatty acid composition during pregnancy are associated with progesterone concentrations and hepatic FADS2 expression

The mechanisms responsible for changes to long-chain polyunsaturated fatty acid (LC PUFA) status during pregnancy have not been fully elucidated. Tissue samples were collected from virgin and pregnant (day 12 and 20) female rats. LC PUFA status, sex hormone concentrations and hepatic mRNA expression of FADS1, FADS2 and elongase were assessed. Day 20 gestation females had higher plasma and liver docosahexaenoic acid and lower arachidonic acid content than virgin females (P<0.05). There was higher FADS2 mRNA expression during pregnancy (P=0.051). Progesterone and oestradiol concentrations positively correlated with hepatic FADS2 mRNA expression (P=0.043, P=0.004). Progesterone concentration positively correlated with hepatic n-6 docosapentaenoic acid content (P=0.006), and inversely correlated with intermediates in LC PUFA synthesis including n-3 docosapentaenoic acid, γ-linolenic acid and 20:2n-6 (P<0.05). Changes in progesterone and oestradiol during pregnancy may promote the synthesis of LC PUFA via increased FADS2 expression.

Dietary intake of PUFAs and colorectal polyp risk

BACKGROUND

Marine-derived n-3 (omega-3) PUFAs may reduce risk of developing colorectal cancer; however, few studies have investigated the association of n-3 PUFA intakes on colorectal polyp risk.

OBJECTIVE

The objective of this study was to examine the associations of dietary PUFA intake on risk of colorectal adenomatous and hyperplastic polyps.

DESIGN

This was a colonoscopy-based case-control study that included 3166 polyp-free control subjects, 1597 adenomatous polyp cases, and 544 hyperplastic polyp cases. Dietary PUFA intake was calculated from food-frequency questionnaires and tested for association by using unconditional logistic regression. The urinary prostaglandin E(2) metabolite, which is a biomarker of prostaglandin E(2) production, was measured in 896 participants by using liquid chromatography and tandem mass spectrometry.

RESULTS

n-6 PUFAs were not associated with adenomatous or hyperplastic polyps in either men or women. Marine-derived n-3 PUFAs were associated with reduced risk of colorectal adenomas in women only, with an adjusted OR of 0.67 (95% CI: 0.47, 0.97) for the highest quintile of intake compared with the lowest quintile of intake (P-trend = 0.01). Dietary intake of α-linolenic acid was associated with an increased risk of hyperplastic polyps in men (P-trend = 0.03), which was not seen in women. In women, but not in men, dietary intake of marine-derived n-3 PUFAs was negatively correlated with urinary prostaglandin E(2) production (r = -0.18; P = 0.002).

CONCLUSION

Higher intakes of marine-derived n-3 PUFAs are associated with lower risk of adenomatous polyps in women, and the association may be mediated in part through a reduction in the production of prostaglandin E(2). This trial was registered at clinicaltrials.gov as NCT00625066.

Unfavourable plasma and erythrocyte phospholipid fatty acid profile in elite amateur boxers

Research on possible physiological changes as a consequence of a specific lifestyle and long-term strenuous exercise in boxing has been sparse. We determined plasma and erythrocyte phospholipid (PL) fatty acids (FA) profile of 16 elite amateur male boxers (22.4±3.3 years of age), and compared them with a control group composed of 19 sedentary (24.4±3.4) year-old men. The percentages of total saturated fatty acids (SFA) and monosaturated FA in plasma phospholipids were significantly higher (P <0.001) in boxers compared to the control group. On the other hand, all studied polyunsaturated fatty acids (PUFA) in plasma PL with the exception of eicosapentaenoic acid (EPA, 20:5, n-3) and docosatetraenoic acid (DTA, 22:4, n-6) were significantly lower in boxers than in sedentary men. Total PUFA, n-6 PUFA and n-3 PUFA were also significantly lower in boxers (P <0.001), whereas the n-6/n-3 ratio was higher in boxers than in control group (P <0.01). Boxers had significantly higher proportion of all SFA in erythrocyte PL compared to the control group (P <0.05). In addition, the percentage of linoleic acid was lower in boxers' erythrocyte PL than in the control group (P <0.05). The results show two potentially unfavourable main features of the FA profile of boxers, that is, a higher n-6/n-3 ratio in plasma PL and a higher percentage of SFA in both plasma and erythrocyte phospholipids compared to controls. As SFA correlates directly with the incidence of cardiovascular disease and high n-6/n-3 ratio has been shown to stimulate carcinogenesis and modulate inflammation and autoimmunity, this profile could be detrimental to the health of boxers. The mechanism underlying these differences requires further investigation; however the results suggest benefits of nutritional intervention.

