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Olive pomace oil can improve blood lipid profile: a randomized, blind, crossover, controlled clinical trial in healthy and at-risk volunteers.
González-Rámila, S, Sarriá, B, Seguido, MA, García-Cordero, J, Mateos, R, Bravo, L
European journal of nutrition. 2023;62(2):589-603
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Morbidity and mortality from cardiovascular diseases (CVD) are increasing. It is known that a healthy diet and physical exercise can modulate the risk of CVD. In this regard, the Mediterranean Diet (MD) is considered a model of healthy eating and olive oil is an essential component of this diet, as its primary fat source. The aims of this study were to assess the possible beneficial role of consuming olive pomace oil (OPO) as the main source of fat in the diet on serum lipid concentrations (primary outcome) and other biomarkers of cardiovascular health such as blood pressure, endothelial function and inflammation (secondary outcomes) in at-risk (hypercholesterolaemic) subjects. This study was a randomised, blind, crossover, controlled clinical trial in free-living subjects. Participants, men and women aged 18–55 years, were randomly assigned to one of the two groups; normocholesterolaemic or hypercholesterolaemic group. Results showed that consumption of OPO for four weeks resulted in an improved blood lipid profile, decreasing low-density lipoprotein cholesterol, Apo B and low-density lipoprotein/ high-density lipoprotein ratio both in healthy and at-risk volunteers, in contrast to the opposite effect observed with high-oleic acid sunflower oil (HOSO), with no significant changes in other CVD risk factors. Furthermore, no changes were observed in relation to blood pressure, and biomarkers linked to inflammation and endothelial function. Authors conclude that OPO could have hypolipidemic actions in healthy consumers and in subjects with high blood cholesterol, contributing to cardiovascular disease prevention.
Abstract
PURPOSE This study aimed to assess the effect of dietary consumption of olive pomace oil (OPO) on blood lipids (primary outcome) and other cardiovascular disease (CVD) risk factors (blood pressure, inflammation and endothelial function as secondary outcomes). METHODS A randomized, controlled, blind, crossover intervention was carried out in healthy and at-risk (hypercholesterolemic) subjects. Participants consumed daily 45 g of OPO or high-oleic acid sunflower oil (HOSO) as control oil during 4 weeks. RESULTS OPO significantly reduced low-density lipoprotein cholesterol (LDL-C; P = 0.003) and apolipoprotein B (Apo B; P = 0.022) serum concentrations, and LDL/HDL ratio (P = 0.027) in healthy and at-risk volunteers. These effects were not observed with HOSO. Blood pressure, peripheral artery tonometry (PAT), endothelial function and inflammation biomarkers were not affected. CONCLUSIONS Regular consumption of OPO in the diet could have hypolipidemic actions in subjects at cardiovascular risk as well as in healthy consumers, contributing to CVD prevention. CLINICAL TRIAL REGISTRY NCT04997122, August 8, 2021, retrospectively registered.
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Diverging metabolic effects of 2 energy-restricted diets differing in nutrient quality: a 12-week randomized controlled trial in subjects with abdominal obesity.
Schutte, S, Esser, D, Siebelink, E, Michielsen, CJR, Daanje, M, Matualatupauw, JC, Boshuizen, HC, Mensink, M, Afman, LA
The American journal of clinical nutrition. 2022;116(1):132-150
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Energy restriction (ER) diets are considered an effective strategy for managing obesity and preventing or reducing the risk of associated comorbidities. However, there are very few previous studies comparing the quality of energy restriction diets and their effect on maximising the health benefits. Therefore, this 12-week, parallel-designed, randomised controlled trial compared the effects of a 25% high-quality ER diet with a 25% low-quality ER diet and a habitual diet on cardiometabolic risk factors of 110 participants with abdominal obesity. Both ER diets were nutritionally balanced. The high-quality ER diet had added Monounsaturated fatty acids (MUFAs), Omega-3 Polyunsaturated fatty acids (n-3 PUFAs), fibre, and plant protein and had less fructose in it. The low-quality ER diet contained Saturated fatty acids (SFAs) and monosaccharides such as fructose. At the end of the 12-week trial, participants on the 25% high-quality diet showed more promising results in weight loss, reduction in cholesterol and triglycerides, and adipose tissue gene expression of energy metabolism pathways compared to the 25% low-quality ER diet. Insulin-sensitive participants with abdominal obesity on a 25% high-quality diet lost more weight compared to the rest of the participants. Further robust studies are required to evaluate the findings due to the limitations of this study. However, healthcare professionals can use the results of this study to understand the beneficial effects of an ER diet when it is enriched with specific nutrients.
