Effects of a rapeseed oil-enriched hypoenergetic diet with a high content of α-linolenic acid on body weight and cardiovascular risk profile in patients with the metabolic syndrome

Does omega-3 PUFAs supplementation improve metabolic syndrome and related cardiovascular diseases? A systematic review and meta-analysis of randomized controlled trials

Literature is inconsistent regarding the effects of omega-3 polyunsaturated fatty acids (omega-3 PUFAs) supplementation on patients with metabolic syndrome (MetS) and related cardiovascular diseases (CVDs). Therefore, the aim of this systematic review and meta-analysis is to summarize data from available randomized controlled trials (RCTs) on the effect of omega-3 PUFAs on lipid profiles, blood pressure, and inflammatory markers. We systematically searched PubMed, Embase, and Cochrane Library databases to identify the relevant RCTs until 1 November 2022. Weighed mean difference (WMD) was combined using a random-effects model. Standard methods were applied to assess publication bias, sensitivity analysis, and heterogeneity among included studies. A total of 48 RCTs involving 8,489 subjects met the inclusion criteria. The meta-analysis demonstrated that omega-3 PUFAs supplementation significantly reduced triglyceride (TG) (WMD: -18.18 mg/dl; 95% CI: -25.41, -10.95; p < 0.001), total cholesterol (TC) (WMD: -3.38 mg/dl; 95% CI: -5.97, -0.79; p = 0.01), systolic blood pressure (SBP) (WMD: -3.52 mmHg; 95% CI: -5.69, -1.35; p = 0.001), diastolic blood pressure (DBP) (WMD: -1.70 mmHg; 95% CI: -2.88, -0.51; p = 0.005), interleukin-6 (IL-6) (WMD: -0.64 pg/ml; 95% CI: -1.04, -0.25; p = 0.001), tumor necrosis factor-α (TNF-α) (WMD: -0.58 pg/ml; 95% CI: -0.96, -0.19; p = 0.004), C-reactive protein (CRP) (WMD: -0.32 mg/l; 95% CI: -0.50, -0.14; p < 0.001), and interleukin-1 (IL-1) (WMD: -242.95 pg/ml; 95% CI: -299.40, -186.50; p < 0.001), and significantly increased in high-density lipoprotein (HDL) (WMD: 0.99 mg/dl; 95% CI: 0.18, 1.80; p = 0.02). However, low-density lipoprotein (LDL), monocyte chemoattractant protein-1 (MCP-1), intracellular adhesion molecule-1 (ICAM-1), and soluble endothelial selectin (sE-selectin) were not affected. In subgroup analyses, a more beneficial effect on overall health was observed when the dose was ≤ 2 g/day; Omega-3 PUFAs had a stronger anti-inflammatory effect in patients with CVDs, particularly heart failure; Supplementation with omega-3 PUFAs was more effective in improving blood pressure in MetS patients and blood lipids in CVDs patients, respectively. Meta-regression analysis showed a linear relationship between the duration of omega-3 PUFAs and changes in TG (p = 0.023), IL-6 (p = 0.008), TNF-α (p = 0.005), and CRP (p = 0.025). Supplementation of omega-3 PUFAs had a favorable effect on improving TG, TC, HDL, SBP, DBP, IL-6, TNF-α, CRP, and IL-1 levels, yet did not affect LDL, MCP-1, ICAM-1, and sE-selectin among patients with MetS and related CVDs.

The effect of different edible oils on body weight: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Obesity is a major public health issue with no definitive treatment. The first-line approach for obesity is lifestyle modification, including a healthy diet. Although the amount of fat has been considered, there is no network meta-analysis (NMA) study investigating the effect of edible oils on body weight. Therefore, we sought to investigate the effect of different edible oils on body weight using a systematic review and NMA study of randomized controlled trials (RCTs).

METHOD

PubMed, Scopus, ISI Web of Science, and the Cochrane Library were searched from inception to April 2019. RCTs of different edible oils for body weight were included. A frequentist network meta-analysis was conducted to appraise the efficacy of different types of edible oils, and the Surface Under the Cumulative Ranking Curve (SUCRA) was estimated. The GRADE framework was used to assess the certainty of evidence.

RESULTS

Forty-two eligible studies were included. Most of the included trials examined the effect of olive oil compared to canola oil (n = 7 studies), followed by canola oil compared to sunflower oil (n = 6 studies), and olive oil compared to sunflower oil (n = 4 studies). Sesame oil had the highest SUCRA value for reducing weight (SUCRA value = 0.9), followed by the mixture of canola and sesame oil (0.8). Palm oil and soy oil were ranked the lowest (SUCRA value = 0.2).

CONCLUSION

There is low to moderate certainty of evidence showing that soybean, palm, and sunflower oils were associated with weight gain, while sesame oil produced beneficial anti-obesity effects.

Current Insights into the Effects of Dietary α-Linolenic Acid Focusing on Alterations of Polyunsaturated Fatty Acid Profiles in Metabolic Syndrome

The plant-derived α-linolenic acid (ALA) is an essential n-3 acid highly susceptible to oxidation, present in oils of flaxseeds, walnuts, canola, perilla, soy, and chia. After ingestion, it can be incorporated in to body lipid pools (particularly triglycerides and phospholipid membranes), and then endogenously metabolized through desaturation, elongation, and peroxisome oxidation to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with a very limited efficiency (particularly for DHA), beta-oxidized as an energy source, or directly metabolized to C18-oxilipins. At this moment, data in the literature about the effects of ALA supplementation on metabolic syndrome (MetS) in humans are inconsistent, indicating no effects or some positive effects on all MetS components (abdominal obesity, dyslipidemia, impaired insulin sensitivity and glucoregulation, blood pressure, and liver steatosis). The major effects of ALA on MetS seem to be through its conversion to more potent EPA and DHA, the impact on the n-3/n-6 ratio, and the consecutive effects on the formation of oxylipins and endocannabinoids, inflammation, insulin sensitivity, and insulin secretion, as well as adipocyte and hepatocytes function. It is important to distinguish the direct effects of ALA from the effects of EPA and DHA metabolites. This review summarizes the most recent findings on this topic and discusses the possible mechanisms.

Effects of rapeseed oil on body composition and glucolipid metabolism in people with obesity and overweight: a systematic review and meta-analysis

To investigate the effects of rapeseed oil on body composition, blood glucose and lipid metabolism in people with overweight and obesity compared to other cooking oils. We searched eight databases for randomized controlled studies (including randomized crossover trials). The risk of bias for the included studies was assessed using the Cochrane Risk of Bias 2.0 tool. The Grading of Recommendations Assessment Development and Evaluation (GRADE) criteria were used to evaluate the quality of the outcomes. The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database (PEDro) scale. Sensitivity analysis was used to check the stability of the pooled results. Statistical analysis was carried out using Review Manager 5.3 software. As a result, fifteen randomized controlled studies (including six parallel studies and nine crossover studies) were included in this study. Compared to other edible oils, rapeseed oil significantly reduced low density lipoprotein cholesterol (LDL-C) (MD = -0.14 mmol/L, 95% CI: -0.21, -0.08, I2 = 0%, P < 0.0001), apolipoprotein B (ApoB) (MD = -0.03 g/L, 95% CI: -0.05, -0.01, I2 = 0%, P = 0.0003), ApoB/ApoA1 (MD = -0.02, 95% CI: -0.04, -0.00, I2 = 0%, P = 0.02) and insulin (MD = -12.45 pmol/L, 95% CI: -19.61, -5.29, I2 = 37%, P = 0.0007) levels, and increased fasting glucose (MD = 0.16 mmol/L, 95% CI: 0.05, 0.27, I2 = 27%, P = 0.003) levels. However, the differences in body weight and body composition between rapeseed oil and control oils were not significant. In a word, rapeseed oil is effective in reducing LDL-C, ApoB and ApoB/ApoA1 levels in people with overweight and obesity, which is helpful in preventing and reducing the risk of atherosclerosis. PROSPERO registration number: CRD42022333436.

Comparison of canola oil and olive oil consumption on the serum lipid profile in adults: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Several randomized clinical trials have investigated the effects of canola oil (CO) compared to olive oil (OO) on the serum lipid profiles in adults. However, the results of these studies are inconsistent. Thus, this study aimed to assess the comparison of CO and OO consumption on the serum lipid components in adults.

METHODS AND RESULTS

The following online databases were searched until February 4th, 2022: PubMed/Medline, Scopus, Clarivate Analytics Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar. The effect sizes were stated as the weighted mean difference (WMD) with 95% confidence intervals (CI). A total of 13 eligible trials were included in this meta-analysis. The results showed that the CO consumption, significantly reduced serum LDL-c (WMD: -6.13 mg/dl, 95%CI: -9.79, -2.46, p = 0.001), TC (WMD: -8.92 mg/dl, 95% CI: -13.52, -4.33, P < 0.001) and LDL-c/HDL-c ratio (WMD: -0.30; 95% CI, -0.53, -0.06, p = 0.01) levels compared to OO. There were no significant changes in the other components of the blood lipids.

