Reducing atherogenic risk in hyperlipemic humans with flax seed supplementation: a preliminary report

Hydroalcoholic extract of Glycyrrhiza glabra root combined with Linum usitatissimum oil as an alternative for hormone replacement therapy in ovariectomized rats

Objective

Plant-derived estrogens (phytoestrogens) with structural similarity to primary female sex hormones could be suitable replacements for sex hormones. Therefore, the effects of the licorice root extract and Linum usitatissimum oil on biochemical and hormonal indices in the serum and uterine stereological changes in ovariectomized rats were evaluated.

Design

In this study, 70 adult female rats were randomly divided into seven groups including 1) control group, 2) sham-operated group, 3) ovariectomized (OVX) group, 4) OVX rats that received 1 mg/kg estradiol for 8 weeks at the day of post-operation, 5) OVX rats which received 2.0 mg/kg body wt Linum usitatissimum oil for 8 weeks at the day of post-operation, 6) OVX rats which received 2.0 mg/kg body wt licorice extract for 8 weeks at the day of post-operation, and 7) OVX rats which received 2.0 mg/kg body wt Linum usitatissimum oil + 2.0 mg/kg body wt licorice extract for 8 weeks at the day of post-operation. After eight weeks, alkaline phosphatase activity, as well as calcium, estradiol, and progesterone concentrations were assessed and tissue samples of the uterus were serologically examined.

Results

The results indicated that after 8 weeks of OVX the alkaline phosphatase activity (Mean = 637.7 IU/L) increased and the calcium (Mean = 7.09 mg/dl), estradiol (5.30 pmol/L), and progesterone (Mean = 3.53 nmol/L) reduced compared to other groups. Moreover, stereological changes in the uterus in ovariectomy groups were seen compared to the other groups. The treatment with Linum usitatissimum oil and licorice extract had a significant therapeutic effect on biochemical factors and stereological changes compared to the ovariectomized group.

Conclusion

The results of this study showed that the combination of Linum usitatissimum oil with licorice extract showed the high potential of hormone replacement therapy in the reduction of OVX complications.

A Pilot Pre and Post 4 Week Intervention Evaluating the Effect of a Proprietary, Powdered, Plant Based Food on Micronutrient Status, Dietary Intake, and Markers of Health in a Healthy Adult Population

Background

A "balanced, adequate, and varied diet" is recommended as the basis of nutritionally sound diet by the World Health Organisation and national public health agencies. Huel is a proprietary, on-the-go, powdered, plant based food, providing all 26 essential vitamins and minerals, protein, essential fats, carbohydrate, fibre, and phytonutrients.

Objectives

Assessing the effect of solely consuming Huel on micronutrient status, dietary intake and markers of health was achieved through a 4-week intervention of solely Huel powder.

Methods

Habitual energy intake was assessed through a one-week lead in period with healthy adult participants (aged 18 or over) logging their food intake, after which only Huel was consumed for 4 weeks. Blood samples and body composition was assessed before and after the lead in week as well the end of the intervention. Thirty participants were recruited with 20 (11 females, median age 31, range 22-44) completing the study, 19 sets of blood samples were collected. 22 blood markers were analysed along with weight, BMI, waist circumference, visceral adipose tissue (VAT), and body composition. All blood micronutrients, except for Thyroid Stimulating Hormone and choline were sent to Royal Victoria Infirmary NHS, Newcastle Laboratory (Newcastle upon Tyne, United Kingdom) for analysis.

Results

Fourteen of the parameters significantly changed over the course of the study with circulating haemoglobin, iron, vitamins B12 and D as well as selenium significantly increasing (p < 0.05). HbA1c, total and non-HDL cholesterol, vitamins A and E, potassium, BMI, VAT, and waist circumference all significantly decreased (p < 0.05) post intervention.

Conclusion

Although energy intake decreased during the intervention period, the adherence to recommended micronutrient intake, as quantified by the dietary Total Adherence Score, significantly increased which tallies with the preservation or improvement of micronutrient status. This study potentially demonstrates that consuming only Huel for 4 weeks does not negatively affect micronutrient status.

The comparison of omega-3 and flaxseed oil on serum lipids and lipoproteins in hyperlipidemic male rats

Hyperlipidemia affects a significant number of patients despite treatment with cholesterol-lowering drugs. Due to the low efficacy of synthetic drugs, there is a need for new agents with low side effects. Therefore, the effects of flaxseeds oil and animal omega-3 on the hyperlipidemic rats were investigated. Forty male Wistar rats were assigned to four groups (n = 10): 1) control group that was fed with a standard diet (pallets). 2) high-fat diet (HFD) control group that was fed with high-fat food for 42 days, 3) Omega-3 group that received HFD for 21 days, followed by HFD + omega-3 capsule (600 mg/kg; 21 days/gavage), and 4) flaxseed oil group that received HFD for 21 days, followed by HFD + flaxseed oil (10 ml/kg; 21 days/gavage). Blood samples were collected three times and at the stages one to third of the experiment from the rats' tail. The results showed that high levels of fat significantly increased cholesterol, triglyceride (TG), and low-density lipoprotein (LDL) in the flaxseed, HFD control, and omega-3 groups in the second stages of the experiment. Inverse, omega-3 or flaxseed oil supplementation decreased cholesterol, TG, and LDL levels and increased high-density lipoprotein (HDL) level in comparison with the HFD control group in the third stages of the experiment. There was no significant difference in the studied parameters between the flaxseed- and omega-3-treated groups. It can be concluded that flaxseed oil similar to omega-3 is effective in the treatment of hyperlipidemia.

Comparisons of the effects of different flaxseed products consumption on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases: systematic review and a dose-response meta-analysis of randomized controlled trials

BACKGROUND

Flaxseed is widely used as a functional food for its rich sources of linolenic acid, lignans and dietary fibers in the world. This systematic review and dose-response meta-analysis on randomized controlled trials (RCTs) is first to evaluate effects of different flaxseed products (whole flaxseed, oil and lignans) on lipid profiles, inflammatory and anthropometric parameters in patients with dyslipidemia related diseases.

METHODS

Literature search was performed in PubMed, Embase, Cochrane Central, Scopus, and Web of Science from the inception dates to January, 2020. Weighted mean differences with the 95% confidence interval (CI) were pooled using fix or random-effects models.