Abstract
BACKGROUND Despite the established relation between energy restriction (ER) and metabolic health, the most beneficial nutrient composition of a weight-loss diet is still a subject of debate. OBJECTIVES The aim of the study was to examine the additional effects of nutrient quality on top of ER. METHODS A parallel-designed, 12-week 25% ER dietary intervention study was conducted (clinicaltrials.gov: NCT02194504). Participants aged 40-70 years with abdominal obesity were randomized over 3 groups: a 25% ER high-nutrient-quality diet (n = 40); a 25% ER low-nutrient-quality diet (n = 40); or a habitual diet (n = 30). Both ER diets were nutritionally adequate, and the high-nutrient-quality ER diet was enriched in MUFAs, n-3 PUFAs, fiber, and plant protein and reduced in fructose. Before and after the intervention, intrahepatic lipids, body fat distribution, fasting and postprandial responses to a mixed-meal shake challenge test of cardiometabolic risk factors, lipoproteins, vascular measurements, and adipose tissue transcriptome were assessed. RESULTS The high-nutrient-quality ER diet (-8.4 ± 3.2) induced 2.1 kg more weight loss (P = 0.007) than the low-nutrient-quality ER diet (-6.3 ± 3.9), reduced fasting serum total cholesterol (P = 0.014) and plasma triglycerides (P < 0.001), promoted an antiatherogenic lipoprotein profile, and induced a more pronounced decrease in adipose tissue gene expression of energy metabolism pathways than the low-quality ER diet. Explorative analyses showed that the difference in weight loss between the two ER diets was specifically present in insulin-sensitive subjects (HOMA-IR ≤ 2.5), in whom the high-nutrient-quality diet induced 3.9 kg more weight loss than the low-nutrient-quality diet. CONCLUSIONS A high-nutrient-quality 25% ER diet is more beneficial for cardiometabolic health than a low-nutrient-quality 25% ER diet. Overweight, insulin-sensitive subjects may benefit more from a high- than a low-nutrient-quality ER diet with respect to weight loss, due to potential attenuation of glucose-induced lipid synthesis in adipose tissue.
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Impact of Replacement of Individual Dietary SFAs on Circulating Lipids and Other Biomarkers of Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Humans.
Sellem, L, Flourakis, M, Jackson, KG, Joris, PJ, Lumley, J, Lohner, S, Mensink, RP, Soedamah-Muthu, SS, Lovegrove, JA
Advances in nutrition (Bethesda, Md.). 2022;13(4):1200-1225
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Cardiovascular disease is one of the leading causes of mortality worldwide, and metabolic disorders such as diabetes, hyperlipidaemia, and hypertension contribute to this risk. Cardiometabolic disease (CMD) can be reduced by reducing saturated fatty acids (SFAs) and replacing them with unsaturated fatty acids (UFAs). Dietary SFA's are classified as a whole group in general dietary guidelines. However, blood lipid levels and other biomarkers of CMD may be affected differently by individual dietary SFAs. In this systematic review and meta-analysis, 44 randomised controlled trials were included that investigated the effects of replacing SFAs with individual dietary SFAs or UFAs on markers of CMD. CMD markers like Total cholesterol (TC), LDL cholesterol, and apoB concentrations were significantly reduced by replacing 1.5%TE of palmitic acid with oleic acid or UFAs for 14 days. The research also showed associations between apoB and LDL-cholesterol and apoA-I and HDL-cholesterol concentrations. Dietary palmitic acid substituted with UFAs significantly reduced fasting LDL-cholesterol and total cholesterol. The majority of studies included in this study focused on dietary palmitic acid and not much on stearic acid, myristic acid, or lauric acid. Therefore, further robust studies are required to assess the effect of individual dietary SFAs on the markers of CMD, including markers of inflammation, hemostasis, glycemic control, or metabolic hormones. Healthcare professionals can use this study to understand the benefits of substituting SFAs with UFAs on CMD markers.