CONCLUSION

The results of this review suggest that CO consumptionhas beneficial effects on LDL-c, TC, and LDL-c/HDL-c ratio compared to OO. Therefore, its replacement with OO can have cardioprotective impacts.

Effect of Alpha-Linolenic Acid Supplementation on Cardiovascular Disease Risk Profile in Individuals with Obesity or Overweight: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Overweight and obesity are highly prevalent worldwide and are associated with cardiovascular disease (CVD) risk factors, including systematic inflammation, dyslipidemia, and hypertension. Alpha-linolenic acid (ALA) is a plant-based essential polyunsaturated fatty acid associated with reduced CVD risks. This systematic review and meta-analysis aimed to investigate the effects of supplementation with ALA compared with the placebo on CVD risk factors in people with obesity or overweight (International Prospective Register of Systematic Reviews Registration No. CRD42023429563). This review included studies with adults using oral supplementation or food or combined interventions containing vegetable sources of ALA. All studies were randomly assigned trials with parallel or crossover designs. The Cochrane Collaboration tool was used for assessing the risk of bias (Version 1). PubMed, Web of Science, Embase, and Cochrane library databases were searched from inception to April 2023. Nineteen eligible randomized controlled trials, including 1183 participants, were included in the meta-analysis. Compared with placebo, dietary ALA supplementation significantly reduced C-reactive protein concentration (standardized mean difference [SMD] = -0.38 mg/L; 95% confidence interval [CI]: -0.72, -0.04), tumor necrosis factor-α concentration (SMD = -0.45 pg/mL; 95% CI: -0.73, -0.17), triglyceride in serum (SMD = -4.41 mg/dL; 95% CI: -5.99, -2.82), and systolic blood pressure (SMD = -0.37 mm Hg; 95% CI: -0.66, -0.08); but led to a significant increase in low-density lipoprotein cholesterol concentrations (SMD = 1.32 mg/dL; 95% CI: 0.05, 2.59). ALA supplementation had no significant effect on interleukin-6, diastolic blood pressure, total cholesterol, or high-density lipoprotein cholesterol (all P ≥ 0.05). Subgroup analysis revealed that ALA supplementation at a dose of ≥3 g/d from flaxseed and flaxseed oil had a more prominent effect on improving CVD risk profiles, particularly where the intervention duration was ≥12 wk and where the baseline CVD profile was poor.

The Influences of Macronutrients on Bone Mineral Density, Bone Turnover Markers, and Fracture Risk in Elderly People: A Review of Human Studies

Osteoporosis is a health condition that involves weak bone mass and a deteriorated microstructure, which consequently lead to an increased risk of bone fractures with age. In elderly people, a fracture attributable to osteoporosis elevates mortality. The objective of this review was to examine the effects of macronutrients on bone mineral density (BMD), bone turnover markers (BTMs), and bone fracture in elderly people based on human studies. A systematic search was conducted in the PubMed®/MEDLINE® database. We included human studies published up to April 2023 that investigated the association between macronutrient intake and bone health outcomes. A total of 11 meta-analyses and 127 individual human studies were included after screening the records. Carbohydrate consumption seemed to have neutral effects on bone fracture in limited studies, but human studies on carbohydrates' effects on BMD or/and BTMs are needed. The human studies analyzed herein did not clearly show whether the intake of animal, vegetable, soy, or milk basic proteins has beneficial effects on bone health due to inconsistent results. Moreover, several individual human studies indicated an association between eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and osteocalcin. Further studies are required to draw a clear association between macronutrients and bone health in elderly people.

The Effect of Plant-Derived Low-Ratio Linoleic Acid/α-Linolenic Acid on Markers of Glucose Controls: A Systematic Review and Meta-Analysis

The objective of this meta-analysis was to examine the impact of a low-ratio linoleic acid/α-linolenic acid (LA/ALA) diet on the glycemic profile of adults. A comprehensive search was performed across four databases (Web of Science, Scopus, Embase, and PubMed) to evaluate the influence of the low-ratio LA/ALA. Relevant references were screened up until February 2023. Intervention effects were analyzed by calculating change values as weighted mean differences (WMD) and 95% confidence intervals (CI) using fixed-effects models. Additionally, subgroup analysis and meta-regression were employed to investigate potential sources of heterogeneity. Twenty-one randomized controlled trials (RCTs) were included, and the low-ratio LA/ALA diet had no significant effect on fasting blood sugar (FBS, WMD: 0.00 mmol/L, 95% CI: -0.06, 0.06, p = 0.989, I2 = 0.0%), insulin levels (WMD: 0.20 μIU/mL, 95% CI: -0.23, 0.63, p = 0.360, I2 = 3.2%), homeostatic model assessment insulin resistance (HOMA-IR, WMD: 0.09, 95% CI: -0.06, 0.23, p = 0.243, I2 = 0.0%), and hemoglobin A1c (HbA1c, WMD: -0.01%, 95% CI: -0.07, 0.06, p = 0.836, I2 = 0.0%). Based on subgroup analyses, it was observed that the impact of a low-ratio LA/ALA diet on elevated plasma insulin (WMD: 1.31 μIU/mL, 95% CI: 0.08, 2.54, p = 0.037, I2 = 32.0%) and HOMA-IR (WMD: 0.47, 95% CI: 0.10, 0.84, p = 0.012, I2 = 0.0%) levels exhibited greater prominence in North America compared to Asian and European countries. Publication bias was not detected for FBS, insulin, HOMA-IR, and HbA1c levels according to the Begg and Egger tests. Furthermore, the conducted sensitivity analyses indicated stability, as the effects of the low-ratio LA/ALA diet on various glycemic and related metrics remained unchanged even after removing individual studies. Overall, based on the available studies, it can be concluded that the low-ratio LA/ALA diet has limited impact on blood glucose-related biomarker levels.

Effects of Dietary Plant-Derived Low-Ratio Linoleic Acid/Alpha-Linolenic Acid on Blood Lipid Profiles: A Systematic Review and Meta-Analysis

This meta-analysis aimed to investigate the impact of low-ratio linoleic acid/alpha-linolenic acid (LA/ALA) supplementation on the blood lipid profiles in adults. We conducted a systematic search for relevant randomized controlled trials (RCTs) assessing the effects of low-ratio LA/ALA using databases including PubMed, Embase, Cochrane, and Web of Science, as well as screened related references up until February 2023. The intervention effects were analyzed adopting weighted mean difference (WMD) and 95% confidence interval (CI). The meta-analysis indicated that low-ratio LA/ALA supplementation decreased total cholesterol (TC, WMD: -0.09 mmol/L, 95% CI: -0.17, -0.01, p = 0.031, I2 = 33.2%), low-density lipoprotein cholesterol (LDL-C, WMD: -0.08 mmol/L, 95% CI: -0.13, -0.02, p = 0.007, I2 = 0.0%), and triglycerides (TG, WMD: -0.05 mmol/L, 95% CI: -0.09, 0.00, p = 0.049, I2 = 0.0%) concentrations. There was no significant effect on high-density lipoprotein cholesterol concentration (HDL-C, WMD: -0.00 mmol/L, 95% CI: -0.02, 0.02, p = 0.895, I2 = 0.0%). Subgroup analysis showed that low-ratio LA/ALA supplementation significantly decreased plasma TC, LDL-C, and TG concentrations when the intervention period was less than 12 weeks. In the subgroup analysis, a noteworthy decrease in both TC and LDL-C levels was observed in individuals receiving low-ratio LA/ALA supplementation in the range of 1-5. These findings suggest that this specific range could potentially be effective in reducing lipid profiles. The findings of this study provide additional evidence supporting the potential role of low-ratio LA/ALA supplementation in reducing TC, LDL-C, and TG concentrations, although no significant impact on HDL-C was observed.

A Comprehensive Review of Health-Benefiting Components in Rapeseed Oil

Rapeseed oil is the third most consumed culinary oil in the world. It is well-known for its high content of unsaturated fatty acids, especially polyunsaturated fatty acids, which make it of great nutritional value. There is increasing evidence that a diet rich in unsaturated fatty acids offers health benefits. Although the consumption of rapeseed oil cuts across many areas around the world, the nutritional elements of rapeseed oil and the exact efficacy of the nutrients remain unclear. In this review, we systematically summarized the latest studies on functional rapeseed components to ascertain which component of canola oil contributes to its function. Apart from unsaturated fatty acids, there are nine functional components in rapeseed oil that contribute to its anti-microbial, anti-inflammatory, anti-obesity, anti-diabetic, anti-cancer, neuroprotective, and cardioprotective, among others. These nine functional components are vitamin E, flavonoids, squalene, carotenoids, glucoraphanin, indole-3-Carbinol, sterols, phospholipids, and ferulic acid, which themselves or their derivatives have health-benefiting properties. This review sheds light on the health-benefiting effects of rapeseed oil in the hope of further development of functional foods from rapeseed.

