Ruminant and industrial trans-fatty acids consumption and cardiometabolic risk markers: A systematic review

Association Between Circulating Fatty Acids and Blood Pressure: A Review

PURPOSE OF REVIEW

High blood pressure (BP) or hypertension (HTN) remains key risk factors for cardiovascular disease (CVD). Circulating fatty acids (FAs) in the blood can affect directly cardiovascular hemodynamics and serves as building blocks for endocrine mediators modifying inflammatory processes and vascular function. This review aims to describe optimal circulating FA profiles for BP to adjust dietary recommendations for HTN prevention.

RECENT FINDINGS

Recent research highlights the critical role of FAs in regulating inflammation and vascular function. Different FAs have varying effects on oxidative stress, insulin resistance, inflammation, and vascular dysfunction, all contributing to HTN. These findings emphasize the importance of FAs in managing BP and preventing CVD. Up-to-now, findings suggest that eicosapentaenoic acid (20:5n3), docosahexaenoic acid (22:6n3), arachidic acid (20:0), behenic acid (22:0) and lignoceric acid (24:0) were promising candidates in reducing BP and thus, dietary intake could be recommended. Conversely, dietary intake of myristic acid (14:0), palmitic acid (16:0), and industrial trans FAs (iTFAs) should be restricted due to their association with elevated BP. Further research is warranted for pentadecanoic acid (15:0), heptadecanoic acid (17:0), stearic acid (18:0), alpha-linolenic acid (18:3n3), docosapentaenoic acid (22:5n3), linoleic acid (18:2n6), dihomo-gamma-linolenic acid (20:3n6), arachidonic acid (20:4n6), palmitoleic acid (16:1n7), and ruminant TFAs since their associations with BP present inconsistencies in the literature. Lifestyle factors such as dietary intake, physical activity, alcohol consumption and smoking should be considered when examining the relationship between FAs and BP. Overall, the FAs profile may contribute to BP level management; therefore, dietary recommendations are important.

Dietary intakes of trans fatty acids before the prohibition of partially hydrogenated oils in Canada

PURPOSE

Canada's public health objective is that ≥ 90% of the population consume <1% of total energy (< 1%En) as trans fatty acids (TFA), in line with World Health Organization recommendations. Our study aimed to estimate usual intakes of total TFA, industrially-produced TFA (i-TFA), and naturally occurring TFA (n-TFA) overall and in subgroups of the population before Canada's 2018 prohibition on the use of partially hydrogenated oils (PHO) in foods.

METHODS

Data from 1-2 24-h recalls was available for 19,670 participants in the cross-sectional Canadian Community Health Survey (CCHS)-Nutrition 2015. Usual intakes of total TFA, i-TFA, n-TFA, and mixed TFA (TFA from foods containing both i-TFA and n-TFA) from all foods and beverages were generated according to the National Cancer Institute method, and weighted to represent the population of Canada aged ≥ 1 and within age, sex, income, and self-reported racial groups.

RESULTS

For the overall population, the mean usual intake of total TFA was 1.2 g/day (SE:0.02) and represented 0.57%En (SE:0.001). All age-sex groups had mean total TFA intakes <1%En, ranging from 0.52 to 0.71%En. On average, foods containing only n-TFA provided >1/2 of total TFA intake (0.32%En, SE:0.01). The target of ≥ 90% of the population consuming <1%En as TFA had already been achieved before the PHO prohibition in all income, racial, and age-sex groups, except children 1-3 years old, with 86% within target. In that group, foods containing only n-TFA provided >2/3 of total TFA intake (0.48%En, SE:0.02).

CONCLUSION

Total TFA intakes in Canada before the PHO prohibition were relatively low, likely due to previous initiatives to reduce i-TFA in foods.

Associations between trans fatty acids and systemic immune-inflammation index: a cross-sectional study

BACKGROUND

Previous studies have demonstrated that trans fatty acids (TFAs) intake was linked to an increased risk of chronic diseases. As a novel systemic inflammatory biomarker, the clinical value and efficacy of the systemic immune-inflammation index (SII) have been widely explored. However, the association between TFAs and SII is still unclear. Therefore, the study aims to investigate the connection between TFAs and SII in US adults.