Abstract
Little is known of the impact of individual SFAs and their isoenergetic substitution with other SFAs or unsaturated fatty acids (UFAs) on the prevention of cardiometabolic disease (CMD). This systematic literature review assessed the impact of such dietary substitutions on a range of fasting CMD risk markers, including lipid profile, markers of glycemic control and inflammation, and metabolic hormone concentrations. Eligible randomized controlled trials (RCTs) investigated the effect of isoenergetic replacements of individual dietary SFAs for ≥14 d on ≥1 CMD risk markers in humans. Searches of the PubMed, Embase, Scopus, and Cochrane CENTRAL databases on 14 February, 2021 identified 44 RCTs conducted in participants with a mean ± SD age of 39.9 ± 15.2 y. Studies' risk of bias was assessed using the Cochrane Risk of Bias tool 2.0 for RCTs. Random-effect meta-analyses assessed the effect of ≥3 similar dietary substitutions on the same CMD risk marker. Other dietary interventions were described in qualitative syntheses. We observed reductions in LDL-cholesterol concentrations after the replacement of palmitic acid (16:0) with UFAs (-0.36 mmol/L; 95% CI: -0.50, -0.21 mmol/L; I2 = 96.0%, n = 18 RCTs) or oleic acid (18:1n-9) (-0.16 mmol/L; 95% CI: -0.28, -0.03 mmol/L; I2 = 89.6%, n = 9 RCTs), with a similar impact on total cholesterol and apoB concentrations. No effects on other CMD risk markers, including HDL-cholesterol, triacylglycerol, glucose, insulin, or C-reactive protein concentrations, were evident. Similarly, we found no evidence of a benefit from replacing dietary stearic acid (18:0) with UFAs on CMD risk markers (n = 4 RCTs). In conclusion, the impact of replacing dietary palmitic acid with UFAs on lipid biomarkers is aligned with current public health recommendations. However, owing to the high heterogeneity and limited studies, relations between all individual SFAs and biomarkers of cardiometabolic health need further confirmation from RCTs. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42020084241.
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Lipid Intake and Breast Cancer Risk: Is There a Link? A New Focus and Meta-Analysis.
Lodi, M, Kiehl, A, Qu, FL, Gabriele, V, Tomasetto, C, Mathelin, C
European journal of breast health. 2022;18(2):108-126
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Incidence of breast cancer is the leading cause of cancer-related mortality, accounting for 15.5% of all cancer-related deaths. However, there is a lack of complete understanding of the effects of different types of dietary lipids on breast cancer development, such as saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), dietary cholesterol, polyunsaturated fatty acids (PUFA), and unsaturated trans fatty acids (TFA). An evaluation of the effect of lipid consumption on breast cancer and the impact it has on menopausal status was conducted in this meta-analysis, which included forty-four studies. Increased saturated fatty acid intake was associated with an increased risk of breast cancer in postmenopausal women. However, breast cancer risk was not associated with increased consumption of total fat, SFA, MUFA, PUFA, and cholesterol in premenopausal women. The effects of estrogen and the release of proinflammatory cytokines by adipocytes should be evaluated, as well as other pathways that contribute to the development of breast cancer. There is a need for further robust studies to evaluate the effects of different types of lipid consumption on breast cancer. Although the association between SFA and breast cancer is weak, healthcare professionals can use this study's findings to better understand the detrimental effect of SFA, despite the fact that there is a great deal of heterogeneity in the current analysis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The authors found no association between total fat, saturated fatty-acids, mono and poly-unsaturated fatty acids and cholesterol intake and breast cancer incidence in the general population and in pre-menopausal women.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
- Among lifestyle-related breast cancer risk factors, the role of diet in breast cancer remains uncertain.
