Trans fatty acids in adipose tissue and the food supply are associated with myocardial infarction

Trans fatty acids in food: A review on dietary intake, health impact, regulations and alternatives

Trans fats are desired by the edible oil industry as they impart firmness, plasticity, and oxidative stability to oil. However, clinical trials have demonstrated the adverse effects of trans fats in food on human health and nutrition. Regulatory actions have been taken up by government and non-government bodies worldwide to eliminate the presence of trans fats in the food supply. The World Health Organization (WHO) has launched a "REPLACE" action plan to eliminate trans-fat from the global food industry by 2023. A few enabling technologies are developed to mitigate trans fats namely, trait-enhanced oils, modification in the hydrogenation process, interesterification, fractionation, blending, and oleogelation. Some of them have the drawback of replacing trans-fat with saturated fats. Interesterification and oleogelation are in-trend techniques with excellent potential in replacing trans fats without compromising the desired functionality and nutritional quality attributes. This review presents an overview of trans fatty acid for example, its dietary intake in food products, possible adverse health impact, regulations, and approaches to reduce the usage of trans fats for food application. PRACTICAL APPLICATION: The requirement for the replacement of trans fatty acids (TFAs) in food supply globally has challenged the food industry to find a novel substitute for trans fats without compromising the desired functionality and nutritional property. This review presents detailed background on trans fats, their health impacts and current trends of reformulation of oils and fats to mitigate their presence in food supply chains. Information compiled in this paper will help food scientists and technologists, chemists, food processors, and retailers as there is an urgent need to find novel technologies and substitutes to replace trans fats in processed foods.

Plasma Free Fatty Acid Concentration as a Modifiable Risk Factor for Metabolic Disease

Plasma free fatty acid (FFA) concentration is elevated in obesity, insulin resistance (IR), non-alcoholic fatty liver disease (NAFLD), type 2 diabetes (T2D), and related comorbidities such as cardiovascular disease (CVD). Furthermore, experimentally manipulating plasma FFA in the laboratory setting modulates metabolic markers of these disease processes. In this article, evidence is presented indicating that plasma FFA is a disease risk factor. Elevations of plasma FFA can promote ectopic lipid deposition, IR, as well as vascular and cardiac dysfunction. Typically, elevated plasma FFA results from accelerated adipose tissue lipolysis, caused by a high adipose tissue mass, adrenal hormones, or other physiological stressors. Reducing an individual’s postabsorptive and postprandial plasma FFA concentration is expected to improve health. Lifestyle change could provide a significant opportunity for plasma FFA reduction. Various factors can impact plasma FFA concentration, such as chronic restriction of dietary energy intake and weight loss, as well as exercise, sleep quality and quantity, and cigarette smoking. In this review, consideration is given to multiple factors which lead to plasma FFA elevation and subsequent disruption of metabolic health. From considering a variety of medical conditions and lifestyle factors, it becomes clear that plasma FFA concentration is a modifiable risk factor for metabolic disease.

Eighteen‑carbon trans fatty acids and inflammation in the context of atherosclerosis

Endothelial dysfunction is a pro-inflammatory state characterized by chronic activation of the endothelium, which leads to atherosclerosis and cardiovascular disease (CVD). Intake of trans fatty acids (TFAs) is associated with an increased risk of CVD. This risk is usually associated with industrial TFAs (iTFAs) rather than ruminant TFAs (rTFAs); however it is not clear how specific TFA isomers differ in their biological activity and mechanisms of action with regard to inflammation. Here we review the literature on 18‑carbon TFAs, including the research associating their intake or levels with CVD and studies relating 18‑carbon TFA exposure to modulation of inflammatory processes. The evidence associating iTFAs with CVD risk factors is fairly consistent and studies in humans usually show a relation between iTFAs and higher levels of inflammatory markers. In contrast, studies in humans, animals and in vitro suggest that rTFAs have null or mildly beneficial effects in cardiovascular health, metabolic parameters and inflammatory markers, although the evidence is not always consistent. More studies are needed to better identify the beneficial and detrimental effects of the different TFAs, including those with 18 carbons.

Trans fatty acids in adipose tissue and risk of myocardial infarction: A case-cohort study

BACKGROUND

The risk of coronary heart disease associated with intake of individual trans fatty acids (TFAs) is not clear. Adipose tissue content of TFAs is a biomarker of TFA intake and metabolism.

OBJECTIVE

We investigated the rate of myocardial infarction (MI) associated with the adipose tissue content of total 18:1t, isomers of 18:1t (18:1 Δ6-10t and 18:1 Δ11t) and 18:2 Δ9c, 11t.

METHODS

A case-cohort study, nested within the Danish Diet, Cancer and Health cohort (n = 57,053), was conducted, which included a random sample (n = 3156) of the total cohort and all incident MI cases (n = 2148) during follow-up (14 years). Information on MI cases was obtained by linkage with nationwide registers and validated. Adipose tissue was taken from the participants buttocks and the fatty acid composition was determined by gas chromatography.

RESULTS

Women with higher adipose tissue content of total 18:1t had a 57% higher MI rate (quintiles 5 versus 1, hazard ratio, 1.57; 95% confidence interval, 1.12-2.20; P-trend = 0.011) and women with higher content of 18:1 Δ6-10t had a 76% higher MI rate (quintiles 5 versus 1, hazard ratio, 1.76; 95% confidence interval, 1.23-2.51; P-trend = 0.002). No association between 18:1 Δ11t content and MI rate was observed. In men, no associations between adipose tissue content of total 18:1t and 18:1 Δ6-10t and MI rate were observed. However, men with higher content of 18:1 Δ11t had a 48% higher MI rate (quintiles 5 versus 1, hazard ratio, 1.48; 95% confidence interval, 1.17-1.86; P-trend = 0.003). Adipose tissue content of 18:2 Δ9c, 11t was not associated with MI rate in women or men.

CONCLUSIONS

Adipose tissue content of 18:2 Δ9c, 11t was not associated with MI rate in women or men, whereas higher contents of isomers of 18:1t were associated with higher MI rates but the associations for individual 18:1t isomers differed, however, in women and men.

