Decreasing the Linoleic Acid to α-Linolenic Acid Diet Ratio Increases Eicosapentaenoic Acid in Erythrocytes in Adults

Normal-Fat vs. High-Fat Diets and Olive Oil vs. CLA-Rich Dairy Fat: A Comparative Study of Their Effects on Atherosclerosis in Male Golden Syrian Hamsters

The relationship between milk fat intake (because of its high saturated fatty acid content) and the risk of suffering from cardiovascular diseases remains controversial. Thus, Golden Syrian hamsters were fed two types of fat-sheep milk fat that was rich in rumenic (cis9,trans11-18:2) and vaccenic (trans11-18:1) acids and olive oil-and two doses (a high- or normal-fat diet) for 14 weeks, and markers of lipid metabolism and atherosclerosis evolution were analyzed. The results revealed that the type and percentage of fat affected most plasma biochemical parameters related to lipid metabolism, while only the expression of five (CD36, SR-B1, ACAT, LDLR, and HMG-CoAR) of the studied lipid-metabolism-related genes was affected by these factors. According to aortic histology, when ingested in excess, both fats caused a similar increase in the thickness of fatty streaks, but the high-milk-fat-based diet caused a more atherogenic plasma profile. The compositions of the fats that were used, the results that were obtained, and the scientific literature indicated that the rumenic acid present in milk fat would regulate the expression of genes involved in ROS generation and, thus, protect against LDL oxidation, causing an effect similar to that of olive oil.

The Effects of a High-Fat Diet on Inflammatory Bowel Disease

The interactions among diet, intestinal immunity, and microbiota are complex and play contradictory roles in inflammatory bowel disease (IBD). An increasing number of studies has shed light on this field. The intestinal immune balance is disrupted by a high-fat diet (HFD) in several ways, such as impairing the intestinal barrier, influencing immune cells, and altering the gut microbiota. In contrast, a rational diet is thought to maintain intestinal immunity by regulating gut microbiota. In this review, we emphasize the crucial contributions made by an HFD to the gut immune system and microbiota.

n-3 index is associated with cardiometabolic risk factors but is not improved by walnut intake in free-living elderly: a single-blind, randomised controlled trial

n-3 index, the erythrocyte proportion of the EPA + DHA fatty acids is a clinical marker of age-related disease risk. It is unclear whether regular intake of α-linolenic acid (ALA), a plant-derived n-3 polyunsaturated fatty acid, raises n-3 index in older adults. Of the 356 participants at the Loma Linda, CA centre from the original study, a randomly selected subset (n 192) was included for this secondary analysis (mostly Caucasian women, mean age 69 years). Participants were assigned to either the walnut (15 % of daily energy from walnuts) or the control group (usual diet, no walnuts) for 2 years. Erythrocyte fatty acids were determined at baseline and 1-year following intervention. No differences were observed for erythrocyte EPA, but erythrocyte DHA decreased albeit modestly in the walnut group (-0·125 %) and slightly improved in the control group (0·17 %). The change in n-3 index between the walnut and control groups was significantly different only among fish consumers (those who ate fish ≥ once/month). Longitudinal analyses combining both groups showed significant inverse association between the 1-year changes of the n-3 index and fasting plasma TAG (ß = -10), total cholesterol (ß = -5·59) and plasma glucose (ß = -0·27). Consuming ALA-rich walnuts failed to improve n-3 index in elders. A direct source of EPA/DHA may be needed to achieve desirable n-3 index, as it is inversely associated with cardiometabolic risk. Nevertheless, incorporating walnuts as part of heart healthy diets is still encouraged.

Effect of essential fatty acid blend on circadian variations of ambulatory blood pressure in patients with essential hypertension and coronary artery disease risk markers

Flaxseed oil is an excellent source of alpha-linolenic acid ALA known for its antihypertensive action. Flaxseed oil is unstable and its dose is not achievable in our conventional diet hence blending of natural flaxseed oil with palm oil, containing high flavonoids may be a better strategy, to stabilize the blend and provide proper balance of essential fatty acids and potential antioxidant effects. Aim of this study was to access the effect of blended flaxseed oil on 24 h 7-day circadian variations of blood pressure in subjects with essential hypertension. Assessment of CHAT (circadian hyper amplitude tension) using ABPM is the best marker for cardiovascular function. We registered 50 subjects with CAD (Group 1) and 50 subjects with Essential hypertension HT (Group 2) and 52 control subjects with CAD/Hypertension. Group 1 and 2 participant was supplemented with blended flaxseed oil (BFO) (30 ml/day) for the period of 24 weeks, while control group administered available oils sunflower in identical containers, for a follow-up period of 24 weeks. Twenty four hour seven days continuous ambulatory blood pressure monitoring was done initially and after six months of BFO supplementation. There were significant changes noted in lipid profile along with Ambulatory blood pressure parameters like MESOR, ACROPHASE, Hyperbaric Indexes, and CHAT. Circadian hyper amplitude tension (CHAT) incidence decreased after BFO supplementation. Study results suggest that blended flaxseed oil administration can be a potent natural vegetarian antihypertensive supplement which helps in synchronization of cardiac rhythms, and can be used as a preventive treatment of hypertension and as effective vegetarian source of maintaining Omega 3 and omega 6 ratios of essential fatty acids in the body.