RESULTS

Thirty-one RCTs involving 1,698 participants were included. The present meta-analysis revealed that flaxseed consumption had an overall beneficial effect on serum TC, LDL-C, TG, apo B and IL-6 in patients with dyslipidemia related diseases, but not on apo A, HDL-C, hs-CRP, CRP and anthropometric indices. However, different flaxseed products showed obviously different effects. Whole flaxseed supplementation significantly reduced TC (- 11.85 mg/dl, 95% CI - 20.12 to - 3.57, P = 0.005), LDL-C (- 10.51 mg/dl, 95% CI - 14.96 to - 6.06, P < 0.001), TG (- 19.77 mg/dl, 95% CI - 33.61 to - 5.94, P = 0.005), apolipoprotein B (- 5.73 mg/dl, 95% CI - 7.53 to - 3.93, P < 0.001), TC/HDL-C (- 0.10, 95% CI - 0.19 to - 0.003, P = 0.044) and weight (- 0.40 kg, 95% CI - 0.76 to - 0.05, P = 0.027); Lignans supplementation significantly reduced TC (- 17.86 mg/dl, P = 0.004), LDL-C (- 15.47 mg/dl, P < 0.001) and TC/HDL-C (- 0.45, P = 0.04). Although flaxseed oil supplementation had no such lowering-effect on lipid, meta-analysis revealed its lowering-effect on IL-6 (- 0.35 pg/ml, P = 0.033) and hs-CRP (- 1.54 mg/l, P = 0.004). Subgroup analysis revealed that whole flaxseed decreased TC, LDL-C and TG levels irrespective of country and the intervention time prescribed, but was more pronounced when the dose of whole flaxseed was ≤ 30 g/day (TC: WMD - 13.61 mg/mL; LDL-C: WMD - 10.52 mg/mL; TG: WMD - 23.52 mg/mL), rather not a dose > 30 g/day. Moreover, a linear relationship between dose of whole flaxseed and absolute changes in C-reactive protein (P = 0.036) and a nonlinear relationship between with IL-6 (P < 0.001) were detected.

CONCLUSIONS

Flaxseed intervention suggested the positive effects on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases. Of these, whole flaxseed and lignans play an important role in reducing blood lipid, while flaxseed oil mainly plays in anti-inflammatory. Lipid- and weight-lowering was significant when whole flaxseed was consumed at doses < 30 mg/d, for lipid status with mixed dyslipidemia and patients with BMI > 25.

The effect of camel milk curd masses on rats blood serum biochemical parameters: Preliminary study

This study aimed to assess potential feeding effect of camel milk curd mass and its mixes to experimental rat's blood serum biochemical parameters, enzymatic activity and the peptide toxicity. Fifty healthy male Sprague-Dawley rats were divided into five groups (n = 10 each). Each group was fed with camel milk pure curd mass and its mixes for 16 days. At the end of the experiment, rats were sacrificed to collect the samples from the blood serum. Blood serum biochemical parameters total protein, cholesterol, glucose, albumin, triglycerides; the enzymatic activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase were determined on the A25 automatic analyser, and peptide toxicity analysed by the reference method. The statistical data have shown no significant differences in body weight gain in all groups. Total protein decreased in group II, IV, and V; however, it increased in group III compared to the control group. Cholesterol grew up in group II and it slightly increased in group V, dropped in groups III and IV compared to group I result. Glucose increased in groups II, III, IV compared to group I; still, group V results show a slight decrease. Albumin decreased in group IV, yet in group V it increased than the group I result. Simultaneously, groups II and III results were changed with less percentage. Triglyceride grew up in groups II, V, and it dropped significantly in groups III, IV compared to the control group. De Ritis ratio of enzymes in groups II, III, and IV fluctuated between 1.31 and 0.98 IU/L; however, group V demonstrated significant data versus group I. Diets peptide toxicity in all groups was lower than control group data. The experimental results indicated that curd mass from camel milk could be used as a pure or with additives and it did not discover the observed side effects.

Effects of Flaxseed on Blood Lipids in Healthy and Dyslipidemic Subjects: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

To address hyperlipidemia, flaxseed demonstrates a great impact on experimental and clinical trials. Therefore, the effects of flaxseed on lipid profiles of healthy and dyslipidemic subjects were assayed. The literature search was performed based on English reports of randomized control trials (RCTs) up to April 2021 to seek the effect of flaxseed on lipid profiles of healthy and dyslipidemic subjects. A total of 14 RCTs with 1107 participants were evaluated. Based on results, flaxseed significantly improves the lipid profile in dyslipidemic patients comprising total cholesterol (TC), low-density lipoprotein (LDL-C) and triglyceride (TG) in comparison with the control group. Nevertheless, no significant changes were observed in high-density lipoprotein (HDL-C). Although in healthy individual flaxseed significantly increased HDL-C, LDL-C and TG. Subgroup analysis on healthy subjects showed that flaxseed improved LDL-C on overweight subjects with BMI>25. The evidence suggests that flaxseed significantly improved TC, LDL-C and TG in dyslipidemic subjects and additionally improved the HDL-C on healthy subjects.

The effects of seed from Linum usitatissimum cultivar with increased phenylpropanoid compounds and hydrolysable tannin in a high cholesterol-fed rabbit

Background

Dietary fat is considered one of the most important factors associated with blood lipid metabolism and plays a significant role in the cause and prevention of atherosclerosis that has been widely accepted as an inflammatory disease of the vascular system. The aim of the present study was to evaluate the effect of genetically modified flaxseed (W86) rich in phenylpropanoid compounds and hydrolysable tannin in high cholesterol-induced atherosclerosis rabbit models compared to parental cultivar Linola.

Methods

Twenty-Eight White New Zealand white rabbits aged 6 months were randomly divided into four groups, control group, high cholesterol group (10 g/kg), Linola flaxseed group (100 g/kg) and W86 flaxseed group (100 g/kg). The rabbits were fed a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, hematological values, total antioxidative status and superoxide dismutase activity in serum were determined. Moreover, body weight and feed intake were measured after sixth and tenth weeks. After each stage of the experiment atherogenic indexes (non-HDL-C/HDL-C, LDL-C/HDL-C, and atherogenic index of plasma) was calculated.