Dietary Fat and Risk of Cardiovascular Disease: Recent Controversies and Advances

Health effects of dietary fats have been extensively studied for decades. However, controversies exist on the effects of various types of fatty acids, especially saturated fatty acid (SFA), on cardiovascular disease (CVD). Current evidence supports that different types of dietary fatty acids have divergent effects on CVD risk, and the effects also depend strongly on the comparison or replacement macronutrient. A significant reduction in CVD risk can be achieved if SFAs are replaced by unsaturated fats, especially polyunsaturated fatty acids. Intake of industrially produced trans fat is consistently associated with higher CVD risk. Both n-6 and n-3 polyunsaturated fatty acids are associated with lower CVD risk, although the effects of fish oil supplementation remains inconsistent. The 2015-2020 Dietary Guidelines for Americans place greater emphasis on types of dietary fat than total amount of dietary fat and recommend replacing SFAs with unsaturated fats, especially polyunsaturated fatty acids for CVD prevention.

The effects of trans-fatty acids on TAG regulation in mice depend on dietary unsaturated fatty acids

The aim of this study was to investigate the effects of trans-fatty acids (TFA) on liver and serum TAG regulation in mice fed diets containing different proportions of n-3, n-6 and n-9 unsaturated fatty acids (UFA) from olive (O), maize (C) or rapeseed (R) oils partially substituted or not with TFA (Ot, Ct and Rt, respectively). Male CF1 mice were fed (30 d) one of these diets. The effects of the partial substitution (1 %, w/w) of different UFA with TFA on the activity and expression of hepatic enzymes involved in lipogenesis and fatty acids oxidation were evaluated, as well as their transcription factor expressions. Some of the mechanisms involved in the serum TAG regulation, hepatic VLDL rich in TAG (VLDL-TAG) secretion rate and lipoprotein lipase (LPL) activity were assessed. In liver, TFA induced an increase in TAG content in the Ot and Rt groups, and this effect was associated with an imbalance between lipogenesis and β-oxidation. In the Ot group, exacerbated lipogenesis may be one of the mechanisms responsible for the liver steatosis induced by TFA, whereas in Rt it has been related to a decreased β-oxidation, compared with their respective controls. The enhanced hepatic VLDL-TAG secretion in the Ot and Rt groups was compensated with a differential removal of TAG by LPL enzyme in extrahepatic tissues, leading to unchanged serum TAG levels. In brief, the effects of low levels of TFA on liver and serum TAG regulation in mice depend on the dietary proportions of n-3, n-6 and n-9 UFA.

Association between Serum Elaidic Acid Concentration and Insulin Resistance in Two Japanese Cohorts with Different Lifestyles

Aim: Many cohort studies have shown that increased trans fatty acid (TFA) intake increases the risk of developing coronary heart disease. However, whether TFA intake is directly associated with the development of diabetes mellitus (DM) remains unknown.

Methods: We performed the 75-g oral glucose tolerance test in two Japanese cohorts: a cohort of 454 native Japanese living in Hiroshima, Japan, and a cohort of 426 Japanese-Americans living in Los Angeles, USA, who shared identical genetic predispositions but had different lifestyles. Serum elaidic acid concentration was measured and compared, and its association with insulin resistance was assessed.

Results: Serum elaidic acid concentrations were significantly higher in the Japanese-Americans (median, 18.2 µmol/L) than in the native Japanese (median, 11.0 µmol/L). The serum elaidic acid concentrations in the native Japanese DM group (16.0 µmol/L) were significantly higher compared with those in the normal glucose tolerance (10.8 µmol/L) and impaired glucose tolerance (11.7 µmol/L) groups. Multiple linear regression analyses showed that serum elaidic acid concentrations were significantly positively associated with homeostasis model assessment for insulin resistance (HOMA-IR) values after adjusting for various factors.

Conclusions: These results suggest that excessive TFA intake worsens insulin resistance and increases the risk of developing DM even in the native Japanese, whose intakes of animal fat and simple carbohydrates were presumed to be lower than those of the Japanese-Americans.

Evaluation of the Impact of Ruminant Trans Fatty Acids on Human Health: Important Aspects to Consider

The definition and evaluation of trans fatty acids (TFA) with regard to foodstuffs and health hazard are not consistent. Based on the current situation, the term should be restricted only to TFA with isolated double bonds in trans-configuration. Conjugated linoleic acids (CLA) should be separately assessed. Ideally, the origin of the consumed fat should be declared, i.e., ruminant TFA (R-TFA) and industrial TFA (non-ruminant; I-TFA). In ruminant fat, more than 50% of R-TFA consists of vaccenic acid (C18:1 t11). In addition, natural CLA, i.e., c9,t11 CLA is also present. Both are elevated in products from organic farming. In contrast to elaidic acid (t9) and t10, which occur mainly in partially hydrogenated industrial fat, t11 is partially metabolized into c9,t11 CLA via Δ9-desaturation. This is the major metabolic criterion used to differentiate between t11 and other trans C18:1. t11 indicates health beneficial effects in several studies. Moreover, CLA in milk fat is associated with the prevention of allergy and asthma. An analysis of the few studies relating to R-TFA alone makes clear that no convincing adverse physiological effect can be attributed to R-TFA. Only extremely high R-TFA intakes cause negative change in blood lipids. In conclusion, in most European countries, the intake of R-TFA is assessed as being low to moderate. Restriction of R-TFA would unjustifiably represent a disadvantage for organic farming of milk.

TransFatty Acids and Coronary Heart Disease

Epidemiologic evidence has linked trans fatty acids (TFAs) in the diet to coronary heart disease in human populations. It has been estimated that dietary TFAs from partially hydrogenated oils may be responsible for between 30,000 and 100,000 premature coronary deaths per year in the United States. Although it is known that TFAs increase low-density lipoprotein (LDL) cholesterol levels and decrease high-density lipoprotein (HDL) cholesterol levels (markers of coronary heart disease), there is little known about the mechanisms by which TFAs actually function at the cellular level. It is unknown what levels of TFAs are clinically significant and it is unclear how TFAs are associated with cardiac arrhythmias or sudden cardiac death. We hypothesize that TFAs affect membrane structure, thus altering enzymatic pathways that may subsequently induce cardiac arrhythmias and sudden death.

Plasma phospholipids fatty acids, dietary fatty acids, and breast cancer risk

PURPOSE

This study prospectively investigates associations between fatty acids assessed in plasma phospholipids (PPL) and diet, and breast cancer risk, including subgroups defined by hormone receptor status.