METHODS

The study retrieved data from the National Health and Nutrition Examination Survey (NHANES) for the years 1999-2000 and 2009-2010. Following the exclusion of ineligible participants, the study encompassed a total of 3047 individuals. The research employed a multivariate linear regression model to investigate the connection between circulating TFAs and SII. Furthermore, the restricted cubic spline (RCS) model was utilized to evaluate the potential nonlinear association. Subgroup analysis was also conducted to investigate the latent interactive factors.

RESULTS

In this investigation, participants exhibited a mean age of 47.40 years, with 53.91% of them being female. Utilizing a multivariate linear regression model, the independent positive associations between the log2-transformed palmitelaidic acid, the log2 transformed-vaccenic acid, the log2-transformed elaidic acid, the log2-transformed linolelaidic acid, and the log2-transformed-total sum of TFAs with the SII (all P < 0.05) were noted. In the RCS analysis, no nonlinear relationship was observed between the log2-transformed palmitelaidic acid, the log2 transformed-vaccenic acid, the log2-transformed elaidic acid, the log2-transformed linolelaidic acid, the log2-transformed-total sum of TFAs and the SII (all P for nonlinear > 0.05). For the stratified analysis, the relationship between the circulating TFAs and the SII differed by the obesity status and the smoking status.

CONCLUSIONS

A positive association was investigated between three types of TFA, the sum of TFAs, and the SII in the US population. Additional rigorously designed studies are needed to verify the results and explore the potential mechanism.

Low intake of ruminant trans fatty acids ameliorates the disordered lipid metabolism in C57BL/6J mice fed a high-fat diet

Currently, the health benefits of ruminant trans fatty acids (R-TFA) are still controversial. Our previous investigations indicated that R-TFA at higher dosages (1.3% and 4% E) caused disordered lipid metabolism in mice; however, through collecting R-TFA intake data in 9 provinces of China, it was suggested that, in 2021, the range of R-TFA intake for Chinese residents was about 0.053-0.307 g d-1. Based on the 2022 Nutritional Dietary Guidelines for Chinese Residents, the recommended daily energy supply from R-TFA was about 0.11%-0.15% E. However, the health effects of R-TFA at a lower dosage are still unknown; therefore, our current research aims to further explore the effects of R-TFA on health. Through in vivo experiments, it was shown that R-TFA (0.15% E) decreased body weight gain and serum cholesterol levels in C57BL/6J mice fed a high-fat diet, while it had no significant effect on mice fed a low-fat diet. Besides, hepatic histopathology analysis suggested that R-TFA (0.15% E) ameliorated the degree of hepatic steatosis and reduced intrahepatocyte lipid droplet accumulation in C57BL/6J mice fed a high-fat diet. Through lipidomics analysis, we further screened 8 potential lipid metabolites that participate in regulating the dysregulation of lipid metabolism. Finally, it was suggested that R-TFA (0.15% E) down-regulated the expression of genes related to inflammation and cholesterol synthesis while up-regulated the expression of genes related to cholesterol clearance, which might partially explain the salutary effect of R-TFA (0.15% E) in ameliorating the hepatic steatosis and improving disordered lipid metabolism in mice fed a high-fat diet. Our current research will provide a reference for the intake of R-TFA and, furthermore, give some insights into understanding the health effects of R-TFA.

Evaluation of edible oil types used in packaged foods in Türkiye with principal component analysis

In our rapidly changing world, where consumers' expectations for healthy food are on the rise, the edible oil content in packaged foods has become a central focus. Among various types of oils, palm oil is often regarded as one of the most contentious. This research study aimed to identify the types of fats present in packaged food products in Türkiye and examined the reasons for their utilization. A total of 1380 packaged food items, classified into 11 categories, were scrutinized, and the types of oils within their ingredients were classified using principal component analysis and hierarchical cluster analysis. The study's results have determined that among packaged food products available in Türkiye, 50.1% contain palm oil, 30.4% contain sunflower oil, 16.4% contain canola oil, 14.9% contain cottonseed oil, 17.9% contain cocoa oil, and 12.6% contain coconut oil. In particular, it was determined that palm oil was used in 91% of bakery products, 81% of margarine and shortening products, and 71.3% of ice creams. Consequently, the data obtained in the context of ongoing debates regarding the fat content in packaged foods, especially concerning palm oil usage, will make a valuable contribution to the literature.

