Higher Intake of PUFAs Is Associated with Lower Total and Visceral Adiposity and Higher Lean Mass in a Racially Diverse Sample of Children

Overfeeding polyunsaturated fat compared with saturated fat does not differentially influence lean tissue accumulation in individuals with overweight: a randomized controlled trial

BACKGROUND

Fatty acids may influence lean tissue volume and skeletal muscle function. We previously reported in young lean participants that overfeeding PUFA compared with SFA induced greater lean tissue accumulation despite similar weight gain.

OBJECTIVES

In a double-blind randomized controlled trial, we aimed to investigate if the differential effects of overfeeding SFA and PUFA on lean tissue accumulation could be replicated in individuals with overweight and identify potential determinants. Further, using substitution models, we investigated associations between SFA and PUFA concentrations with lean tissue volume in a large population-based sample (UK Biobank).

METHODS

Sixty-one males and females with overweight [BMI (kg/m2): 27.3 (interquartile range (IQR), 25.4-29.3); age: 43 (IQR, 36-48)] were overfed SFA (palm oil) or n-6 (ω-6) PUFA (sunflower oil) for 8 wk. Lean tissue was assessed by MRI. We had access to n = 13,849 participants with data on diet, covariates, and MRI measurements of lean tissue, as well as 9119 participants with data on circulating fatty acids in the UK Biobank.

RESULTS

Body weight gain mean (SD) was similar in PUFA (2.01 ± 1.90 kg) and SFA (2.31 ± 1.38 kg) groups. Lean tissue increased to a similar extent [0.54 ± 0.93 L and 0.67 ± 1.21 L for PUFA and SFA groups, respectively, with a difference between groups of 0.07 (-0.21, 0.35)]. We observed no differential effects on circulating amino acids, myostatin, or IL-15 and no clear determinants of lean tissue accumulation. Similar nonsignificant results for SFA and PUFA were observed in UK Biobank, but circulating fatty acids demonstrated ambiguous and sex-dependent associations.

CONCLUSIONS

Overfeeding SFA or PUFA does not differentially affect lean tissue accumulation during 8 wk in individuals with overweight. A lack of dietary fat type-specific effects on lean tissue is supported by specified substitution models in a large population-based cohort consuming their habitual diet. This trial was registered at clinicaltrials.gov identifier as NCT02211612.

Important roles of linoleic acid and α-linolenic acid in regulating cognitive impairment and neuropsychiatric issues in metabolic-related dementia

Metabolic syndrome (MetS), which is characterized by insulin resistance, high blood glucose, obesity, and dyslipidemia, is known to increase the risk of dementia accompanied by memory loss and depression. The direct pathways and specific mechanisms in the central nervous system (CNS) for addressing fatty acid imbalances in MetS have not yet been fully elucidated. Among polyunsaturated acids, linoleic acid (LA, n6-PUFA) and α-linolenic acid (ALA, n3-PUFA), which are two essential fatty acids that should be provided by food sources (e.g., vegetable oils and seeds), have been reported to regulate various cellular mechanisms including apoptosis, inflammatory responses, mitochondrial biogenesis, and insulin signaling. Furthermore, inadequate intake of LA and ALA is reported to be involved in neuropathology and neuropsychiatric diseases as well as imbalanced metabolic conditions. Herein, we review the roles of LA and ALA on metabolic-related dementia focusing on insulin resistance, dyslipidemia, synaptic plasticity, cognitive function, and neuropsychiatric issues. This review suggests that LA and ALA are important fatty acids for concurrent treatment of both MetS and neurological problems.

Investigation the interaction of dietary fat quality indices and the MC4R gene in metabolically healthy and unhealthy overweight and obese women