Results

The intake of a dyslipidaemic diet negatively influenced lipid profile in rabbits at the 10 weeks of feeding. W86 flaxseed significantly decreased total cholesterol, LDL-C, VLDL-C and TG serum levels in cholesterolemic rabbits compared with parental Linola after 10 weeks. Atherogenic indexes decreased over time with a significant difference between the diets and they were the best for W86 flaxseed. Similarly, the experimental addition of W86 significantly decreased atherogenic predictors such as heterophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and the mean platelet volume-to-lymphocyte ratio. In rabbits, W86 flaxseed increased the activity of superoxide dismutase and total antioxidative status compared to Linola.

Conclusions

Results of the presented study suggest that the addition of W86 flaxseed alleviate serum lipid changes in high cholesterolemic diet-administered rabbits. W86 flaxseed significantly reduced atherogenic indexes, as compared with the Linola and indicate that W86 flaxseed more effectively red CVD risk factors during hypercholesterolemia. Moreover, the presented result suggested that W86 flaxseed can be a part of a heart-healthy and antiatherogenic diet for the human.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0726-4) contains supplementary material, which is available to authorized users.

Effect of Flaxseed Consumption on Blood Pressure, Serum Lipids, Hemopoietic System and Liver and Kidney Enzymes in Healthy Humans

Background: Effects of flaxseed on serum lipids have been studied in humans, but the results are variable. Flaxseed is ineffective in lowering blood pressure in rats. Its effect on blood pressure in humans is not known. It is also not known if long-term use of flaxseed in humans has deleterious effects on the hemopoietic system, serum glucose, and renal and kidney function. We investigated the effect of short-term use of flaxseed in humans on arterial pressure and serum lipids (triglycerides, total cholesterol; high-, low-, and very-low-densitylipoprotein cholesterol [HDL-C, LDL-C, VLDL-C], hemopoietic system (red blood cells, neutrophils, hemoglobin) and the various biochemical parameters, such as serum protein, albumin, total bilirubin, aspartate aminotransferase, alkaline phosphatase, creatinine, urea, related to hepatic and renal function, and serum glucose.

Methods: Fifteen healthy men, aged 22 to 47 years, consumed three muffins daily containing 32.7 g of total flaxseed for 4 weeks, in addition to their normal daily diet. Blood pressure and blood samples for various biochemical measurements were collected before and after 4 weeks of flaxseed diet.

Results: Blood pressures, heart rate, hemoglobin, and counts of red blood cells, white blood cells, and neutrophils remained unaltered after flaxseed diet. Serum total cholesterol, HDLC, LDL-C, and VLDL-C remained unchanged, but serum triglycerides levels were elevated. Serum total bilirubin, aspartate aminotransferase, alkaline phosphatase, protein, albumin, glucose, and urea remained unaltered, but serum levels of creatinine decreased.

Conclusion: These results suggest that 4 weeks use of flaxseed does not have deleterious effects on the hemopoietic system or renal and hepatic function and does not lower blood pressure and serum lipids. However, the level of serum triglyceride level was elevated.

Flaxseed prevents leukocyte and platelet adhesion to endothelial cells in experimental atherosclerosis by reducing sVCAM-1 and vWF

We studied the possible effect of flaxseed to prevent leukocytes and platelets adhesion to endothelial cells and to reduce soluble adhesion molecules (sVCAM-1) and endothelial integrity markers (vWF) in ovariectomized rats fed a high-fat diet. Forty-two female Wistar rats were either sham-operated or ovariectomized and randomly assigned for 36 weeks to three different diets: (1) low-fat diet (8% energy as fat); (2) high-fat diet (40% energy as fat, lard based, lard group); (3) high-fat diet enriched with ground flaxseed 15 g/100 g of food (40% energy as fat, lard + flaxseed group). The ovariectomized rats fed with lard + flaxseeds had significantly lower serum concentrations of sVCAM and vWF, reduced platelet adhesiveness, and lower extent of platelet and leukocyte adherence to endothelium in the histological evaluation of the aorta as compared to Ovx + lard group. In our study, high dose of ground flaxseed incorporated to lard-based diet prevented the progression of atherosclerotic lesions in estrogen deficiency rats by decreasing platelet and endothelium reactivity. Assessment of platelet adhesion, serum soluble adhesion molecule sVCAM, and endothelium integrity molecule vWF could be useful to detect the risk for atherosclerotic lesions in estrogen deficiency states and to estimate the effect of flaxseed supplementation.

Tackling metabolic syndrome by functional foods

The metabolic syndrome is one of the most vibrant and widely prevailing health concerns worldwide. It is characterized by several metabolic abnormalities, which involve obesity, insulin resistance, dyslipidemia, enhanced oxidative stress; hypertension and increased pro-inflammatory state that ultimate contribute towards poor health. The prevalence of metabolic syndrome in Pakistan according to different definitions is reported to be from 18 % to 46 %. Fifty percent of Pakistani population is at high risk of metabolic syndrome as being hypertensive. In studying dyslipidemia in Pakistan, hypertriglyceridemia is found in 27-54 % of the population, whereas 68-81 % has low levels of high-density lipoprotein (HDL). Population likes to eat healthier diet without changing their fundamental dietary pattern. Nutrition science has moved on from the classical concepts of avoiding nutrient deficiencies and basic nutritional adequacy to the concept of positive or optimal nutrition. Many traditional food products including fruits, vegetables, flaxseed, oat, barley, whole grains, soy and milk have been found to contain component with potential health benefits. Nowadays, functional foods are used in the prevention and amelioration of several chronic diseases, such as the metabolic syndrome. The relation of the consumption of certain functional foods and the improvement in health status is regulated through health claims. This review focuses on the different features of the metabolic syndrome and the influence of functional foods on these aspects, involving dyslipidemia, improvement of insulin sensitivity, serum lipid profile, antioxidant status, anti-inflammatory status and weight management of humans.