Fat and fatty acids - a scoping review for Nordic Nutrition Recommendations 2023

Two de novo NNR2022 systematic reviews (SRs) as well as 21 qualified SRs (qSRs) were available. A literature search yielded an additional ~70 SRs, meta-analyses and biomarker papers. Diets lower in total fat are associated with reductions in body weight and blood pressure compared with diets higher in total fat in adults. Partial replacement of saturated fatty acid (SFA) with n-6 polyunsaturated fatty acid (PUFA) improves blood lipid profile, decreases the risk of cardiovascular disease (CVD), improves glucose-insulin homeostasis and may decrease the risk of total mortality. Long-chain n-3 PUFAs (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) decrease triglycerides and are associated with lower risk of CVD. Dietary PUFAs, both n-3 and n-6, may be associated with reduced risk of type 2 diabetes (T2D). There is inconclusive evidence to suggest that the type of dietary fat is associated with blood pressure, risk of hypertension or musculoskeletal health. Higher intake of total PUFA is associated with lower mortality from any cancer. Long-chain n-3 PUFA is associated with reduced risk of breast cancer, whereas biomarker levels of n-6 PUFA are associated with lower risk of any cancer. Intake of long-chain n-3 PUFA during pregnancy increases length of gestation and child birth weight and reduces the risk of preterm delivery, but there is inconclusive evidence to suggest that it may influence child neurodevelopment, growth or development of allergic disease. In studies with higher versus lower dietary cholesterol intake levels, total blood cholesterol increased or were unaffected by the dietary cholesterol, resulting in inconclusive results. Trans fatty acid (TFA), regardless of source, impairs blood lipid profile compared to unsaturated fat. In observational studies, TFA is positively associated with CVD and total mortality but whether associations differ by source is inconclusive. Ruminant TFA, as well as biomarker levels of odd-chain fatty acids, might be associated with lower risk of T2D.

Use of Olives-derived Phytochemicals for Prevention and Treatment of Atherosclerosis: An Update

Mediterranean diet is frequently associated with longevity and a lower incidence of adverse cardiovascular events because of the biological activities and health effects of olives - its key component. Olive oil, olive leaf extract, fruits and different by-products contain many bioactive components that exert anti-oxidant, anti-inflammatory and anti-apoptotic activities. In this review, we focus on the recent studies exploring molecular mechanisms underlying the cardioprotective properties of different olive oils, olive leave extracts, and specific micro-constituents (such as oleuropein, tyrosol, hydroxytyrosol and others) in vitro on rodent models and in clinical trials on human subjects. Particularly, hydroxytyrosol and oleuropein were identified as the major bioactive compounds responsible for the antioxidant, anti-inflammatory, anti-platelet aggregation and anti-atherogenic activities of olive oil. In total, the discussed results demonstrated a positive association between the consumption of olive oil and improvement in outcomes in atherosclerosis, diabetes, myocardial infarction, heart failure, hypertension and obesity.

Integration of hepatic lipidomics and transcriptomics reveals the effect of butter-derived ruminant trans fatty acids on lipid metabolism in C57BL/6J mice

Dysregulation of lipid metabolism results in metabolism-related diseases. Our previous research indicated that 1.3% E and 4% E ruminant trans fatty acids (R-TFA) caused dyslipidemia and promoted atherosclerotic plaques in ApoE-/- mice, presenting detrimental effects. However, the effect of R-TFA on the lipid metabolism of normal mice remains unclear. Therefore, our current research aims to explore the effects of butter-derived R-TFAs on the lipid metabolism of C57BL/6J mice through the integration of lipidomics and transcriptomics. As a result, we found that 1.3% E butter-derived R-TFA promoted dyslipidemia and impaired hepatic function in C57BL/6J mice fed a high-fat diet, which was associated with an increase in DG (18:1/22:5), TG (18:1/18:2/22:4) and FA (24:5) as determined through lipidomics analysis, but had a less significant effect on C57BL/6J mice fed a low-fat diet. Through a combination analysis and verification of gene expression, we found that the arachidonic acid pathway might be involved in the disruption of lipid metabolism by butter-derived R-TFA. In addition, butter-derived R-TFA up-regulated the expression of unigene thromboxane-A synthase 1 (Tbxas1), arachidonate lipoxygenase 3 (Aloxe3), acyl-coenzyme A thioesterase 2 (Acot2), epoxide hydrolase 2 (Ephx2) and carbonyl reductase 3 (Cbr3) in C57BL/6J mice fed a high-fat diet. Herein, our research provides a new perspective for exploring the effects of butter-derived R-TFA on lipid metabolism and speculates on the possible mechanism of lipid metabolism disorder induced by butter-derived R-TFA in C57BL/6J mice fed a high-fat diet.