Obesity has become a common global problem. Some obese people can be metabolically healthy. Gene-environment interaction can be important in this context. This study aimed to assess the interaction between dietary fat quality indices and the Melanocortin 4 receptor (MC4R) gene in metabolically healthy and unhealthy overweight and obese women. This cross-sectional study was conducted on 279 women with overweight and obesity. The definition of metabolically healthy and unhealthy phenotypes was done according to Karelis criteria. Dietary assessment was done using a 147-item validated semi-quantitative food frequency questionnaire and dietary fat quality was assessed by cholesterol-saturated fat index (CSI) and the ratio of omega-6/omega-3 (N6/N3) essential fatty acids. MC4R was genotyped by polymerase chain reaction-restriction fragment length polymorphism technique. A generalized linear model was used to evaluate the interaction between dietary fat quality indices and the MC4R gene in both crude and adjusted models. Study subjects with higher ratio of N6/N3 had higher homeostatic model assessment for insulin resistance (HOMA IR) index (P = 0.03) and other variables showed no difference according to the tertile of CSI and N6/N3. Participants with the C allele of MC4R rs17782313 had lower height (P < 0.001) and higher HOMA index (P = 0.01). We found that the CC genotype of MC4R interacts with the N6/N3 ratio on the metabolically unhealthy phenotype in the crude model (β = 9.94, CI 2.49-17.39, P = 0.009) and even after adjustment for all confounders (β = 9.002, CI 1.15-16.85, P = 0.02, β =  - 12.12, CI 2.79-21.46, P = 0.01). The data of this study can justify one inconsistency observed in society, regarding dietary recommendations about metabolic health status. Those with CC genotype, are more likely to have an unhealthy phenotype with an increase in N6/N3 as one fat quality indices than those who do not have CC genotype. We found the interaction of dietary fat quality indices such as N6/N3 and the MC4R gene in metabolically unhealthy overweight and obese women.

Linoleate-Rich Safflower Oil Diet Increases Linoleate-Derived Bioactive Lipid Mediators in Plasma, and Brown and White Adipose Depots of Healthy Mice

Polyunsaturated fats are energy substrates and precursors to the biosynthesis of lipid mediators of cellular processes. Adipose tissue not only provides energy storage, but influences whole-body energy metabolism through endocrine functions. How diet influences adipose-lipid mediator balance may have broad impacts on energy metabolism. To determine how dietary lipid sources modulate brown and white adipose tissue and plasma lipid mediators, mice were fed low-fat (15% kcal fat) isocaloric diets, containing either palm oil (POLF) or linoleate-rich safflower oil (SOLF). Baseline and post body weight, adiposity, and 2-week and post fasting blood glucose were measured and lipid mediators were profiled in plasma, and inguinal white and interscapular brown adipose tissues. We identified over 30 species of altered lipid mediators between diets and found that these changes were unique to each tissue. We identified changes to lipid mediators with known functional roles in the regulation of adipose tissue expansion and function, and found that there was a relationship between the average fold difference in lipid mediators between brown adipose tissue and plasma in mice consuming the SOLF diet. Our findings emphasize that even with a low-fat diet, dietary fat quality has a profound effect on lipid mediator profiles in adipose tissues and plasma.

Intake of n-3 LCPUFA and trans-fatty acids is unrelated to development in body mass index and body fat among children

BACKGROUND

The number of children and adolescents with obesity has increased worldwide. Some studies have found an increase in the intake of n-3 long-chain polyunsaturated fatty acid (LCPUFA) to be beneficial for weight and obesity status. The objectives of this study were to examine if intake of trans-fatty acids (TFA) and n-3 LCPUFA at school start was associated with weight and body fat development in the following 3 and 7 years, and if substituting other fats for n-3 LCPUFA in regression models influenced weight and body fat development.

METHODS

A total of 285 children (boys:130, girls:155) were included in this study. Weight, height and skinfold thickness (SF) of children were measured at age 6, 9 and 13 years by trained research personnel. Multivariate linear regression models were used to investigate the associations between n-3 LCPUFA or TFA intake and subsequent changes in body mass index (BMI) or SF. To investigate substitution effects, we constructed regression models including information on n-3 LCPUFA and all other energy given components of the diet, except for the nutrient to be substituted (all other fats and specific subgroups; saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and other polyunsaturated fatty acids (PUFAs)).

RESULTS

No significant associations were observed between intake of TFA or n-3 LCPUFA and changes in BMI and SF. Also, results from regression analysis showed substituting other fats for n-3 LCPUFA did not associate with BMI or SF development.

CONCLUSION

The lack of associations between n-3 LCPUFA and TFA and adiposity suggests that fat composition in the diet does not play a major role in obesity development among school-aged children.

Beneficial effects of eicosapentaenoic acid on the metabolic profile of obese female mice entails upregulation of HEPEs and increased abundance of enteric Akkermansia muciniphila