Perilla Pomace, a By-product of Oil Extraction, Is Rich in Nutrients and Can Favorably Modulate Lipid Metabolism in Sprague-Dawley Rats

Perilla pomace, a by-product of oil extraction, is rich in nutrients, such as proteins, but it has not been used for purposes other than livestock feeding. The aim of this study was to determine how perilla pomace modulates glucose and lipid metabolism in Sprague-Dawley rats. Dried perilla pomace was added to diet at a concentration of 16%. One experimental group was administered perilla oil equivalent to that in the perilla pomace. After four weeks, the animals were euthanized, and biochemical parameters were measured. Two experiments were conducted using a low-fat (7% by weight) and a high-fat (21% by weight) diet. Regardless of the level of fat in the diets, no differences in food intake were found among the groups. In the low-fat diet-fed rats (Experiment 1), epididymal adipose tissue weight was slightly, but not significantly, lower in perilla pomace-fed rats than in those fed the control diet. Hepatic triglyceride and cholesterol levels were significantly reduced by perilla pomace compared to those in the control group. Serum lipid profiles (triglycerides and cholesterol) were similar to those in the liver, without statistically significant differences. Perilla pomace significantly diminished hepatic fatty acid synthase (FAS) activity. In high-fat diet-fed rats (Experiment 2), pomace did not significantly lower epididymal adipose tissue weight. Hepatic cholesterol levels were lower in rats on the perilla oil than in control rats. The activity of hepatic enzymes involved in fat oxidation was significantly higher in rats fed the perilla pomace than in those fed the control diet. Collectively, these results show that perilla pomace favorably modulates fat metabolism, and the specific effects depend on the fat content in the diet.

Metabolome and transcriptome signatures shed light on the anti-obesity effect of Polygonatum sibiricum

Obesity has become one of the major threats to human health across the globe. The rhizomes of Polygonatum sibiricum have shown promising anti-obesity effect. However, the metabolic and genetic basis mediating this beneficial effect are not fully resolved. It is well known that older rhizomes of P. sibiricum exert stronger pharmacological effects. Here, we performed high-resolution metabolome profiling of P. sibiricum rhizomes at different growth stages, and identified that three candidate anti-obesity metabolites, namely phloretin, linoleic acid and α-linolenic acid, accumulated more in adult rhizomes. To elucidate the genetic basis controlling the accumulation of these metabolites, we performed transcriptome profiling of rhizomes from juvenile and adult P. sibiricum. Through third-generation long-read sequencing, we built a high-quality transcript pool of P. sibiricum, and resolved the genetic pathways involved in the biosynthesis and metabolism of phloretin, linoleic acid and α-linolenic acid. Comparative transcriptome analysis revealed altered expression of the genetic pathways in adult rhizomes, which likely lead to higher accumulation of these candidate metabolites. Overall, we identified several metabolic and genetic signatures related to the anti-obesity effect of P. sibiricum. The metabolic and transcriptional datasets generated in this work could also facilitate future research on other beneficial effects of this medicinal plant.

Polyphenolic compounds from rapeseeds (Brassica napus L.): The major types, biofunctional roles, bioavailability, and the influences of rapeseed oil processing technologies on the content

The rapeseed (Brassica napus L.) are the important oil bearing material worldwide, which contain wide variety of bioactive components with polyphenolic compounds considered the most typical. The rapeseed polyphenols encompass different structural variants, and have been considered to have many bioactive functions, which are beneficial for the human health. Whereas, the rapeseed oil processing technologies affect their content and the biofunctional activities. The present review of the literature highlighted the major types of the rapeseed polyphenols, and summarized their biofunctional roles. The influences of rapeseed oil processing technologies on these polyphenols were also elucidated. Furthermore, the directions of the future studies for producing nutritional rapeseed oils preserved higher level of polyphenols were prospected. The rapeseed polyphenols are divided into the phenolic acids and polyphenolic tannins, both of which contained different subtypes. They are reported to have multiple biofunctional roles, thus showing outstanding health improvement effects. The rapeseed oil processing technologies have significant effects on both of the polyphenol content and activity. Some novel processing technologies, such as aqueous enzymatic extraction (AEE), subcritical or supercritical extraction showed advantages for producing rapeseed oil with higher level of polyphenols. The oil refining process involved heat or strong acid and alkali conditions affected their stability and activity, leading to the loss of polyphenols of the final products. Future efforts are encouraged to provide more clinic evidence for the practical applications of the rapeseed polyphenols, as well as optimizing the processing technologies for the green manufacturing of rapeseed oils.

Nutritional supplements improve cardiovascular risk factors in overweight and obese patients: A Bayesian network meta-analysis

Background

Overweight and obesity are considered as one of the major risk factors for cardiovascular diseases (CVD). At present, many studies have proved that multiple nutritional supplements play an active role in metabolic diseases. However, the comparative efficacy of different nutritional supplements in improving indicators of cardiometabolic risk in obese and overweight patients is uncertain.

Methods

Cochrane Library, PubMed, Embase, and Web of Science were searched for the period from January 1990 to March 2022. A random-effect model was built in the Bayesian network meta-analysis. The surface under the cumulative ranking analysis (SUCRA) and clustering rank analysis was performed for ranking the effects.

Results

The study included 65 RCTs with 4,241 patients. In terms of glucose control, probiotic was more conductive to improve FBG (MD: -0.90; 95%CrI: -1.41 to -0.38), FINS (MD: -2.05; 95%CrI: -4.27 to -0.02), HOMA-IR (MD: -2.59; 95%CI -3.42 to -1.76). Probiotic (MD: -11.15, 95%CrI -22.16 to -1.26), omega-3 (MD: -9.45; 95%CrI: -20.69 to -0.93), VD (MD: -17.86; 95%CrI: -35.53 to -0.27), and probiotic +omega-3 (MD: 5.24; 95%CrI: 0.78 to 9.63) were beneficial to the improvement of TGs, TC and HDL-C, respectively. The SUCRA revealed that probiotic might be the best intervention to reduce FBG, FINS, HOMA-IR; Simultaneously, α-lipoic acid, VD, and probiotic + omega-3 might be the best intervention to improve TGs, TC, and HDL-C, respectively. Cluster-rank results revealed probiotic had the best comprehensive improvement effect on glucose metabolism, and probiotic + omega-3 may have a better comprehensive improvement effect on lipid metabolism (cluster-rank value for FBG and FINS: 3290.50 and for TGs and HDL-C: 2117.61).

Conclusion

Nutritional supplementation is effective on CVD risk factors in overweight and obese patients. Probiotic supplementation might be the best intervention for blood glucose control; VD, probiotic + omega-3 have a better impact on improving lipid metabolism. Further studies are required to verify the current findings.

The effects of olive oil consumption on blood lipids: a systematic review and dose-response meta-analysis of randomised controlled trials

We performed a systematic review and dose-response meta-analysis of randomised trials on the effects of olive oil consumption on blood lipids in adults. A systematic search was performed in PubMed, Scopus and Web of Science databases until May 2021. Randomised controlled trials (RCT) evaluating the effect of olive oil intake on serum total cholesterol (TC), TAG, LDL-cholesterol and HDL-cholesterol in adults were included. The mean difference (MD) and 95 % CI were calculated for each 10 g/d increment in olive oil intake using a random-effects model. A total of thirty-four RCT with 1730 participants were included. Each 10 g/d increase in olive oil consumption had minimal effects on blood lipids including TC (MD: 0·79 mg/dl; 95 % CI (-0·08, 1·66); I² = 57 %; n 31, GRADE = low certainty), LDL-cholesterol (MD: 0·04 mg/dl, 95 % CI (-1·01, 0·94); I² = 80 %; n 31, GRADE = very low certainty), HDL-cholesterol (MD: 0·22 mg/dl; 95 % CI (-0·01, 0·45); I² = 38 %; n 33, GRADE = low certainty) and TAG (MD: 0·39 mg/dl; 95 % CI (-0·33, 1·11); I² = 7 %; n 32, GRADE = low certainty). Levels of TC increased slightly with the increase in olive oil consumption up to 30 g/d (MD_{30 g/d}: 2·76 mg/dl, 95 % CI (0·01, 5·51)) and then appeared to plateau with a slight downward curve. A trivial non-linear dose-dependent increment was seen for HDL-cholesterol, with the greatest increment at 20 g/d (MD_{20 g/d}: 1·03 mg/dl, 95 % CI (-1·23, 3·29)). Based on existing evidence, olive oil consumption had trivial effects on levels of serum lipids in adults. More large-scale randomized trials are needed to present more reliable results.

