The effect of flaxseed supplementation on body weight and body composition: a systematic review and meta-analysis of 45 randomized placebo-controlled trials

Fluorescence Spectroscopy Based Characterization of Flaxseed Oil

Fluorescence spectroscopy has been employed for the compositional analysis of flaxseed oil, detection of its adulteration and investigation of the thermal effects on its molecular composition. Excitation wavelengths from 320 to 420 nm have been used to explore the valued ingredients in flaxseed oil. The emission bands of flaxseed oil centred at 390, 414, 441, 475, 515 and 673/720 nm represent vitamin K, isomers of vitamin E, carotenoids and chlorophylls, which can be used as a marker for quality analysis. Due to its high quality, it is highly prone to adulteration and in this study, detection of its adulteration with canola oil is demonstrated by applying principal component analysis. Moreover, the effects of temperature on the molecular composition of cold pressed flaxseed oil has been explored by heating them at cooking temperatures of 100, 110, 120, 130, 140, 150, 160, 170 and 180 °C, each for 30 min. On heating, the deterioration of vitamin E, carotenoids and chlorophylls occurred with an increase in the oxidation products. However, it was found that up to 140 °C, flaxseed oil retains much of its natural composition whereas up to 180 oC, it loses much of its valuable ingredients along with increase of oxidized products.

The Effect of Chia Seed on Blood Pressure, Body Composition, and Glycemic Control: A GRADE-Assessed Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

CONTEXT

Numerous studies have demonstrated the positive effects on metabolic factors of consuming chia seeds. However, the results of clinical trials have been inconsistent.

OBJECTIVE

The aim of this study was to conduct a systematic review and meta-analysis of available randomized controlled trials to explore the effects of chia seed consumption on body weight (BW), body composition, blood pressure, and glycemic control.

DATA SOURCES

A comprehensive search was conducted on the Scopus, PubMed, Medline via Ovid, ISI Web of Science, and Scholar Google databases up to August 2023.

DATA EXTRACTION

The outcomes of interest included systolic blood pressure (SBP), diastolic blood pressure (DBP), BW, body mass index (BMI), body fat percentage, waist circumference (WC), fasting blood glucose (FBG), and hemoglobin A1c (HbA1c).

DATA ANALYSIS

Weighted mean difference (WMD) and 95% CIs were used to determine the effect size.

RESULTS

A total of 8 eligible studies were included in the analysis. The findings revealed a significant reduction in SBP (WMD: -7.19 mmHg; 95% CI, -10.63 to -3.73; P < .001) and DBP (WMD: -6.04 mmHg, 95% CI, -9.58 to -2.49; P = .001). However, no significant effects were observed on BW, body fat percentage, WC, BMI, FBG, and HbA1c. Subgroup analysis indicated that the effect of chia seed on SBP was significant in participants with a baseline SBP of less than 140 mmHg, but the effect was not dependent on the administered dose.

CONCLUSION

Chia seed consumption has positive effects on SBP and DBP but does not significantly impact BW, body composition, or glycemic parameters. However, the limited amount of data from included studies should be considered as a limitation while interpreting these findings.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023462575.

Efficacy of flaxseed in reducing blood pressure among patients with cardiovascular risk factors: A systematic review and meta-analysis of parallel randomized controlled trials

The prevalence rate of hypertension is on the rise at an alarming rate. Studies conducted on the influence of flaxseed on blood pressure (BP) have come up with conflicting conclusions. The current investigation's major purpose is to conduct a literature review and a meta-analysis focusing on the effect of flaxseed supplementation on BP in people with cardiovascular disease (CVD) risk factors. PubMed, Scopus, Web of Science, and Cochrane Central Library databases were searched from the inception date to April 2024 to find the randomized controlled trials (RCTs). A random-effects model combined the weighted mean difference (WMD). Standard methodologies were applied to evaluate publication bias, heterogeneity, and sensitivity analysis. Eighteen RCTs were included in the present systematic review and meta-analysis. Pooled analysis suggested that flaxseed supplementation can reduce systolic BP (SBP) (WMD: -4.75 mmHg, 95% CI: -7.05 to -2.44, P≤0.001; I2=93.6%) and diastolic BP (DBP) (WMD: -3.09 mmHg, 95% CI: -4.37 to -1.81, P≤0.001; I2=91.2%). In conclusion, the current meta-analysis has demonstrated that flaxseed supplementation can markedly lower BP in individuals exhibiting CVD risk factors. Given the significant heterogeneity, it is crucial to interpret the current results with careful consideration. In addition, further high-quality RCTs are required to better assess the causal relationships.

Dietary flaxseed: Cardiometabolic benefits and its role in promoting healthy aging

Flaxseed, a rich source of omega-3 polyunsaturated fatty acid alpha-linolenic acid (ALA), lignans, and soluble fiber, has attracted attention for its potential to improve multiple cardiometabolic risk factors. While its benefits are well-recognized, comprehensive evaluations of its direct impact on clinical outcomes, such as the prevention or progression of cardiometabolic diseases, remain limited. Additionally, its potential to support healthy aging and longevity through fundamental biological mechanisms has not been fully elucidated. This review synthesizes existing research on flaxseed supplementation, highlighting its effects on cardiometabolic risk factors and outcomes, the underlying biological mechanisms, and its broader implications for health promotion and aging. Findings demonstrate that flaxseed supplementation significantly improves several cardiometabolic risk factors, including body weight, body mass index, lipid levels, blood pressure, glycemic measures, markers of inflammation (e.g., C-reactive protein and interleukin-6), oxidative stress, and liver enzymes. Blood pressure reductions range from approximately 2 to 15 mmHg for systolic blood pressure and 1 to 7 mmHg for diastolic blood pressure, with the magnitude influenced by dose, duration, and baseline risk profiles. While direct evidence linking flaxseed to the prevention of hypertension, metabolic syndrome, metabolic dysfunction-associated steatotic liver disease, type 2 diabetes, chronic kidney disease, and cardiovascular disease is limited, its bioactive components-ALA, lignans, and fiber-are strongly associated with reduced risks of these conditions. The benefits of flaxseed are mediated through multiple pathways, including anti-inflammatory and antioxidant effects, improved lipid levels, improved glucose metabolism and insulin sensitivity, modulation of gut microbiota, and enhanced vascular health. Beyond cardiometabolic outcomes, flaxseed may influence key biological processes relevant to aging, underscoring its potential to promote healthy aging and longevity. Optimal cardiometabolic benefits appear to be achieved with ground whole flaxseed at doses of ≥ 30 g/day for at least 12 weeks, particularly among individuals at high cardiometabolic risk. Future research should focus on elucidating flaxseed's mechanisms of action, clarifying its role in disease prevention, and refining dietary recommendations to harness its potential for cardiometabolic health and aging interventions.

Effect of Flaxseed on Pain Relief and Quality of Life in Patients With Mastalgia: A Single Arm Interventional Study

Objective

Mastalgia, a common complaint among women, denotes breast discomfort that can manifest as cyclical or non-cyclical. Reassurance, mechanical support and various non-pharmacological treatments, like flaxseeds, have been seen to have a good effect in treating mastalgia. Thus, the aim of this study was to investigates the efficacy of flaxseed in alleviating pain associated with mastalgia and its impact on the overall health-related quality of life among female patients.

Materials and Methods

Conducted at a tertiary care center in Northern India over 18 months, it employed a single-arm interventional design. The participants included females aged 18 years and older presenting with breast pain at the Department of General Surgery. The intervention involved daily consumption of 30 g of milled flaxseed for each participant, administered over a period of six months. Pain severity was assessed using the visual analogue scale (VAS) before supplementation and at follow-up intervals up to six months. Concurrently, the Short Form-12 (SF-12) items Health Survey measured health-related quality of life, encompassing both physical and mental health domains. Statistical analysis employed parametric (paired t-test) and non-parametric tests (chi-square, McNemar) where appropriate, with statistical significance set at p<0.05.

Results

Two hundred women with mastalgia were included with a significant reduction in mean VAS scores from 6.03±0.83 at baseline to 2.19±0.66 at six months post-intervention (p = 0.0001). This reduction in pain intensity demonstrated a positive correlation with duration of flaxseed supplementation, notably declining after the initial three months. The mean difference in physical and mental SF-12 score at first visit and at 6 months after intervention was significant (p = 0.0001).

Conclusion

This study underscores the potential of flaxseed as a therapeutic option for managing mastalgia and enhancing health-related quality of life among affected individuals.