Eicosapentaenoic acid (EPA) ethyl esters are of interest given their clinical approval for lowering circulating triglycerides and cardiometabolic disease risk. EPA ethyl esters prevent metabolic complications driven by a high fat diet in male mice; however, their impact on female mice is less studied. Herein, we first investigated how EPA influences the metabolic profile of female C57BL/6J mice consuming a high fat diet. EPA lowered murine fat mass accumulation, potentially through increased biosynthesis of 8-hydroxyeicosapentaenoic acid (HEPE), as revealed by mass spectrometry and cell culture studies. EPA also reversed the effects of a high fat diet on circulating levels of insulin, glucose, and select inflammatory/metabolic markers. Next, we studied if the improved metabolic profile of obese mice consuming EPA was associated with a reduction in the abundance of key gut Gram-negative bacteria that contribute toward impaired glucose metabolism. Using fecal 16S-ribosomal RNA gene sequencing, we found EPA restructured the gut microbiota in a time-dependent manner but did not lower the levels of key Gram-negative bacteria. Interestingly, EPA robustly increased the abundance of the Gram-negative Akkermansia muciniphila, which controls glucose homeostasis. Finally, predictive functional profiling of microbial communities revealed EPA-mediated reversal of high fat diet-associated changes in a wide range of genes related to pathways such as Th-17 cell differentiation and PI3K-Akt signaling. Collectively, these results show that EPA ethyl esters prevent some of the deleterious effects of a high fat diet in female mice, which may be mediated mechanistically through 8-HEPE and the upregulation of intestinal Akkermansia muciniphila.

Adipose Tissue Dysfunctions in Response to an Obesogenic Diet Are Reduced in Mice after Transgenerational Supplementation with Omega 3 Fatty Acids

Obesity is characterized by profound alterations in adipose tissue (AT) biology, leading to whole body metabolic disturbances such as insulin resistance and cardiovascular diseases. These alterations are related to the development of a local inflammation, fibrosis, hypertrophy of adipocytes, and dysregulation in energy homeostasis, notably in visceral adipose tissue (VAT). Omega 3 (n-3) fatty acids (FA) have been described to possess beneficial effects against obesity-related disorders, including in the AT; however, the long-term effect across generations remains unknown. The current study was conducted to identify if supplementation with n-3 polyunsaturated FA (PUFA) for three generations could protect from the consequences of an obesogenic diet in VAT. Young mice from the third generation of a lineage receiving a daily supplementation (1% of the diet) with fish oil rich in eicosapentaenoic acid (EPA) or an isocaloric amount of sunflower oil, were fed a high-fat, high-sugar content diet for 4 months. We explore the transcriptomic adaptations in each lineage using DNA microarray in VAT and bioinformatic exploration of biological regulations using online databases. Transgenerational intake of EPA led to a reduced activation of inflammatory processes, perturbation in metabolic homeostasis, cholesterol metabolism, and mitochondrial functions in response to the obesogenic diet as compared to control mice from a control lineage. This suggests that the continuous intake of long chain n-3 PUFA could be preventive in situations of oversupply of energy-dense, nutrient-poor foods.

Total Fat and Fatty Acid Intake among 1-7-Year-Old Children from 33 Countries: Comparison with International Recommendations

This work reviews available data on dietary intakes of total fat, saturated fatty acids (SFA) and individual polyunsaturated fatty acids (PUFA) in children in different countries worldwide and for the first time, compares them with recent international recommendations. Studies published before June 2021 reporting total fat, total SFA and individual PUFA intakes in children aged 1-7 y were included. Observed intakes were evaluated against FAO/WHO and EFSA recommendations. 65 studies from 33 countries were included. Fat intake was too low in 88% of studies in young children (1-3 y). SFA intake was >10%E in 69-73% of children, especially in Europe. Linoleic acid intake was <3%E in 24% of studies in 1-2 y olds and within FAO/WHO recommendations among all other ages. Alpha-linolenic acid intake was <0.5%E in almost half of studies. Docosahexaenoic acid (DHA) or eicosapentaenoic acid + DHA intakes were below recommendations in most studies. In summary, while total fat intake was too low among younger children, SFA intake was above, especially in Europe and n-3 PUFA intake, especially DHA, were below recommendations for all ages. Intake of n-3 PUFA, especially DHA, is generally suboptimal. More data, particularly from developing countries, are required to refine these findings and guide implementation of adapted nutrition policies.

The Healthy Gluten-Free Diet: Practical Tips to Prevent Metabolic Disorders and Nutritional Deficiencies in Celiac Patients

The gluten-free diet (GFD) is the cornerstone treatment for coeliac disease (CD). However, a healthy GFD is more complex than the only exclusion of gluten-containing foods. Most celiac patients do not receive nutritional advice and tend to consume industrial gluten-free products (GFPs), which often lack fiber, vitamins, and other micronutrients while being rich in saturated fats and refined sugars. This review focuses on the main potential metabolic disorders and nutritional deficiencies in CD patients at diagnosis and dissects the main nutritional and metabolic issues due to a non-balanced GFD. Nutritional tips to achieve an adequate dietary approach in CD are provided. We also compared the main nutritional components of naturally gluten-free cereals (including pseudocereals) to give an exhaustive overview of the possible healthy alternatives to processed GFPs. Clinicians and dietitians should be systematically involved in the diagnosis of CD to monitor the appropriateness of GFD and the patient’s nutritional status over time.