Implications of Organic Dairy Management on Herd Performance and Milk Fatty Acid Profiles and Interactions with Season

Interest in organic cows' milk has increased due to the perceived superior nutritional quality and improved sustainability and animal welfare. However, there is a lack of simultaneous assessments on the influence of organic dairy practices and dietary and breed drivers on productivity, feed efficiency, health parameters, and nutritional milk quality at the herd level. This work aimed to assess the impact of organic vs. conventional management and month on milk yield and basic composition, herd feed efficiency, health parameters, and milk fatty acid (FA) composition. Milk samples (n = 800) were collected monthly from the bulk tanks of 67 dairy farms (26 organic and 41 conventional) between January and December 2019. Data on breed and feeding practices were gathered via farm questionnaires. The samples were analyzed for their basic composition and FA profile using Fourier transform infrared spectroscopy (FTIR) and gas chromatography (GC), respectively. The data were analyzed using a linear mixed model, repeated measures design and multivariate redundancy analysis (RDA). The conventional farms had higher yields (kg/cow per day) of milk (+7.3 kg), fat (+0.27 kg), and protein (+0.25 kg) and higher contents (g/kg milk) of protein, casein, lactose, and urea. The conventional farms produced more milk (+0.22 kg), fat (+8.6 g), and protein (+8.1 g) per kg offered dry matter (DM). The organic farms produced more milk per kg of offered non-grazing and concentrate DM offered, respectively (+0.5 kg and +1.23 kg), and fat (+20.1 g and +51 g) and protein (+17 g and +42 g). The organic milk had a higher concentration of saturated fatty acid (SFA; +14 g/kg total FA), polyunsaturated fatty acid (PUFA; +2.4 g/kg total FA), and nutritionally beneficial FA alpha linolenic acid (ALNA; +14 g/kg total FA), rumenic acid (RA; +14 g/kg total FA), and eicosapentaenoic acid (EPA; +14 g/kg total FA); the conventional milk had higher concentrations of monounsaturated FA (MUFA; +16 g/kg total FA). Although the conventional farms were more efficient in converting the overall diet into milk, fat, and protein, the organic farms showed better efficiency in converting conserved forages and concentrates into milk, fat, and protein as a result of reduced concentrate feeding. Considering the relatively small differences in the FA profiles between the systems, increased pasture intake can benefit farm sustainability without negatively impacting consumer nutrition and health.

Supplementation with Sunflower/Fish Oil-Containing Concentrates in a Grass-Based Beef Production System: Influence on Fatty Acid Composition, Gene Expression, Lipid and Colour Stability and Sensory Characteristics of Longissimus Muscle

Beef contains an array of conjugated linoleic acid (CLA) isomers for which positive effects have been reported in animal models of human disease. The objectives were to develop a CLA-enriched beef production system and to assess its quality. Sixty Spring-born heifers were housed in Autumn and offered unwilted grass silage and a barley/soyabean concentrate or wilted grass silage and a concentrate containing sunflower oil and fish oil. In May, both groups were offered either pasture for 22 weeks, restricted pasture and sunflower oil and fish oil for 22 weeks, or pasture for 11 weeks and restricted pasture and sunflower oil and fish oil for the final 11 weeks. The predominant CLA isomer in beef was cis9, trans11 representing on average, 80% total CLA. The modified winter diet followed by supplementation for 22 weeks resulted in beef that had a CLA concentration that was higher, at a comparable intramuscular fatty acid concentration, than previously reported. The lipid and colour stability (over 10 days in modified atmosphere packaging) and sensory characteristics were generally not negatively affected. There were minor effects on the expression of candidate genes involved in lipid metabolism. Consumption of this beef would make a substantial contribution to the quantity of CLA suggested to have a positive effect on consumer health.