Dietary Omega-3 PUFA Intake in Patients with Chronic Kidney Disease: The Association with Vitamin D Deficiency, Intima-Media Thickness and Blood Pressure

Background/Objectives: Numerous risk factors associated with development of cardiovascular disease (CVD) have been unfavorably altered in patients with chronic kidney disease (CKD). Low omega-3 polyunsaturated fatty acid (PUFA) intake and vitamin D deficiency are potential cardiometabolic risk factors in patients with CKD. The aim of this study was to evaluate dietary intake and status of omega-3 PUFA and vitamin D in pre-dialysis and hemodialysis patients and to examine the association of dietary α-linolenic acid (ALA) and fish consumption with blood pressure and carotid intima-media thickness (C-IMT), representing a non-invasive marker of atherosclerosis in CKD patients. Methods: All 77 selected patients (36 pre-dialysis, 41 on hemodialysis) underwent standardized clinical, nutritional, and laboratory assessments. Repeated 24 h recalls were performed to assess dietary intake. The fatty acid profile was determined by gas-liquid chromatography. Results: Inadequate vitamin D intake and vitamin D status were found in 95% of patients. PUFA profiles did not differ between hemodialysis and pre-dialysis participants. Dietary intake of ALA was negatively correlated with systolic blood pressure (SBP) (p = 0.013), C-IMT (p = 0.002), serum CRP (p = 0.044), iPTH (p = 0.01), and 25(OH)D3 (p = 0.006). ALA intake of more than 0.23 g daily was linked with lower SBP (p = 0.001), serum 25(OH)D3 (p = 0.004), and C-IMT (p = 0.002). Conclusions: This study contributes to a better understanding of the relationship between dietary ALA intake and C-IMT in CKD. The results of this study could emphasize the significant role of the high prevalence of vitamin D deficiency and inadequate omega-3 PUFA intake and status regarding CVD health in CKD patients.

Health Effects of Various Edible Vegetable Oil: An Umbrella Review

Vegetable oils, derived from diverse sources such as seeds, nuts, and some fruits, play a significant role in dietary health. However, the current evidence on the health effects of different types of vegetable oil consumption remains controversial. This umbrella review aims to synthesize evidence from systematic reviews and meta-analyses to assess the health outcomes associated with various vegetable oils. A comprehensive literature search was performed up to 31 July, 2023 on 12 databases for studies examining the association of different vegetable oils with health outcomes in adults. Data was extracted independently by 2 authors, with evidence strength assessed using the grading of recommendations, assessment, development, and evaluation criteria. A total of 48 studies, including 206 meta-analyses, were included. Moderate to very low certainty evidence showed that monounsaturated and polyunsaturated fatty acids such as canola oil, virgin olive oil, and rice bran oil are beneficial in reducing serum total cholesterol and low-density lipoprotein (LDL) concentrations. Conversely, low to very low certainty evidence suggests that oils high in saturated fats, such as coconut oil and palm oil, increase total cholesterol and LDL concentrations but also raise high-density lipoprotein concentrations. Very low certainty evidence showed the consumption of olive oil, sesame oil, and coconut oil could improve blood sugar control. Low certainty evidence showed olive oil consumption reduced risk of breast, digestive, and other cancers. Moderate to very low certainty evidence suggested that canola oil and sesame oil consumption reduced body weight. The consumption of vegetable oil appears to offer different health benefits, with summary estimates indicating beneficial effects on reducing lipid concentrations, especially with monounsaturated and polyunsaturated rich oils when consumed in recommended amounts. Future research should focus on long-term studies and comprehensive dietary assessments to better understand the health impacts of vegetable oils, providing a basis for informed dietary recommendations. This study was registered at PROSPERO as CRD42021239210.

The effects of flaxseed (Linum usitatissimum) supplementation on anthropometric indices: An updated systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

Flaxseed (Linum usitatissimum) supplementation has shown promise as an anti-obesity agent in various clinical trials, although results have been inconsistent. To provide a more accurate assessment of the impact of flaxseed supplementation on anthropometric indices, a systematic review and meta-analysis was performed.

METHODS

We searched several international databases until August 2023, including Scopus, PubMed, Web of Science, Embase, and Cochrane Library. Weighted mean differences (WMDs) were analyzed using a random-effects model.

RESULTS

Sixty-four trials comprising 72 treatment arms were included. All studies reported the intervention types (Lignans, Whole flaxseed, and Flaxseed oil) and dosage. However, three studies did testing for purity, and 40 studies reported potency. Also, the risk of contamination with heavy metals was not mentioned in studies. Another limitation was the lack of blind evaluation in the studies. According to three trials included in the systematic review, flaxseed did not affect anthropometric indices. Our meta-analysis revealed significant reductions in body weight (WMD = -0.63 kg; 95 % CI: -1.00, -0.27, P < 0.001; I2 = 76.7 %, P < 0.001), body mass index (BMI) (WMD: -0.24 kg/m2, 95 % CI: -0.36, -0.11, P < 0.001; I2 = 78.5 %, P < 0.001) and waist circumference (WC) (WMD: -1.43 cm, 95 % CI: -2.06, -0.80, P < 0.001; I2 = 81.1 %, P < 0.001) following flaxseed supplementation. Subgroup analyses indicated that interventions lasting 10-20 weeks, and studies involving subjects with higher BMI (>30 kg/m2) showed more significant anti-obesity effects. Based on the GRADE evaluation, body weight, BMI, and WC results were considered as moderate-certainty evidence.

CONCLUSION

Our systematic review and meta-analysis suggests that supplementation with flaxseed (Linum usitatissimum) leads to meaningful improvements in body weight, BMI, and WC. Therefore, flaxseed can be considered as an adjunctive therapeutic approach in improving obesity.

Flaxseed promotes productive performance through regulating gut microbiome in ducks

BACKGROUND

Flaxseed has been widely used in animal diets to increase the omega-3 polyunsaturated fatty acid content in animal products and promote overall animal health, but little known about its effects on the productive performance and the mictobita of gut of laying duck.

METHODS AND RESULTS

Jinding duck, a Chinese indigenous breed, was used in the study. The corn-soybean basal diet supplemented with 0, 2%, 3% 4% and 5% flaxseed were provided to Control, 2% Fla, 3% Fla, 4% Fla and 5% Fla groups for 53 days, respectively. Compared with Control group, groups fed with flaxseed diets showed higher egg production, egg mass, ovary weight and more preovulatory follicles. The Docosahexaenoic Acid content of egg was extremely significantly elevated by flaxseed diets (P < 0.01), and the albumen height and haugh unit were elevated, especially in 4% Fla and/or 5% Fla group (P < 0.05). Groups 4% Fla and 5% Fla had highest ileal villus height, jejunal and ileal crypt depth. Moreover, Flaxseed diets significantly increased the levels of IgG and IgM in all Fla groups (P < 0.01), while increased IgA levels except for in 3% Fla group (P < 0.05). The results of 16s rDNA sequencing showed that flaxseed diet altered the microbial composition of gut and reduced the diversity and evenness of gut microbial communities except for 5% Fla. The correlation analysis identified Blautia, Butyricicoccus and Subdoligranulum positively associated with egg production. Genera Fourinierella, Fusobacterium and Intestinimonas positively associated with ovary weight, haught unit and album height. And Mucispirillum positively associated with haugh unit and album height.

CONCLUSION

This study has suggested that flaxseed play a positive role in productive performance, the overall or intestinal health of laying ducks.

Impact of flaxseed supplementation on lipid profile and liver enzymes in patients with non-alcoholic fatty liver disease: Systematic review and meta-analysis of randomized controlled trials

Since the effects of flaxseed supplementation on lipid profile and liver enzymes are still controversial, a meta-analysis of randomized controlled trials was conducted in the present study to assess the effect of flaxseed supplementation on lipid profile and liver enzymes. The study was designed, conducted, and reported according to the guidelines of the 2020 preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement. A systematic and comprehensive search was performed in several databases from inception up to January 10, 2024. The meta-analysis on the impact of flaxseed supplementation on lipid profile and liver enzymes indicates that the overall effect of flaxseed supplementation on triglycerides, combining different doses, revealed a significant reduction with a WMD of - 230.72 (-53.95, - 27.49) and a P-value of 0.010. High-density lipoprotein (HDL) demonstrated a positive effect, with an overall WMD of 1.82 (0.27, 3.38) and a P-value of 0.021, indicating an increase in HDL levels. The liver enzymes AST and ALT displayed reductions in their levels, with overall WMDs of - 21.18 (-2.95, 0.59) and - 24.83 (-8.74, - 20.91), respectively. Subgroup analysis based on dosage revealed more pronounced reductions in ALT levels for doses below 2000 mg/day. Findings from this study suggest that a flaxseed supplement might be beneficial to modulate the blood lipid profile and liver enzymes.