Polyunsaturated fatty acids as modulators of fat mass and lean mass in human body composition regulation and cardiometabolic health

It is now recognized that the amount and type of dietary fat consumed play an important role in metabolic health. In humans, high intake of polyunsaturated fatty acids (PUFAs) has been associated with reductions in cardiovascular disease risk, improvements in glucose homeostasis, and changes in body composition that involve reductions in central adiposity and, more recently, increases in lean body mass. There is also emerging evidence, which suggests that high intakes of the plant-based essential fatty acids (ePUFAs)-n-6 linoleic acid (LA) and n-3 α-linolenic acid (ALA)-have a greater impact on body composition (fat mass and lean mass) and on glucose homeostasis than the marine-derived long-chain n-3 PUFA-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In addition, high intake of both ePUFAs (LA and ALA) may also have anti-inflammatory effects in humans. The purpose of this review is to highlight the emerging evidence, from both epidemiological prospective studies and clinical intervention trials, of a role for PUFA, in particular ePUFA, in the long-term regulation of body weight and body composition, and their impact on cardiometabolic health. It also discusses current notions about the mechanisms by which PUFAs modulate fat mass and lean mass through altered control of energy intake, thermogenesis, or lean-fat partitioning.

Comparative Effects of Dietary Hemp and Poppy Seed Oil on Lipid Metabolism and the Antioxidant Status in Lean and Obese Zucker Rats

The objective of this study was to compare the effects of the dietary inclusion of hemp seed oil (HO) and poppy seed oil (PO) on the lipid metabolism and antioxidant status of lean and genetically obese Zucker rats. The rats were fed a control diet for laboratory rodents or a modification with HO or PO. Both oils reduced body and epididymal fat and liver cholesterol levels and promoted oxidative stress in the liver of obese rats. The HO reduced plasma triglycerides and had a stronger liver cholesterol-lowering effect in obese rats than PO. In the lean rats, HO and PO had no effects on the body fat content, plasma lipid profile, or lipid metabolism in the liver. HO considerably elevated the content of α-linolenic acid in the liver and increased the liver ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) in the lean rats. In conclusion, the regular consumption of both oils increases the accumulation of essential fatty acids in the liver of healthy animals, whilst not having any adverse effects on the body, whereas in genetically obese rats, the effects of both dietary oils on the lipid metabolism and antioxidant status are unequivocal and only partially beneficial.

Dietary fat quantity and quality in relation to general and abdominal obesity in women: a cross-sectional study from Ghana

BACKGROUND

Although relationships between obesity and total fat and fat types have been widely examined, the associations between the relative proportions of fatty acids calculated in the form of indices and obesity/overweight are lacking. The objective of this study was to assess associations between dietary fat quality indices and odds of obesity/overweight in women from Ghana.

METHODS

In this cross-sectional study, dietary information was obtained using 24-h dietary recall. The odds of obesity were evaluated across quintiles of specific DFQ indices [atherogenicity index (AI), thrombogenic index (TI), hypo- and hypercholesterolemic fatty acids ratio (h/H), omega-3 to omega-6 polyunsaturated fatty acids ratio (∑ω-3/∑ω-6), polyunsaturated fatty acids/saturated fatty acids ratio (PSR), dietary lipophilic index (LI) and percentage of energy from total fat (TF)].

RESULTS

After adjustment for covariates, general obesity and overweight were inversely associated with ∑ω-3/∑ω-6 ratio (OR: 0.63; 95% CI: 0.24-1.63; P for trend (P) = 0.005) and positively with TI (4.14; 95% CI: 1.78-9.66; P = 0.01) and LI (2.49; 95% CI: 1.14-5.43; P = 0.01). The odds of abdominal obesity based on waist circumference (WC) were significantly higher among participants in the fifth quintile (Q) compared with those in the first Q of AI (1.24; 95% CI: 0.56-2.74; P = 0.01), TI (4.14; 95% CI: 1.78-9.66; P = 0.009), LI (2.11; 95% CI: 0.98-4.55; P = 0.02) and TF (1.59; 95% CI: (0.73-3.46; P = 0.003). Similarly, waist to height ratio (WHtR) was positively associated with AI (2.89; 95% CI: 1.32-6.31; P = 0.04), TI (2.65; 95% CI: 1.22-5.76; P = 0.03), LI (3.32; 95% CI: 1.52-7.28; P = 0.007) and TF (1.83; 95% CI: 0.85-3.93; P = 0.009).