Impact of flaxseed intake upon metabolic syndrome indicators in female Wistar rats

PURPOSE: To evaluate whether the prolonged consumption of flaxseed minimize the factors that trigger MS in healthy rats. METHODS: Pregnant rats were divided immediately after delivery into two groups during the lactation period, a control group (CG) receiving casein-based diet with 17% of protein, and a Flaxseed group (FG) with casein-based diet plus 25% of flaxseed. At weaning, 12 offspring of each group continued to receive the same feed but with 10% of protein up to 200 days old. RESULTS: FG showed a significant reduction in body weight (p=0.001), total cholesterol levels (p<0.0001), triglycerides (p=0.0001), and glucose (p=0.001). CONCLUSION: The flaxseed alters the indicators related to development of metabolic syndrome, because it has beneficial effects on lipids and glucose profiles and prevents the excess of body weight gain.

The effect of Linola and W92/72 transgenic flax seeds on the rabbit caecal fermentation--in vitro study

The effect of W92/72 transgenic flax seeds taken from a variety of Linola on the production of SCFA, ammonia and methane by bacteria inhabiting rabbit caecum was studied. The in vitro method was used where caecal contents from rabbits was incubated with W92/72 transgenic or Linola flax seeds, or without any additives (control samples). The total concentration of SCFA was higher in samples with the addition of flax seeds than in the control samples. The increase in concentrations of acetic, propionic and butyric acids was the highest in samples with Linola seeds added. A higher percentage of propionic and butyric acids was observed in the contents incubated with addition of flax seeds as compared to the control samples. This increase was the result of a percentage decrease in acetic acid. No differences were observed in the concentration of ammonia between fermented samples. Moreover, the addition of flax seeds resulted in slight decrease of pH in incubated samples. In gas samples, the methane level was higher in samples with flax seeds added, although the highest level was found in samples with transgenic seeds. In addition, gas pressure was significantly higher in samples with flax seeds added as compared to control samples, and this may indicate a higher intensity of microbiological fermentation processes. These studies suggest that neither Linola nor W92/72 flax seeds have any unfavorable effect on the caecal microflora activity of rabbits. A beneficial influence of flax seeds on the microbiological fermentation process in rabbit caecum was observed, based on an increase in percentage ratio of propionic acid in samples with flax seeds added.

The health promoting properties of the conjugated isomers of α-linolenic acid

The bioactive properties of the conjugated linoleic acid (CLA) isomers have long been recognised and are the subject of a number of excellent reviews. However, despite this prominence the CLA isomers are not the only group of naturally occurring dietary conjugated fatty acids which have shown potent bioactivity. In a large number of in vitro and in vivo studies, conjugated α-linolenic acid (CLNA) isomers have displayed potent anti-inflammatory, immunomodulatory, anti-obese and anti-carcinogenic activity, along with the ability to improve biomarkers of cardio-vascular health. CLNA isomers are naturally present in high concentrations in a large variety of seed oils but can also be produced in vitro by strains of lactobacilli and bifidobactena through the activity of the enzyme linoleic acid isomerase on α-linolenic acid. In this review, we will address the possible therapeutic roles that CLNA may play in a number of conditions afflicting Western society and the mechanisms through which this activity is mediated.

Randomized, placebo-controlled trial of flax oil in pediatric bipolar disorder

OBJECTIVES

This clinical trial evaluated whether supplementation with flax oil, containing the omega-3 fatty acid alpha-linolenic acid (alpha-LNA), safely reduced symptom severity in youth with bipolar disorder.

METHODS

Children and adolescents aged 6-17 years with symptomatic bipolar I or bipolar II disorder (n = 51), manic, hypomanic, mixed, or depressed, were randomized to either flax oil capsules containing 550 mg alpha-LNA per 1 gram or an olive oil placebo adjunctively or as monotherapy. Doses were titrated to 12 capsules per day as tolerated over 16 weeks. Primary outcomes included changes in the Young Mania Rating Scale, Child Depression Rating Scale-Revised, and Clinical Global Impressions-Bipolar ratings using Kaplan-Meier survival analyses.

RESULTS

There were no significant differences in primary outcome measures when compared by treatment assignment. However, clinician-rated Global Symptom Severity was negatively correlated with final serum omega-3 fatty acid compositions: %alpha-LNA (r = -0.45, p < 0.007), % eicosapentaenoic acid (EPA) (r = -0.47, p < 0.005); and positively correlated with final arachidonic acid (AA) (r = 0.36, p < 0.05) and docosapentaenoic acid (DPA) n-6 (r = 0.48, p < 0.004). The mean duration of treatment for alpha-LNA was 11.8 weeks versus 8 weeks for placebo; however, the longer treatment duration for alpha-LNA was not significant after controlling for baseline variables. Subjects discontinued the study for continued depressive symptoms.

CONCLUSIONS

Studies of essential fatty acid supplementation are feasible and well tolerated in the pediatric population. Although flax oil may decrease severity of illness in children and adolescents with bipolar disorder who have meaningful increases in serum EPA percent levels and/or decreased AA and DPA n-6 levels, individual variations in conversion of alpha-LNA to EPA and docosahexaenoic acid as well as dosing burden favor the use of fish oil both for clinical trials and clinical practice. Additionally, future research should focus on adherence and analysis of outcome based on changes in essential fatty acid tissue compositions, as opposed to group randomization alone.

Changes in Lipid Profile by Vegetable Oil Blends Rich in Polyunsaturated Fatty Acids in Rats with Hypercholesterolemia

The objective of this study was to investigate the effect of different blended vegetable oils having different levels and profiles of polyunsaturated fatty acids (PUFA) on hypercholesterolemia by analyzing the changes in lipid profile in high-cholesterol diet fed rats. Three vegetable oils (soy oil, sunflower oil, and the nonconventional flaxseed oil) were blended to obtain blends rich in PUFA. Thirty albino rats were used over the 2-month period. The animals were divided into five groups, wherein group 5 represents negative control, where rats were fed basal diet, while rats in group 4 received high cholesterol diet and served as positive controls. The other three groups were fed hypercholesterolemic diet (1% cholesterol + 0.25% colic acid) supplemented with blended oils. Generally, rats fed blended oils showed significantly lower levels of total cholesterol (TC), triacylglycerol (TG), and low-density lipoprotein (LDL) cholesterol as well as higher levels of high-density lipoprotein (HDL) cholesterol, in comparison with animals fed high-cholesterol diet and cholesterol-free diet. Thus, oil blends under study may be useful formulations for the treatment of hypercholesterolemia. In addition to improving the lipid profile by lowering TC, total TG, and total LDL and increasing HDL, blending of vegetable oils can result in an economic advantage of lower prices.