Effect of Crushed Flaxseed Consumption on Cardiovascular Risk Indicators in Menopausal Women

Flaxseed is known for its numerous health benefits and is often used in the prevention and treatment of civilizational diseases. This study aimed to evaluate the impact of consuming crushed flaxseed on cardiovascular risk in 51 menopausal women. The intervention lasted for 8 weeks, during which participants received a daily dose of 40 g of crushed flaxseed from two varieties with differing lignan contents. Participants were divided into three subgroups based on the variety of flaxseed consumed: (1) high-lignan group (HL), (2) low-lignan group (LL), and (3) control group (no flaxseed consumption). Biochemical blood parameters were measured using a BiOLis 24i Premium automatic analyzer. Body composition was assessed using an InBody 720 device. In the lipid profile, we observed a significant increase in total cholesterol (T-C) and high-density lipoprotein cholesterol (HDL-C) levels, along with a significant decrease in low-density lipoprotein cholesterol (LDL-C) levels in both the HL and LL groups. Triglyceride (TG) levels exhibited no significant change, whereas high-sensitivity C-reactive protein (hs-CRP) levels were significantly reduced in both the HL (p < 0.01) and LL (p < 0.01) groups. Visceral fat area (VFA) and percent body fat (PBF) showed a slight decreasing trend in the HL group, whereas in the LL group, VFA showed a slight increase. Body mass index (BMI) remained stable across all groups. These findings suggest that for the modulation of cardiovascular disease (CVD) risk factors, the daily dosage, duration of consumption, form of intake, and the specific variety of flaxseed (based on lignan content) are crucial factors.

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.

Nuts and seeds - a scoping review for Nordic Nutrition Recommendations 2023

Background

Nuts and seeds have been part of diets in most of the world for millenniums, and they have also been consumed in the Nordic and Baltic countries for centuries. Consumption of nuts and seeds is linked with various health outcomes. Therefore, when updating the Nordic Nutrition Recommendations (NNR), summarizing the best evidence on key health outcomes from the consumption of nuts and seeds is essential.

Objectives

This study aims to evaluate the updated evidence on the consumption of nuts and seeds and health outcomes regarded relevant for the Nordic and Baltic countries, as well as their dose-response relationship presented in updated systematic reviews and meta-analyses.

Method

The scoping review is built on a de novo systematic review and an umbrella review published in 2022 on the consumption of nuts and seeds and its various health outcomes, including cardiovascular disease and diabetes.

Results

Intake of nuts and seeds is associated with a lower risk of cardiovascular diseases, with evidence assessed as probable. This conclusion is mirrored by evidence from trials on biomarkers for chronic diseases. An intake of a serving of nuts of 28-30 g/day compared to not eating nuts is estimated to translate into approximately 20% relative reduction in the risks of cardiovascular disease and premature deaths. For cancers, consumption of a serving of nuts is inversely associated with cancer mortality. However, for type 2 diabetes, there are mixed and inconclusive results. Additionally, there are inverse associations between nut consumption and respiratory and infectious disease mortality. Allergies for nuts are seen among 1-2% of the population.

Conclusion

Overall, the current evidence supports dietary recommendations to increase nut consumption to a serving of nuts and seeds per day for people without allergies to these foods.

Flaxseed Reduces Cancer Risk by Altering Bioenergetic Pathways in Liver: Connecting SAM Biosynthesis to Cellular Energy

This article illustrates how dietary flaxseed can be used to reduce cancer risk, specifically by attenuating obesity, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). We utilize a targeted metabolomics dataset in combination with a reanalysis of past work to investigate the "metabo-bioenergetic" adaptations that occur in White Leghorn laying hens while consuming dietary flaxseed. Recently, we revealed how the anti-vitamin B6 effects of flaxseed augment one-carbon metabolism in a manner that accelerates S-adenosylmethionine (SAM) biosynthesis. Researchers recently showed that accelerated SAM biosynthesis activates the cell's master energy sensor, AMP-activated protein kinase (AMPK). Our paper provides evidence that flaxseed upregulates mitochondrial fatty acid oxidation and glycolysis in liver, concomitant with the attenuation of lipogenesis and polyamine biosynthesis. Defatted flaxseed likely functions as a metformin homologue by upregulating hepatic glucose uptake and pyruvate flux through the pyruvate dehydrogenase complex (PDC) in laying hens. In contrast, whole flaxseed appears to attenuate liver steatosis and body mass by modifying mitochondrial fatty acid oxidation and lipogenesis. Several acylcarnitine moieties indicate Randle cycle adaptations that protect mitochondria from metabolic overload when hens consume flaxseed. We also discuss a paradoxical finding whereby flaxseed induces the highest glycated hemoglobin percentage (HbA1c%) ever recorded in birds, and we suspect that hyperglycemia is not the cause. In conclusion, flaxseed modifies bioenergetic pathways to attenuate the risk of obesity, type 2 diabetes, and NAFLD, possibly downstream of SAM biosynthesis. These findings, if reproducible in humans, can be used to lower cancer risk within the general population.

Genetic dissection of thousand-seed weight in linseed (Linum usitatissimum L.) using multi-locus genome-wide association study

Flaxseed/linseed is an important oilseed crop having applications in the food, nutraceutical, and paint industry. Seed weight is one of the most crucial determinants of seed yield in linseed. Here, quantitative trait nucleotides (QTNs) associated with thousand-seed weight (TSW) have been identified using multi-locus genome-wide association study (ML-GWAS). Field evaluation was carried out in five environments in multi-year-location trials. SNP genotyping information of the AM panel of 131 accessions comprising 68,925 SNPs was employed for ML-GWAS. From the six ML-GWAS methods employed, five methods helped identify a total of 84 unique significant QTNs for TSW. QTNs identified in ≥ 2 methods/environments were designated as stable QTNs. Accordingly, 30 stable QTNs have been identified for TSW accounting up to 38.65% trait variation. Alleles with positive effect on trait were analyzed for 12 strong QTNs with r ² ≥ 10.00%, which showed significant association of specific alleles with higher trait value in three or more environments. A total of 23 candidate genes have been identified for TSW, which included B3 domain-containing transcription factor, SUMO-activating enzyme, protein SCARECROW, shaggy-related protein kinase/BIN2, ANTIAUXIN-RESISTANT 3, RING-type E3 ubiquitin transferase E4, auxin response factors, WRKY transcription factor, and CBS domain-containing protein. In silico expression analysis of candidate genes was performed to validate their possible role in different stages of seed development process. The results from this study provide significant insight and elevate our understanding on genetic architecture of TSW trait in linseed.

The effects of flaxseed or its oil supplementations on polycystic ovary syndrome: A systematic review of clinical trials

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders around the world that can endanger reproductive, metabolic, and psychological health in women. Flaxseed is considered as a functional food which provides remarkable amounts of α-linolenic acid (ALA), phytosterogenic lignans, and dietary fibers. This study aimed to investigate the effectiveness of flaxseed or its oil supplementation on PCOS patients. We systematically searched all published randomized clinical trials indexed in PubMed, Scopus, and Google Scholar databases from inception up to May 2022. Intended exposure and outcome were flaxseed or its oil and metabolic, anthropometric, and hormonal status of women with PCOS, respectively. Initial search via related keywords revealed 69 articles. After excluding duplicates, title and abstract of 55 remaining papers were screened. Fourteen papers were obtained for full text screening. Finally, nine clinical trials published between 2011 and 2021 were included in qualitative synthesis. Based on the results of the present systematic review, we suggest that flaxseed supplementation has the potential to improve metabolic, hormonal, and anthropometric parameters in women with PCOS. However, we also deduce that due to the scarcity of high-quality studies, additional studies need to be conducted in order to derive a solid conclusion.