CONCLUSION

There was an inverse association between ∑ω-3/∑ω-6 ratio and general obesity and WC. We also found positive associations between abdominal obesity and AI and TF. Furthermore, TI and LI showed positive relationships with both general and abdominal obesity. Therefore, intake of dietary fatty acids in favor of higher ratios of ∑ω-3/∑ω-6 may be important in obesity prevention.

Body Composition and Circulating Polyunsaturated Fatty Acids at Age 6 Years: A Longitudinal Pilot Study

Maternal polyunsaturated fatty acid (PUFA) status during pregnancy may influence birth outcomes and offspring adiposity during childhood. Cord blood PUFA levels associate positively with maternal PUFA and negatively with the newborn's abdominal adiposity. However, longitudinal, prospective studies consistently evaluating maternal and cord blood and PUFA levels in childhood and their association with the child's body composition are so far lacking. In a population of 16 apparently healthy children born appropriate for gestational age and followed longitudinally since birth, we assessed circulating PUFA (by gas chromatography) in maternal, cord, and peripheral blood at age 6 years and studied their correlation with body composition (by absorptiometry) and endocrine-metabolic variables at age 6 years. No associations were found among parameters of body composition and endocrine-metabolic variables at age 6 years and maternal, cord blood or circulating PUFA in peripheral blood. Maternal levels of n-6 linoleic acid, total n-6, and the ratio of n-6:n-3 correlated with their corresponding PUFA levels at age 6 years. In conclusion, in this pilot study, maternal, cord blood, and children's circulating PUFA do not appear to have an impact on body composition and endocrine-metabolic status at the age of 6 years. The close association between maternal PUFA and offspring PUFA at that age may reflect a similarity in nutritional habits in the mother and child.

The association between allostatic load and anthropometric measurements among a multiethnic cohort of children

OBJECTIVE

This study investigated if levels of allostatic load (ALoad) differed according to race/ethnicity in children and if ALoad was associated with obesity-related measures.

METHODS

A multiethnic sample of 307 children aged seven to 12 was evaluated, composed of 39% European American (EA), 35% African American (AA), and 26% Hispanic American (HA) youth. Anthropometric measurements were evaluated by dual-energy X-ray absorptiometry, and other measurements included body mass index (BMI) and waist circumference (WC). Allostatic load scores were estimated based on two different calculations, including seven and eight biomarkers (ALoad1 and ALoad2), respectively. Analyses of variance, independence tests, and multiple regression models were performed.

RESULTS

From the total sample, 22.80% (n = 70) of children were characterized as "no load," 46.58% (n = 143) "low load," and 30.62% (n = 94) "high load." Hispanic American children showed the highest ALoad scores (2.07 ± 1.54; 95% CI, 1.73-2.41) compared with AA children (1.71 ± 1.43; 95% CI, 1.43-1.99) and EA children (1.56 ± 1.34; 95% CI, 1.32-1.80) (P < 0.05). Higher scores of ALoad (using both ALoad1 and ALoad2 calculations) were associated with higher BMI, total body fat mass, body percent fat, and WC (P < 0.05).

CONCLUSION

Significant differences in ALoad were observed in children according to race/ethnicity. Increased exposure to stressors captured by ALoad may result in increased risk for excessive adiposity and potential health risk in children. Further, ALoad may serve as a preventive marker for conditions known to continue throughout adulthood.