Effects of the flaxseed lignans secoisolariciresinol diglucoside and its aglycone on serum and hepatic lipids in hyperlipidaemic rats

The present study involved a comparative analysis of the effects of purified flaxseed lignans, secoisolariciresinol diglucoside (SDG) and its aglycone metabolite (SECO), in hyperlipidaemic rats. For hypercholesterolaemia, female Wistars (six rats per group) were fed a standard or 1 % cholesterol diet and orally administered 0, 3 or 6 mg SDG/kg or 0, 1·6 or 3·2 mg SECO/kg body weight once daily for 4 weeks. Hypertriacylglycerolaemia was induced in male Sprague–Dawley rats (ten rats per group) by supplementing tap water with 10 % fructose. These rats were orally administered 0, 3 or 6 mg SDG/kg body weight once daily for 2 weeks. Fasting blood samples (12 h) were collected predose and at the end of the dosing period for serum lipid analyses. Rats were killed and livers rapidly excised and sectioned for lipid, mRNA and histological analyses. Chronic administration of equimolar amounts of SDG and SECO caused similar dose-dependent reductions in rate of body-weight gain and in serum total and LDL-cholesterol levels and hepatic lipid accumulation. SDG and SECO failed to alter hepatic gene expression of commonly reported regulatory targets of lipid homeostasis. SDG had no effect on serum TAG, NEFA, phospholipids and rate of weight gain in 10 % fructose-supplemented rats. In conclusion, our data suggest that the lignan component of flaxseed contributes to the hypocholesterolaemic effects of flaxseed consumption observed in humans. Future studies plan to identify the biochemical mechanism(s) through which flaxseed lignans exert their beneficial effects and the lignan form(s) responsible.

A comparison of fish oil, flaxseed oil and hempseed oil supplementation on selected parameters of cardiovascular health in healthy volunteers

OBJECTIVE

The impact of dietary polyunsaturated fatty acids (PUFAs) of the n-6 and n-3 series on the cardiovascular system is well documented. To directly compare the effects of three dietary oils (fish, flaxseed and hempseed) given in concentrations expected to be self-administered in the general population on specific cardiovascular parameters in healthy volunteers.

DESIGN

86 healthy male and female volunteers completed a 12 week double blinded, placebo controlled, clinical trial. They were randomly assigned to one of the four groups. Subjects were orally supplemented with two 1 gm capsules of placebo, fish oil, flaxseed oil or hempseed oil per day for 12 weeks.

RESULTS

Plasma levels of the n-3 fatty acids docosahexanoic acid and eicosapentanoic acid increased after 3 months supplementation with fish oil. Alpha linolenic acid concentrations increased transiently after flaxseed supplementation. However, supplementation with hempseed oil did not significantly alter the concentration of any plasma fatty acid. The lipid parameters (TC, HDL-C, LDL-C and TG) did not show any significant differences among the four groups. Oxidative modification of LDL showed no increase in lag time over the 12 wk period. None of the dietary interventions induced any significant change in collagen or thrombin stimulated platelet aggregation and no increase in the level of inflammatory markers was observed.

CONCLUSION

From a consumer's perspective, ingesting 2 capsules of any of these oils in an attempt to achieve cardiovascular health benefits may not provide the desired or expected result over a 3 month period.

Effects of flaxseed derivatives in experimental polycystic kidney disease vary with animal gender

Flaxseed derivatives, including both oil and flax lignan, modify progression of renal injury in animal models, including Han:SPRD-cy polycystic kidney disease (PKD). Gender is a significant factor in the rates of progression of many forms of human renal disease, but the role of gender in the response to nutrition intervention in renal disease is unexplored. In this study, male and female Han:SPRD-cy rats or normal littermates were fed either corn oil (CO) or flax oil (FO) diets, with or without 20 mg/kg of the diet flax lignan secoisolaricinoresinol dyglycoside (SDG). Renal injury was assessed morphometrically and biochemically. Renal and hepatic PUFA composition was assessed by GC and renal PGE2 release by ELISA. FO preserved body weight in PKD males, with no effect in females. SDG reduced weight in both normal and PKD females. FO reduced proteinuria in both male and female PKD. FO reduced cystic change and renal inflammation in PKD males but reduced cystic change, fibrosis, renal inflammation, tissue lipid peroxides, and epithelial proliferation in PKD females. SDG reduced renal inflammation in all animals and lipid peroxides in PKD females. A strong interaction between SDG and FO was observed in renal FA composition of female kidneys only, suggesting increased conversion of C18 PUFA to C20 PUFA. FO reduced renal release of PGE2 in both genders. Gender influences the effects of flaxseed derivatives in Han:SPRD-cy rats. Gender-based responses to environmental factors, such as dietary lipid sources and micronutrients, may contribute to gender-based differences in disease progression rates.

Effects of dietary flaxseed on vascular contractile function and atherosclerosis during prolonged hypercholesterolemia in rabbits

Dietary flaxseed has significant anti-atherogenic effects. However, the limits of this action and its effects on vascular contractile function are not known. We evaluated the effects of flaxseed supplementation on atherosclerosis and vascular function under prolonged hypercholesterolemic conditions in New Zealand White rabbits assigned to one of four groups for 6, 8, or 16 wk of feeding: regular diet (RG), 10% flaxseed-supplemented diet (FX), 0.5% cholesterol-supplemented diet (CH), and 0.5% cholesterol- and 10% flaxseed-supplemented diet (CF). Cholesterol feeding resulted in elevated plasma cholesterol levels and the development of atherosclerosis. The CF group had significantly less atherosclerotic lesions in the aorta and carotid arteries after 6 and 8 wk than the CH animals. However, the anti-atherogenic effect of flaxseed supplementation was completely attenuated by 16 wk. Maximal tension induced in aortic rings either by KCl or norepinephrine was not impaired by dietary cholesterol until 16 wk. This functional impairment was not prevented by including flaxseed in the high-cholesterol diet. Aortic rings from the cholesterol-fed rabbits exhibited an impaired relaxation response to acetylcholine at all time points examined. Including flaxseed in the high-cholesterol diet completely normalized the relaxation response at 6 and 8 wk and partially restored it at 16 wk. No significant changes in the relaxation response induced by sodium nitroprusside were observed in any of the groups. In summary, dietary flaxseed is a valuable strategy to limit cholesterol-induced atherogenesis as well as abnormalities in endothelial-dependent vasorelaxation. However, these beneficial effects were attenuated during prolonged hypercholesterolemic conditions.