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= .

Unsaturated Fatty Acids Improve Atherosclerosis Markers in Obese and Overweight Non-diabetic Elderly Patients

BACKGROUND

Several studies have demonstrated the benefits of replacing trans and saturated fats with unsaturated fatty acids on cardiovascular diseases. We aimed to demonstrate the effect of polyunsaturated and monounsaturated fat supplementation on the biochemical and endothelial markers of atherosclerotic disease in obese or overweight non-diabetic elderly patients.

METHOD

Seventy-nine patients were randomly divided into three groups: flaxseed oil, olive oil, and sunflower oil; patients in each group received 30 mL of oil for 90 days. Patients were subjected to anthropometric and bioimpedance assessments; biochemical and endothelial evaluations were performed through ultrasonography of the brachial artery and carotid artery for endothelium-dependent dilation and intima-media thickness assessment, respectively, before and after the intervention. The participants' usual diet remained unchanged.

RESULTS

The flaxseed oil group had improved ultra-sensitive C-reactive protein levels (p = 0.074) and reduced carotid intima-media thickness (CIMT) (p = 0.028); the olive oil group exhibited an improved apolipoprotein (Apo)B/ApoA ratio (p = 0.021), reduced CIMT (p = 0.028), and improved flow-mediated vasodilation (FMV) (p = 0.054); and similarly, the sunflower oil group showed an improved ApoB/ApoA ratio (p = 0.024), reduced CIMT (p = 0.048), and improved FMV (p = 0.001).

CONCLUSION

Unsaturated fatty acid supplementation using the three vegetable oils attenuated pro-inflammatory properties and improved prothrombotic conditions. Therefore, introducing or replacing saturated and trans fat with unsaturated fatty acids is beneficial for cardiovascular risk reduction in obese or overweight non-diabetic elderly people. Further studies are needed to determine which unsaturated fat best prevents cardiovascular disease in elderly patients.

Effect of Altering Dietary n-6:n-3 Polyunsaturated Fatty Acid Ratio with Plant and Marine-Based Supplement on Biomarkers of Bone Turnover in Healthy Adults

Although there is accumulating evidence for a protective role of n-3 polyunsaturated fatty acids (n-3 PUFAs) on bone health, there are limited studies that examine the effect of altering dietary n-6:n-3 PUFA ratio with plant and marine sources of n-3 PUFA on bone health. Healthy adults (n = 24) were randomized into an eight-week crossover study with a four-week washout between treatments, with each subject consuming three of four diets. The four diets differed in the dietary n-6:n-3 PUFA ratios and either had an algal oil supplement added or not: (Control diet (10:1); α-linolenic acid (ALA) diet (2:1); Eicosapentaenoic acid/Docosahexaenoic acid (EPA/DHA) diet (10:1 plus supplement (S) containing EPA/DHA; Combination diet (2:1 + S)). The supplement was microalgae oil that provided 1 g EPA + DHA/day. Flaxseed oil and walnuts provided 8.6 g of ALA/day in the 2:1 diets. Serum levels of c-telopeptide (CTX), procollagen Type I N-terminal peptide, and osteocalcin showed significant correlation with age but none of the bone markers or peroxisomal proliferator-activated receptor-γ mRNA expression was significantly different between the diets. Serum CTX was negatively associated with red blood cell membrane linoleic acid and ALA and positively associated with membrane DHA. Neither altering dietary n-6:n-3 PUFA ratio from a 10:1 to a 2:1 ratio nor adding EPA/DHA supplement significantly changed bone turnover in the short term in healthy adults.