METHODS

We performed a case-cohort analysis within the Melbourne Collaborative Cohort Study using a random sample of 2,021 women and 470 breast cancer cases. At baseline, fatty acids were assessed in PPL and estimated from diet using a 121-item food frequency questionnaire. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated using Cox regression.

RESULTS

Breast cancer risk was positively associated with %PPL saturated fatty acids (SFA); HRQ5vsQ1 = 1.64 (95 % CI 1.17-2.30); p trend = 0.004. Positive associations were found for ER+ or PR+ tumors for %PPL SFA and palmitic acid and for ER-/PR- tumors for %PPL n-6 polyunsaturated fatty acid (PUFA), TFA, TFA 16:1, and TFA 18:1n-7 (all p homogeneity <0.05). Breast cancer risk was inversely associated with dietary docosapentaenoic acid (DPA); HRQ5vsQ1 = 0.57 (95 % CI 0.40-0.82); p trend = 0.001 [with similar inverse associations observed for dietary docosahexaenoic (DHA) and eicosapentaenoic acid (EPA)] and positively associated with dietary n-6:n-3 PUFA. Inverse associations for ER-/PR- tumors were found for dietary dihomo-γ-linolenic acid (DGLA) for older women (p homogeneity = 0.04).

CONCLUSIONS

Breast cancer risk was positively associated with %PPL SFA and the ratio of dietary n-6 to n-3 PUFA and inversely associated with dietary long-chain n-3 PUFA intake. Some associations between fatty acids and breast cancer varied by age and tumor phenotype defined by hormone receptor status. Increased intake of fish and other foods rich in long-chain n-3 PUFAs and reduced n-6 PUFA intake might reduce breast cancer risk.

Trans fatty acids: are its cardiovascular risks fully appreciated?

OBJECTIVE

The goal of this article was to review the causal link between trans fatty acids (TFA) produced from partially hydrogenated vegetable oil (PHVO) and cardiovascular disease (CVD) risk and its likely mechanisms. The potential risk of TFA from ruminant dairy and meats, which are currently the major sources of dietary TFA, is also discussed.

METHODS

Evidence was derived from observational studies of large cohorts followed up prospectively; from randomized controlled trials of clinical interventions; and from specific case-control studies that investigated biomarkers in tissues. Searches included PubMed and Medline from 1990 to 2013.

RESULTS

Despite TFA from PHVO being associated more strongly with CVD risk than even saturated fats, it may prove difficult to totally eliminate PHVO from all foods. This raises the issue of the lower limit of TFA consumption below which CVD risk is not increased. Limits of <1% of total energy have been suggested. The major mechanism underlying the increased CVD risk from TFA is an increase in LDL-C and Lp(a) lipoproteins and a decrease in HDL-C; increased inflammation and adverse effects on vascular function have also been shown. Both PHVO and ruminant TFA comprise a range of isomers, some specific to each source but including a substantial commonality that supports findings of similar adverse effects at equivalent intakes of TFA. However, the amount of TFA in ruminant fat is relatively small; this limits the CVD risk from eating ruminant products, an inference supported by analysis of prospective cohort studies.

CONCLUSIONS

Two key challenges to the health industry arise from this evidence. They must first determine whether a small intake of TFA from PHVO is safe and what constitutes a safe amount. They must also determine whether TFA from ruminant fat in currently consumed amounts represent limited cardiovascular risk that is balanced by the nutritional benefits of dairy products.

The relation of saturated fatty acids with low-grade inflammation and cardiovascular disease

The mantra that dietary (saturated) fat must be minimized to reduce cardiovascular disease (CVD) risk has dominated nutritional guidelines for decades. Parallel to decreasing intakes of fat and saturated fatty acids (SFA), there have been increases in carbohydrate and sugar intakes, overweight, obesity and type 2 diabetes mellitus. The "lipid hypothesis" coined the concept that fat, especially SFA, raises blood low-density lipoprotein-cholesterol and thereby CVD risk. In view of current controversies regarding their adequate intakes and effects, this review aims to summarize research regarding this heterogenic group of fatty acids and the mechanisms relating them to (chronic) systemic low-grade inflammation, insulin resistance, metabolic syndrome and notably CVD. The intimate relationship between inflammation and metabolism, including glucose, fat and cholesterol metabolism, revealed that the dyslipidemia in Western societies, notably increased triglycerides, "small dense" low-density lipoprotein and "dysfunctional" high-density lipoprotein, is influenced by many unfavorable lifestyle factors. Dietary SFA is only one of these, not necessarily the most important, in healthy, insulin-sensitive people. The environment provides us not only with many other proinflammatory stimuli than SFA but also with many antiinflammatory counterparts. Resolution of the conflict between our self-designed environment and ancient genome may rather rely on returning to the proinflammatory/antiinflammatory balance of the Paleolithic era in consonance with the 21st century culture. Accordingly, dietary guidelines might reconsider recommendations for SFA replacement and investigate diet in a broader context, together with nondietary lifestyle factors. This should be a clear priority, opposed to the reductionist approach of studying the effects of single nutrients, such as SFA.

Hepatocytes respond differently to major dietary trans fatty acid isomers, elaidic acid and trans-vaccenic acid

BACKGROUND

It has been discussed if the adverse health effect associated with the ingestion of trans fatty acids correlates with the food source, as the composition of the isomers varies in different foods. We have investigated the hepatocellular responses to the predominant trans fatty acid isomers in industrially produced partially hydrogenated vegetable oils (elaidic acid) and products of ruminant origin (trans-vaccenic acid).

RESULTS

The responses of HepG2-SF cells exposed to 100 μM fatty acids during 7 days were examined. Elaidic acid decreased the cellular proliferation rate while trans-vaccenic acid had no effect. Analysis of cellular triacylglycerol fractions showed, that both trans fatty acids were metabolized by HepG2-SF cells, although elaidic acid, to a higher degree than trans-vaccenic, accumulated in the triacylglycerol fraction. Proteome analysis revealed that the overlap of differentially regulated proteins only contained four proteins, suggesting that the two trans fatty acid isomers affect the cells in different ways. The data are available via ProteomeXchange with identifier PXD000760.