Flaxseed oil supplementation does not affect plasma lipoprotein concentration or particle size in human subjects

alpha-Linolenic acid (ALA) is a major dietary (n-3) fatty acid. Some clinical trials with ALA supplementation have shown reduced cardiovascular risk; however the specific cardioprotective mechanism is not known. We studied the effects of daily supplementation with ALA derived from flaxseed oil on concentrations of plasma LDL cholesterol, HDL cholesterol, intermediate density lipoprotein cholesterol, and lipid particle sizes. In a randomized double-blind trial, 56 participants were given 3 g/d of ALA from flaxseed oil in capsules (n = 31) or olive oil containing placebo capsules (n = 25) for 26 wk. Changes in plasma HDL cholesterol, LDL cholesterol, and triglyceride concentrations did not differ between the 2 groups at 26 wk. The adjusted plasma total cholesterol concentration at 26 wk was 0.45 mmol/L higher in the flaxseed oil group (5.43 +/- 0.03 mmol/L) compared with the olive oil group (5.17 +/- 0.07 mmol/L) (P = 0.026). ALA did not affect LDL, HDL, or IDL particle size; however, the concentrations of the large, less atherogenic LDL1 (P = 0.058) and LDL2 (P = 0.083) subfractions tended to be greater in the ALA group. In conclusion, ALA does not decrease CVD risk by altering lipoprotein particle size or plasma lipoprotein concentrations.

Beneficial effects of alpha linolenic acid rich flaxseed oil on growth performance and hepatic cholesterol metabolism in high fat diet fed rats

The purpose of the study was to investigate the effect of flaxseed oil (FO), rich in alpha-linolenic acid (ALA) (18:3 n-3) on growth parameters and lipid metabolism of rats fed with high fat diet. High fat diet (HFD) resulted in significant alterations in hepatic lipids, increase in body weight gain and negative effect on lipoprotein metabolism. FO supplementation significantly lowered the increase in body weight gain, liver weight, plasma cholesterol, triglycerides, phospholipids, free fatty acids, high-density lipoprotein (HDL), low-density lipoprotein-cholesterol (LDL-C), very low-density lipoprotein (VLDL), LDL/HDL and TC/HDL ratio in HFD fed rats. FO significantly reduced the hepatic and plasma lipid levels indicating its hypolipidemic activity. On the other hand, oral administration of FO exhibited lower plasma lipoprotein profile as compared to HFD rats. Hepatic protection by FO is further substantiated by the normal liver histological findings in HFD fed rats. These data suggest that FO participate in the normal regulation of plasma lipid concentration and cholesterol metabolism in liver. No adverse effect of FO on growth parameters and plasma lipids in rats fed with fat-free diet. The results of the present study demonstrate that FO may be developed as a useful therapy for hyperlipidemia through reducing hepatic lipids, thereby proving its hypolipidemic activity.

Flaxseed reduces plasma cholesterol and atherosclerotic lesion formation in ovariectomized Golden Syrian hamsters

BACKGROUND

Dietary modification contributes significantly in reducing cardiovascular disease (CVD) risk factors including lowering cholesterol and atherosclerosis. The purpose of this study was to investigate the effects of flaxseed, a rich source of lignans, alpha-linolenic acid and soluble fiber mucilage, on the prevention of ovariectomy-induced rise in total cholesterol and atherosclerotic lesions.

METHODS

Seventy-two 6-month-old female Golden Syrian hamsters were either ovariectomized (ovx) or sham-operated (sham) and randomly assigned to six groups (n = 12): sham, ovx, or ovx plus either 17beta-estradiol (E(2), 10 microg/kg body weight) or semi-purified diet adjusted for macronutrients and fiber to contain one of the three doses of flaxseed (7.5, 15, or 22.5%) for 120 days.

RESULTS

Ovariectomy significantly elevated plasma total-, HDL-, and free-cholesterol concentrations. Similar to estrogen, all doses of flaxseed were effective in preventing the ovx-induced rise in plasma total cholesterol. Triglyceride concentrations were significantly higher in the flax-fed hamsters. There were no significant differences in plasma non-HDL- and esterified-cholesterol among the treatment groups. Ovariectomy also increased the number of hamsters with lesions and the aortic fatty streak area. All three doses of flaxseed reduced the fatty streak area and the incidence of lesions to levels similar to the sham group.

CONCLUSION

The findings of this study show that flaxseed is beneficial in reducing plasma cholesterol and plaque formation induced by ovarian hormone deficiency.

Lifestyle recommendations to prevent prostate cancer, part II: time to redirect our attention?

This article provides a foundation for men who want to incorporate lifestyle changes to reduce their risk for prostate cancer and, more importantly, impact all-cause mortality. Table 1 summarizes some of these lifestyle changes that can be recommended to patients in most settings. Minimal time is required to suggest these changes, and a copy of Table 1 can be provided as a reminder to patients. Although these recommendations may seem simple, past studies of men have demonstrated that few (less than 5%) adhere to numerous healthy behaviors simultaneously. It seems to be more common to follow one healthy change in excess than to make multiple changes in moderation. This may be the result of past studies focusing on one lifestyle change to affect disease risk; poor compliance; lack of attention, time, or understanding to this detail; or lack of motivation on the part of the health professional and the patient. Clinical trials of combined moderate lifestyle changes, however, demonstrate that the total effort to make healthy lifestyle changes is more important than one or two behavioral changes in affecting cardiovascular markers, cancer, and all-cause mortality. Recommending a pill is an easy answer, but few supplements for prostate-cancer prevention or total mortality reduction can be recommended, and long-term compliance is a concern with any agent. Additionally, the potential for supplements to increase the risk for prostate cancer or interfere with conventional treatment continues to be a concern, and no dietary supplement has come close to matching the reduction in all-cause mortality observed in clinical trials of lifestyle changes. The time seems ripe to redirect our attention regarding lifestyle changes and prostate cancer risk. What is heart-healthy is prostate-healthy, which makes it more likely that any man concerned about the risk for prostate cancer will make healthy lifestyle changes.