Flaxseed supplementation significantly reduces hemoglobin A1c in patients with type 2 diabetes mellitus: A systematic review and meta-analysis

Flaxseed is a functional food because of its high content of alpha-linolenic acid, lignans, and dietary fiber. We hypothesized that flaxseed supplementation would improve cardiometabolic parameters in patients with type 2 diabetes mellitus (T2DM); however, clinical trials have shown conflicting results. Therefore, this systematic review and meta-analysis was conducted to determine the impact of flaxseed supplementation in patients with T2DM. Randomized controlled trials were systematically searched in PubMed, Web of Science, Scopus, Cochrane Library, and Embase until 25 March 2022. A total of 13 studies were included, and the results showed that flaxseed supplementation significantly reduced hemoglobin A1c (HbA1c) in participants with T2DM compared with the control group. In contrast, it had no effects on body weight, body mass index, blood pressure, fasting blood glucose (FBG), homeostatic model assessment for insulin resistance, quantitative insulin sensitivity check index, and lipid parameters. In the subgroup analyses, FBG was significantly reduced with supplementation of flaxseed in participants with baseline FBG ≥8.0 mmol/L or baseline HbA1c ≥7.0%. And a significant decrease in HbA1c in participants with baseline HbA1c ≥7.0% after flaxseed supplementation. In addition, subgroup analyses indicated that whole flaxseed supplementation significantly increased high-density lipoprotein cholesterol and reduced total cholesterol or low-density lipoprotein cholesterol in participants with T2DM. In conclusion, flaxseed supplementation significantly reduced HbA1c in participants with T2DM, especially those with poorly controlled blood sugar levels. However, larger scale studies with better designs are needed to confirm insignificant and/or ambiguous findings.

Consumption of Nuts and Seeds and Health Outcomes Including Cardiovascular Disease, Diabetes and Metabolic Disease, Cancer, and Mortality: An Umbrella Review

Consumption of nuts and seeds is associated with a range of health outcomes. Summarizing the best evidence on essential health outcomes from the consumption of nuts is essential to provide optimal recommendations. Our objective is to comprehensively assess health outcome associations related to the consumption of nuts and seeds, using a culinary definition including tree nuts and peanuts (registered in PROSPERO: CRD42021258300). Health outcomes of interest include cardiovascular disease, cancer, diabetes, obesity, respiratory disease, mortality, and their disease biomarkers. We present associations for high compared with low consumption, per serving, and dose-response relations. MEDLINE, Embase, Cochrane, and Epistemonikos were searched and screened for systematic reviews and meta-analyses. Evidence was extracted from 89 articles on the consumption of nuts and relevant health outcomes, including 23 articles with meta-analysis on disease and mortality, 66 articles on biomarkers for disease, and 9 articles on allergy/adverse outcomes. Intake of nuts was associated with reduced risk of cardiovascular diseases and related risk factors, with moderate quality of evidence. An intake of 28 g/d nuts compared with not eating nuts was associated with a 21% RR reduction of cardiovascular disease (including coronary heart disease incidence and mortality, atrial fibrillation, and stroke mortality), an 11% risk reduction of cancer deaths, and 22% reduction in all-cause mortality. Nut consumption was also inversely associated with mortality from respiratory diseases, infectious diseases, and diabetes; however, associations between nut consumption and diabetes incidence were mixed. Meta-analyses of trials on biomarkers for disease generally mirrored meta-analyses from observational studies on cardiovascular disease, cancers, and diabetes. Allergy and related adverse reactions to nuts were observed in 1-2% of adult populations, with substantial heterogeneity between studies. Overall, the current evidence supports dietary recommendations to consume a handful of nuts and seeds per day for people without allergies to these foods.

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.

Human body weight, nutrients, and foods: a scoping review

Background

The aim of this article (scoping review) is to elucidate the current knowledge for the potential role of body weight for setting and updating Dietary Reference Values (DRVs) and Food-Based Dietary Guidelines (FBDGs). The following research questions were formulated:What is known about the association between intakes of specific nutrient and/or foods (exposure/intervention) and body weight (outcome) in the general population?What is known about the association between body weight (exposure) and intakes of specific nutrient and/or foods (outcomes)?Is there any evidence suggesting specific effects of foods or nutrients on body weight independent of caloric content?

Methods

To identify potentially relevant articles, PubMed was searched from January 1, 2011 to June 9, 2021. The search strategy was drafted by the NNR2022 Committee. The final results were exported into EndNote. Systematic reviews (SRs), scoping reviews (ScRs), reviews, and meta-analyses (MAs) on the topic 'Body weight' published between January 1, 2011 and June 9, 2021, including human participants from the general population, in English or Scandinavian language (Norwegian, Swedish, or Danish), were considered eligible.

Main findings

First, the overall body of evidence based on findings from SRs and MAs of observational and clinical studies indicates that changes in intakes of specific nutrients (sugar, fiber, and fat) and/or foods (sugar sweetened beverages, fiber rich food, and vegetables) are associated with modest or small short-term changes (0.3-1.3 kg) in body weight in the general population (with or without obesity/overweight), while long-term studies are generally lacking. Second, no study in our search assessed any association between body weight (exposure) and intakes of specific nutrients or foods (outcomes). Third, limited evidence suggests, but does not prove, that some foods or nutrients may have specific effects on body weight or body weight measures independent of caloric content (e.g. nuts and dairy). These findings may inform the setting and updating of DRVs and FBDGs in NNR2022.

Changes in (poly)phenols intake and metabolic syndrome risk over ten years from adolescence to adulthood

BACKGROUND AND AIMS

(Poly)phenols might contribute to prevent cardiovascular disease, but limited prospective studies exist among adolescents. This study aimed to evaluate within-subject longitudinal changes in (poly)phenols intakes and food group contributors while also exploring the association with metabolic syndrome risk (MetS) during 10 years of follow up in European adolescents becoming young adults.

METHODS AND RESULTS

In 164 participants (58% girls, 13-18 y at baseline) from Ghent, Zaragoza and Lille, longitudinal data (2006-2016) on (poly)phenol intake was retrieved via 2 or 3 24 h recalls. Linear and logistic longitudinal regression tested the association of (poly)phenols intake (total and classes) with Mets risk or its components (waist-height-ratio, HDL cholesterol, LDL cholesterol, triglycerides, blood pressure and insulin resistance index), adjusted for age, sex, country and other nutrient intakes. The total (poly)phenols intake was 421 ± 107 mg/day (192 mg/1000 kcal/day) at baseline, while 610 ± 101 mg/day (311 mg/1000 kcal/day) at follow-up. The three major food sources for (poly)phenols were 'chocolate', 'fruit and vegetable juices', 'cakes and biscuits' during adolescence and 'coffee', 'tea' and 'chocolate' during adulthood. Phenolic acid intake was associated with less LDL increase over time, while stilbene intake with a steeper increase in triglycerides over time.

CONCLUSIONS

Differences in major (poly)phenols contributors over time were partially explained by age-specific dietary changes like increased coffee and tea during adulthood. Some significant (poly)phenols-MetS associations might argue for nutrition-based disease prevention during adolescence, especially since adolescents had low (poly)phenols intake.

The effect of flaxseed oil consumtion on blood pressure among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized clinical trials

We systematically reviewed randomized clinical trials (RCTs) to elucidate the overall effects of flaxseed oil consumption on blood pressure (BP) in patients with metabolic syndrome and related disorders. PubMed, Scopus, Cochrane Library, and ISI Web of Science databases were systematically searched until March 31, 2020, to find RCTs that examined the effect of flaxseed oil consumption on BP. Weighed mean difference (WMD) was pooled using a random-effects model. Standard methods were used for the assessment of heterogeneity, sensitivity analysis, and publication bias. Meta-analysis of five trials (6 arms) showed significant reductions in systolic (WMD: -3.86 mmHg, 95% CI: -7.59 to -0.13, p = .04) BP (SBP) after flaxseed oil consumption. However, the overall effect illustrated no significant change in diastolic (WMD: -1.71 mmHg, 95% CI: -3.67 to 0.26, p = .09) BP (DBP) in the intervention group compared with the control group. Our findings revealed that flaxseed oil consumption has favorable effects on SBP in patients with metabolic syndrome and related disorders. However, further investigations are needed to provide more reliable evidence.

Effect of flaxseed (Linum usitatissimum) supplementation on glycemic control and insulin resistance in prediabetes and type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Prediabetes and type 2 Diabetes Mellitus (T2DM) are characterized by increased blood sugar concentration and insulin resistance. Although there are only a few reports of potential benefits of flaxseed's consumption on different metabolic parameters, there is no evidence of its effect among people with these conditions.