CONCLUSIONS

Our investigations revealed that the hepatocellular response to the two most abundant dietary positional C18:1 trans fatty acid isomers differ substantially. In addition, the results suggest that trans-vaccenic acid does not affect cholesterol metabolism adversely compared to elaidic acid.

Fasting enriches liver triacylglycerol with n-3 polyunsaturated fatty acids: implications for understanding the adipose-liver axis in serum docosahexaenoic acid regulation

We investigated the effect of short-term fasting on coordinate changes in the fatty acid composition of adipose triacylglycerol (TAG), serum non-esterified fatty acids (NEFA), liver TAG, and serum TAG and phospholipids in mice fed ad libitum or fasted for 16 h overnight. In contrast to previous reports under conditions of maximal lipolysis, adipose tissue TAG was not preferentially depleted of n-3 PUFA or any specific fatty acids, nor were there any striking changes in the serum NEFA composition. Short-term fasting did, however, increase the hepatic proportion of n-3 PUFA, and almost all individual species of n-3 PUFA showed relative and absolute increases. The relative proportion of n-6 PUFA in liver TAG also increased but to a lesser extent, resulting in a significant decrease in the n-6:n-3 PUFA ratio (from 14.3 ± 2.54 to 9.6 ± 1.20), while the proportion of MUFA decreased significantly and SFA proportion did not change. Examination of genes involved in PUFA synthesis suggested that hepatic changes in the elongation and desaturation of precursor lipids could not explain this effect. Rather, an increase in the expression of fatty acid transporters specific for 22:6n-3 and other long-chain n-3 and n-6 PUFA likely mediated the observed hepatic enrichment. Analysis of serum phospholipids indicated a specific increase in the concentration of 22:6n-3 and 16:0, suggesting increased specific synthesis of DHA-enriched phospholipid by the liver for recirculation. Given the importance of blood phospholipid in distributing DHA to neural tissue, these findings have implications for understanding the adipose-liver-brain axis in n-3 PUFA metabolism.

Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies

OBJECTIVE

To systematically review associations between intake of saturated fat and trans unsaturated fat and all cause mortality, cardiovascular disease (CVD) and associated mortality, coronary heart disease (CHD) and associated mortality, ischemic stroke, and type 2 diabetes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane Central Registry of Controlled Trials, Evidence-Based Medicine Reviews, and CINAHL from inception to 1 May 2015, supplemented by bibliographies of retrieved articles and previous reviews.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Observational studies reporting associations of saturated fat and/or trans unsaturated fat (total, industrially manufactured, or from ruminant animals) with all cause mortality, CHD/CVD mortality, total CHD, ischemic stroke, or type 2 diabetes.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data and assessed study risks of bias. Multivariable relative risks were pooled. Heterogeneity was assessed and quantified. Potential publication bias was assessed and subgroup analyses were undertaken. The GRADE approach was used to evaluate quality of evidence and certainty of conclusions.

RESULTS

For saturated fat, three to 12 prospective cohort studies for each association were pooled (five to 17 comparisons with 90,501-339,090 participants). Saturated fat intake was not associated with all cause mortality (relative risk 0.99, 95% confidence interval 0.91 to 1.09), CVD mortality (0.97, 0.84 to 1.12), total CHD (1.06, 0.95 to 1.17), ischemic stroke (1.02, 0.90 to 1.15), or type 2 diabetes (0.95, 0.88 to 1.03). There was no convincing lack of association between saturated fat and CHD mortality (1.15, 0.97 to 1.36; P=0.10). For trans fats, one to six prospective cohort studies for each association were pooled (two to seven comparisons with 12,942-230,135 participants). Total trans fat intake was associated with all cause mortality (1.34, 1.16 to 1.56), CHD mortality (1.28, 1.09 to 1.50), and total CHD (1.21, 1.10 to 1.33) but not ischemic stroke (1.07, 0.88 to 1.28) or type 2 diabetes (1.10, 0.95 to 1.27). Industrial, but not ruminant, trans fats were associated with CHD mortality (1.18 (1.04 to 1.33) v 1.01 (0.71 to 1.43)) and CHD (1.42 (1.05 to 1.92) v 0.93 (0.73 to 1.18)). Ruminant trans-palmitoleic acid was inversely associated with type 2 diabetes (0.58, 0.46 to 0.74). The certainty of associations between saturated fat and all outcomes was "very low." The certainty of associations of trans fat with CHD outcomes was "moderate" and "very low" to "low" for other associations.

CONCLUSIONS

Saturated fats are not associated with all cause mortality, CVD, CHD, ischemic stroke, or type 2 diabetes, but the evidence is heterogeneous with methodological limitations. Trans fats are associated with all cause mortality, total CHD, and CHD mortality, probably because of higher levels of intake of industrial trans fats than ruminant trans fats. Dietary guidelines must carefully consider the health effects of recommendations for alternative macronutrients to replace trans fats and saturated fats.

Trans fatty acids in diets act as a precipitating factor for gut inflammation?

Fatty acids in our daily diet are broadly classified into cis and trans fatty acids (TFAs). TFAs are formed during the manufacturing process of hydrogenated vegetable oils such as margarine. Modern diets such as deep-fried products, frozen foods, and packaged snacks commonly include large quantities of margarine containing TFAs. Although an increased report in the effects of the diet containing TFAs on a risk factor of metabolic syndrome, diabetes mellitus, and coronary heart disease has been observed in the recent years, influence on intestinal inflammation remains unknown. This review describes pro-inflammatory effects of TFAs in our diary diet on various systemic disorders and also discusses a possible role of TFAs on gut inflammation.

A maternal diet of fatty fish reduces body fat of offspring compared with a maternal diet of beef and a post-weaning diet of fish improves insulin sensitivity and lipid profile in adult C57BL/6 male mice

AIM

The maternal diet during pregnancy and lactation may affect the long-term health of the offspring. Our aim was to study how a fish or meat diet perinatal and after weaning affects body composition, insulin sensitivity and the profile of n-3 and n-6 polyunsaturated fatty acids (PUFAs) in breast milk, fat depots, skeletal muscle and liver in male adult mice offspring.