- The authors highlight a weak association between high SFA consumption and breast cancer risk in post-menopausal women.
- The authors found no association between total fat, saturated fatty-acids, mono and poly-unsaturated fatty acids and cholesterol intake and breast cancer incidence in the general population and in pre-menopausal women.
Objectives
- To determine if there is an association between total lipid intake, saturated fatty acid (SFA), Poly- and Mono-Unsaturated Fatty Acid (PUFA and MUFA) and cholesterol intake and breast cancer risk.
Results
- Forty-four articles were included in the meta-analysis, consisting of 28 case-control studies and 16 cohort studies.
- In total, this meta-analysis involved 1,185,896 women, of whom 54,553 had breast cancer.
- There was no association between total fat, SFA, MUFA, PUFA and cholesterol intake and breast cancer in the general population and in pre-menopausal women.
- In postmenopausal women, high SFA consumption was associated with increased breast cancer risk in case-control studies [relative risk (RR): 1.12; confidence interval (CI) 95%: 1.03–1.21; p = 0.006 but not in cohort studies (RR: 1.01; CI 95%: 0.85–1.19; p = 0.93).
Limitations
- Studies included in the meta-analysis were carried out on populations from five continents with significant cultural and dietary diversity, and well as different types of oils used in the diet
Conclusion
- At this stage, the authors state it is not possible to establish nutritional recommendations regarding the consumption of lipids to decrease breast cancer risk.
Clinical practice applications:
- The results of this meta-analysis does not demonstrate a statistically significant link between high consumption of total lipids, PUFA, MUFA and cholesterol and the occurrence of breast cancer.
- However, the results suggest that there is an association between SFA intake and breast cancer risk in postmenopausal women, although this was only found in case-controlled studies and not cohort studies.
- While obesity is a known breast cancer risk factor after menopause, the link between the effect of diet and the effect of obesity on the breast may be through different mechanisms.
- The authors investigated if high lipid consumption acts on breast tissue by the same mechanisms as obesity, and found the association between SFA intake and breast cancer risk in postmenopausal women must be through other biological explanations.
- The authors found that while high SFA consumption may increase breast cancer risk among post-menopausal women, biological mechanisms linking SFA and breast cancerogenesis are still unknown.
- The meta-analysis found high blood cholesterol levels appear to increase the risk of breast cancer. However, the authors could not confirm that high dietary cholesterol intake is a risk factor for breast cancer. The authors postulated this may be in part due to the low proportion of cholesterol (about 30%) in the diet, while the rest comes from the degradation of lipids and carbohydrates by the liver.
Considerations for future research:
- As lipids can have different actions in the same family, studies should rather focus on specific lipid consumption
Abstract
Objective: To determine if there is an association between total lipid intake, saturated fatty acid (SFA), Poly- and Mono-Unsaturated Fatty Acid (PUFA and MUFA) and cholesterol intake and breast cancer risk. Materials and Methods: We conducted a systematic review of the literature and a meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included all cohort and case-control studies published up to December 2020 with subgroup analysis according to menopausal status. Results: We included 44 articles for analysis. There was no association between total fat, SFA, MUFA, PUFA and cholesterol intake and breast cancer in the general population and in pre-menopausal women. In postmenopausal women, high SFA consumption was associated with increased breast cancer risk in case-control studies [relative risk (RR): 1.12; confidence interval (CI) 95%: 1.03-1.21; p = 0.006 but not in cohort studies (RR: 1.01; CI 95%: 0.85-1.19; p = 0.93). Conclusion: There was a weak association between high SFA consumption and breast cancer risk in post-menopausal women, however there was high heterogeneity for this analysis. As lipids can have different actions in the same family, studies should rather focus on specific lipid consumption.
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Nutrition to Prevent or Treat Cognitive Impairment in Older Adults: A GRADE Recommendation.