OBJECTIVES

The present systematic review and meta-analysis aimed to assess the effect of flaxseed supplementation on glycemic control variables and insulin resistance in prediabetes and T2DM.

METHODS

A literature search was conducted through PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science, to identify Randomized Control Trials (RCTs) that evaluated the effect of milled or ground flaxseed supplementation on fasting blood glucose, HbA1c, insulin concentrations, or HOMA-IR. The data were analyzed using Comprehensive Meta-Analysis (CMA) software version 3.3 in a fixed-effect model.

RESULTS

Seven studies were included in the systematic review and the meta-analysis, the results showed a significant reduction on fasting blood sugar (SMD: -0.392, 95% CI: -0.596, -0.187, p = <0.001, I² = 64.81%) insulin concentrations, (SMD: -0.287, 95% CI: -0.534, -0.041, p = 0.022, I² = 32.53%), HbA1c (SMD: -0.442, 95% CI: -0.770, -0.114, p = 0.008, I² = 11.058%), and HOMA-IR (SMD: -0.284, 95% CI: -0.530, -0.038, p = 0.024, I² = 0.00%) after flaxseed supplementation.

CONCLUSIONS

Flaxseed supplementation seems to improve glycemic control variables and insulin resistance in prediabetes and T2DM; however, more RCTs are needed to have more decisive evidence about doses, method of supplementation, and the possible effect of synergy with the dietetic treatment.

The Effect of Flaxseed Oil Supplementation on Body Composition and Inflammation Indices in Overweight Adults With Pre-Diabetes

Background:

Flaxseed has rich content of alpha linolenic acid for preventing pro inflammatory process. The aim of present study is exploring the effect of flaxseed oil supplementation on inflammatory biomarkers and body composition in overweight adults with pre-diabetes.

Material and methods:

this double-blind randomized clinical trial conducted with 80 overweight pre-diabetic patients in 2 clusters (flaxseed oil group (2000-mg daily) and control group) across a 14-week period. Anthropometric indices, body composition and inflammatory indices were measured between 2 groups before and after the treatment.

Result:

this study found a significant decrease in visceral fat level in the intervention group (P = .009) and control group (P = .004) at the end of the survey. However, the mean change of it (P = .06) was not significant. Also, this study showed that percentage of body fat (P = .31) and its mean change (P = .6) did not have significantly different between the 2 groups at the 14th week. The skeletal muscle% had a significant rise in the intervention group (P = .005) and control group (P = .003) by the end of 14th week. However, the mean change of it (P = .19) was not significant between the 2 groups. In addition, there was no significant change in the fasting blood glucose (P = . 7), C reactive protein (P = .12) and TNF-α (P = .22) between the 2 groups at the end of study.

Conclusion:

It showed that flaxseed oil supplementation cannot improve body composition and inflammation.

Efficacy of omega-3-rich Camelina sativa on the metabolic and clinical markers in nonalcoholic fatty liver disease: a randomized, controlled trial

OBJECTIVE

Recently, omega-3 fatty acids and antioxidants co-supplementation was considered as alternative treatment in the management of nonalcoholic fatty liver disease (NAFLD). This trial evaluated effects of Camelina sativa oil (CSO) as a rich source of omega-3 fatty acids and antioxidants on anthropometric indices, lipid profile, liver enzymes, and adiponectin in NAFLD patients.

PARTICIPANTS AND METHODS

This triple-blind, placebo-controlled, randomized clinical trial was conducted on 46 NAFLD patients who were randomly assigned to either a CSO supplement or placebo for 12 weeks. Both groups received a loss weight diet. Levels of liver enzymes, adiponectin, lipid profile, atherogenic index, and anthropometric indices were assessed for all patients at baseline and post-intervention.

RESULTS

CSO caused significant differences in weight, BMI, waist circumference, waist-to-hip ratio, triglyceride, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), TC/HDL-c, LDL-c/HDL-c, atherogenic index, alanine aminotransferase, and adiponectin concentrations in the CSO group compared with the placebo group (P < 0.046 for all). No significant differences were found in hip circumference, neck circumference, HDL-c, and other liver enzymes in the CSO group compared with the placebo group (P = 0.790, P = 0.091, P = 0.149, P < 0.159 for liver enzymes, respectively).

DISCUSSION AND CONCLUSION

This study showed that CSO supplementation for 12 weeks causes significant changes in all of anthropometric indices (except hip circumference and neck circumference), ALT, lipid profile (except HDL-c), atherogenic index, and adiponectin in NAFLD patients.

Flaxseed Mucilage (IQP-LU-104) Reduces Body Weight in Overweight and Moderately Obese Individuals in a 12-week, Three-Arm, Double-Blind, Randomized, and Placebo-Controlled Clinical Study

INTRODUCTION

The aim of this study was to evaluate the benefit and tolerability of two dosages of a proprietary flaxseed mucilage (IQP-LU-104) in reducing body weight in overweight and moderately obese individuals.

METHODS

In a double-blind, randomized, placebo-controlled, bi-center trial, 108 participants (body mass index [BMI] 25-<35 kg/m2) were randomly allocated to receive either IQP-LU-104 high dose (104HD), IQP-LU-104 low dose (104LD), or placebo. Participants were instructed to consume 1 sachet of the investigational product (containing IQP-LU-104 or matching placebo) before or with main meals twice daily and to follow a balanced but hypocaloric diet (20% reduction of individual's daily energy requirements) for 12 weeks. At week 0 (baseline), and weeks 4, 8, and 12 of the intervention periods, the participants' body weight, BMI, body fat composition, and waist and hip circumferences were measured. Blood samples were collected for safety assessment at screening visit (week -2) and at the end of the study. Adverse events were assessed by the investigators through interviewing the participants and were recorded at every visit post screening.

RESULTS

At the end of the 12-week study, body weight reduction was greater in the 104HD group (4.96 ± 1.89 kg, p < 0.001 vs. placebo) and 104LD group (3.70 ± 2.57 kg, p < 0.001 vs. placebo) compared to the placebo group (1.33 ± 2.05 kg). 68% and 46% of participants in the 104HD group (p < 0.001 vs. placebo) and 104LD group (p = 0.002 vs. placebo), respectively, experienced at least 5% weight loss, compared to 9% of participants in the placebo group. Significant decreases in waist and hip circumferences were observed in both the 104HD and 104LD groups compared to the placebo group (each p < 0.001). 104HD group had significantly higher reduction in body fat mass (4.25 ± 5.86 kg) than the placebo group (1.06 ± 3.20 kg) (p = 0.002). Respiratory tract infections and gastrointestinal symptoms were the main adverse events reported and none of the adverse events were related to the intake of IQP-LU-104.

CONCLUSION

Results demonstrated IQP-LU-104 is safe and efficacious in body weight reduction at both dosages in overweight and moderately obese individuals.

Effects of sesame, canola and sesame-canola oils on body weight and composition in adults with type 2 diabetes mellitus: a randomized, triple-blind, cross-over clinical trial

BACKGROUND

Recent investigations have proposed that sesame and canola oils might affect body fat distribution. The present study aimed to examine the effects of sesame, canola and sesame-canola (a blend of sesame and canola oils) oils on body weight and composition in adults with type 2 diabetes mellitus in the context of a randomized, triple-blind, three-way, cross-over clinical trial.

RESULTS

Eligible participants were randomized to replace their regular dietary oil with sesame oil (SO), canola oil (CO) and sesame-canola oil (SCO) (with 40% SO and 60% CO). Treatment periods lasted 9 weeks and were separated by 4-week wash-out periods. Body weight and composition were measured at the beginning, in the middle and at the end of each intervention phase. In total, 93 participants completed the study. After adjustment for confounders, within-period changes were observed following SO and CO intake for body weight (0.34 ± 0.16 kg and 0.33 ± 0.17 kg) and visceral fat (0.13 ± 0.06% and 0.13 ± 0.05%, P < 0.05), respectively. Body mass index was increased within SO intake (0.13 ± 0.05 kg m^-2 , P = 0.031). All of the treatment oils resulted in reduced waist circumference and index of central obesity (P < 0.05). A significant difference in change values was observed for visceral fat between SCO (-0.14 ± 0.07%) and SO (0.12 ± 0.08%) treatment periods in females (P = 0.02).

CONCLUSION

Sesame and canola oils might lead to a modest favorable body fat redistribution by reducing central adiposity, particularly in females; however, the changes were of little clinical importance. © 2021 Society of Chemical Industry.