Impact of α-Linolenic Acid, the Vegetable ω-3 Fatty Acid, on Cardiovascular Disease and Cognition

Given the evidence of the health benefits of plant-based diets and long-chain n-3 (ω-3) fatty acids, there is keen interest in better understanding the role of α-linolenic acid (ALA), a plant-derived n-3 fatty acid, on cardiometabolic diseases and cognition. There is increasing evidence for ALA largely based on its major food sources (i.e., walnuts and flaxseed); however, this lags behind our understanding of long-chain n-3 fatty acids. Meta-analyses of observational studies have shown that increasing dietary ALA is associated with a 10% lower risk of total cardiovascular disease and a 20% reduced risk of fatal coronary heart disease. Three randomized controlled trials (RCTs) [AlphaOmega trial, Prevención con Dieta Mediterránea (PREDIMED) trial, and Lyon Diet Heart Study] all showed benefits of diets high in ALA on cardiovascular-related outcomes, but the AlphaOmega trial, designed to specifically evaluate ALA effects, only showed a trend for benefit. RCTs have shown that dietary ALA reduced total cholesterol, LDL cholesterol, triglycerides, and blood pressure, and epidemiologic studies and some trials also have shown an anti-inflammatory effect of ALA, which collectively account for, in part, the cardiovascular benefits of ALA. A meta-analysis reported a trend toward diabetes risk reduction with both dietary and biomarker ALA. For metabolic syndrome and obesity, the evidence for ALA benefits is inconclusive. The role of ALA in cognition is in the early stages but shows promising evidence of counteracting cognitive impairment. Much has been learned about the health benefits of ALA and with additional research we will be better positioned to make strong evidence-based dietary recommendations for the reduction of many chronic diseases.

Effects of Dietary α-Linolenic Acid Treatment and the Efficiency of Its Conversion to Eicosapentaenoic and Docosahexaenoic Acids in Obesity and Related Diseases

The essential fatty acid alpha-linolenic acid (ALA) is present in high amounts in oils such as flaxseed, soy, hemp, rapeseed, chia, and perilla, while stearidonic acid is abundant in echium oil. ALA is metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by desaturases and elongases in humans. The conversion of ALA to EPA and DHA is limited, and these long-chain n−3 polyunsaturated fatty acids (PUFAs) are mainly provided from dietary sources (fish and seafood). This review provides an overview of studies that explored the effects of dietary supplementation with ALA in obesity and related diseases. The obesity-associated changes of desaturase and elongase activities are summarized, as they could influence the metabolic conversion of ALA. Generally, supplementation with ALA or ALA-rich oils leads to an increase in EPA levels and has no effect on DHA or omega-3 index. According to the literature data, stearidonic acid could enhance conversion of ALA to long-chain n−3 PUFA in obesity. Recent studies confirm that EPA and DHA intake should be considered as a primary dietary treatment strategy for improving the omega-3 index in obesity and related diseases.

The effects of sesame, canola, and sesame-canola oils on cardiometabolic markers in patients with type 2 diabetes: a triple-blind three-way randomized crossover clinical trial

AIMS

To compare the effects of replacing regular dietary oils intake with sesame (SO), canola (CO), and sesame-canola (SCO) oils (a novel blend), on cardiometabolic markers in adults with type 2 diabetes mellitus (T2DM), in a triple-blind, three-way, randomized, crossover clinical trial.

METHODS

Participants were assigned to receive SO, CO, and SCO in three 9-week phases (4 weeks apart). Cardiometabolic makers (serum lipids, Apolipoprotein, cardiovascular risk scores, kidney markers, and blood pressure) were considered at the beginning and the end of intervention phases.

RESULTS

Ninety-two, ninety-five, and ninety-five participants completed the SO, SCO, and CO periods, respectively. After CO consumption, serum Apo A-1 concentrations were significantly higher compared with the SCO period in the whole population (p < 0.05). A considerable reduction in visceral adiposity index values was seen in the CO compared with the SO period in males (p < 0.05). Serum high-density lipoprotein concentration was also significantly higher after the SO intake compared with SCO in females (p < 0.05). The between-period analysis showed a substantial reduction in diastolic blood pressure in the SCO period compared with the CO and SO periods and lower systolic blood pressure after SCO versus CO intake in males (p < 0.05).

CONCLUSIONS

Canola oil might protect CVD through improving Apo A-1 levels in patients with T2DM (particularly in females) and visceral adiposity index in male patients. However, the blend oil might beneficially affect blood pressure in men. Future sex-specific studies might warrant the current findings.

REGISTRY OF CLINICAL TRIALS

This trial was registered in the Iranian Registry of Clinical Trials (IRCT, registration ID: IRCT2016091312571N6).

The review of alpha-linolenic acid: Sources, metabolism, and pharmacology

α-linolenic acid (ALA, 18:3n-3) is a carboxylic acid composed of 18 carbon atoms and three cis double bonds, and is an essential fatty acid indispensable to the human body. This study aims to systematically review related studies on the dietary sources, metabolism, and pharmacological effects of ALA. Information on ALA was collected from the internet database PubMed, Elsevier, ResearchGate, Web of Science, Wiley Online Library, and Europe PMC using a combination of keywords including "pharmacology," "metabolism," "sources." The following findings are mainly contained. (a) ALA can only be ingested from food and then converted into eicosapentaenoic acid and docosahexaenoic acid in the body. (b) This conversion process is relatively limited and affected by many factors such as dose, gender, and disease. (c) Pharmacological research shows that ALA has the anti-metabolic syndrome, anticancer, antiinflammatory, anti-oxidant, anti-obesity, neuroprotection, and regulation of the intestinal flora properties. (d) There are the most studies that prove ALA has anti-metabolic syndrome effects, including experimental studies and clinical trials. (e) The therapeutic effect of ALA will be affected by the dosage. In short, ALA is expected to treat many diseases, but further high quality studies are needed to firmly establish the clinical efficacy of ALA.

Canola oil compared with sesame and sesame-canola oil on glycaemic control and liver function in patients with type 2 diabetes: A three-way randomized triple-blind cross-over trial

BACKGROUND

This study aimed to compare the effects of sesame (SO), canola (CO), and sesame-canola (SCO: a blend) oils on glycaemic control markers and liver function enzymes in adults with type 2 diabetes.

METHODS

In this randomized, triple-blind, three-way, cross-over clinical trial, participants replaced their usual oil with the intervention oils for 9 weeks. Serum fasting blood sugar, fasting serum insulin (FSI), insulin resistance (HOMA2-IR), beta-cell function (HOMA2-%B), insulin sensitivity (HOMA2-%S), quantitative insulin sensitivity check index (QUICKI), as well as serum liver function enzymes were measured at baseline and end of intervention periods.

RESULTS

Ninety-two participants completed all treatment periods. After adjusting for confounders, all treatment oils resulted in significant improvements in FSI and HOMA2-%S (p < 0.05). SO and SCO led to favourable changes in HOMA2-IR and QUICKI (p < 0.05). Following CO and SCO, there was a significant decrease in HOMA2-%B (p < 0.05). The sex-stratified analysis revealed that FSI and HOMA2-IR were decreased after SO compared to CO in males (p = 0.024). Serum gamma-glutamyltransferase (GGT) was significantly lower following SO compared to CO in females (p = 0.02), however, the difference in change values was not significant (p = 0.058).

CONCLUSIONS

SO consumption appears to improve glycaemic control markers in males and serum GGT in females compared with CO in patients with type 2 diabetes (registration code: IRCT2016091312571N6).

Oral administration of camellia oil ameliorates obesity and modifies the gut microbiota composition in mice fed a high-fat diet

Obesity, which is often caused by adipocyte metabolism dysfunction, is rapidly becoming a serious global health issue. Studies in the literature have shown that camellia oil (Camellia oleifera Abel) exerted potential lipid regulation and other multiple biological activities. Here, we aimed to investigate the effects of camellia oil on obese mice induced by a high-fat diet and to explore gut microbiota alterations after camellia oil intervention. The results showed that oral administration of camellia oil dramatically attenuated the fat deposits, serum levels of the total cholesterol, triacylglycerol, low-density lipoprotein cholesterol, fasting plasma glucose, the atherosclerosis index, the hepatic steatosis and inflammation in high-fat diet-induced obese mice. Meanwhile, the high-density lipoprotein cholesterol level in obese mice was enhanced after the camellia oil treatment. Furthermore, 16S rRNA analysis showed that certain aspects of the gut microbiota, especially the gut microbiota diversity and the relative abundance of Actinobacteria, Coriobacteriaceae, Lactobacillus and Anoxybacillus, were significantly increased by camellia oil treatment while the ratio of Firmicutes to Bacteroidetes was decreased. Taken together, our finding suggested that camellia oil was a potential dietary supplement and functional food for ameliorating fat deposits, hyperglycemia and fatty liver, probably by modifying the gut microbiota composition.