Serum lipid and fatty acid profiles are highly changed in patients with alcohol induced acute pancreatitis

BACKGROUND/AIMS

Hyperlipidemia is one known etiology of acute pancreatitis. Alcohol use is known to induce changes in lipid metabolism and might alter the serum lipid and fatty acid profile. We hypothesized that these changes may explain individual susceptibility of developing acute pancreatitis. We compared lipid and fatty acid profiles of patients with acute alcoholic pancreatitis and alcoholic controls.

METHODS

19 patients with their first alcoholic pancreatitis and 20 controls were included. Late follow-up samples were obtained from 16 patients. Serum lipids were analyzed enzymatically and the fatty acid profile using gas chromatography.

RESULTS

The concentrations of serum total cholesterol, LDL-cholesterol and HDL-cholesterol were markedly lower in patients than in controls during the acute disease but normalized after follow-up. Patients had statistically significantly lower fatty acid proportions of saturated C14:0, polyunsaturated C18:2, C18:3 and C20:3 of the n-6-series and C18:3 of the n-3-series than controls. In contrast, patients had higher percentages of saturated C16:0 and monounsaturated C18:1n9 fatty acids than controls. Mead acid, C20:3n9, marker of essential fatty acid deficiency, was lower in patients than in controls. C14:0, C20:3n6, C18:3n3 and C20:3n9 remained altered after follow-up.

CONCLUSION

Serum lipid and fatty acid levels were significantly altered during the acute disease and returned toward normal after 18-24 months, suggesting that the changes are secondary to acute pancreatitis. They are unlikely to be the much sought 'trigger factor' of pancreatic necro-inflammation. However, further studies are warranted to fully establish this point.

Sex-specific differences in essential fatty acid metabolism

Sex hormones may influence the enzymatic synthesis of long-chain polyunsaturated fatty acids (LC-PUFAs), which may lead to sex-specific differences in LC-PUFA status. Isotope studies with U-(13)C α-linolenic acid (ALA) have shown a considerably higher conversion rate of ALA to n-3 (omega-3) LC-PUFAs in women than in men. A review of the literature generally suggested that there was a higher contribution of arachidonic acid (AA) and docosahexaenoic acid (DHA) in blood lipids in women than in men; however, sex-specific differences were not seen in every study. The fatty acid composition of plasma phospholipids was recently reported separately for a large group of women and men (n > 3000) living in 15 regions of Europe. The contributions of saturated and monounsaturated fatty acids were higher, whereas those of AA and DHA were lower in men than in women; however, sex explained only ≈ 2% of the variability of plasma phospholipid DHA values. Results reported from a limited number of randomized controlled trials of perinatal LC-PUFA supplementation have, on occasion, shown sex-specific differences in some outcomes; however, the heterogeneity both in the interventions and outcomes measured made it difficult to draw conclusions on the direction or the extent of the effects. Data summarized in the current review highlight the importance of planning a subgroup analysis by sex in perinatal LC-PUFA supplementation trials.

Association of serum n-3 polyunsaturated fatty acids with C-reactive protein in men

BACKGROUND/OBJECTIVES

N-3 polyunsaturated fatty acids (PUFAs) have been associated with reduced inflammation. We tested the hypothesis that high serum concentrations of the n-3 PUFAs are associated with lower serum C-reactive protein (CRP) concentrations in healthy middle-aged Finnish men. We also examined whether exposure to mercury, an environmental contaminant in fish, which is also a major source of long-chain n-3 PUFA, was associated with CRP.

SUBJECTS/METHODS

Data from the prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor Study were analyzed cross-sectionally to determine the associations between serum n-3 PUFAs, hair mercury and serum CRP in 1395 healthy men, aged 42-60 years. Linear regression analyses were performed to analyze the associations.