Flaxseed Increases Animal Lifespan and Reduces Ovarian Cancer Severity by Toxically Augmenting One-Carbon Metabolism

We used an LC-MS/MS metabolomics approach to investigate one-carbon metabolism in the plasma of flaxseed-fed White Leghorn laying hens (aged 3.5 years). In our study, dietary flaxseed (via the activity of a vitamin B6 antagonist known as "1-amino d-proline") induced at least 15-fold elevated plasma cystathionine. Surprisingly, plasma homocysteine (Hcy) was stable in flaxseed-fed hens despite such highly elevated cystathionine. To explain stable Hcy, our data suggest accelerated Hcy remethylation via BHMT and MS-B12. Also supporting accelerated Hcy remethylation, we observed elevated S-adenosylmethionine (SAM), an elevated SAM:SAH ratio, and elevated methylthioadenosine (MTA), in flaxseed-fed hens. These results suggest that flaxseed increases SAM biosynthesis and possibly increases polyamine biosynthesis. The following endpoint phenotypes were observed in hens consuming flaxseed: decreased physiological aging, increased empirical lifespan, 9-14% reduced body mass, and improved liver function. Overall, we suggest that flaxseed can protect women from ovarian tumor metastasis by decreasing omental adiposity. We also propose that flaxseed protects cancer patients from cancer-associated cachexia by enhancing liver function.

Dietary flaxseed reduces Myocardial Ischemic Lesions, improves cardiac function and lowers cholesterol levels despite the presence of severe obesity in JCR:LA-cp Rats

Previous work has shown that dietary flaxseed can significantly reduce cardiac damage from a coronary artery ligation-induced myocardial infarction. However, this model uses healthy animals and the ligation creates the infarct in an artificial manner. The purpose of this study was to determine if dietary flaxseed can protect the hearts of JCR:LA-cp rats, a model of genetic obesity and metabolic syndrome, from naturally occurring myocardial ischemic lesions. Male and female obese rats were randomized into four groups (n = 8 each) to receive, for 12 weeks, either a) control diet (Con), b) control diet supplemented with 10% ground flaxseed (CFlax), c) a high-fat, high sucrose (HFHS) diet, or d) HFHS supplemented with 10% ground flaxseed (HFlax). Male and female JCR:LA-cp lean rats served as genetic controls and received similar dietary interventions. In male obese rats, serum total cholesterol and LDL-C were significantly lower in CFlax compared to Con.  Obese rats on HFHS exhibited increased myocardial ischemic lesions and diastolic dysfunction regardless of sex. HFlax significantly lowered the frequency of cardiac lesions and improved diastolic function in male and female obese rats compared to HFHS. Blood pressures were similar in obese and lean rats. No aortic atherosclerotic lesions were detectable in any group. Collectively, this study shows that a HFHS diet increased myocardial ischemic lesion frequency and abolished the protective effect of female sex on cardiac function. More importantly, the data demonstrates dietary flaxseed protected against the development of small spontaneous cardiac infarcts despite the ingestion of a HFHS diet and the presence of morbid obesity.

Co-supplementation of camelina oil and a prebiotic is more effective for in improving cardiometabolic risk factors and mental health in patients with NAFLD: a randomized clinical trial

This trial evaluated the effects of co-supplementing Camelina sativa oil (CSO) and a prebiotic as modulators of the gut microbiota on cardiometabolic risk factors and mental health in NAFLD patients. In all, 44 subjects with NAFLD were allocated to either an intervention (20 g d-1 CSO + resistant dextrin) or a placebo (20 g d-1 CSO + maltodextrin) group and received a calorie-restricted diet (-500 kcal d-1) for 12 weeks. Fasting plasma levels of gucose, insulin, hs-CRP, endotoxin, antioxidant enzyme activity, total antioxidant capacity (TAC), malondialdehyde (MDA), 8-iso-prostaglandin F2α, and uric acid were measured at the baseline and post-intervention. The depression, anxiety and stress scale (DASS) and the general health questionnaire (GHQ) were used to assess mental health. Co-supplementing CSO and resistant dextrin significantly decreased the level of insulin concentration (-0.84 μU ml-1, p = 0.011), HOMA-IR (-0.27, p = 0.021), hs-CRP (-1.25 pg ml-1, p = 0.023), endotoxin (-3.70 EU mL-1, p = 0.001), cortisol (-2.43, p = 0.033), GHQ (-5.03, p = 0.035), DASS (-9.01, p = 0.024), and MDA (-0.54 nmol mL-1, p = 0.021) and increased the levels of TAC (0.16 mmol L-1, p = 0.032) and superoxide dismutase (106.32 U g-1 Hb, p = 0.45) in the intervention group compared with the placebo group. No significant changes were observed in the levels of other biomarkers. Co-supplementing CSO and resistant dextrin in combination with a low-calorie diet may improve metabolic risk factors and mental health in NAFLD patients.

Effects of flaxseed on blood pressure, body mass index, and total cholesterol in hypertensive patients: A randomized clinical trial

OBJECTIVES

Given the antioxidant properties of flaxseed and its biologically active ingredients, this study was conducted to determine the effects of flaxseed supplementation on body mass index (BMI), blood pressure, and total cholesterol levels in patients with hypertension.

METHODS

In this triple-blind clinical trial, 112 patients, with an age range of 35 to 70 years, were randomized to 2 groups receiving 10 g (n = 45) and 30 g (n = 45) of flaxseed supplementation and 1 group receiving placebo (n = 45) for 12 weeks by stratified block randomization. They were evaluated in terms of systolic (SBP) and diastolic blood pressure (DBP), BMI, and total serum cholesterol. Physical activity was measured using the International Physical Activity Questionnaire-Short Form (IPAQ-SF) and food intake was assessed using the Food Frequency Questionnaire (FFQ). The data were analyzed with SPSS, version 22, using the chi-square, Kruskal-Wallis, repeated measures analysis, ANOVA, and ANCOVA tests.

RESULTS

The interaction effects among the study groups and time on the mean SBP (p = 0.001), DBP (p = 0.001), total cholesterol level (p = 0.032), and BMI (p < 0.001) were significant. During the study, the 30-g group achieved the best results, so that a 13.38-unit decrease in SBP was observed compared to a 1.72 unit increase in the placebo group and a 5.6-unit decrease in DBP was measured compared to a 2.39 unit increase in the placebo group. BMI decreased by 0.86 units compared to 0.06 units in the placebo group. Total cholesterol also decreased by 20.4 units compared to 11.86 units in the placebo group.

CONCLUSION

The results of this study showed that flaxseed can be effective in reducing blood pressure, total cholesterol, and body mass index in hypertensive patients in a twelve-week period.

Combination therapy of flaxseed and hesperidin enhances the effectiveness of lifestyle modification in cardiovascular risk control in prediabetes: a randomized controlled trial

BACKGROUND

Regarding the increasing prevalence of cardiometabolic abnormalities, and its association with non-communicable chronic diseases, providing preventive and therapeutic strategies is a priority. A randomized placebo-controlled study was conducted to assess the effects of combination therapy of milled brown flaxseed and hesperidin during lifestyle intervention on controlling cardiovascular risk in prediabetes.

METHODS

A total of forty-eight subjects were randomly assigned to receive lifestyle intervention plus combination therapy of brown flaxseed (30 g milled) and hesperidin (two 500 mg capsules) or lifestyle modification alone for 12 weeks. Changes from baseline in anthropometric measures, lipid profile and atherogenic indices, glucose homeostasis parameters, and inflammatory biomarkers was assessed as a primary end point.

RESULTS

Anthropometric data comparison between the two groups showed a significant reduction in weight (p = 0.048). Waist circumference reduction was about twice that of the control group (- 6.75 cm vs - 3.57 cm), but this difference was not statistically significant. Comparison of blood pressure changes throughout the study indicated a greater reduction in blood pressure in the intervention group rather than control group (- 5.66 vs. - 1.56 mmHg, P = 0.049). Improvements of lipid profile and atherogenic indices, glucose homeostasis parameters, and inflammatory biomarkers in flaxseed-hesperidin group was significantly more than the control group after 12 weeks of intervention (p < 0.05).

CONCLUSION

Our results indicate that co-administration of flaxseed and hesperidin as an adjunct to lifestyle modification program is more effective than lifestyle modification alone in the metabolic abnormalities remission of prediabetic patients.