Effects of Hay, Baleage, and Soybean Hulls Waste Used as Supplemental Feeds on the Nutritional Profile of Grass-Finished Beef

Grass-finished beef (GFB) has demonstrated wide nutritional variations with some GFB having a considerably higher n-6:n-3 ratio compared to grain-finished beef. To better understand these variations, the current study investigated the effects of commonly used supplemental feeds on the nutritional profile of GFB. This two-year study involved 117 steers randomly allocated to one of four diets: (1) grass+hay (G-HAY), (2) grass+baleage (G-BLG), (3) grass+soybean hulls (G-SH), and (4) baleage+soybean hulls in feedlot (BLG-SH). Feed samples were analyzed for their nutritional value, and beef samples underwent analysis for fatty acids (FAs), vitamin E, minerals, lipid oxidation, and shear force. FAs were measured by GC-MS, vitamin E was analyzed chromatographically, minerals were analyzed by ICP-MS, and lipid oxidation was measured via a thiobarbituric acid reactive substances (TBARS) assay. G-SH beef had the highest n-6:n-3 ratio (p < 0.001), while BLG-SH beef contained less vitamin E (p < 0.001) and higher TBARS values (p < 0.001) compared to the other groups. G-HAY beef contained more long-chain n-3 polyunsaturated FAs compared to the other groups (p < 0.001). In conclusion, G-HAY beef had the most beneficial nutritional profile, while soybean hulls increased the n-6:n-3 ratio of beef.

Fatty Acid and Micronutrient Profile of Longissimus Lumborum from Red Angus and Red Angus x Akaushi Cattle Finished on Grass or Grain

Cattle diet and breed modify the nutritional profile of beef. The objective of this study was to compare the fatty acid (FA) and micronutrient profiles of Red Angus (RA) and RA x Akaushi (AK) crossbreed steers fed either a grass or grain diet. This two-year study randomly assigned steers to the diets using a 2 × 2 factorial experiment. FAs and micronutrients were analyzed. Diet effect was the strongest with grass-finished beef being higher in n-3 polyunsaturated FAs (p < 0.001), conjugated linoleic acid (p < 0.05), vaccenic acid (p < 0.05), iron (p < 0.001), and vitamin E (p < 0.001) compared to grain-finished beef. Breed effects were observed for lauric and myristic acids (p < 0.05), selenium (p < 0.05), and zinc (p < 0.01) with AK containing more of these compounds than RA. Diet × breed effects were non-existent. These results indicate that diet has a stronger influence than breed on modifying the nutritional profile of beef. Because of a more favorable FA and antioxidant profile, consumption of grass-finished beef could benefit human health.

Trans Fatty Acids Content in Whole-Day Diets Intended for Pregnant and Breastfeeding Women in Gynaecological and Obstetric Wards: Findings from the Study under the “Mum’s Diet” Pilot Program in Poland

Trans fatty acids (TFAs) have been proven to have an adverse effect on human health by interfering with n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) synthesis. LC-PUFA n-3 are necessary for the development and maturation of the nervous system and retina during the prenatal period and infancy. TFAs are not synthesized de novo in the human body. Their presence in body fluids arises from the diet. The aim of our study was to determine the content of TFAs in individual meals and in a whole-day hospital diet intended for pregnant and breastfeeding women. Samples were collected from six different hospitals in Poland which voluntarily applied to the “Mum’s Diet” Pilot Program. The content of fatty acids, including TFAs, was determined by gas chromatography coupled with mass spectrometry (GC-MS). The TFAs content in the whole-day hospital diets ranged from 3.86 to 8.37% of all fatty acids (% wt/wt). Food products served for elevenses and afternoon snacks contributed the highest amounts of TFAs. These mainly included dairy products containing TFAs of natural origins. The estimated average intake of TFAs with the hospital diet was 0.72 g/person/day (range: 0.34–1.16 g/person/day) and did not exceed the maximum level of 1% of dietary energy recommended by the World Health Organization.