Buckinx, F, Aubertin-Leheudre, M
The journal of prevention of Alzheimer's disease. 2021;8(1):110-116
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Cognitive impairment is a public health problem due to its increasing prevalence in the aging population. Despite pharmacological advances, there are not yet effective treatments to delay or reverse cognitive impairment. Moreover, there is limited knowledge of Alzheimer disease modifiable risk factors namely nutrition. The aim of this review was to grade, classify and provide recommendations for the preferred diet to prevent or to treat cognitive impairment. This review shows that: - some nutritional factors appear to either increase the risk of cognitive decline or protect against it. - risk could be conferred by diets high in milk and dairy products whereas some protection can be offered by adhering to a Mediterranean diet to decrease the risk of cognitive decline. - it is important to follow a diet rich in mono- and poly- unsaturated fatty acids, fruit and vegetable, vitamin D and low in saturated fatty acids. Authors conclude that diet is an important modifiable factor to prevent or protect against cognitive decline.
Abstract
Aging is associated with cognitive declines leading to mild cognitive impairments or Alzheimer disease. Nutrition appear to protect from aging. Some dietary factors could either increase or protect against cognitive declines. This article aimed to provide GRADE recommendations related to nutrition aspects able to prevent or to treat cognitive impairments. A comprehensive literature review was performed using Medline database. The GRADE approach was used to classify quality of the existing evidence (systematic review or meta-analysis).The GRADE process led us to formulate seven key nutritional recommendations to manage cognitive declines, but did not allow us to do it for protein, vitamin B or antioxidants. Thus, 1) adherence to a Mediterranean diet (GRADE 1B); 2) high-level of consumption of mono- or poly- unsaturated fatty acids combined to a low consumption of saturated fatty acids (GRADE 1B); 3) high consumption of fruits and vegetables (GRADE 1B); 4) higher vitamin D intake (GRADE 1C) than the recommended daily allowance. In addition, a ketogenic diet, a low consumption of whole-fat dairy products or a caloric restriction are promising nutritional habits although the evidence does not yet support widespread uptake (GRADE 2C). In conclusion, nutrition is an important modifiable factor to prevent or protect against cognitive decline. Nevertheless, more studies are required to determine specific guidelines such as duration and amounts of nutrients to help older adult to maintain a healthy cognitive life.
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Mediterranean Diet and its Benefits on Health and Mental Health: A Literature Review.
Ventriglio, A, Sancassiani, F, Contu, MP, Latorre, M, Di Slavatore, M, Fornaro, M, Bhugra, D
Clinical practice and epidemiology in mental health : CP & EMH. 2020;16(Suppl-1):156-164
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Mediterranean Diet (MD) is currently considered one of the healthiest dietary models worldwide due to the high intake of antioxidants, dietary fibre, monounsaturated and omega-3 fatty acids, phytosterols and probiotics. The aim of this review was to present current literature showing evidence on the possible impact of MD on health and mental health. The review was based on 27 articles of which 13 were carried out in Spain, 3 in the USA, 3 in Italy, 4 in Australia and 4 in other EU countries. Literature shows that MD improves: - metabolic cardiovascular parameters with a reduced incidence of major cardiovascular events by approximately 30%. - metabolic balance in patients affected by type 2 diabetes mellitus. - biochemical markers for metabolic disorders as well as in patients at risk of specific cancer diseases. Additionally, not enough data is available on the MD effects on specific psychopathological issues. In fact, besides adherence to MD, other factors - which should be further investigated - also play a role in the effectiveness of the MD. Authors conclude that further studies are needed to address the efficacy of diet as an adjunctive treatment for mental disorders as well as for the management of comorbid cardiovascular and metabolic issues.
Abstract
Mediterranean Diet (MD) is currently considered one of the most healthy dietary models worldwide. It is generally based on the daily intake of fruit and vegetables, whole grains, legumes, nuts, fish, white meats, and olive oil. It may also include moderate consumption of fermented dairy products, a low intake of red meat, and red/white wine during the main course. Even if the effect of MD on cancer prevention as well as on human metabolic and cardiovascular balance has been discussed, including the quality of life of the exposed population, the putative effects on mental health are still not properly investigated. This narrative review reports on some emerging pieces of evidence on the possible impact of MD on general health and the outcome of psychiatric disorders (e.g., major depression, anxiety) and encourages further studies to test the benefits of healthy food selection on the health of the general population.