TRIAL REGISTRATION

 The trial was registered with ClinicalTrials.gov, number NCT03737422. Registered 11 November 2018. Retrospectively registered, https://clinicaltrials.gov/ct2/results?cond=&term=NCT03737422&cntry=&state=&city=&dist= .

The efficacy of flaxseed and hesperidin on non-alcoholic fatty liver disease: an open-labeled randomized controlled trial

BACKGROUND/OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is growing in prevalence globally and no definitive evidence for any approved pharmacological approaches for patients with NAFLD has been found yet. This study was aimed to assess the clinical effects of flaxseed and hesperidin in patients with NAFLD.

SUBJECTS/METHODS

In this randomized, controlled, clinical trial, one hundred eligible patients with NAFLD were enrolled and randomly assigned to four dietary intervention groups including lifestyle modification program (control), lifestyle modification program with 30 g whole flaxseed powder, lifestyle modification program with 1 g hesperidin supplementation, and lifestyle modification program with combination of 30 g flaxseed and 1 g hesperidin (flax-hes) for 12 weeks. The changes in anthropometric parameters, metabolic profiles of glucose and lipids, inflammatory biomarkers and hepatic steatosis and fibrosis were evaluated.

RESULTS

After the 12-week dietary interventions, significant reductions in body mass index, glucose hemostasis parameters and hepatic steatosis were observed in all groups. Repeated measures analysis of variance revealed a significant effect for time relative to almost all paraclinical parameters. Post hoc analysis with Bonferroni correction revealed that the three intervention groups experienced significant decreases in plasma levels of alanine aminotransferase, indices of insulin resistance and insulin sensitivity, fasting glucose and fatty liver index compared to control (p < 0.008).

CONCLUSIONS

In conclusion, our study confirmed that hesperidin and flaxseed supplementation improved glucose and lipid metabolism, while reduced inflammation and hepatic steatosis (controlled attenuation parameter) in NAFLD patients. The synergistic effects of their combination were observed on plasma glucose concentration and HOMA-IR.

Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review

The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.

Protective Effect of Flaxseed on the Health of Experimental Animals Exposed to Xylene

Xylene is mainly used as a solvent in the printing, tire and leather industries. It is also used as: a facility cleaner, paint and varnish thinner, component of fuel, and chemical for the laboratory processing of histological preparations. For these reasons people are frequently exposed to xylene and the risk of intoxication is high. This study focused on the protective effect of flaxseed on mice experimentally intoxicated with xylene. The experiment lasted 14 days. The mice used in this study (n = 60) were allocated to 3 groups: the control group (C) received only the standard diet; the xylene group (X) was fed a standard diet and was administered xylene p. o. (10 µl daily); and the xylene + flaxseed group (XF) received the standard feed, crushed flaxseed and xylene at the same dose as group X. The observations involved changes in: body weight, liver enzyme levels, and caspase activity in the liver of the mice. The administration of additives resulted in significant changes in the body weight of the mice on day 7 of the experiment (P < 0.05). The highest weight gain was observed in mice from the XF group. In contrast, the body weight of the mice from group X exposed only to xylene was the lowest. The biochemical analysis of the liver cells of the xylene intoxicated mice showed elevated levels of: aspartate aminotransferase (AST), De Ritis ratio (AST/ALT ratio), and lactate dehydrogenase isoenzymes LDH-3 and LDH-5. Caspase-3, the marker of apoptosis, was increased in the XF group. Thus, the administration of flaxseed in our experiment had a beneficial effect on the clinical and metabolic parameters of mice intoxicated with xylene. Our results indicated that the administration of flaxseed, may act as a preventative measure with respect to xylene intoxication of animals; however, further analyses are needed to confirm this assumption.

Flaxseed oil in the context of a weight loss programme ameliorates fatty liver grade in patients with non-alcoholic fatty liver disease: a randomised double-blind controlled trial

Long-chain n-3 fatty acids have been shown to regulate lipid metabolism and reduce fat accumulation in the liver. This trial investigated the effect of flaxseed oil, as a rich source of α-linolenic acid, on fatty liver and cardiometabolic risk factors in patients with non-alcoholic fatty liver disease (NAFLD). The randomised, double-blind, controlled trial was performed on sixty-eight NAFLD patients who were divided into flaxseed (n 34) and sunflower (n 34) oil groups. Patients were given a hypoenergetic diet (−2092 kJ/d) and 20 g/d of the corresponding oil for 12 weeks. Fatty liver grade, liver enzymes and cardiometabolic parameters were determined. The intention-to-treat approach was used for data analysis. Fatty liver grade significantly decreased in both groups (−0·68 in flaxseed v. −0·29 in sunflower, P = 0·002). Alanine aminotransferase and aspartate aminotransferase decreased in both groups (P < 0·01). Also, significant reduction was observed in blood glucose (P = 0·005) and fat mass (P = 0·01) in the flaxseed and muscle mass (P = 0·01) in the sunflower group. However, none of these alterations was significantly different between the groups. Weight, waist circumference and blood pressure were significantly decreased in both groups but only weight change was significantly different between the groups (P = 0·01). IL-6 did not significantly change in either group but showed a significant between-group difference (P = 0·03). Overall, the results showed that in the context of a low-energy diet and moderate physical activity, flaxseed oil may benefit NAFLD patients to improve fatty liver grade, weight and IL-6 compared with sunflower oil.

The effects of flaxseed supplementation on metabolic status in women with polycystic ovary syndrome: a randomized open-labeled controlled clinical trial

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is known as the most common endocrine disorder of women in reproductive ages. With the increasing prevalence of PCOS in different countries, the use of herbal medicine as an alternative treatment is growing in these patients. This study aimed to evaluate the effects of flaxseed powder supplementation on metabolic biomarkers of patients with PCOS.

METHODS

This randomized open-labeled controlled clinical trial was conducted on 41 patients with PCOS. The participants were randomized to take either flaxseed powder (30 g/day) plus lifestyle modification or only lifestyle modification for 12 weeks. Anthropometric and biochemical evaluations were performed for all patients at the beginning and end of the study.

RESULTS

The flaxseed group showed a significant reduction in body weight, insulin concentration, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), Triglycerides (TG), high-sensitivity C-Reactive Protein (hs-CRP), and leptin and an increase in Quantitative Insulin-Sensitivity Check Index (QUICKI), High Density Lipoprotein (HDL), and adiponectin compared to the baseline (p < 0.05). Flaxseed supplementation also led to a significant reduction in insulin concentration, HOMA-IR, TG, hs-CRP, Interleukin 6 (IL- 6), and leptin and an increase in QUICKI, HDL, and adiponectin compared to the control group (p < 0.05). No significant changes were observed in other parameters.

CONCLUSIONS

Flaxseed supplementation plus lifestyle modification was more effective compared to lifestyle modification alone in biochemical and anthropometric variables in patients with PCOS.

TRIAL REGISTRATION

The trial protocol was approved by the Ethics Board at Ahvaz Jundishapur University of Medical Sciences and was registered at Iranian Registry of Clinical Trials (code: IRCT20120704010181N11).

Seeds

A wide variety of plant species provide edible seeds. Seeds are the dominant source of human calories and protein. The most important and popular seed food sources are cereals, followed by legumes and nuts. Their nutritional content of fiber, protein, and monounsaturated/polyunsaturated fats make them extremely nutritious. They are important additions to our daily food consumption. When consumed as part of a healthy diet, seeds can help reduce blood sugar, cholesterol, and blood pressure.

The Effect of Flaxseed Enriched Yogurt on the Glycemic Status and Cardiovascular Risk Factors in Patients with Type 2 Diabetes Mellitus: Randomized, Open-labeled, Controlled Study

Flaxseed is one of the rich sources of α-linolenic acid and lignan. Flaxseed and its components have antioxidant, hypolipidemic and hypoglycemic effects. The study aimed to investigate the effect of flaxseed enriched yogurt on glycemic control, lipid profiles and blood pressure in patients with type 2 diabetes. A randomized, open-labeled, controlled clinical trial was conducted on 57 patients with type 2 diabetes. Participants were assigned to receive 200 g 2.5% fat yogurt containing 30-g flaxseed or plain yogurt daily for 8 weeks. Anthropometrics and biochemical parameters were evaluated at the beginning and end of the study. After 8 weeks of supplementation, Hemoglobin A1c was significantly decreased in the intervention group compared to control (p = 0.007). Also, at the end of the study, significant differences were seen between the flaxseed enriched yogurt and control groups in triglycerides and total cholesterol concentrations (p = 0.04 and p = 0.01), systolic blood pressure and diastolic blood pressure (p = 0.02 and p = 0.002, respectively). However, we did not find any difference between 2 groups in low-density lipoprotein, high-density lipoprotein, body weight and waist circumference (p > 0.05). Our results showed that the addition of flaxseed to yogurt can be effective in the management of type 2 diabetes.