Flaxseed and cardiovascular risk

Flaxseed has recently gained attention in the area of cardiovascular disease primarily because it is the richest known source of both alpha-linolenic acid (ALA) and the phytoestrogen, lignans, as well as being a good source of soluble fiber. Human studies have shown that flaxseed can modestly reduce serum total and low-density lipoprotein cholesterol concentrations, reduce postprandial glucose absorption, decrease some markers of inflammation, and raise serum levels of the omega-3 fatty acids, ALA and eicosapentaenoic acid. Data on the antiplatelet, antioxidant, and hypotensive effects of flaxseed, however, are inconclusive. More research is needed to define the role of this functional food in reducing cardiovascular risk.

Antithrombic and anti-atherogenic effects of partially defatted flaxseed meal using a laser-induced thrombosis test in apolipoprotein E and low-density lipoprotein receptor deficient mice

Atherothrombosis can be regarded as a 'life-style related disease' of which diet is one of the important risk factors. The prophylactic effect of partially defatted flaxseed meal (PDFM) on atherothrombosis has not yet been studied. The aim of this study was to assess the effect of PDFM and a lignan from flaxseed, secoisolariciresinol diglucoside (SDG), on thrombosis and atherogenesis. An earlier developed test, the quantitative assessment of laser-induced thrombus formation in the carotid artery of apolipoprotein E and low-density lipoprotein receptor deficient mice was used in this study. Thrombotic and atherosclerotic status was assessed in mice kept on a high-fat diet for 8 weeks (40% in energy). The diet contained 0.05% cholesterol alone (control) or the same cholesterol with added PDFM (5% w/w; 8.3 g/kg body weight per day) or SDG (0.06% w/w; 100 mg/kg body weight per day). PDFM showed antithrombotic (P < 0.01) and anti-atherogenic effect (P < 0.01). SDG did not affect either atherogenesis or thrombosis. This study suggests that dietary intake of PDFM can be beneficial in reducing the risk of high-fat-induced atherothrombosis.

The Effect of Flax Seed Cultivars with Differing Content of α-Linolenic Acid and Lignans on Responses to Mental Stress

BACKGROUND

Phytoestrogens offer a possible alternative to hormone replacement therapy. Flax seed contains large quantities of a phytoestrogen precursor, secoisolariciresinol diglucoside (SDG), as well as large quantities of alpha-linolenic acid; these factors may be protective against vascular disease. We have previously shown that the rise in blood pressure during mental stress is a strong predictor of atherosclerosis progression.

METHODS

35 postmenopausal women with vascular disease, 62 +/- 8 years of age, were treated in a random-sequence double-blind Latin square crossover study comparing three strains of flax seed: Flanders (low in lignan and high in alpha-linolenic acid), Linola 989 (high in lignan and low in alpha-linolenic acid) and AC Linora (intermediate in both lignan and alpha-linolenic acid).

RESULTS

Compared to the pre-treatment baseline diet, all three strains of flax significantly reduced blood pressure during mental stress induced by a frustrating cognitive task (Stroop color-word interference task) (p = 0.004). Linola 989, the strain highest in lignan and lowest in alpha-linolenic acid, was associated with the least increase in peripheral resistance during stress, the greatest reduction in plasma cortisol during stress and the smallest increase in plasma fibrinogen during mental stress.

CONCLUSION

Flax phytoestrogens ameliorate certain responses to stress and thus may afford protection against atherosclerosis; this hypothesis should be tested in clinical trials.

Flaxseed increased alpha-linolenic and eicosapentaenoic acid and decreased arachidonic acid in serum and tissues of rat dams and offspring

The effects of dietary flaxseed (FS), and defatted flaxseed meal (FLM) on serum and tissue fatty acid profiles were investigated. Pregnant Sprague-Dawley rats were fed AIN-93 based diets balanced in calories, fat, nitrogen, and fiber. Diets contained 0, 20%, 40% FS or 13% or 26% FLM by weight. The control, FS and FLM diets differed in linoleic acid to alpha-linolenic acid (ALA) fatty acid ratio. These diets were fed continuously during gestation, suckling period and 8 weeks post-weaning (F(1)). FS fatty acids were bioavailable and metabolized by pregnant and F(1) rats. ALA and eicosapentaenoic acid increased; linoleic and arachidonic acid decreased; and docosahexaeonic acid was unchanged in serum, 'gastric milk' and liver of FS and FLM-fed pregnant and F(1) rats. FS more than FLM, changed fatty acids profiles, but FLM and 40% FS significantly reduced serum cholesterol. Dietary 40% FS may have increased oxidative stress as evidenced by a reduction in liver vitamin E.

Effects of flaxseed and defatted flaxseed meal on reproduction and development in rats

Flaxseed, a rich source of reportedly beneficial n-3 fatty acid and phytoestrogens, has not been thoroughly tested for reproductive effects. High levels of flaxseed (FS, 20 or 40%) or defatted flaxseed meal (FLM, 13 or 26%) added to AIN-93 diet were evaluated in a two-phase study: dosed during gestation only or during gestation and maturation in a lifetime study. At cesarean section on gestation day 20, neither FS nor FLM affected fertility, body weight gain, litter size, or fetal development. FLM, but not FS, decreased gestation length. The offspring of dams allowed to litter were observed to postnatal day (PND) 21 or 90. Neither FS nor FLM affected PND 21 survival indices of F1 pups. FS (20 and 40%), but not FLM, increased the anogenital index (AGI) of F1 females at PND 21. The AGI of F1 males was not affected by either FS or FLM. FLM (13 and 26%), but not FS, delayed puberty in F1 males. Age and weight at the onset of puberty in females were not affected by FS or FLM. FS and FLM caused dose-related increases in the number of F1 females with irregular estrous cycles. During PND 21-90, F1 females fed 20% FS, 13% FLM, or 26% FLM gained more weight than the controls. FS and FLM decreased thymus/body weight and thymus/brain weight ratios in weanling F1 males and females. FS and FLM decreased liver/body weight and liver/brain weight ratios in weanling F1 females, and 26% FLM decreased the same two ratios in F1 males. In conclusion, FS did not affect fetal development but did affect indices of postnatal development such as the estrous cycle.