The impact of dietary fatty acids on human adipose tissue

Nutrition is a major variable factor in human environments. The composition of nutrients has changed markedly in recent decades which may contribute to the increased prevalence of metabolic diseases, such as obesity and type 2 diabetes. Fat is an important component of the diet which comes in various forms with fatty acids (FA) of different carbon chain lengths and saturation degrees. In addition to being an energy supply, FA function as potent signalling molecules and influence transcriptional activity. Among other tissues, dietary FA target white adipose tissue function, which is central in maintaining metabolic health. This review focuses on the possible role of dietary FA composition and its effect on human white adipose tissue expandability and transcriptional response. Altogether, the existing literature suggests that unsaturated fat has more benign effects on adipose tissue distribution when compared to long-chain saturated fat. However, the mechanisms of action remain poorly characterised.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects and associations of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective cohort studies if they related baseline total fat intake to weight or body fatness at least 12 months later.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted body weight and blood lipid levels outcomes at six months, six to 12 months, one to two years, two to five years and more than five years for RCTs; and for cohort studies, at baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three studies were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous to combine.Effects of dietary counselling to reduce total fat intake from RCTsTwo studies recruited children aged between 4 and 11 years and a third recruited children aged 12 to 13 years. Interventions were combinations of individual and group counselling, and education sessions in clinics, schools and homes, delivered by dieticians, nutritionists, behaviourists or trained, supervised teachers. Concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability.One study of dietary counselling to lower total fat intake found that the intervention may make little or no difference to weight compared with usual diet at 12 months (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; n = 620; low-quality evidence) and at three years (MD -0.60 kg, 95% CI -2.39 to 1.19; n = 612; low-quality evidence). Education delivered as a classroom curriculum probably decreased BMI in children at 17 months (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence). The effects were smaller at longer term follow-up (five years: MD 0 kg/m2, 95% CI -0.63 to 0.63; n = 541; seven years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; n = 576; low-quality evidence).Dietary counselling probably slightly reduced total cholesterol at 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Dietary counselling probably slightly decreased low-density lipoprotein (LDL) cholesterol at 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and at five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. Dietary counselling probably made little or no difference to HDL-C at 12 months (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), and at five years (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, counselling probably made little or no difference to triglycerides in children at 12 months (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height at seven years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Associations between total fat intake, weight and body fatness from cohort studiesOver half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to dietary counselling or education to lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls. There were no consistent effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Most studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings to look at both possible benefits and harms.

Higher n-6:n-3 Fatty Acid Intake Is Associated with Decreased Cardiometabolic Risk Factors in a Racially Diverse Sample of Children

BACKGROUND

Accumulating evidence implicates diet quality in childhood as playing a significant role in adult cardiometabolic health. Polyunsaturated fatty acids (PUFAs) of the n-6 (ω-6) and n-3 (ω-3) series contribute unique protective effects against cardiometabolic disease. As such, the ratio between n-6 and n-3 PUFAs is a dietary metric of interest in the early life span, although an optimum intake ratio has yet to be determined.

OBJECTIVE

This cross-sectional study assesses relations between the ratio of total n-6:n-3 PUFA intake and cardiometabolic risk factors in a racially diverse sample of children (n = 191) from the Admixture Mapping of Ethnic and Racial Insulin Complex Outcomes (AMERICO) study.

METHODS

Outcome measures included waist circumference, lipid concentrations, fasting glucose, and two 24-h dietary recalls from boys and girls aged 7-12 y who self-reported as European American (n = 81), African American (n = 55), or Hispanic American (n = 55). Linear regression analyses were used to assess associations between predictors of interest and outcomes after adjusting for covariates.

RESULTS

PUFA intake reflected in the n-6:n-3 ratio was inversely associated with concentrations of total and LDL cholesterol [β ± SE: -0.359 ± 0.107 (P = 0.001) and -0.189 ± 0.069 (P = 0.007), respectively]. Exploratory analyses showed that the intake of total n-6 PUFAs was not significantly predictive of any cardiometabolic risk factor assessed, whereas total n-3 PUFA intake was positively associated with concentrations of HDL cholesterol (β ± SE: 0.114 ± 0.042; P = 0.007).

CONCLUSIONS

Results suggest that the effect of n-6 and n-3 PUFA intake reflected in the ratio may be largely driven by n-3 PUFAs in reducing 2 lipid cardiometabolic risk factors among this multiethnic cohort of children. Until an ideal intake ratio is determined, nutritional counseling should focus on meeting recommended levels of both n-3 and n-6 PUFAs in order to establish beneficial childhood dietary patterns that may positively influence adult cardiometabolic health.

Linoleic acid, glycemic control and Type 2 diabetes

Dietary fat quality, especially the intake of specific types of fatty acids, impacts the risk of many chronic diseases, including cardiovascular diseases, certain cancers and type 2 diabetes (T2DM). A recent pooled analysis involving 20 studies from around the world revealed that higher linoleic acid (18:2n-6 LA) biomarker is associated with dose-dependent decreases in the incidence of T2DM. This latest study corroborates earlier cross-sectional studies and intervention trials showing that biomarkers of LA intake are associated with reduced risk of T2DM and better glycemic control and/or insulin sensitivity. This review highlights key clinical trials that have evaluated the role of LA in glycemia and the related condition, insulin sensitivity.