Butter-Derived Ruminant Trans Fatty Acids Do Not Alleviate Atherosclerotic Lesions in High-Fat Diet-Fed ApoE-/- Mice

Atherosclerosis (AS) is the most common cardiovascular disease (CVD). Currently, it is widely believed that R-TFA and I-TFA may cause different biological effects. In the present study, we aim to elucidate the effect of mixed R-TFA derived from butter on the development of AS in high-fat diet-fed ApoE^-/- mice and find the possible mechanism. It was shown that butter-derived R-TFA promoted dyslipidemia, reduced thoracic and abdominal aorta diameters, and induced aortic lipid deposition and atherosclerotic lesions in high-fat diet-fed ApoE^-/- mice. Meanwhile, butter-derived R-TFA affected the serum lipid profile of high-fat diet-fed ApoE^-/- mice and the lipid metabolism of human umbilical vein endothelial cells (HUVECs). Through lipidomic techniques, we found that butter-derived R-TFA had a significant effect on the glycerophospholipid metabolic pathway. In conclusion, our results demonstrated that butter-derived R-TFA does not alleviate but promotes atherosclerotic lesions in high-fat diet-fed ApoE^-/- mice and that the glycerophospholipid metabolic pathway plays a major role in this pro-atherosclerotic effect.

Attention to the Details: How Variations in U.S. Grass-Fed Cattle-Feed Supplementation and Finishing Date Influence Human Health

As the global population increases, so does meat consumption. This trend is accompanied by concerns regarding the meat industry, and consumers are demanding transparency on the environmental and health effects of the products they are purchasing. Many leading health organizations recommend reducing red meat consumption. Nevertheless, no differentiation is made among red meats and beef. The beef production system is generally ignored despite nutritional differences between grain- and grass-fed beef. Compared to grain-fed beef, grass-fed beef contains a healthier fatty acid profile, including more omega-3 polyunsaturated fatty acids and conjugated linoleic acid, and increased concentrations of phytochemicals desired by health-conscious customers. However, there is a lack of consistency among grass-fed beef in the United States regarding clear product labeling and cattle dietary components. Grass-fed beef labeling confusion has emerged, including misunderstandings between grass-fed and grass-finished beef. Along with this, previous studies observed significant nutritional variation among grass-finished beef from different producers across the country. Cattle diet has the strongest influence on the nutritional composition of beef. Therefore, understanding differences in feeding practices is key to understanding differing nutritional quality of grass-fed beef. Feeding cattle diverse pastures composed of multiple plant species including grasses and legumes managed in a rotational grazing fashion results in higher omega-3 polyunsaturated fatty acids and phytochemical levels in beef compared to feedlots and monocultures. Seasonal differences including changes in temperature, rainfall, grazing practices, and plant growth cycles affect the nutritional composition of feeds and ultimately meat. Additional feeds utilized in grass-fed beef production systems such as conserved forages may reduce or increase health-promoting nutrients in grass-fed beef, while supplements such as grape byproducts and flaxseed may improve its nutritional profile. Further research should measure the effects of individual feedstuff and the finishing period on the nutritional profile on grass-fed beef. A better understanding of these details will be a step toward the standardization of pasture-raised ruminant products, strengthening the relationship between grass-fed beef consumption and human health.

Trans-Fatty Acids in Fast-Food and Intake Assessment for Yerevan’s Population, Armenia

There are stringent regulations applicable for trans-fatty acid (TFA) limitations from food supply across the world. However, in Armenia, there is a scarcity of data on TFA content in food products and their consumption levels. Considering that fast-food is among the major contributors to TFA intake, this study aims to assess the dietary exposure of TFAs through the consumption of fast-food in Yerevan, Armenia. Eleven types of fast-food were included in the study. The Food Frequency Questionnaire (FFQ) was used to evaluate daily fast-food consumption. TFA contents in samples were determined using gas chromatography-mass spectrometry. Mean daily fast-food consumption values ranged from 14.68 g/day to 76.09 g/day, with popcorn as the lowest and pastry as the highest consumed food. The study results indicate that the aggregate average daily intake (DI) of TFA is 0.303 g/day. Even though TFA DI values do not exceed the WHO limit of 1%, they substantially contribute to daily TFA intake and may exceed the limit when combined with other foods. Hence, it is recommended to carry out continuous monitoring of TFA content in the food supply to ensure consumer health protection.