RESULTS

In the multivariate models, the mean serum CRP in quartiles of serum total n-3 PUFA concentration was 1.23, 1.27, 1.18 and 1.08 mg/l, P for trend = 0.01. Statistically significant inverse associations were also observed with the total serum long-chain n-3 PUFA concentration and with the individual long-chain n-3 PUFAs docosapentaenoic acid and docosahexaenoic acid, but not with eicosapentaenoic acid or with the intermediate-chain n-3 PUFA alpha-linolenic acid. Hair methylmercury content was not associated with serum CRP levels and it did not modify the associations between serum n-3 PUFAs and CRP either.

CONCLUSIONS

Serum n-3 PUFAs and especially the long-chain n-3 PUFA concentration, a marker of fish or fish oil consumption, were inversely associated with serum CRP in men. Exposure to mercury was not associated with serum CRP.

Fatty acids in serum and diet--a canonical correlation analysis among toddlers

Fatty acid concentrations in blood are potential biomarkers of dietary fat intake, but methodological studies among children are scarce. The large number of fatty acids and their complex interrelationships pose a special challenge in research on fatty acids. Our target was to assess the interrelationships between the total fatty acid profiles in diet and serum of young children. The study subjects were healthy control children from the birth cohort of the Type 1 Diabetes Prediction and Prevention Study. A 3-day food record and a frozen serum sample were available from 135 children at the age of 1 year, from 133 at 2 years, and from 92 at 3 years. The relationship between dietary and serum fatty acid profiles was analysed using canonical correlation analysis. The consumption of fatty milk correlated positively with serum fatty acids, pentadecanoic acid, palmitic acid and conjugated linoleic acid (CLA) at all ages. Correlations between dietary and serum eicosapentaenoic and/or docosahexaenoic acid were observed at 2 and 3 years of age. Serum linoleic acid was positively associated with the consumption of infant formula at the age of 1 year, and with the consumption of vegetable margarine at 2 and 3 years. The results indicate a high quality of the 3-day food records kept by parents and other caretakers of the children, and suitability of non-fasting, un-fractioned serum samples for total fatty acid analyses. The correlation between intake of milk fat and serum proportion of CLA is a novel finding.

Alterations in circulating fatty acid composition in patients with systemic lupus erythematosus: a pilot study

INTRODUCTION

Circulating fatty acids (FAs) may play a role in the disease pathogenesis of patients with systemic lupus erythematosus (SLE).

OBJECTIVES

To compare red blood cell (RBC) and plasma FA composition: (1) between female SLE patients and age-matched healthy female (HF) controls and in SLE with history of cardiovascular disease (CVD) and those with no history (SLE+CVD vs SLE-CVD); and (2) between SLE patients who were or were not receiving prednisone treatment at the time of blood sampling.

METHODS

This cross-sectional study consisted of 33 female patients with SLE (11 SLE+CVD, 22 SLE-CVD) and 20 HF controls. Demographics, CVD risk, medication profile, blood biochemistry, and FA composition of RBC and plasma total lipids were determined.

RESULTS

Waist circumference and body mass index were higher in SLE patients than in HF controls. These variables along with serum triglycerides, blood glucose, and systolic blood pressure were higher in SLE+CVD than SLE-CVD patients. RBC FA composition showed lower eicosapentaenoic acid (EPA, ω-3 active metabolite) and ω-3 index (EPA+ docosahexaenoic acid) in SLE patients compared with HF controls. The ratio of the RBC inflammatory metabolite, arachidonic acid, to the anti-inflammatory metabolite EPA was also significantly higher in SLE patients than in HF controls. No differences were seen in plasma FA between SLE and HF groups. However, SLE-CVD patients had a more favorable lipid profile than SLE+CVD patients. In SLE patients, the use of prednisone resulted in alteration of both RBC and plasma FA composition.

CONCLUSION

SLE patients, regardless of their history of CVD, have altered plasma and RBC FA composition favoring inflammation. The use of prednisone was associated with differences in FA profile.