Trial Registration

ClinicalTrials.gov Identifier: NCT02436369.

Linseed Components Are More Effective Than Whole Linseed in Reversing Diet-Induced Metabolic Syndrome in Rats

Linseed is a dietary source of plant-based ω–3 fatty acids along with fiber as well as lignans including secoisolariciresinol diglucoside (SDG). We investigated the reversal of signs of metabolic syndrome following addition of whole linseed (5%), defatted linseed (3%), or SDG (0.03%) to either a high-carbohydrate, high-fat or corn starch diet for rats for the final eight weeks of a 16–week protocol. All interventions reduced plasma insulin, systolic blood pressure, inflammatory cell infiltration in heart, ventricular collagen deposition, and diastolic stiffness but had no effect on plasma total cholesterol, nonesterified fatty acids, or triglycerides. Whole linseed did not change the body weight or abdominal fat in obese rats while SDG and defatted linseed decreased abdominal fat and defatted linseed increased lean mass. Defatted linseed and SDG, but not whole linseed, improved heart and liver structure, decreased fat vacuoles in liver, and decreased plasma leptin concentrations. These results show that the individual components of linseed produce greater potential therapeutic responses in rats with metabolic syndrome than whole linseed. We suggest that the reduced responses indicate reduced oral bioavailability of the whole seeds compared to the components.

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.

The effects of chitosan supplementation on body weight and body composition: a systematic review and meta-analysis of randomized controlled trials

Although several clinical trials studied the efficacy of chitosan on weight loss, controversial results have been found. Herein, we evaluated randomized controlled trials (RCTs) of chitosan consumption in adult participants on body weight and body composition through a meta-analysis with trial sequential analysis (TSA). We searched EMBASE, MEDLINE, Web of Science, and CENTRAL databases. The primary body composition indices including body weight, body mass index (BMI), waist circumference, body fat, and hip circumference were extracted. The quality of included articles was assessed according to the Cochrane risk of bias tool. Data were pooled using the random-effects models and calculated as weighted mean difference (WMD) with 95% confidence intervals (CI). Heterogeneity investigated using I² statistics. TSA, subgroup analyses, sensitivity analysis, meta-regression and publication bias were also evaluated. Overall, 15 eligible trials (18 treatment arms) with 1130 subjects were included. The pooled analyses revealed a significant reduction in body weight (WMD, -0.89 kg; 95% CI, -1.41 to -0.38; P = 0.0006), BMI (WMD, -0.39 kg/m²; 95% CI, -0.64 to -0.14; P = 0.002) and body fat (WMD, -0.69%; 95% CI, -1.02 to -0.35; P = 0.0001) receiving chitosan supplementation. Subgroup analyses also showed that consuming chitosan in dose (>2.4 g/d), shorter-term (<12 weeks), studies with parallel design and studies including participants with obese or overweight had positive effects on body composition. TSA provided conclusive evidence for the benefit of chitosan supplementation. Our findings provided evidence that chitosan consumption might be a useful adjunctive pharmacological therapeutic tool for body weight management particularly in overweight/obese participants. Further well-constructed clinical trials that target body weight and body composition as their primary outcomes are needed.

Does pomegranate consumption affect weight and body composition? A systematic review and meta-analysis of randomized controlled clinical trials

Pomegranate is rich in tannins, polyphenols, flavonoids, and several other types of antioxidant compounds whose role in weight loss has been shown in previous studies. However, the results have been mixed regarding the effects of pomegranate consumption on weight loss. Electronic databases such as PubMed, Scopus, ISI Web of Science, and Google Scholar were systematically searched up to May 2018 for controlled clinical trials assessing the effect of pomegranate consumption on weight loss. A random effects model was used to calculate the weighted mean difference (WMD) and 95% confidence interval (CI) as the difference between the mean for the intervention and control groups. Thirteen randomized controlled trials (including 513 participants) were included in the present meta-analysis. Compared with the control groups, there was no significant reduction in bodyweight, body mass index, waist circumference, and body fat percentage after pomegranate consumption (WMD = -0.23 kg, 95% CI: -0.94, 0.47, P = 0.515; WMD = -0.12 kg/m² , 95% CI: -0.29, 0.03, P = 0.132; WMD = -0.08 cm, 95% CI: -0.33, 0.17, P = 0.534; WMD = -0.05, 95% CI: -1.66, 1.55, P = 0.947, respectively). According to the results of the present systematic review and meta-analysis, there was no significant effect of pomegranate consumption on weight and body composition indices.

Effects of superfoods on risk factors of metabolic syndrome: a systematic review of human intervention trials

Functional foods can be effective in the prevention of metabolic syndrome and subsequently the onset of cardiovascular diseases and type II diabetes mellitus. More recently, however, another term was introduced to describe foods with additional health benefits: "superfoods", for which, to date, no generally accepted definition exists. Nonetheless, their consumption might contribute to the prevention of metabolic syndrome, for example due to the presence of potentially bioactive compounds. This review provides an overview of controlled human intervention studies with foods described as "superfoods" and their effects on metabolic syndrome parameters. First, an Internet search was performed to identify foods described as superfoods. For these superfoods, controlled human intervention trials were identified until April 2017 investigating the effects of superfood consumption on metabolic syndrome parameters: waist circumference or BMI, blood pressure, or concentrations of HDL cholesterol, triacylglycerol or glucose. Seventeen superfoods were identified, including a total of 113 intervention trials: blueberries (8 studies), cranberries (8), goji berries (3), strawberries (7), chili peppers (3), garlic (21), ginger (10), chia seed (5), flaxseed (22), quinoa (1), cocoa (16), maca (1), spirulina (7), wheatgrass (1), acai berries (0), hemp seed (0) and bee pollen (0). Overall, only limited evidence was found for the effects of the foods described as superfoods on metabolic syndrome parameters, since results were not consistent or the number of controlled intervention trials was limited. The inconsistencies might have been related to intervention-related factors, such as duration or dose. Furthermore, conclusions may be different if other health benefits are considered.

A randomized trial of the effects of flaxseed to manage constipation, weight, glycemia, and lipids in constipated patients with type 2 diabetes

Background

To compare the effects of baked flaxseed versus those who received a placebo on constipation symptom scores, weight, glycemic and lipid control in constipated patients with type 2 diabetes (T2D).

Methods

In a single-blinded, randomized controlled trial, 53 constipated patients with T2D with body mass index (BMI) 20.5-48.9 kg/m² received either 10 g of flaxseed pre-mixed in cookies twice per day or placebo cookies for 12 weeks. The constipation symptom scores, BMI, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), and lipid profile were determined at the beginning and end of 4, 8, and 12-week period. Constipation was evaluated with a stool diary (ROME III).

Results

After the 12-week intervention, constipation symptom scores (2.46), weight (- 3.8 kg), BMI (- 1.5 kg/m²), FPG (- 26.7 mg/dl), cholesterol (- 37.3 mg/dl), triglycerides (- 10.4 mg/dl), LDLC (- 21.0 mg/dl), HDLC (4.7 mg/dl), cholesterol/ HDLC ratio (- 1.4 mg/dl) significantly decreased from baseline in the flaxseed group (all P-values < 0.05). The differences of absolute change of constipation symptom scores (2.46 vs. 0.41), weight (- 3.8 vs. 0.0 kg), BMI (- 1.5 vs.-0.1 kg/m²), FPG (- 26.7 vs.-1.9 mg/dl), >HbA1c (- 0.8 vs. 1.0%), cholesterol (- 37.3 vs. -10.4 mg/dl), LDLC (- 21.0 vs. -4.3 mg/dl), and HDLC (4.7 vs. -4.4 mg/dl) between the flaxseed and placebo groups were statistically significant (all P-values < 0.05). The compliance was good and no adverse effects were observed.

Conclusion

In constipated patients with T2D, flaxseed cookies used as a snack may be a useful tool for decreasing constipation symptoms, weight, glycemic and lipid levels.

Trial registration

irct.ir: IRCT20110416006202N2.