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

Flaxseed consumption may be inversely associated with obesity; however, findings of available randomized controlled trials (RCTs) are conflicting. The present study aimed to systematically review and analyse RCTs assessing the effects of flaxseed consumption on body weight and body composition. PubMed, Medline via Ovid, SCOPUS, EMBASE and ISI Web of Sciences databases were searched up to November 2016. Mean changes in body composition indices including body weight, body mass index (BMI) and waist circumference were extracted. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity between studies was assessed with the I² test. Publication bias and subgroup analyses were also performed. The quality of articles was assessed via the Jadad scale. A total of 45 RCTs were included. Meta-analyses suggested a significant reduction in body weight (WMD: -0.99 kg, 95% CI: -1.67, -0.31, p = 0.004), BMI (WMD: -0.30 kg m^-2 , 95% CI: -0.53, -0.08, p = 0.008) and waist circumference (WMD: -0.80 cm, 95% CI: -1.40, -0.20, p = 0.008) following flaxseed supplementation. Subgroup analyses showed that using whole flaxseed in doses ≥30 g d^-1 , longer-term interventions (≥12 weeks) and studies including participants with higher BMI (≥ 27 kg m^-2 ) had positive effects on body composition. Whole flaxseed is a good choice for weight management particularly for weight reduction in overweight and obese participants.

Adipose tissue α-linolenic acid is inversely associated with insulin resistance in adults

BACKGROUND

There is emerging evidence of the beneficial effects of n-3 (ω-3) fatty acids (FAs) on cardiometabolic risk factors. Nevertheless, not much is known about the association between adipose tissue α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) and insulin resistance.

OBJECTIVE

We determined the association between adipose tissue n-3 FAs (total n-3 FAs, ALA, and EPA plus DHA) and insulin resistance in healthy adults.

DESIGN

In this cross-sectional study, multivariable analyses were used to assess the association between adipose tissue FAs (ALA, EPA plus DHA, and total n-3 FAs) and the homeostasis model assessment of insulin resistance (HOMA-IR) in a subset of adult participants (n= 716; mean age: 58 y) from the Adventist Health Study-2 (AHS-2) cohort.

RESULTS

Compared with the lowest tertile, the third tertile (β = -0.13; 95% CI: -0.24, -0.01) of adipose tissue ALA was inversely associated with the HOMA-IR. When stratified by waist circumference, ALA continued to be inversely associated [third tertile: β = -0.17 (95% CI: -0.31, -0.02)] with the HOMA-IR in subjects with a waist circumference ≤88 cm in women or ≤102 cm in men but not in those with a larger waist circumference. No significant association was noted between adipose tissue EPA plus DHA and HOMA-IR.

CONCLUSIONS

Higher adipose tissue ALA was inversely associated with insulin resistance in this cohort of healthy adult men and women. This finding appears to be more pronounced in individuals with a normal waist circumference.

The effect of modifying dietary LA and ALA intakes on omega-3 long chain polyunsaturated fatty acid (n-3 LCPUFA) status in human adults: a systematic review and commentary

This paper presents a systematic review of human studies investigating the effect of altering dietary omega-3 polyunsaturated fatty acid (n-3 PUFA) alpha-linolenic acid (ALA) and omega-6 polyunsaturated fatty acid (n-6 PUFA) linoleic acid (LA) intakes on n-3 long-chain polyunsaturated fatty acid (LCPUFA) status in adult humans. The results suggest that it is possible to increase n-3 LCPUFA status by reducing LA and/or increasing ALA intake in humans, although decreasing LA intake to below 2.5%E may be required to specifically increase levels of the n-3 LCPUFA docosahexaenoic acid (DHA). The majority of studies in this area to date have been relatively poor in quality, which limits the ability to draw robust conclusions, and we present a series of recommendations to improve the quality of future studies in fatty acid nutrition in humans.

Flaxseed consumption may reduce blood pressure: a systematic review and meta-analysis of controlled trials

BACKGROUND

High blood pressure is a major health burden positively associated with the risk of cardiovascular disease and other chronic diseases. Flaxseed is a rich dietary source of α-linolenic acid, lignans, and fiber, with a number of positive health benefits on blood pressure.

OBJECTIVE

The purpose of this study was to clarify the effect of flaxseed consumption on blood pressure. Further, the influence of baseline blood pressure, type of flaxseed supplementation, and duration of flaxseed supplementation on blood pressure was explored.

METHOD

PubMed (MEDLINE), Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library (Central) were searched through July 2014 for studies in which humans supplemented their habitual diet with flaxseed or its extracts (i.e., oil, lignans, fiber) for ≥2 wk.