METHODS

During gestation and lactation, C57BL/6 dams were fed a herring- or beef-based diet. Half of the pups in each group changed diets after weaning. In offspring, body composition measured by DEXA, plasma lipid profile and insulin sensitivity measured by euglycemic clamp or QUICKI were monitored to adulthood. Analysis of total FAs by GC-MS were performed in the diet, breast milk and in different tissues.

RESULTS

At 9 week of age, offspring of herring-fed dams had less body fat than offspring of beef-fed dams. Mice fed herring after weaning had increased insulin sensitivity at 15 week of age, reduced total plasma cholesterol and triglyceride levels, and compared with beef-fed mice, larger interscapular brown adipose tissue depots. The FA composition of the maternal diet was mirrored in breast milk, and the herring diet significantly affected the FA profile of different tissues, leading to an increased content of n-3 PUFAs.

CONCLUSION

A herring-based maternal diet reduces body fat in the offspring, but the insulin sensitivity, plasma lipids and amount of brown adipose tissue are affected by the offspring's own diet; the herring diet is more beneficial than the beef diet.

Moderate compared to low dietary intake of trans-fatty acids impairs strength of old and aerobic capacity of young SAMP8 mice in both sexes

The senescence accelerated SAMP8 mouse is a model for sarcopenia and provides an opportunity to study the effects of lifelong dietary composition on the loss of physical function with age. We studied the effects of trans-fatty acids (2 % of total energy, TFA diet) on the loss of strength and aerobic exercise capacity (VO₂peak) with age. SAMP8 mice were studied at two ages (young, 25 weeks; old, 60 weeks) and on two diets (control vs TFA). Body composition, grip strength, VO₂peak, blood metabolites, and biochemical parameters were assessed. Body weight, fat mass, and body fat percentage all increased with age (p < 0.05) but were not significantly impacted by diet. There was a significant age-related decline in total grip strength as well as that normalized to fat-free mass (FFM) (p < 0.05) with a further decrease at old age in these metrics of strength on the TFA diet vs control diet (p < 0.05). Total VO₂peak exhibited no change with age or diet, but when normalized to FFM, VO₂peak exhibited age and TFA-related declines (p < 0.05). Intramuscular triacylglycerol (p < 0.05) and collagen content (p < 0.05) significantly increased with age, while blood triacylglycerol was increased by the TFA diet (p < 0.05). These data further characterize the SAMP8 mouse as a model for sarcopenia and indicate that dietary fatty acid composition can impact the degree of this age-related loss of physical function.

Trans fatty acids consumption in type 1 diabetic patients: evaluation by dietary records and measurement in serum phospholipids

The consumption of foods containing trans fatty acids (TFA), especially those produced by food industries, induces pleiotropic negative effects on health. Therefore, it is important to assess the amount of TFA consumed, especially in age groups more exposed to the consumption of TFA-containing foods. The present pilot study evaluates TFA intake in 54 young people with and without type 1 diabetes (29 young subjects with type 1 diabetes and 25 healthy subjects) through both dietary records (7-day food record) and the measurement of TFA levels in serum phospholipids, a possibly more objective marker of TFA intake. The comparison between the two groups was made by the student t test for independent samples. The intake of synthetic TFA was low in both groups (type 1 diabetic patients: 0.25 ± 0.25 g/day; healthy subjects 0.48 ± 0.37 g/day), but significantly lower in diabetic patients vs controls (P < 0.05); TFA levels in serum phospholipids also confirmed a low intake of these fatty acids. These data indicate that the intake of trans fatty acids is relatively low in our population, i.e.,<1% of total calories in the diet, in line with what recommended by the World Health Organization.

Plasma concentrations of trans fatty acids in persons with type 2 diabetes between September 2002 and April 2004

BACKGROUND

transFatty acids (TFAs) increase cardiovascular disease risk. TFAs and polyunsaturated fatty acids (PUFAs) in the food supply may be declining with reciprocal increases in cis-monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs).

OBJECTIVES

We sought to determine whether plasma 18-carbon TFA and PUFA concentrations might decrease over time and whether there might be reciprocal increases in plasma cis-MUFAs and SFAs.

DESIGN

We studied 305 persons (171 women) taking part in Look AHEAD (Action for Health in Diabetes), a randomized trial of lifestyle intervention for weight loss to reduce major cardiovascular events in overweight and obese adults (aged 45-76 y) with type 2 diabetes who also participated in an ancillary study of oxidative stress. This study was a cross-sectional analysis of TFAs, cis-MUFAs, SFAs, and PUFAs measured in plasma before intervention (September 2002-April 2004).

RESULTS

In a model that included demographic characteristics, plasma total fatty acid concentration, BMI, serum insulin, statin use, season, and longitudinal time trend (R(2) = 0.167, P < 0.0001), plasma TFAs decreased by 13.5%/y (95% CI: -22.7, -3.2%/y; absolute decrease 7.0 mg · L(-1) · y(-1); 95% CI: -12.5, -1.6 mg · L(-1) · y(-1); P = 0.012). This longitudinal trend was not significantly altered by further adjustment for dietary variables and physical activity. In contrast, longitudinal trends for PUFAs, cis-MUFAs, and SFAs were weak and not significant.

CONCLUSIONS

This change in plasma concentrations of TFAs is consistent with changes in fatty acid composition that food manufacturers are likely to have made to avoid declaring TFAs on food labels. Further research will be needed to determine the overall effect of these changes on cardiovascular risk. The Look AHEAD trial is registered at clinicaltrials.govas NCT00017953.

Evidence of lifestyle modification in the management of hypercholesterolemia

BACKGROUND

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide. The growth of ageing populations in developing countries with progressively urbanized lifestyles are major contributors. The key risk factors for CHD such as hypercholesterolemia, diabetes mellitus, and obesity are likely to increase in the future. These risk factors are modifiable through lifestyle.

OBJECTIVES

To review current literature on the potential benefit of cholesterol lowering in CHD risk reduction with a particular focus on the evidence of non-pharmacological/lifestyle management of hypercholesterolemia.

METHODS

Medline/PubMed systematic search was conducted using a two-tier approach limited to all recent English language papers. Primary search was conducted using key words and phrases and all abstracts were subsequently screened and relevant papers were selected. The next tier of searching was conducted by (1) reviewing the citation lists of the selected papers and (2) by using PubMed weblink for related papers. Over 3600 reports were reviewed.