Phytotherapy for Cardiovascular Disease: A Bench-to-Bedside Approach

At present, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and global trends suggest that this panorama will persist or worsen in the near future. Thus, optimization of treatment strategies and the introduction of novel therapeutic alternatives for CVD represent key objectives in contemporary biomedical research. In recent years, phytotherapy-defined as the therapeutic use of whole or minimally modified plant components-has ignited large scientific interest, with a resurgence of abundant investigation on a wide array of medicinal herbs (MH) for CVD and other conditions. Numerous MH have been observed to intervene in the pathophysiology of CVD via a myriad of molecular mechanisms, including antiinflammatory, anti-oxidant, and other beneficial properties, which translate into the amelioration of three essential aspects of the pathogenesis of CVD: Dyslipidemia, atherosclerosis, and hypertension. Although the preclinical data in this scenario is very rich, the true clinical impact of MH and their purported mechanisms of action is less clear, as large-scale robust research in this regard is in relatively early stages and faces important methodological challenges. This review offers a comprehensive look at the most prominent preclinical and clinical evidence currently available concerning the use of MH in the treatment of CVD from a bench-to-bedside approach.

The Nordic diet and the risk of non-communicable chronic disease and mortality: a systematic review and dose-response meta-analysis of prospective cohort studies

We aimed to investigate the association between adherence to the Nordic diet (ND) and the risk of chronic disease. PubMed, Scopus, and ISI Web of Science were searched to February 2020 to find prospective cohort studies. The relative risks (RRs) were calculated using a fixed-effects/random-effects model. The certainty of evidence was rated using the GRADE approach. Thirteen prospective cohort studies with 930,153 participants were included. The RRs for the highest compared to the lowest category of adherence to the ND were 0.78 (95%CI: 0.69, 0.87; I² = 51%, n = 6) for all-cause mortality, 0.78 (95%CI: 0.74, 0.83; I² = 70%, n = 4) for cardiovascular mortality, 0.86 (95%CI: 0.80, 0.93; I² = 83%, n = 4) for cancer mortality, 0.88 (95%CI: 0.79, 0.98; I² = 3%, n = 3) for stroke, 0.80 (95%CI: 0.68, 0.95; I² = 47%, n = 3) for myocardial infarction, and 0.90 (95%CI: 0.82, 0.99; I² = 33%, n = 4) for type 2 diabetes. There was an inverse linear association between the ND score and the risk of mortality, and an inverse monotonic association for type 2 diabetes. The certainty in the estimates ranged from very low to low.

A review on differential effects of dietary fatty acids on weight, appetite and energy expenditure

The association between weight and chronic diseases is well defined. The quality and quantity of dietary fatty acids is an important external factor and appetite and energy expenditure, are important internal factors in determining body weight. On the other hand, dietary fatty acids composition can modulate appetite and energy metabolism, but not all fats are equal in producing metabolic responses.Given the accumulating evidence for differential effects of various dietary fatty acids, one important area of investigation is to scrutinize their roles in weight, appetite and energy expenditure modulation. There is substantial evidence to suggest that saturated fatty acids have a greater effect on appetite control, although in the long run may result in more weight gain than unsaturated fatty acids due to a weaker stimulation of energy expenditure. In contrast, mono-unsaturated fats do not have much effects on appetite control, but they can be beneficial in weight control over the long term due to stimulatory effects on energy expenditure. Interestingly, in case of poly unsaturated fats, including n-3 and n-6, their effect on increasing energy expenditure is aligned, but they act differently in controlling weight and appetite.

The effects of Canola oil on cardiovascular risk factors: A systematic review and meta-analysis with dose-response analysis of controlled clinical trials

BACKGROUND AND AIMS

Canola oil (CO) is a plant-based oil with the potential to improve several cardiometabolic risk factors. We systematically reviewed controlled clinical trials investigating the effects of CO on lipid profiles, apo-lipoproteins, glycemic indices, inflammation, and blood pressure compared to other edible oils in adults.

METHODS AND RESULTS

Online databases were searched for articles up to January 2020. Forty-two articles met the inclusion criteria. CO significantly reduced total cholesterol (TC, -0.27 mmol/l, n = 37), low-density lipoprotein cholesterol (LDL-C, -0.23 mmol/l, n = 35), LDL-C to high-density lipoprotein cholesterol ratio (LDL/HDL, -0.21, n = 10), TC/HDL (-0.13, n = 15), apolipoprotein B (Apo B, -0.03 g/l, n = 14), and Apo B/Apo A-1 (-0.02, n = 6) compared to other edible oils (P < 0.05). Compared to olive oil, CO decreased TC (-0.23 mmol/l, n = 9), LDL-C (-0.17 mmol/l, n = 9), LDL/HDL (-0.39, n = 2), and triglycerides in VLDL (VLDL-TG, -0.10 mmol/l, n = 2) (P < 0.05). Compared to sunflower oil, CO improved LDL-C (-0.14 mmol/l, n = 11), and LDL/HDL (-0.30, n = 3) (P < 0.05). In comparison with saturated fats, CO improved TC (-0.59 mmol/l, n = 11), TG (-0.08 mmol/l, n = 11), LDL-C (-0.49 mmol/l, n = 10), TC/HDL (-0.29, n = 5), and Apo B (-0.09 g/l, n = 4) (P < 0.05). Based on the nonlinear dose-response curve, replacing CO with ~15% of total caloric intake provided the greatest benefits.

CONCLUSION

CO significantly improved different cardiometabolic risk factors compared to other edible oils. Further well-designed clinical trials are warranted to confirm the dose-response associations.

Effects of canola or olive oil on plasma lipids, lipoprotein-associated phospholipase A2 and inflammatory cytokines in patients referred for coronary angiography

BACKGROUND

The potential cardioprotective benefits of olive oil (OO) and canola oil (CO) consumption have been shown in some studies. The present study compared the effects of CO and OO on plasma lipids, some inflammatory cytokines, and lipoprotein-associated phospholipase A₂ (Lp-PLA₂) mass and activity in patients undergoing coronary angiography.

METHODS

The current randomized, controlled, parallel-arm, clinical trial involved 48 patients (44 men and 4 women, aged 57.63 ± 6.34 years) with at least one classic cardiovascular risk factor (hypertension, dyslipidemia, or diabetes) who referred for coronary angiography. Patients were randomly divided into two groups and received 25 mL/day refined olive oil (n = 24) or canola oil (n = 24) for 6 weeks. Plasma lipids, some selected inflammatory markers, and Lp-PLA₂ levels were measured at baseline and after the intervention.

RESULTS

CO consumption produced a significant reduction in plasma Lp-PLA₂ mass (- 0.97 ± 1.84 vs. 0.34 ± 1.57 ng/mL, p = 0.008 for CO and OO, respectively), whereas the mean changes in interleukine-6 concentration were significantly lower after OO consumption compared with CO (- 9.46 ± 9.46 vs. -0.90 ± 6.80 pg/mL, p = 0.008 for OO and CO, respectively). After 6 weeks of intervention, no significant changes were observed in plasma Lp-PLA₂ activity, complement C3, C4, or lipid profiles in the two intervention groups.

CONCLUSIONS

Comparing the two vegetable oils in subjects with cardiovascular risk factors showed that the consumption of olive oil is more effective in reducing the level of inflammatory cytokine interleukine-6, whereas canola oil was more effective in lowering Lp-PLA₂ levels; however, this finding should be interpreted with caution, because Lp-PLA₂ activity did not change significantly.

TRIAL REGISTRATION

IRCT20160702028742N5 at www.irct.ir (04/19/2019).

Effects of α-linolenic acid intake on blood lipid profiles：a systematic review and meta-analysis of randomized controlled trials

To investigate the effect of ALA intake on blood lipid profiles, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very-low-density lipoprotein (VLDL-C) and ratio of TC to HDL-C. We systematically searched randomized controlled trials of ALA intervention on PubMed, Embase, Cochrane library and related references up to March 2018. The final values were calculated as weighted mean difference (WMD) by using a random effects model. Subgroup analysis and meta-regression were used to explore the source of heterogeneity. Generalized least square was performed for dose-response analysis. Forty-seven studies with 1305 individuals in the ALA arm and 1325 individuals in the control arm were identified. Compared with control group, dietary intake of ALA significantly reduced the concentrations of TG (WMD -0.101 mmol/L; 95% CI: -0.158 to -0.044 mmol/L; P = 0.001), TC (WMD -0.140 mmol/L; 95% CI: -0.224 to -0.056 mmol/L; P = 0.001), LDL-C (WMD -0.131 mmol/L; 95% CI: -0.191 to -0.071 mmol/L; P < 0.001), VLDL-C (WMD -0.121 mmol/L; 95% CI: -0.170 to -0.073 mmol/L; P < 0.001), TC/HDL-C ratio (WMD -0.165 mmol/L; 95% CI: -0.317 to -0.013 mmol/L; P = 0.033) and LDL-C/HDL-C ratio (WMD -0.158 mmol/L; 95% CI: -0.291 to -0.025 mmol/L; P = 0.02). There is no effect of ALA intake on HDL-C (WMD 0.008 mmol/L; 95% CI: -0.018 to 0.034 mmol/L; P = 0.541). Dose-response analysis indicated that 1 g per day increment of ALA was associated with a 0.0016 mmol/L, 0.0071 mmol/L, 0.0015 and 0.0061 mmol/L reduction in TG (95% CI: -0.0029 to -0.0002 mmol/L), TC (95% CI: -0.0085 to -0.0058 mmol/L), HDL-C (95% CI: -0.0020 to -0.0011 mmol/L) and LDL-C (95% CI: -0.0073 to -0.0049 mmol/L) levels, respectively. The effects of ALA intake on TG, TC and LDL-C concentrations were more obvious among Asian participants, and also more obvious on patients with hyperlipidemia or hyperglycemia compared to healthy individuals. Dietary ALA intervention improves blood lipid profiles by decreasing levels of TG, TC, LDL and VLDL-C. Our findings add to the evidence that increasing ALA intake could potentially prevent risk of cardiovascular diseases.

Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its "globesity" still remains a big challenge all over the world. The current systematic review and meta-analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta-analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: -0.75 [-1.18, -0.319]), body mass index ([SMD]: -1.2 [-1.82, -0.57]), waist circumference ([SMD]: -1.71 [-2.66, -0.77]), hip circumference ([SMD]: -0.42 [-1.02, -0.19]), and total cholesterol, ([SMD]: -0.43 [-0.77, -0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: -0.88, 95 % CI: [-1.13, -0.63]) and triglyceride ([SMD]: -1.67, 95 % CI: [-2.54, -0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

Biochemistry of blood platelet activation and the beneficial role of plant oils in cardiovascular diseases

The main function of blood platelets is to form hemostatic plugs and enable thrombosis. These properties, however, can be greatly influenced by dietary components which may inhibit certain steps of platelet activation, including platelet aggregation. Such inhibition can play a role in the prophylaxis and treatment of cardiovascular diseases associated with blood platelet hyperactivation. In fact, plant and fish oils have been identified and specifically used for this purpose. Numerous in vivo and in vitro experiments have explored the potential use of these oils to inhibit platelet activation as well as their role in reducing oxidative stress and blood pressure, and lowering triglyceride and cholesterol. This chapter presents and compares the anti-platelet effects of fish and plant oils and their constituents, especially fatty acids. Studies on healthy subjects and patients with various cardiovascular diseases are also examined. Findings indicate that both fish and plant oils contain protective components with anti-platelet activity having clearly defined mechanisms of action. Although both are excellent sources of omega fatty acids and vitamins, plant oils contain components with cardioprotective benefit in hypercholesterolemics, i.e., phytosterols. Plant oils may hence play a key role in strategies for preventing and treating cardiovascular diseases associated with platelet hyperactivation. Further studies are clearly needed to determine the precise dose of these components needed for effective prophylaxis and treatment.

The Relationship Between Omega-3, Omega-6 and Total Polyunsaturated Fat and Musculoskeletal Health and Functional Status in Adults: A Systematic Review and Meta-analysis of RCTs

We conducted a systematic review and meta-analysis to assess the effects of increasing dietary omega-3, omega-6 and mixed polyunsaturated fatty acids (PUFA) on musculoskeletal health, functional status, sarcopenia and risk of fractures. We searched Medline, Embase, The Cochrane library, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) databases for Randomised Controlled Trials (RCTs) of adults evaluating the effects of higher versus lower oral omega-3, omega-6 or mixed PUFA for ≥ 6 months on musculoskeletal and functional outcomes. We included 28 RCTs (7288 participants, 31 comparisons), 23 reported effects of omega-3, one of omega-6 and four of mixed total PUFA. Participants and doses were heterogeneous. Six omega-3 trials were judged at low summary risk of bias. We found low-quality evidence that increasing omega-3 increased lumbar spine BMD by 2.6% (0.03 g/cm², 95% CI - 0.02 to 0.07, 463 participants). There was also the suggestion of an increase in femoral neck BMD (of 4.1%), but the evidence was of very low quality. There may be little or no effect of omega-3 on functional outcomes and bone mass; effects on other outcomes were unclear. Only one study reported on effects of omega-6 with very limited data. Increasing total PUFA had little or no effect on BMD or indices of fat-free (skeletal) muscle mass (low-quality evidence); no data were available on fractures, BMD or functional status and data on bone turnover markers were limited. Trials assessing effects of increasing omega-3, omega-6 and total PUFA on functional status, bone and skeletal muscle strength are limited with data lacking or of low quality. Whilst there is an indication that omega-3 may improve BMD, high-quality RCTs are needed to confirm this and effects on other musculoskeletal outcomes.

The effect of canola oil compared with sesame and sesame-canola oil on cardio-metabolic biomarkers in patients with type 2 diabetes: Design and research protocol of a randomized, triple-blind, three-way, crossover clinical trial

BACKGROUND

Both canola and sesame oils consumption have been associated with favorable effects on cardio-metabolic biomarkers. However, to the best of our knowledge, no study has compared their effects on cardiovascular risk factors. The present study aimed to assess the effect of canola, sesame, and sesame-canola oils consumption on cardio-metabolic biomarkers in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study was a randomized, triple-blind, three-way, crossover clinical trial. The study participants included 102 individuals with T2DM. Their spouses were also included in the study. The participants were entered into a 4-week run-in period. After that, their regular dietary oil was replaced with canola, sesame, or sesame-canola oils (a blend of sesame and canola oils) in three 9-week phases, which were separated by two 4-week washout periods (sunflower oil was consumed during the run-in and the washout periods). Dietary, physical activity, blood pressure, and anthropometric measurements were assessed at the beginning, in the middle (week 4-5), and at the end of each treatment phase. Blood samples were taken at the beginning and at the end of each phase. Serum, plasma, buffy coat, and whole blood samples were extracted and kept at -80 ºC for further analysis. Serum fasting blood sugar (FBS), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were selected as the primary outcomes.

RESULTS

102 participants with T2DM were randomly assigned to one of the 6 rolling methods. Through them, 93 individuals (91.2%) completely participated in all phases.

CONCLUSION

The present study will provide an exceptional opportunity to examine the effect of canola, sesame, and sesame-canola oil on cardio-metabolic markers in adults with and without T2DM. This trial will also provide a good medium for the investigation of gene-dietary oils interaction in the future.

Total and Subtypes of Dietary Fat Intake and Its Association with Components of the Metabolic Syndrome in a Mediterranean Population at High Cardiovascular Risk

Background: The effect of dietary fat intake on the metabolic syndrome (MetS) and in turn on cardiovascular disease (CVD) remains unclear in individuals at high CVD risk. Objective: To assess the association between fat intake and MetS components in an adult Mediterranean population at high CVD risk. Design: Baseline assessment of nutritional adequacy in participants (n = 6560, men and women, 55-75 years old, with overweight/obesity and MetS) in the PREvención con DIeta MEDiterránea (PREDIMED)-Plus randomized trial. Methods: Assessment of fat intake (total fat, monounsatured fatty acids: MUFA, polyunsaturated fatty acids: PUFA, saturated fatty acids: SFA, trans-fatty acids: trans-FA, linoleic acid, α-linolenic acid, and ω-3 FA) using a validated food frequency questionnaire, and diet quality using 17-item Mediterranean dietary questionnaire and fat quality index (FQI). Results: Participants in the highest quintile of total dietary fat intake showed lower intake of energy, carbohydrates, protein and fiber, but higher intake of PUFA, MUFA, SFA, TFA, LA, ALA and ω-3 FA. Differences in MetS components were found according to fat intake. Odds (5th vs. 1st quintile): hyperglycemia: 1.3-1.6 times higher for total fat, MUFA, SFA and ω-3 FA intake; low high-density lipoprotein cholesterol (HDL-c): 1.2 higher for LA; hypertriglyceridemia: 0.7 lower for SFA and ω-3 FA intake. Conclusions: Dietary fats played different role on MetS components of high CVD risk patients. Dietary fat intake was associated with higher risk of hyperglycemia.

The Effect of Canola Oil on Body Weight and Composition: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

A number of clinical trials have examined the effect of canola oil (CO) on body composition in recent years; however, the results have been inconsistent. The present investigation aims to examine the effect of CO on body weight (BW) and body composition using a systematic review and meta-analysis of controlled clinical trials. Online databases including PubMed, Scopus, and Google Scholar were searched up to February, 2018 for randomized controlled clinical trials that examined the effect of CO on anthropometric measures and body composition indexes in adults. The Cochrane Collaboration's tool was used to assess the risk of bias in individual studies. A random-effects model was used to evaluate the effect of CO consumption on several outcomes: BW, body mass index, waist circumference, hip circumference, waist-to-hip ratio, android-to-gynoid ratio, and body lean and fat mass. In total, 25 studies were included in the systematic review. The meta-analysis revealed that CO consumption reduces BW [weighted mean difference (WMD) = -0.30 kg; 95% CI: -0.52, -0.08 kg, P = 0.007; n = 23 effect sizes], particularly in participants with type 2 diabetes (WMD = -0.63 kg; 95% CI: -1.09, -0.17 kg, P = 0.007), in studies with a parallel design (WMD = -0.49 kg; 95% CI: -0.85, -0.14 kg, P = 0.006), in nonfeeding trials (WMD = -0.32 kg; 95% CI: -0.55, -0.09 kg, P = 0.006), and when compared with saturated fat (WMD = -0.40 kg; 95% CI: -0.74, -0.06 kg, P = 0.019). CO consumption did not significantly affect any other anthropometric measures or body fat markers (P > 0.05). Although CO consumption results in a modest decrease in BW, no significant effect was observed on other adiposity indexes. Further well-constructed clinical trials that target BW and body composition as their primary outcomes are needed.