RESULTS

A total of 11 studies (14 trials) were included in the analysis. Random-effects meta-analyses were conducted for the mean difference in blood pressure. Results indicated that flaxseed supplementation reduced systolic blood pressure (-1.77 mm Hg; 95% CI: -3.45, -0.09 mm Hg; P = 0.04) and diastolic blood pressure (-1.58 mm Hg; 95% CI: -2.64, -0.52 mm Hg; P = 0.003). These results were not influenced by categorization of participants into higher baseline blood pressure (≥130 mm Hg). An improvement in diastolic blood pressure was observed in subgroup analysis for consuming whole flaxseed (-1.93 mm Hg; 95% CI: -3.65, -0.21 mm Hg; P < 0.05) and duration of consumption ≥12 wk (-2.17 mm Hg; 95% CI: -3.44, -0.89 mm Hg; P < 0.05).

CONCLUSION

The present meta-analysis suggests that consumption of flaxseed may lower blood pressure slightly. The beneficial potential of flaxseed to reduce blood pressure (especially diastolic blood pressure) may be greater when it is consumed as a whole seed and for a duration of >12 wk.

Health benefits of plant-derived α-linolenic acid

α-Linolenic acid (ALA) is an n-3 (ω-3) fatty acid found mostly in plant foods such as flaxseed, walnuts, and vegetable oils, including canola and soybean oils. Most of the health benefits observed for n-3 fatty acids have been attributed to the marine-derived long-chain n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid, because of the strength of evidence from both epidemiologic studies and randomized controlled trials. Furthermore, the observed cardioprotective and other health effects of ALA have been credited to its precursor role in converting to EPA in the body. The promotion of fatty fish consumption for its documented health benefits may not be practical for those who are concerned with the unsustainability of marine sources or who avoid eating fish for a variety of reasons. ALA-rich plant sources are more abundant and may serve as a suitable alternate. It is therefore worthwhile to consider the evidence for the health benefits of ALA. The purpose of this review is to present the evidence from recent studies on the association between ALA and cardiovascular disease, type 2 diabetes, and fracture risk. The potential mechanisms that explain these associations will also be briefly discussed.

Plant compared with marine n-3 fatty acid effects on cardiovascular risk factors and outcomes: what is the verdict?

Plants provide α-linolenic acid [ALA; 18:3n-3 (18:3ω-3)], which can be converted via eicosapentaenoic acid (EPA; 20:5n-3) to docosahexaenoic acid (DHA; 22:6n-3), which is required for normal visual and cognitive function. Dietary ALA is provided mainly by vegetable oils, especially soybean and rapeseed oils, but is destroyed by partial hydrogenation; it is also present in high amounts in walnuts and flaxseed. Dietary EPA and DHA are provided mainly by fish and so are absent from vegan diets and only present in trace amounts in vegetarian diets. Vegetarians and vegans have lower proportions of DHA in blood and tissue lipids compared with omnivores. High intakes of EPA and DHA (typically in the range of 3-5 g/d) but not ALA have favorable effects on several cardiovascular disease (CVD) risk factors and have been postulated to delay arterial aging and cardiovascular mortality, but these intakes are beyond the range of normal dietary intake. Arterial stiffness, which is a measure of arterial aging, appears to be lower in vegans than in omnivores; and risk of CVD in vegetarians and vegans is approximately one-third that in omnivores. Prospective cohort studies showed higher intakes of EPA+DHA, and less consistently ALA, to be associated with a lower risk of CVD, especially fatal coronary heart disease, but meta-analyses of randomized controlled trials of supplementation of EPA+DHA or ALA in secondary prevention of CVD showed no clear benefit. Current evidence is insufficient to warrant advising vegans and vegetarians to supplement their diets with EPA or DHA for CVD prevention.

A meta-analysis shows that docosahexaenoic acid from algal oil reduces serum triglycerides and increases HDL-cholesterol and LDL-cholesterol in persons without coronary heart disease

Certain algae contain the (n-3) fatty acid DHA, yet the relation between algal oil supplementation and cardiovascular disease risk factors has not been systematically examined. Our objective was to examine the relation between algal oil supplementation and cardiovascular disease risk factors. We conducted a systematic review of randomized controlled trials published between 1996 and 2011 examining the relation between algal oil supplementation and cardiovascular disease risk factors and performed a meta-analysis of the association between algal oil DHA supplementation and changes in the concentrations of TG, LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C). We identified 11 randomized controlled trials with 485 healthy participants that evaluated the relation between algal oil DHA supplementation and TG, LDL-C, and HDL-C. The median dose of algal DHA was 1.68 g/d. The pooled estimate for the change in TG concentration was -0.20 mmol/L (95% CI: -0.27 to -0.14), 0.23 mmol/L (95% CI: 0.16-0.30) for LDL-C, and 0.07 mmol/L (95% CI: 0.05-0.10) for HDL-C. DHA supplementation from algal oil, a marine source of (n-3) fatty acids not extracted from fish, may reduce serum TG and increase HDL-C and LDL-C in persons without coronary heart disease.