RESULTS

Target cholesterol levels set out in various guidelines could be achieved by lifestyle changes, including diet, weight reduction, and increased physical activity with the goal of reducing total cholesterol to <200 mg/dL and LDL-C<100 mg/dL. Various dietary constituents such as green tea, plant sterols, soy protein have important influences on total cholesterol. Medical intervention should be reserved for those patients who have not reached this goal after 3 months of non-pharmacological approach.

CONCLUSION

CHD remains as a leading cause of death worldwide and hypercholesterolemia is an important cause of CHD. Non-pharmacological methods provide initial as well as long-term measures to address this issue.

Trans fat involvement in cardiovascular disease

Coronary heart disease is becoming a worldwide epidemic and diet and lifestyle are well known contributing factors. Identifying the kinds of foods that may have a cardioprotective or cardiotoxic effect and understanding their molecular mechanisms of action has become of increasing importance. Through largely epidemiological evidence, trans fatty acid (TFA) intake has been associated with a variety of cardiovascular complications including atherosclerosis. Traditionally, industrial TFAs (iTFAs) have been associated with these deleterious cardiovascular effects. However, there is a current body of research that suggests that ruminant trans fats (rTFAs) may have a cardioprotective role within the heart. The molecular mechanisms whereby TFAs are delivering their effects are largely unknown. In the following review, we discuss recent in vitro, animal and epidemiological research to better understand the effect of TFAs in the diet on cardiovascular disease, particularly atherosclerosis.

Changes in erythrocyte membrane trans and marine fatty acids between 1999 and 2006 in older Americans

Over the last several years, national programs to lower the content of industrially produced (IP) C18:1 and C18:2 trans fatty acids in foods have been implemented, but whether this has resulted in lower blood trans fatty acid levels is unknown. Likewise, an increased perception of the health benefits of fish oils rich in EPA and DHA may have resulted in an increase in consumption and blood levels of these fatty acids. To explore these issues, we analyzed the changes in RBC fatty acid composition between the 7th (1998-2001) and 8th (2005-2007) examination cycles in a random sample of the Framingham Offspring cohort. This was a retrospective cohort study of 291 participants from whom blood was drawn at both examinations and for whom complete covariate data were available. Overall, the proportion of trans fatty acids in RBC changed by -23% (95% CI: -26 to -21%). RBC EPA+DHA proportions increased by 41% (95% CI: 31 to 52%) in 38 individuals who were taking fish oil supplements at examination 8, but in 253 participants not taking fish oil, the proportion of RBC EPA+DHA did not change. In conclusion, in a random subsample of Framingham Offspring participants with serial observations over 6.7 y, the proportion of trans fatty acids in RBC decreased. Those of EPA+DHA increased in people taking fish oil supplements. These changes could potentially translate into a lower risk for cardiovascular disease.

Changes in fat contents of US snack foods in response to mandatory trans fat labelling

OBJECTIVE

Impact of mandatory trans fat labelling on US snack food introductions is examined.

DESIGN

Using label information, lipid ingredients and fat profiles are compared pre- and post-labelling.

SETTING

Key products in the US snack food industry contribute significant amounts of artificial trans fat. Industry efforts to reformulate products to lower trans fat may alter the overall fat profile, in particular saturates.

SUBJECTS

Composition data for more than 5000 chip and cookie products introduced for sale between 2001 (pre-labelling) and 2009 (post-labelling) were analysed.

RESULTS

One-way ANOVA was used to test for significant changes in saturated fat content per serving and the ratio of saturated to total fat. The shares of chip and cookie introductions containing partially hydrogenated vegetable oil declined by 45 and 42 percentage points, respectively. In cookies, there was an increase of 0·49 (98 % CI 0·01, 0·98) g in the average saturated fat content per 30 g serving and an increase of 9 (98 % CI 3, 15) % in the average ratio of saturated to total fat. No statistically significant changes in fat content were observed in chips.

CONCLUSIONS

This research suggests that, holding other factors constant, the policy has resulted in a decreased use of partially hydrogenated vegetable oil in chip products without a corresponding increase in saturated fat content, but led to significantly higher levels of saturated fat and ratio of saturated fat to total fat in cookie products.

The α-linolenic acid content of flaxseed can prevent the atherogenic effects of dietary trans fat

Dietary intake of industrially hydrogenated trans fatty acids (TFA) has been associated with coronary heart disease. Dietary flaxseed can inhibit atherosclerosis induced by dietary cholesterol. The aim of this study was to determine whether supplementing the diet with flaxseed could protect against atherosclerosis induced by a diet enriched in TFA. Low-density lipoprotein receptor-deficient (LDLr−/−) mice were fed 1 of 14 experimental diets for 14 wk containing one of two fat sources [regular (pork/soy) or trans fat] at two concentrations (4 or 8%) and supplemented with or without dietary cholesterol (2%), whole ground flaxseed, or one of the components of flaxseed [α-linolenic acid (ALA), defatted fiber, or lignan]. Adding flaxseed to the diet partially mitigated the rise in circulating cholesterol levels induced by the cholesterol-enriched diet. Atherosclerosis was stimulated by TFA and/or cholesterol. Including milled flaxseed to an atherogenic diet significantly reduced atherosclerosis compared with the groups that consumed cholesterol and/or TFA. ALA was the only component within flaxseed that could inhibit the atherogenic action of cholesterol and/or TFA on its own. Dietary flaxseed protects against atherosclerotic development induced by TFA and cholesterol feeding through its content of ALA.