Diets Enriched with Conventional or High-Oleic Acid Canola Oils Lower Atherogenic Lipids and Lipoproteins Compared to a Diet with a Western Fatty Acid Profile in Adults with Central Adiposity

BACKGROUND

Novel oils high in monounsaturated fatty acids (MUFAs) and low in saturated fatty acids (SFAs) are an alternative to partially hydrogenated oils high in trans-unsaturated fatty acids. There is widespread use of high-MUFA oils across the food industry; however, limited knowledge of their cardiovascular impact exists.

OBJECTIVES

We investigated the effects of diets containing canola oil, high-oleic acid canola oil (HOCO), and a control oil blend (diet formulated to emulate a Western fat profile) on lipids, lipoproteins, and apolipoproteins (apos), as secondary outcomes of the trial.

METHODS

In a multi-center, double-blind, randomized, 3-period crossover, controlled feeding trial, men (n = 44) and women (n = 75) with a mean age of 44 y, mean body mass index (BMI; in kg/m2) of 31.7, and an increased waist circumference plus ≥1 metabolic syndrome criteria consumed prepared, weight-maintenance diets containing canola oil [17.5% MUFAs, 9.2% polyunsaturated fatty acids (PUFAs), 6.6% SFAs], HOCO (19.1% MUFAs, 7.0% PUFAs, 6.4% SFAs), or control oil (10.5% MUFAs, 10.0% PUFAs, 12.3% SFAs) for 6 wk with ≥4-wk washouts. Fasting serum lipids were assessed at baseline and 6 wk. Diet effects were examined using a repeated measures mixed model.

RESULTS

Compared with the control, canola and HOCO diets resulted in lower endpoint total cholesterol (TC; -4.2% and -3.4%; P < 0.0001), LDL cholesterol (-6.6% and -5.6%; P < 0.0001), apoB (-3.7% and -3.4%; P = 0.002), and non-HDL cholesterol (-4.5% and -4.0%; P = 0.001), with no differences between canola diets. The TC:HDL cholesterol and apoB:apoA1 ratios were lower after the HOCO diet than after the control diet (-3.7% and -3.4%, respectively). There were no diet effects on triglyceride, HDL cholesterol, or apoA1 concentrations.

CONCLUSIONS

HOCO, with increased MUFAs at the expense of decreased PUFAs, elicited beneficial effects on lipids and lipoproteins comparable to conventional canola oil and consistent with reduced cardiovascular disease risk in adults with central adiposity. This trial was registered at www.clinicaltrials.gov as NCT02029833.

Effect ofα-linolenic acid on 24-h ambulatory blood pressure in untreated high-normal and stage I hypertensive subjects

Results of intervention studies on the effects ofα-linolenic acid (ALA; C18 : 3n-3) on blood pressure (BP) are conflicting. Discrepancies between studies may be due to differences in study population, as subjects with increased baseline BP levels may be more responsive. Therefore, we examined specifically the effects of ALA on 24-h ambulatory blood pressure (ABP) in (pre-)hypertensive subjects. In a double-blind, randomised, placebo-controlled parallel study, fifty-nine overweight and obese adults (forty males and nineteen females) with (pre-)hypertension (mean age of 60 (sd8) years) received daily 10 g refined cold-pressed flaxseed oil, providing 4·7 g (approximately 2 % of energy) ALA (n29) or 10 g of high-oleic sunflower oil as control (n30) for 12 weeks. Compliance was excellent as indicated by vial count and plasma phospholipid fatty-acid composition. Compared with control, the changes of –1·4 mmHg in mean arterial pressure (MAP; 24 h ABP) after flaxseed oil intake (95 % CI –4·8, 2·0 mmHg,P=0·40) of –1·5 mmHg in systolic BP (95 % CI –6·0, 3·0 mmHg,P=0·51) and of –1·4 mmHg in diastolic BP (95 % CI –4·2, 1·4 mmHg,P=0·31) were not statistically significant. Also, no effects were found for office BP and for MAP, systolic BP, and diastolic BP when daytime and night-time BP were analysed separately and for night-time dipping. In conclusion, high intake of ALA, about 3–5 times recommended daily intakes, for 12 weeks does not significantly affect BP in subjects with (pre-)hypertension.

Effects of Canola Oil Consumption on Lipid Profile: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials

Hyperlipidemia is a well- known risk factor of cardiovascular disease. A healthy diet containing vegetable oils such as canola oil (CO) may help to reduce serum lipids. This study aimed to quantify the effects of CO on lipid parameters using a systematic review and meta-analysis of randomized controlled trials. PubMed, Web of Science, Scopus, ProQuest, and Embase were systematically searched until December 2017, with no time and design restrictions. Also, a manual search was performed to find extra relevant articles. Lipid parameters including total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), triglycerides (TG), apolipoprotein A1 (Apo A1), and apolipoprotein B (Apo B) were entered the meta-analysis. Weighed mean difference (WMD) and 95% confidence interval (CI) were stated as the effect size. Sensitivity analyses and prespecified subgroup were conducted to evaluate potential heterogeneity. Twenty-seven trials, comprising 1359 participants, met the eligibility criteria. Results of this study showed that CO consumption significantly reduced TC (-7.24 mg/dl, 95% CI, -12.1 to -2.7), and LDL (-6.4 mg/dl, 95% CI, -10.8 to -2), although it had no effects on HDL, TG, Apo B, and Apo A1. Effects of CO on TC and LDL significantly decreased after CO consumption in subgroups of >50 years of age participants and >30 intervention duration subgroup. Moreover, CO decreased LDL and TC compared to sunflower oil and saturated fat. This meta-analysis suggested that CO consumption improves serum TC and LDL, which could postpone heart disease progression. Key Teaching Points CO consumption could decrease serum TC and LDL, although it had no effects on other blood lipids. There was an overall significant effect of canola oil on TC and LDL compared to sunflower oil and saturated fats. CO could have beneficial effects on serum TC and LDL just when consumed longer than 30 days. CO consumption improved lipid profiles in participants older than 50 years.

Comparison of blood lipid-lowering effects of olive oil and other plant oils: A systematic review and meta-analysis of 27 randomized placebo-controlled clinical trials

Objective: We aim to report a systematic review and meta-analysis of randomized controlled trials (RCTs) on effects of olive oil consumption compared with other plant oils on blood lipids. Methods: PubMed, web of science, Scopus, ProQuest, and Embase were systematically searched until September 2017, with no age, language and design restrictions. Weighed mean difference (WMD) and 95% confidence interval (CI) were expressed as effect size. Sensitivity analyses and pre specified subgroup was conducted to evaluate potential heterogeneity. Meta-regression analyses were performed to investigate association between blood lipid-lowering effects of olive oil and duration of treatment. Results: Twenty-seven trials, comprising 1089 participants met the eligibility criteria. Results of this study showed that compared to other plant oils, high-density lipoprotein level increased significantly more for OO (1.37 mg/dl: 95% CI: 0.4, 2.36). Also OO consumption reduced total cholesterol (TC) (6.27 mg/dl, 95% CI: 2.8, 10.6), Low-density lipoprotein (LDL-c) (4.2 mg/dl, 95% CI: 1.4, 7.01), and triglyceride (TG) (4.31 mg/dl, 95% CI: 0.5, 8.12) significantly less than other plant oils. There were no significant effects on Apo lipoprotein A1 and Apo lipoprotein B. Conclusion: This meta-analysis suggested that OO consumption decreased serum TC, LDL-c, and TG less but increased HDL-c more than other plant oils.

Assessment of diet-related GHG emissions using the environmental hourglass approach for the Mediterranean and new Nordic diets

Food production and preparation affect the environment in many ways, with effects on greenhouse gases, use of land, biodiversity, etc. The impact is influenced by consumer demand and eating habits. Two different recommended dietary models were considered, the Mediterranean Diet and the New Nordic Diet, with quantitative analysis of GHG emissions through LCA. An environmental hourglass (EH) approach based on LCA was introduced to help translate health-promoting dietary recommendations that consider regional circumstances and cultural diversity into practical eating habits, to promote sustainable and environmentally friendly consumption. Using the environmental hourglass approach, we examined whether dietary choices based on nutritional recommendations can minimise certain negative effects on the food production environment. Using two examples of health-enhancing, regionally-oriented and culturally appropriate dietary patterns - the Mediterranean Diet and the New Nordic Diet - we showed that consumption of high protein foods has a similar and comparable environmental impact to fruit and vegetable consumption. The results of this work may provide a starting point for integrated policy addressing issues related to the healthy diet of the population, aware food choices and sustainable agriculture.