A Systematic Review of Trans Fat Reduction Initiatives in the Eastern Mediterranean Region

High intakes of trans fatty acids (TFA), particularly industrially-produced TFA, are implicated in the etiology of cardiovascular diseases, which represent the leading cause of mortality in the Eastern Mediterranean Region (EMR). This systematic review aims to document existing national TFA reduction strategies in the EMR, providing an overview of initiatives that are implemented by countries of the region, and tracking progress toward the elimination of industrially-produced TFA. A systematic review of published and gray literature was conducted using a predefined search strategy. A total of 136 peer-reviewed articles, gray literature documents, websites and references from country contacts were obtained, up until 2 August 2021. Randomized-control trials, case-control studies, and studies targeting unhealthy population groups were excluded. Only articles published after 1995, in English, Arabic or French, were included. Key characteristics of strategies were extracted and classified according to a pre-developed framework, which includes TFA intake assessment; determination of TFA levels in foods; strategic approach; implementation strategies (TFA bans/limits; consumer education, labeling, interventions in public institution settings, taxation), as well as monitoring and evaluation of program impact. Thirteen out of the 22 countries of the EMR (59%) have estimated TFA intake levels, 9 have determined TFA levels in foods (41%), and 14 (63.6%) have national TFA reduction initiatives. These initiatives were mainly led by governments, or by national multi-sectoral committees. The most common TFA reduction initiatives were based on TFA limits or bans (14/14 countries), with a mandatory approach being adopted by 8 countries (Bahrain, Iran, Jordan, KSA, Kuwait, Morocco, Oman and Palestine). Complementary approaches were implemented in several countries, including consumer education (10/14), food labeling (9/14) and interventions in specific settings (7/14). Monitoring activities were conducted by few countries (5/14), and impact evaluations were identified in only Iran and the UAE. The robustness of the studies, in terms of methodology and quality of assessment, as well as the lack of sufficient data in the EMR, remain a limitation that needs to be highlighted. Further action is needed to initiate TFA reduction programs in countries that are lagging behind, and to ensure rigorous implementation and evaluation of ongoing programs.

The Effect of Trans Fatty Acids on Human Health: Regulation and Consumption Patterns

Health effects of trans fatty acids (TFAs) on human organisms can vary according to their type, structure, composition, and origin. Even though the adverse health effects of industrial TFAs (iTFAs) have been widely discussed, the health effects of natural TFAs (nTFAs) are still questionable. Hence, it is important to review the literature and provide an overall picture on the health effects of different TFAs coming from industrial and ruminant sources, underlining those types that have adverse health effects as well as suggesting methods for reducing their harmful effects. Multiple databases (PubMed, Medline, Cochrane Library, etc.) were searched with the key words "trans fatty acid sources", "ruminant", "industrial", "conjugated trans linoleic acid", "human", "coronary heart disease", "cancer", etc. Reference lists of the studies were scanned discussing the health effects of iTFAs and nTFAs. The review of the literature showed that iTFAs are found to be more harmful than ruminant-produced nTFAs. Although several beneficial effects (such as reduced risk of diabetes) for nTFAs have been observed, they should be used with caution. Since during labeling it is usually not mentioned whether the TFAs contained in food are of industrial or natural origin, the general suggestion is to reduce their consumption.

Systematic Literature Review and Meta-Analysis of the Relationship Between Polyunsaturated and Trans Fatty Acids During Pregnancy and Offspring Weight Development

Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and trans fatty acids (TFAs) may have an impact on offspring weight development. We conducted a systematic review and meta-analysis according to PRISMA guidelines to evaluate whether levels of these fatty acids during pregnancy influenced offspring weight development. Randomized controlled trials (RCTs) with DHA and/or EPA supplementation or cohort studies, which examined levels of DHA, EPA, or TFAs in maternal or neonatal blood samples and recorded offspring weight, were included. Overall, 27 RCTs and 14 observational studies were identified. The results showed that DHA and/or EPA supplementation doses >650 mg/day resulted in slightly higher birth weight (MD 87.5 g, 95% CI 52.3-122.6, n = 3,831) and combined BMI and BMI z score at 5-10 years (SMD 0.11, 95% CI 0.04-0.18, n = 3,220). These results were rated as moderate quality. Results from the observational studies were generally inconsistent. High TFA levels during pregnancy seemed to be associated with lower birth weight. Finally, this review and meta-analysis supports a relationship between high maternal or neonatal DHA and/or EPA levels and higher offspring birth weight and weight in childhood. More high-quality long-term studies are still needed.