A prospective study of intake of trans-fatty acids from ruminant fat, partially hydrogenated vegetable oils, and marine oils and mortality from CVD

Trans-fatty acids (TFA) have adverse effects on blood lipids, but whether TFA from different sources are associated with risk of CVD remains unresolved. The objective of the present study was to evaluate the association between TFA intake from partially hydrogenated vegetable oils (PHVO), partially hydrogenated fish oils (PHFO) and ruminant fat (rTFA) and risks of death of CVD, CHD, cerebrovascular diseases and sudden death in the Norwegian Counties Study, a population-based cohort study. Between 1974 and 1988, participants were examined for up to three times. Fat intake was assessed with a semi-quantitative FFQ. A total of 71 464 men and women were followed up through 2007. Hazard ratios (HR) and 95 % CI were estimated with Cox regression. Energy from TFA was compared to energy from all other sources, carbohydrates or unsaturated cis-fatty acids with different multivariable models. During follow-up, 3870 subjects died of CVD, 2383 of CHD, 732 of cerebrovascular diseases and 243 of sudden death. Significant risks, comparing highest to lowest intake category, were found for: TFA from PHVO and CHD (HR 1·23 (95 % CI 1·00, 1·50)) and cerebrovascular diseases (HR 0·65 (95 % CI 0·45, 0·94)); TFA from PHFO and CVD (HR 1·14 (95 % CI 1·03, 1·26)) and cerebrovascular diseases (HR 1·32 (95 % CI 1·04, 1·69)); and rTFA intake and CVD (HR 1·30 (95 % CI 1·05, 1·61)), CHD (HR 1·50 (95 % CI 1·11, 2·03)) and sudden death (HR 2·73 (95 % CI 1·19, 6·25)) in women. These associations with rTFA intake were not significant in men (Pinteraction ≥ 0·01). The present study supports that TFA intake, irrespective of source, increases CVD risk. Whether TFA from PHVO decreases risk of cerebrovascular diseases warrants further investigation.

The prognostic value of adipose tissue fatty acids for incident cardiovascular disease: results from 3944 subjects in the Scottish Heart Health Extended Cohort Study

AIMS

Dietary fats are routinely considered key determinants of cardiovascular risk, yet the scientific basis of this association has never been demonstrated using objective measures of fat intakes in a large prospective study in a general population.

METHODS AND RESULTS

Adipose tissue was taken from 3944 participants, predominantly aged 40-59 years, in Scotland, 1984-87. Percentages of individual fatty acids were measured using gas chromatography. Over a median of 19.5 years, 870 incident cardiovascular disease (CVD) events occurred. Hazard ratios (HRs) were obtained from Cox models and the additional prognostic value, accounting for variables in the Framingham and ASSIGN CVD risk scores, were assessed using discrimination indices. Adjusting for age, sex, total and HDL-cholesterol, systolic blood pressure, smoking, hypertensive medication use, diabetes, socio-economic status and family history, the percentage of monounsaturated adipose tissue fatty acids had a positive log-linear relationship with incident CVD: the HR comparing risk between the fourth and first quartiles was 1.29 (95% confidence interval: 1.05, 1.59). n-3 polyunsaturated fat showed the reverse trend, the corresponding result being 0.77 (0.63, 0.94). These two composite variables improved the classification of incident CVD events by 1.0 and 6.4%, respectively, with only the latter being significant at the 5% level.

CONCLUSIONS

A diet which is proportionately rich in polyunsaturated fat, as opposed to other fats, is expected to decrease the risk of CVD independently of the effects of common CVD risk factors, including social deprivation. Taking account of such diets improves the classification of future CVD events.

Nutritional profiles in a public health perspective: a critical review

Nutritional profiling is defined as 'the science of categorizing foods according to their nutritional composition' and it is useful for food labelling and regulation of health claims. The evidence for the link between nutrients and health outcomes was reviewed. A reduced salt intake reduces blood pressure, but only a few randomized controlled trials have verified the effect of salt on overall and cardiovascular mortality. Evidence linking a reduced fat intake with cardiovascular mortality and obesity is generally non-significant. Studies that have examined the relationship between obesity and diet have produced contrasting results. A simulation exercise that demonstrated that the impact of a reduced salt and fat intake on overall mortality would be negligible in the European population was carried out. Consideration of the literature and the results of this simulation exercise suggest that the introduction of nutritional profiles in Europe would be expected to have a very limited impact on health outcomes.

Comparative analysis of two FFQ

OBJECTIVE

To examine the utility of a shorter FFQ compared with a longer FFQ, both of which are commonly used in Australia.

DESIGN

Comparative study.

SETTING

Community setting.

SUBJECTS

One hundred and fifty-nine men (mean 55 (sem 7) years) screened for participation in an intervention study completed both the Commonwealth Scientific and Industrial Research Organisation FFQ and the Cancer Council of Victoria FFQ. Agreement between both questionnaires was assessed according to Bland-Altman plots and limits of agreement (LOA) and ordinary least products regression to test for the presence of fixed and proportional bias.

RESULTS

There was good relative agreement between the methods for energy and macronutrients (Pearson's correlation coefficients: energy r = 0.7, protein r = 0.6, fat r = 0.8, carbohydrate r = 0.7, alcohol r = 0.8; P < 0.01). Mean group-level agreement for the majority of nutrients (70 %) fell between 80 % and 110 %. According to the criteria used (maximum LOA was 50-200 % and no significant proportional bias), there was acceptable agreement between the FFQ for energy and total saturated and monounsaturated fat, but not for protein, carbohydrate and fibre. Micronutrients that did not meet the agreement criteria including calcium, iron, thiamin, niacin, riboflavin and folate. When the data were analysed according to quintiles, the majority of subjects were either in exactly the same quintile or within one quintile for most nutrients, and 1-2 % were grossly misclassified by three or four quintiles.

CONCLUSIONS

We conclude that there is sufficient agreement between the instruments for group-level comparisons in men, but they are not interchangeable for estimation of individual intakes.

Human health benefits of vaccenic acid

The health risks associated with consumption of diets high in trans fats from industrially produced hydrogenated fats are well documented. However, trans fatty acids are not a homogeneous group of molecules, and less is known about the health effects of consuming diets containing vaccenic acid (VA), a positional and geometric isomer of oleic acid, the predominant trans isomer in ruminant fats. The presence of VA in industrial trans fats has raised the question of whether VA produces the same adverse health effects as industrially produced trans fats. VA is also the major trans fat in ruminant fats, and questions have arisen as to whether consuming this trans fat has the same effects on health risk. The purpose of this paper is to critically review the published studies in humans, animals, and cell lines. Epidemiological, but not rodent, studies suggest that VA intake or serum concentrations may be associated with increased cancer risk. However, epidemiological, clinical, and rodent studies to date have not demonstrated a relationship with heart or cardiovascular disease, insulin resistance, or inflammation. VA is the only known dietary precursor of c9,t11 conjugated linoleic acid (CLA), but recent data suggest that consumption of this trans fat may impart health benefits beyond those associated with CLA.