Serum fatty acid profile in subjects with irritable bowel syndrome

OBJECTIVE

Irritable bowel syndrome (IBS) is a fluctuating disorder of the gastrointestinal tract, characterized by abdominal pain and change in bowel habit. We wanted to investigate subjects with IBS for signs of disturbed intestinal absorption of fatty acids, as reflected in serum composition.

MATERIAL AND METHODS

Serum samples were obtained from 32 adults with IBS, and from 59 controls. Serum fatty acids were analyzed by capillary gas-liquid chromatography.

RESULTS

Especially the proportions of arachidonic acid (20:4 n-6) and the long-chain polyunsaturated fatty acids of the n-3 family docosapentaenoic acid (22:5 n-3) and docosahexaenoic acid (22:6 n-3) were decreased in subjects with IBS. The proportions of unsaturated and monounsaturated fatty acids were generally increased in IBS compared to controls.

CONCLUSIONS

Although organic disease has been ruled out in patients with IBS, they presented signs of inadequate supply of long-chain fatty acids. Supplementation with n-3 fatty acids may be implicated.

Nutrition and human health from a sex-gender perspective

Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.

Serum polyunsaturated fatty acids are not associated with the risk of severe depression in middle-aged Finnish men: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) study

PURPOSE

The aim of this study is to investigate whether serum n - 3 polyunsaturated fatty acids (PUFAs) or n - 6 to n - 3 ratio is associated with risk of severe depression in middle-aged Finnish men.

METHODS

The association between the serum concentrations of fatty acids and depression was investigated in 2077 men aged 42-60 years at baseline in a prospective follow-up setting. The population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study cohort was recruited between 1984 and 1989 and followed until the end of 2007. The baseline levels of serum total n - 3 PUFAs, n - 6 PUFAs and individual fatty acids were determined. Data on hospital treatments due to major depressive disorder were derived from the national hospital discharge register.

RESULTS

During the average follow-up time of 18 years, 46 men received a discharge diagnosis of depression. When the Cox proportional hazards model was adjusted for age, examination year, baseline socioeconomic status, alcohol consumption, smoking, maximal oxygen uptake and body mass index, there was no association between serum total n - 3 PUFAs and the risk of depression [relative risk (RR) in the highest compared to the lowest tertile 0.71, 95% confidence interval (CI): 0.38; 1.43]. Serum concentrations of n - 6 PUFAs, n6/n3 PUFA ratio, or individual fatty acids were not associated with the risk of severe depression, either.

CONCLUSIONS

We did not find evidence that serum n - 3 PUFA concentration or n - 6/n - 3 ratio would be associated with risk of severe depression in middle-aged Finnish men.

Serum fatty acid profile in celiac disease patients before and after a gluten-free diet

OBJECTIVE

Celiac disease (CD) is characterized by villous atrophy with crypt hyperplasia and inflammation of the small intestinal mucosa leading to disturbed epithelial transport. In untreated CD, fat malabsorption can occur. The aim of this study was to investigate the profile of serum fatty acids in newly detected CD before and after treatment with a gluten-free diet.

MATERIAL AND METHODS

Serum samples were obtained from 50 adults with active CD showing small-bowel mucosal villous atrophy, from the same patients in remission after treatment with a gluten-free diet, and from 59 controls. Serum fatty acids were analyzed by capillary gas-liquid chromatography.

RESULTS

Especially the proportions of arachidonic acid (20:4 n-6) and the long-chain polyunsaturated fatty acids of the n-3 family docosapentaenoic acid (22:5 n-3) and docosahexaenoic acid (22:6 n-3) were decreased in subjects with active CD. Serum levels of these fatty acids increased during remission, but still remained significantly lower than control values. Levels of unsaturated and monounsaturated fatty acids were generally increased in subjects with CD compared with those in controls.

CONCLUSIONS

In patients with CD, determination of serum fatty acid composition can be considered if the dietary history or symptoms suggest an inadequate supply of long-chain fatty acids.