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Thrombosis and COVID-19: The Potential Role of Nutrition.
Tsoupras, A, Lordan, R, Zabetakis, I
Frontiers in nutrition. 2020;7:583080
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COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). The lungs seem to be the initial target organ of SARS-CoV-2, however it became clear that other systems including the cardiovascular and neurological systems were also involved. Literature shows that thrombotic complications are a significant risk factor for COVID-19 patients. In fact, adopting healthy dietary habits: - will prevent the onset of non-communicable diseases, which is a significant risk factor for the development of COVID-19, - may support the immune system to lessen the severity of an infection, and - may prevent the onset of severe thrombotic complications due to the presence of bioactive compounds with antiplatelet effects (for non-infected individuals, especially those with or at increased risk of underlying non-communicable diseases). Authors emphasise on the importance of establishing clinical trials to investigate potential pharmacological and nutritional mitigation strategies to prevent thrombotic complications as a result of severe COVID-19 infection.
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease (COVID-19), is a contagion that has rapidly spread around the globe. COVID-19 has caused significant loss of life and disrupted global society at a level never before encountered. While the disease was predominantly characterized by respiratory symptoms initially, it became clear that other systems including the cardiovascular and neurological systems were also involved. Several thrombotic complications were reported including venous thrombosis, vasculitis, cardiomyopathy, and stroke. Thrombosis and inflammation are implicated in various non-communicable diseases (NCDs). This is of significant concern as people with pre-existing conditions such as cardiovascular disorders, renal disorders, obesity, metabolic syndrome, and diabetes are at greater risk of severe COVID-19 infection. Consequently, the research surrounding the use of anticoagulants, antiplatelet, and antithrombotic strategies for prophylaxis and treatment of COVID-19 is of critical importance. The adoption of a healthy diet, physical exercise, and lifestyle choices can reduce the risk factors associated with NCDs and the thrombo-inflammatory complications. In this review, these thrombotic complications and potential foods, nutraceuticals, and the antithrombotic constituents within that may prevent the onset of severe thrombotic complications as a result of infection are discussed. While nutrition is not a panacea to tackle COVID-19, it is apparent that a patient's nutritional status may affect patient outcomes. Further intensive research is warranted to reduce to incidence of thrombotic complications.
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Mixed Nut Consumption May Improve Cardiovascular Disease Risk Factors in Overweight and Obese Adults.
Abbaspour, N, Roberts, T, Hooshmand, S, Kern, M, Hong, MY
Nutrients. 2019;11(7)
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A large portion of heart disease cases are preventable through lifestyle and dietary modifications. The aim of this study was to assess the effect of daily intake of 42.5 g of mixed nuts on cardiovascular disease (CVD) risk factors in overweight and obese adults. This study is an 8-week randomized, parallel-arm, controlled trial with two isocaloric treatment groups of mixed-nuts and pretzels. A total of 54 participants (22 females and 32 males) were recruited. Results indicate that supplementation of 42.5 g/day of mixed nuts for 8 weeks decreases body weight, insulin, blood glucose, and lactate dehydrogenase [enzyme] levels compared with consumption of an isocaloric amount of pretzels. Additionally, consumption of pretzels increased low-density lipoprotein cholesterol and triglyceride levels while decreasing high-density lipoprotein cholesterol. Authors conclude that the incorporation of mixed nuts into a usual diet improves some risk factors for CVD.