Trans-fatty acids in the diet stimulate atherosclerosis

Epidemiological evidence has associated dietary trans-fatty acids (TFAs) with coronary heart disease. It is assumed that TFAs stimulate atherosclerosis, but this has not been proven. The purpose of this study was to determine the effects of consuming 2 concentrations of TFAs obtained from commercially hydrogenated vegetable shortening on atherosclerotic development in the presence or absence of elevated dietary cholesterol. Low-density lipoprotein receptor-deficient mice were fed 1 of 7 experimental diets for 14 weeks: low regular fat (LR), low trans-fat (LT), regular high fat, high trans-fat (HT), or a diet containing 2% cholesterol with low regular fat (C + LR), low trans-fat (C + LT), or high trans-fat (C + HT). The extent of lesion development was quantified by en face examination of the dissected aortae. Dietary cholesterol supplementation significantly elevated serum cholesterol levels. Surprisingly, this rise was partially attenuated by the addition of TFAs (C + LT and C + HT) in the diet. Serum triglyceride levels were elevated with the higher-fat diets and with the combination of trans-fat and cholesterol. Animals consuming TFAs in the absence of dietary cholesterol developed a significantly greater extent of aortic atherosclerotic lesions as compared with control animals (LT > LR and HT > regular high fat). Atherosclerotic lesions were more extensive after cholesterol feeding, but the addition of TFAs to this atherogenic diet did not advance atherosclerotic development further. In summary, TFAs are atherogenic on their own; but they do not stimulate further effects beyond the strongly atherogenic effects of dietary cholesterol.

Feasibility of recommending certain replacement or alternative fats

Expert groups and public health authorities recommend that trans-fatty acid (TFA) intakes from industrially produced partially hydrogenated vegetable oils (PHVOs) should be less than 1% of total energy intake. The starting point for any regulatory or nonregulatory response to this recommendation is to assess the extent of the problem by determining where in the food supply TFAs are found and the amounts consumed in the population. Unfortunately, this is a particularly difficult task using traditional methods of dietary assessment inasmuch as food composition databases with TFA data are either nonexistent or incomplete in most countries. Current evidence on estimates of intake suggests there is high variability in TFA intakes and their food sources between countries. The ubiquitous presence of PHVOs in the global food supply in bakery products, deep-fried foods, snack foods, confectionery products and table spreads attests to their commercial value and convenience. However, their common use is more the result of historical convenience from an industry infrastructure developed over 50 years based on efficient, cost-effective hydrogenation of vegetable oils rather than any inherent sensory or physical superiority of the hydrogenated fats over purpose-made zero-trans fats and oils. Current global supply of appropriate zero-trans replacement fats high in cis-unsaturated fatty acids is insufficient to meet the demand if all PHVOs in the food supply were replaced. Regulatory action needs to be coordinated with supply to maximize the opportunity for health gains by replacing partially hydrogenated fats with purpose-ready zero-trans vegetable oils low in saturates and high in cis-unsaturates rather than animal fats and tropical oils high in saturated fatty acids.

Erythrocyte fatty acid profiles can predict acute non-fatal myocardial infarction

The risk of CHD has been linked to n-3 and trans-fatty acids. The purpose of the present study was to evaluate the hypothesis that lower n-3 fatty acids and higher trans-fatty acids in erythrocytes are associated with an increased risk of acute non-fatal myocardial infarction (MI), and that fatty acid profiles can discriminate MI cases from controls. Fifty cases with acute non-fatal MI and fifty age- and sex-matched controls without MI were recruited. The Omega-3 Index (the sum of EPA and DHA in erythrocytes) was significantly lower in cases than controls (9.57 (SEM 0.28) v. 11.81 (SEM 0.35) %; P < 0.001), while total trans-fatty acids were significantly higher (1.01 (SEM 0.04) v. 0.56 (SEM 0.03) %; P < 0.001). The Omega-3 Index was associated with decreased risk of MI (OR 0.08 (95 % CI 0.02, 0.38); P = 0.001), while total trans-fatty acids were associated with an increased risk of MI (OR 72.67 (95 % CI 6.68, 790.74); P < 0.001). The area under the receiver operating characteristic curve of fatty acid profiles was larger than that for traditional risk factors, suggesting that fatty acid profiles make a higher contribution to the discrimination of MI cases from controls compared with modified Framingham risk factors. In conclusion, a higher Omega-3 Index and lower trans-fatty acids in erythrocytes are associated with a decreased risk of MI. Furthermore, fatty acid profiles improve discrimination of acute non-fatal MI compared with established risk factors.

Lifestyle approaches and dietary strategies to lower LDL-cholesterol and triglycerides and raise HDL-cholesterol

This article discusses specific dietary factors as well as dietary patterns that affect the major coronary heart disease (CHD) lipid risk factors (ie, LDL-C, HDL-C, and TG). Based on a very large evidence base, it is clear that diet and lifestyle practices can markedly affect these major CHD lipid risk factors, and consequently decrease CHD risk substantively.

Dietary total fat intake and ischemic stroke risk: the Northern Manhattan Study

BACKGROUND

Dietary fat intake is associated with coronary heart disease risk, but the relationship between fat intake and ischemic stroke risk remains unclear. We hypothesized that total dietary fat as part of a Western diet is associated with increased risk of ischemic stroke.

METHODS

As part of the prospective Northern Manhattan Study, 3,183 stroke-free community residents over 40 years of age underwent evaluation of their medical history and had their diet assessed by a food-frequency survey. Cox proportional hazard models calculated risk of incident ischemic stroke.

RESULTS

The mean age of participants was 69 years, 63% were women, 21% were white, 24% black and 52% Hispanic. During a mean of 5.5 years of follow-up, 142 ischemic strokes occurred. After adjusting for potential confounders, risk of ischemic stroke was higher in the upper quintile of total fat intake compared to the lowest quintile (HR 1.6, 95% CI 1.0-2.7). Total fat intake >65 g was associated with increased risk of ischemic stroke (HR 1.6, 95% CI 1.2-2.3). Risk was attenuated after controlling for caloric intake.

CONCLUSIONS

The results suggest that increased daily total fat intake, especially above 65 g, significantly increases risk of ischemic stroke.