The relationship between diet quality and insulin resistance in obese children: adaptation of the Healthy Lifestyle-Diet Index in Turkey

BACKGROUND

Childhood obesity and its complications are serious health problems and diet/lifestyle changes can be beneficial for the prevention of diseases. Adaptation of the Healthy Lifestyle-Diet (HLD) Index in accordance with the dietary guidelines for Turkey (TR) and determination of the relationship between metabolic syndrome risk factors in obese children were the aims of this study.

METHODS

This study was conducted on 164 overweight or obese children (87 male, 77 female) aged 9-13 years. For all participants, the HLD-TR Index and a 24-h dietary recall were performed and the mean adequacy ratio (MAR) was calculated. Anthropometric measurements and the body composition of the children were taken. Metabolic syndrome risk factors and insulin resistance were assessed.

RESULTS

The mean age of the male and female children was 11.2±1.49 and 11.0±1.40 years, respectively. The majority of the children were obese in both genders. There were no statistically significant differences in the HLD-TR scores between the genders. As the index scores increased, a decrease in the energy intake and an increase in the MAR were observed. Negative correlations between the index scores and body mass, waist circumference and body fat mass were observed. Furthermore, a one-unit increase in the index score decreases the insulin resistance risk by 0.91 times after adjustments for age and gender (odds ratio: 0.91 [0.85-0.97]).

CONCLUSIONS

The HLD-TR Index is a valid tool that can give an idea about the quality of the diet in obese children. Furthermore, with the increase in the compliance with recommendations for diet/lifestyle changes, indicators of obesity and metabolic syndrome were decreased.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective analytical cohort studies in these children if they related baseline total fat intake to weight or body fatness at least 12 months later. We duplicated inclusion decisions and resolved disagreement by discussion with other authors.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted outcome data using the following time point ranges, when available: RCTs: baseline to six months, six to 12 months, one to two years, two to five years and more than five years; cohort studies: baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous.For the RCTs, concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability. Lower versus usual or modified total fat intake may have made little or no difference to weight over a six- to twelve month period (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; 1 RCT; n = 620; low-quality evidence), nor a two- to five-year period (MD -0.60 kg, 95% CI -2.39 to 1.19; 1 RCT; n = 612; low-quality evidence). Compared to controls, lower total fat intake (30% or less TE) probably decreased BMI in children over a one- to two-year period (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence), with no other differences evident across the other time points (two to five years: MD 0.00 kg/m2, 95% CI -0.63 to 0.63; 1 RCT; n = 541; greater than five years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; 1 RCT; n = 576; low-quality evidence). Lower fat intake probably slightly reduced total cholesterol over six to 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Lower fat intake probably slightly decreased low-density lipoprotein (LDL) cholesterol over six to 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and over two to five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. However, lower total fat intake probably made little or no difference to HDL-C over a six- to 12-month period (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), nor a two- to five-year period (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, lower total fat intake probably made little or no difference to triglycerides in children over a six- to 12-month period (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height over more than five years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Over half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to a lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls, and no consistent differences in effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Twenty-three out of 24 included studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings and look at both possible benefits and risks.

Comparison of the effects of flaxseed oil and sunflower seed oil consumption on serum glucose, lipid profile, blood pressure, and lipid peroxidation in patients with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetSyn) increases the risk of type II diabetes and morbidity and mortality due to cardiovascular diseases. Flaxseed oil (FO), as a functional food, is one of the major vegetal sources of essential omega-3 fatty acids.

OBJECTIVE

This study aimed to compare the effects of consumption of FO and sunflower seed oil (SO) on lipid peroxidation and other symptoms of MetSyn.

METHODS

This randomized controlled interventional trial was conducted on 60 volunteers aged 30 to 60 years who were diagnosed with MetSyn in Shiraz, Iran. The participants who fulfilled the inclusion criteria were randomly assigned to SO (n = 30, receiving 25 mL/d SO) and FO (n = 30, receiving 25 ml/d FO) groups using block randomization. The diets were identical for all the participants. Blood pressure (BP), serum lipid, fasting blood sugar, and malondialdehyde were measured at baseline and at the end of week 7.

RESULT

The results showed no significant difference between the 2 groups regarding blood lipid levels and fasting blood sugar at the end of the study. However, significant reductions in total cholesterol, low-density lipoprotein cholesterol (5.6% in FO and 10.8% in SO), and triglyceride levels were seen within each group after treatment with FO and SO (P < .05). Nonetheless, between-group changes were significant (<0.05) for systolic BP (mean [±standard deviation {SD}] changes were -14.0 ± 22.41 in the FO group [P = .004] and 0.92 ± 8.70 in the SO group [P = .594]) and diastolic BP (mean [±SD] changes were -4.26 ± 7.44 in the FO group [P = .007] and 1.30 ± 6.91 in the SO group [P = .344]), but marginally significant (P = .053) for malondialdehyde level (mean [±SD] changes were -1.29 ± 1.48 in the FO group [P < .001] and -0.52 ± 1.34 in the SO group [P = .52]). A significant decrease in weight was also found in both groups. However, waist circumference decreased significantly only in the FO group at the end of the study (P < .05).