The polyunsaturated fatty acid composition of hepatic and plasma lipids differ by both sex and dietary fat intake in rats

In rats and humans, females have higher liver and/or plasma docosahexaenoic acid (DHA) content than males. We hypothesized that the effect of variation in total fat or essential fatty acid intakes on liver and plasma fatty acid composition would differ between sexes. Rats were fed a low-fat soybean oil (LFS), high-fat soybean oil (HFS), or high-fat linseed oil (HFL) diet for 20 d. There were significant sex differences in LFS rats in proportions of (n-3) and (n-6) fatty acids in plasma and liver contingent on lipid class. Significant diet x sex interactions were observed for eicosapentaenoic acid (EPA), DHA, and arachidonic acid (AA) status. HFL females had a higher proportion of EPA in plasma and liver phosphatidylcholine (PC), DHA in liver triacylglycerol (TAG), and AA in plasma PC than HFS and LFS females. These findings show that the effect of varying dietary fat intake on (n-3) and (n-6) long-chain PUFA (LCPUFA) status is modified by sex. Liver phospholipid and TAG fatty acid product:substrate ratios suggested greater Delta6 desaturase (Delta6D) activity in females than in males. The HFL diet induced higher Delta6D mRNA expression compared with the LFS or HFS diets and HFL females had 10% higher expression of Delta6D mRNA than HFL males. Together, these findings show that sex is an important determinant of the effect of variations in fat and fatty acid intake on LCPUFA status, which may have implications for recommendations for fat and fatty acid intake in humans.

Fatty acid composition of plasma, erythrocytes and adipose: their correlations and effects of age and sex

The composition of fatty acids in abdominal subcutaneous adipose tissue and the correlation of fatty acid values of plasma and erythrocytes had not been reported in Japan. The aim of the present study was to investigate the fatty acid composition and correlation of plasma and erythrocyte phospholipids (PL) and adipose triacylglycerols (TG) in 75 adult patients admitted for non-malignant diseases. We also examined the relationship of n-3 and n-6 polyunsaturated fatty acid (PUFA) with patients' characteristics. The total n-3 PUFA were 11.2, 11.8 and 1.9%, and the ratios of n-6/n-3 were 2.41, 1.87 and 8.20 in plasma and erythrocyte PL and adipose TG, respectively. There were the highest correlations for total n-3 PUFA and the n-6/n-3 ratio between plasma and erythrocyte PL and adipose TG. There was a positive correlation between n-3 PUFAs and age, but a negative correlation was found between n-6 PUFAs and age. There was no significant difference in the values of PUFAs in plasma and erythrocyte PL and adipose TG between men and women. The patients with cholesterol cholecystolithiasis showed a significantly lower proportion of eicosapentaenoic acid in plasma and erythrocyte PL than those of the other patients. Our findings suggest that PUFA in plasma and erythrocyte PL may be good biomarkers and more acceptable for studying participants than adipose TG.

Gender-specific fatty acid profiles in platelet phosphatidyl-choline and -ethanolamine

Previous studies suggested that women synthesise docosahexaenoic acid (DHA) more efficiently from their precursors than men. This study investigated the relationship between diet, platelet phospholipids fatty acids and gender. Dietary intake and platelet phosphatidyl-choline (PC) and phosphatidylethanolamine (PE) fatty acids were determined in Caucasian 40 men and 34 women. Absolute and %energy intakes of arachidonic acid (AA), eicosapentaenoic acid (EPA), and DHA, and the ratios of total n-6/n-3 PUFA and linoleic/alpha-linolenic acids did not differ between the sexes. However, women had higher DHA in PC (1.19 vs 1.05 wt%, p<0.05) and PE (3.62 vs 3.21 wt%, p<0.05) than men. Also EPA (1.10 vs 0.93 wt%, p<0.05) was higher in women's PE. Conversely, men had elevated AA and total n-6 fatty acids in PC. The higher platelet DHA levels and lower platelet AA/EPA and AA/DHA ratios in women of child-bearing age compared with men, may lead to less platelet aggregation and vaso-occlusion.

Serum long-chain n-3 polyunsaturated fatty acids and risk of hospital diagnosis of atrial fibrillation in men

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia. Regular fish consumption has been shown to reduce the risk of AF in some but not all studies. Long-chain n-3 polyunsaturated fatty acids (PUFAs) from fish have been suggested to account for these beneficial effects. We tested this hypothesis by studying the association between the serum long-chain n-3 PUFAs eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid and risk of AF in men.