Role of phytochemicals in the management of metabolic syndrome

BACKGROUND

The World Health Organization (WHO) for some years has been focusing on what is now commonly referred to as an "epidemic of obesity and diabetes" ("diabesity"): behind this outbreak, there are several risk factors grouped in what is called "metabolic syndrome" (MetS). The basis of this "epidemic" is either a diet too often characterized by excessive consumption of saturated and trans-esterified fatty acids, simple sugars and salt, either a sedentary lifestyle.

PURPOSE

The aim of this review is to focus on the phytochemicals that have a more positive effect on the treatment and/or prevention of MetS.

CHAPTERS

Treatment strategies for MetS include pharmacologic and non-pharmacologic options, with varying degrees of success rate. The first is indicated for patients with high cardiovascular risk, while the second one is the most cost-effective preventive approach for subjects with borderline parameters and for patients intolerant to pharmacological therapy. MetS non-pharmacological treatments could involve the use of nutraceuticals, most of which has plant origins (phytochemicals), associated with lifestyle improvement. The chapter will discuss the available evidence on soluble fibres from psyllium and other sources, cinnamaldehyde, cinnamic acid and other cinnamon phytochemicals, berberine, corosolic acid from banaba, charantin from bitter gourd, catechins and flavonols from green tea and cocoa. Vegetable omega-3 polyunsaturated fatty acids, alliin from garlic, soy peptides, and curcumin from curcuma longa.

CONCLUSION

Some nutraceuticals, when adequately dosed, should improve a number of the MetS components.

n-3 Fatty acids preserve muscle mass and insulin sensitivity in a rat model of energy restriction

In obese subjects, the loss of fat mass during energy restriction is often accompanied by a loss of muscle mass. The hypothesis thatn-3 PUFA, which modulate protein homoeostasis via effects on insulin sensitivity, could contribute to maintain muscle mass during energy restriction was tested in rats fed a high-fat diet (4 weeks) rich in 18 : 1n-9 (oleic acid, OLE-R), 18 : 3n-3 (α-linolenic acid, ALA-R) orn-3 long-chain (LC-R) fatty acid and then energy restricted (8 weeks). A control group (OLE-ad libitum(AL)) was maintained with AL diet throughout the study. Rats were killed 10 min after an i.v. insulin injection. All energy-restricted rats lost weight and fat mass, but only the OLE-R group showed a significant muscle loss. TheGastrocnemiusmuscle was enriched with ALA in the ALA-R group and with LC-PUFA in the ALA-R and LC-R groups. The proteolytic ubiquitin–proteasome system was differentially affected by energy restriction, with MAFbx and muscle ring finger-1 mRNA levels being decreased in the LC-R group (−30 and −20 %, respectively). RAC-αserine/threonine-protein kinase and insulin receptor substrate 1 phosphorylation levels increased in the LC-R group (+70 %), together with insulin receptor mRNA (+50 %). The ALA-R group showed the same overall activation pattern as the LC-R group, although to a lesser extent. In conclusion, dietaryn-3 PUFA prevent the loss of muscle mass associated with energy restriction, probably by an improvement in the insulin-signalling pathway activation, in relation to enrichment of plasma membranes inn-3 LC-PUFA.

Omega 3 Fatty Acids: Novel Neurotherapeutic Targets for Cognitive Dysfunction in Mood Disorders and Schizophrenia?

An increasing body of evidences from preclinical as well as epidemiological and clinical studies suggest a potential beneficial role of dietary intake of omega-3 fatty acids for cognitive functioning. In this narrative review, we will summarize and discuss recent findings from epidemiological, interventional and experimental studies linking dietary consumption of omega-3 fatty acids to cognitive function in healthy adults. Furthermore, affective disorders and schizophrenia (SZ) are characterized by cognitive dysfunction encompassing several domains. Cognitive dysfunction is closely related to impaired functioning and quality of life across these conditions. Therefore, the current review focues on the potential influence of omega-3 fatty acids on cognition in SZ and affective disorders. In sum, current data predominantly from mechanistic models and animal studies suggest that adjunctive omega-3 fatty acid supplementation could lead to improved cognitive functioning in SZ and affective disorders. However, besides its translational promise, evidence for clinical benefits in humans has been mixed. Notwithstanding evidences indicate that adjunctive omega-3 fatty acids may have benefit for affective symptoms in both unipolar and bipolar depression, to date no randomized controlled trial had evaluated omega-3 as cognitive enhancer for mood disorders, while a single published controlled trial suggested no therapeutic benefit for cognitive improvement in SZ. Considering the pleiotropic mechanisms of action of omega-3 fatty acids, the design of well-designed controlled trials of omega-3 supplementation as a novel, domain-specific, target for cognitive impairment in SZ and affective disorders is warranted.

Is there A Role for Alpha-Linolenic Acid in the Fetal Programming of Health?

The role of ω3 alpha linolenic acid (ALA) in the maternal diet during pregnancy and lactation, and its effect on the prevention of disease and programming of health in offspring, is largely unknown. Compared to ALA, ω3 docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids have been more widely researched due to their direct implication in fetal neural development. In this literature search we found that ALA, the essential ω3 fatty acid and metabolic precursor of DHA and EPA has been, paradoxically, almost unexplored. In light of new and evolving findings, this review proposes that ALA may have an intrinsic role, beyond the role as metabolic parent of DHA and EPA, during fetal development as a regulator of gene programming for the prevention of metabolic disease and promotion of health in offspring.

Ingestão de ácidos graxos monoinsaturados e metabolismo lipídico

Resumo Esta revisão teve como objetivo apresentar e discutir os achados mais recentes do efeito dos ácidos graxos monoinsaturados (AGMI) sobre marcadores plasmáticos do metabolismo lipídico em estudos pós-prandiais e de intervenção clínica nutricional. Realizou-se busca em diferentes bases de dados entre 2010 e 2014, usando os seguintes termos de indexação: MUFA, Lipemia, Lipid Metabolism, Triglycerides e Postprandial. O consumo de refeição com alto conteúdo de AGMI tem demonstrado efeito benéfico na resposta lipidêmica pós-prandial, mas se essa resposta pode ser alterada em indivíduos com excesso de peso e/ou outras doenças crônicas após consumo de AGMI, ainda não está totalmente elucidado. De modo geral, após a intervenção com AGMI, os fatores de risco cardiovascular diminuíram, além de haver melhora no perfil lipídico. Em conclusão, os estudos recentes têm demonstrado um efeito benéfico do consumo de AGMI em curto e longo prazos, mediante aumento/manutenção das concentrações de HDL colesterol e diminuição do LDL colesterol.

α-Linolenic acid increases the G0/G1 switch gene 2 mRNA expression in peripheral blood mononuclear cells from obese patients: a pilot study

Background

Recent evidence has demonstrated that the G0/G1 switch gene 2 (G0S2) is an important negative regulator of the rate-limiting lipolytic enzyme adipose triglyceride lipase-mediated lipolysis. It has been revealed that α-linolenic acid (ALA), a plant-based essential omega-3 polyunsaturated fatty acids, reduces adipose tissue lipolysis. However, it is not known whether G0S2 is implicated in ALA-induced inhibition of lipolysis. The purpose of this pilot study is to investigate the effect of ALA on G0S2 gene expression in peripheral blood mononuclear cells (PBMC) of obese patients and the potential influence of G0S2 gene expression in ALA-induced inhibition of lipolysis.

Methods

A total of 26 obese patients were randomly assigned to be treated with or without ALA treatment (~4.0 g daily) for 12 weeks: the ALA-treated group (n = 14) or the untreated control group (n = 12). Plasma triglyceride (TG), free fatty acids (FFA), glycerol, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), as well as the mRNA expression levels of proliferator-activated receptor gamma (PPAR-γ), G0S2, and G protein-coupled receptor 120 (GPR120) in PBMC were repeatedly examined from fasting obese patients before and after ALA treatment.

Results

ALA significantly decreased plasma TG, FFA, glycerol, IL-6, and TNF-α levels and increased the mRNA expression levels of PPAR-γ, G0S2, and GPR120 in PBMC, compared with the untreated control group. In obese patients from the ALA-treated group, decreased plasma FFA (a biomarker for lipolysis) level was significantly correlated with increased PPAR-γ (a functional omega-3 fatty acids receptor) and G0S2 (a direct target gene of PPAR-γ) mRNA expression in PBMC, while decreased plasma FFA level was not correlated with increased GPR120 (another functional omega-3 fatty acids receptor) mRNA expression in PBMC.

Conclusion

This study shows that ALA increases G0S2 gene expression in PBMC in parallel with the decrease of plasma FFA level in obese patients. Increased G0S2 gene expression might contribute to the beneficial anti-lipolytic effect of ALA in obese patients.