CONCLUSION

Our results indicated that dietary FO could be effective in amelioration of some symptoms of MetSyn and decrease BP and lipid peroxidation.

Polyunsaturated fatty acids and endocannabinoids in health and disease

Polyunsaturated fatty acids (PUFAs) are lipid derivatives of omega-3 (docosahexaenoic acid, DHA, and eicosapentaenoic acid, EPA) or of omega-6 (arachidonic acid, ARA) synthesized from membrane phospholipids and used as a precursor for endocannabinoids (ECs). They mediate significant effects in the fine-tune adjustment of body homeostasis. Phyto- and synthetic cannabinoids also rule the daily life of billions worldwide, as they are involved in obesity, depression and drug addiction. Consequently, there is growing interest to reveal novel active compounds in this field. Cloning of cannabinoid receptors in the 90s and the identification of the endogenous mediators arachidonylethanolamide (anandamide, AEA) and 2-arachidonyglycerol (2-AG), led to the characterization of the endocannabinoid system (ECS), together with their metabolizing enzymes and membrane transporters. Today, the ECS is known to be involved in diverse functions such as appetite control, food intake, energy balance, neuroprotection, neurodegenerative diseases, stroke, mood disorders, emesis, modulation of pain, inflammatory responses, as well as in cancer therapy. Western diet as well as restriction of micronutrients and fatty acids, such as DHA, could be related to altered production of pro-inflammatory mediators (e.g. eicosanoids) and ECs, contributing to the progression of cardiovascular diseases, diabetes, obesity, depression or impairing conditions, such as Alzheimer' s disease. Here we review how diets based in PUFAs might be linked to ECS and to the maintenance of central and peripheral metabolism, brain plasticity, memory and learning, blood flow, and genesis of neural cells.

Very-long-chain ω-3 fatty acid supplements and adipose tissue functions: a randomized controlled trial

Background: Increased omega-3 (n-3) fatty acid consumption is reported to benefit patients with metabolic syndrome, possibly due to improved adipose tissue function.Objective: We tested the effects of high-dose, very-long-chain ω-3 fatty acids on adipose tissue inflammation and insulin regulation of lipolysis.Design: A double-blind, placebo-controlled study compared 6 mo of 3.9 g eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)/d (4.2 g total ω-3/d; n = 12) with a placebo (4.2 g oleate/d; n = 9) in insulin-resistant adults. Before and after treatment, the volunteers underwent adipose tissue biopsies to measure the total (CD68⁺), pro- (CD14⁺ = M1), and anti- (CD206⁺ = M2) inflammatory macrophages, crown-like structures, and senescent cells, as well as a 2-step pancreatic clamping with a [U-¹³C]palmitate infusion to determine the insulin concentration needed to suppress palmitate flux by 50% (IC_{50(palmitate)}f).Results: In the ω-3 group, the EPA and DHA contributions to plasma free fatty acids increased (P = 0.0003 and P = 0.003, respectively), as did the EPA and DHA content in adipose tissue (P < 0.0001 and P < 0.0001, respectively). Despite increases in adipose and plasma EPA and DHA in the ω-3 group, there were no significant changes in the IC_{50(palmitate)}f (19 ± 2 compared with 24 ± 3 μIU/mL), adipose macrophages (total: 31 ± 2/100 adipocytes compared with 33 ± 2/100 adipocytes; CD14⁺: 13 ± 2/100 adipocytes compared with 14 ± 2/100 adipocytes; CD206⁺: 28 ± 2/100 adipocytes compared with 29 ± 3/100 adipocytes), crown-like structures (1 ± 0/10 images compared with 1 ± 0/10 images), or senescent cells (4% ± 1% compared with 4% ± 1%). There were no changes in these outcomes in the placebo group.Conclusions: Six months of high-dose ω-3 supplementation raised plasma and adipose ω-3 fatty acid concentrations but had no beneficial effects on adipose tissue lipolysis or inflammation in insulin-resistant adults. This trial was registered at clinicaltrials.gov as NCT01686568.

Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit

Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = - 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish impaired β-F1-ATPase translation as an important consequence of obesity.