METHODS AND RESULTS

A total of 2174 men from the prospective population-based Kuopio Ischemic Heart Disease Risk Factor Study, 42 to 60 years old and free of AF at baseline in 1984 to 1989, were studied. During the average follow-up time of 17.7 years, 240 AF events occurred. In the Cox proportional hazards model, the multivariable-adjusted hazard ratio in the highest (>5.33%) versus the lowest (<3.61%) quartile of eicosapentaenoic acid plus docosapentaenoic acid plus docosahexaenoic acid was 0.65 (95% confidence interval 0.44 to 0.96, P for trend=0.07). Evaluated individually, only serum docosahexaenoic acid was associated with the risk of AF (hazard ratio in the highest versus the lowest quartile 0.62, 95% confidence interval 0.42 to 0.92, P for trend=0.02). Exclusion of subjects (n=233) with myocardial infarction or congestive heart failure either at baseline or that preceded the AF event during follow-up slightly strengthened the associations. Serum intermediate chain-length n-3 PUFA, alpha-linolenic acid, or hair methylmercury concentration were not associated with the risk.

CONCLUSIONS

An increased concentration of long-chain n-3 PUFAs in serum, a marker of fish or fish oil consumption, may protect against AF. Serum docosahexaenoic acid concentration had the greatest impact.

Plasmodium falciparum biology: analysis of in vitro versus in vivo growth conditions

Recent studies of Plasmodium falciparum isolated directly from infected patients indicate that alternative parasite biological states occur in the natural host that are not observed with in vitro cultivated parasites. Variation in host substrates, immune responses and other factors probably induce modifications in parasite biology. These biological states could have important implications for pathogenesis, transmission and therapy. We review the differences between P. falciparum in vitro culture systems and in vivo host environments, as well as evidence that host conditions can alter pathogen biology. For select biological questions, the incorporation of naturally occurring conditions into in vitro experimental manipulation of microbes may provide novel insight into pathogen biology.

Plasma and erythrocyte phospholipid fatty acid profile in professional basketball and football players

The effect of intensive long-term physical activity on phospholipid fatty acid (FA) composition has not been studied thoroughly. We determined plasma and erythrocyte phospholipid FA status of professional basketball and football players. Our results showed differences in plasma FA profile not only between sportsmen and sedentary subjects, but also between two groups of sportsmen. Plasma FA profile in basketball players showed significantly higher proportion of n-6 FA (20:3, 20:4, and 22:4) and total polyunsaturated FA (PUFA) than controls, while football players had higher palmitoleic acid (16:1) than basketball players and controls. Total PUFA and 22:4 were also higher in basketball than in football players. Erythrocyte FA profile showed no differences between football players and controls. However, basketball players had higher proportion of 18:0 than controls, higher saturated FA and lower 18:2 than two other groups, and higher 22:4 than football players. These findings suggest that long-term intensive exercise and type of sport influence FA profile.

Serum fatty acids in postinfarction middle‐aged men

There is a multitude of data showing that coronary heart disease is affected by the quality of dietary fat. The fatty acid composition of serum lipids has been shown to reflect that of the diet. It is likely that, after myocardial infarction, both the health-care professionals and the patients themselves pay more attention to dietary guidelines. In order to assess the correctness of this assumption, we compared the composition of serum fatty acids in 40 male subjects with a history of myocardial infarction (MI) with that of 40 age-matched controls, both from the FINRISK study. The percentage composition of fatty acids of total serum lipids was analysed by gas chromatography. In comparison with the control group, the MI group had higher body mass index (BMI), a higher prevalence of diabetes, higher level of serum triglycerides and a lower level of serum high-density lipoprotein (HDL) cholesterol, all indicators of the metabolic syndrome. The MI group had higher proportions of serum palmitic (16:0) and oleic acids (18:1), and a lower proportion of linoleic (18:2 n-6) acid than the control group. The metabolic syndrome is accompanied by an elevated level of serum insulin, which is known to enhance the synthesis of saturated and monounsaturated fatty acids, such as 16:0 and 18:1, and to stimulate the activity delta-6 desaturase, decreasing the concentration of linoleic acid. Our results suggest that the observed serum fatty acid composition in subjects with coronary heart disease is dependent on metabolic factors in addition to dietary fatty acid composition.