Impact of high flaxseed diet on mitogen-induced proliferation, IL-2 production, cell subsets and fatty acid composition of spleen cells from pregnant and F1 generation Sprague-Dawley rats

Flaxseed (FS) being rich in alpha-linolenic acid may alter the immune parameters. Therefore, we assessed the impact of FS and defatted flaxseed meal (FLM) on fatty acid composition, cell subsets, proliferation and IL-2 production by splenic lymphocytes. Pregnant female Sprague-Dawley rats were fed diets containing 0% FS and FLM, 20 or 40% FS, 13 or 26% FLM during gestation or gestation, lactation and 8 week post-weaning period. FS and FLM resulted in up to 8.3 fold and 4.6 fold increase in splenic ALA among pregnant rats, 4.5 fold and 1.2 fold increase in splenic ALA among F(1) generation rats. Splenic linoleic acid (LA) and arachidonic acid (AA) were 18 and 40% lower in 40% FS fed pregnant rats, and AA was 15% lower in all the other groups. Among F(1) rats, splenic LA and AA were 16 and 48% lower in 40% FS group, and AA was 18% lower in 20% FS and 26% FLM groups. Concanavalin A and phytohemagglutinin mediated proliferation of spleen cells were 60 and 52% lower in 40% FS fed pregnant and F(1) generation rats, respectively. No significant changes were observed in the cell subsets or IL-2 production by splenic cells from different groups.

Dietary flaxseed meal is more protective than soy protein concentrate against hypertriglyceridemia and steatosis of the liver in an animal model of obesity

OBJECTIVE

Soy protein and flaxseed meal have been reported to have beneficial effects on many chronic diseases in humans and animals. The primary objective of the study was to evaluate the beneficial effects of soy protein and flaxseed meal on hypertriglyceridemia and liver steatosis associated with obesity and diabetes. We compared the effects of dietary soy protein and flaxseed meal with that of casein on plasma and liver lipids in a genetic model of obesity, type II diabetes and insulin resistance, namely the SHR/N-cp rat.

METHODS

Lean and obese phenotypes of SHR/-cp rats were fed AIN 93 diets containing 20% of energy from casein (control), soy protein concentrate or flaxseed meal for six months. Plasma was analyzed for total cholesterol, LDL cholesterol, triglyceride and total protein. Liver was analyzed for steatosis by light microscopy after staining samples with Hematoxylin-Eosin and Oil-Red-O.

RESULTS

In lean rats soy protein and flaxseed meal significantly decreased plasma total cholesterol (26.0% and 20.3% respectively) compared to casein. In obese rats flaxseed meal had significant cholesterol lowering effect compared to control rats (41%). Soy protein significantly lowered both plasma LDL-cholesterol and HDL-cholesterol in lean phenotypes while in obese phenotypes flaxseed meal significantly lowered LDL-cholesterol and HDL-cholesterol compared to casein-fed rats. Flaxseed meal also significantly lowered plasma triglyceride in both lean and obese rats compared to casein fed rats (33.7% and 37% respectively). There was significantly greater fat accumulation in livers of obese rats than lean rats (200%) regardless of dietary protein type. Flaxseed meal significantly lowered fat deposition in livers of both lean and obese rats compared to rats fed casein or soy protein. Dietary component(s) present in flaxseed meal or soy protein responsible for hypolipidemic effects is not clear.

CONCLUSIONS

The marked hypotriglyceridemic and hypocholesterolemic effects of flaxseed meal may have important therapeutic implications in patients with hypertriglyceridemia and hypercholesterolemia and deserve further study in humans with these disorders. Flaxseed meal supplementation may provide a new therapeutic strategy to reduce hypertriglyceridemia and fatty liver.

Beneficial role of dietary phytoestrogens in obesity and diabetes

Evidence is emerging that dietary phytoestrogens play a beneficial role in obesity and diabetes. Nutritional intervention studies performed in animals and humans suggest that the ingestion of soy protein associated with isoflavones and flaxseed rich in lignans improves glucose control and insulin resistance. In animal models of obesity and diabetes, soy protein has been shown to reduce serum insulin and insulin resistance. In studies of human subjects with or without diabetes, soy protein also appears to moderate hyperglycemia and reduce body weight, hyperlipidemia, and hyperinsulinemia, supporting its beneficial effects on obesity and diabetes. However, most of these clinical trials were relatively short and involved a small number of patients. Furthermore, it is not clear whether the beneficial effects of soy protein and flaxseed are due to isoflavones (daidzein and genistein), lignans (matairesinol and secoisolariciresinol), or some other component. Isoflavones and lignans appear to act through various mechanisms that modulate pancreatic insulin secretion or through antioxidative actions. They may also act via estrogen receptor-mediated mechanisms. Some of these actions have been shown in vitro, but the relevance of these studies to in vivo disease is not known. The diversity of cellular actions of isoflavones and lignans supports their possible beneficial effects on various chronic diseases. Further investigations are needed to evaluate the long-term effects of phytoestrogens on obesity and diabetes mellitus and their associated possible complications.

Differential effects of dietary flaxseed protein and soy protein on plasma triglyceride and uric acid levels in animal models

The effect of dietary soy protein and flaxseed meal on metabolic parameters was studied in two animal models, F344 rats with normal lipid levels and obese SHR/N-cp rats with elevated levels of cholesterol and triglyceride. The rats were fed AIN 93 diet differing only in the source of protein. The rats were fed either 20% casein, 20% soy protein or 20% flaxseed meal. Plasma was analyzed for cholesterol, triglyceride, uric acid, blood urea nitrogen (BUN), creatinine and total protein. In both strains of rats, flaxseed meal significantly decreased plasma cholesterol and triglyceride concentrations. The effect of soy protein on lipids was not as striking as that of flaxseed meal. Flaxseed meal also lowered uric acid in F344 rats and BUN in SHR/N-cp rats. Since cholesterol, triglyceride and uric acid are independent risk factors for cardiovascular disorders, our data show that both flaxseed meal and soy protein may have beneficial effects. Which chemical constituent(s) of flaxseed meal or soybean is (are) responsible for the beneficial effects need to be identified.