Abstract
Emerging research indicates that nuts are a source of health-promoting compounds demonstrating cardioprotective benefits. However, most studies have assessed the effect of single nuts rather than a nut mixture. The objective of this study was, therefore, to examine the effect of mixed-nut consumption on cardiovascular disease (CVD) risk factors in overweight and obese adults. In a randomized, parallel-arm, controlled trial, 48 participants consumed isocaloric (250 kcal) amounts of pretzels or mixed-nuts. Body weight (BW) (p = 0.024), BMI (p = 0.043), and insulin levels (p = 0.032) were significantly lower in the nut group compared to the pretzel group. Mixed-nut consumption also significantly reduced glucose (p = 0.04) and insulin (p = 0.032) levels after 4 and 8 weeks compared to baseline, respectively. Lactate dehydrogenase of the nut group was significantly lower than the pretzel group (p = 0.002). No significant differences were detected between groups for triglycerides, LDL-C, and HDL-C. However, pretzel consumption increased triglycerides (p = 0.048) from 4 weeks to 8 weeks. Moreover, LDL-C increased (p = 0.038) while HDL-C transiently decreased (p = 0.044) from baseline to 4 weeks. No significant lipid changes were detected within the nut group. Our results suggest that supplementing the diet with mixed-nuts could improve CVD risk factors by improving BW and glucose regulation in comparison to a common carbohydrate-rich snack without promoting the negative effects on lipids detected with pretzels.
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A Mediterranean Diet with Fresh, Lean Pork Improves Processing Speed and Mood: Cognitive Findings from the MedPork Randomised Controlled Trial.
Wade, AT, Davis, CR, Dyer, KA, Hodgson, JM, Woodman, RJ, Keage, HAD, Murphy, KJ
Nutrients. 2019;11(7)
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Dementia is characterised by severe cognitive impairment and reduced quality of life. Observational studies have demonstrated that populations following a traditional Mediterranean diet experience less cognitive decline and a lowered risk of dementia. The aim of this study was to examine a Mediterranean diet modified to include 2–3 fresh servings of pork each week across measures of cognitive function and well-being. The study is a 24-week parallel randomised controlled crossover design to compare a Mediterranean diet with 2-3 weekly servings of fresh, lean pork (MedPork) and a low-fat control diet (LF). It recruited adults aged 45–80 years due to their increased risk of developing cardiovascular disease. Results indicate that compared with the LF control diet, the MedPork intervention led to higher performance in the cognitive domain of processing speed and higher scores for the SF-36 subscale emotional role functioning. No significant differences were observed for other domains of cognitive function, nor for additional measures of psychological well-being. Authors conclude that the MedPork intervention can improve processing speed and mood in a population at risk of cardiovascular disease and therefore dementia.
Abstract
BACKGROUND The Mediterranean diet may be capable of improving cognitive function. However, the red meat restrictions of the diet could impact long-term adherence in Western populations. The current study therefore examined the cognitive effects of a Mediterranean diet with additional red meat. METHODS A 24-week parallel crossover design compared a Mediterranean diet with 2-3 weekly servings of fresh, lean pork (MedPork) and a low-fat (LF) control diet. Thirty-five participants aged between 45 and 80 years and at risk of cardiovascular disease followed each intervention for 8 weeks, separated by an 8-week washout period. Cognitive function was assessed using the Cambridge Neuropsychological Test Automated Battery. Psychological well-being was measured through the SF-36 Health Survey and mood was measured using the Profile of Mood States (POMS). RESULTS During the MedPork intervention, participants consumed an average of 3 weekly servings of fresh pork. Compared to LF, the MedPork intervention led to higher processing speed performance (p = 0.01) and emotional role functioning (p = 0.03). No other significant differences were observed between diets. CONCLUSION Our findings indicate that a Mediterranean diet inclusive of fresh, lean pork can be adhered to by an older non-Mediterranean population while leading to positive cognitive outcomes.
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Fat Quantity and Quality, as Part of a Low-Fat, Vegan Diet, Are Associated with Changes in Body Composition, Insulin Resistance, and Insulin Secretion. A 16-Week Randomized Controlled Trial.
Kahleova, H, Hlozkova, A, Fleeman, R, Fletcher, K, Holubkov, R, Barnard, ND
Nutrients. 2019;11(3)
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Dietary macronutrients play an important role in the risk of obesity and type 2 diabetes. The aim of this study was to assess the effect of diet changes on body weight and metabolism. This study is a 16-week randomized clinical trial. Adult men and women, with a body-mass index between 28 and 40 kg/m2, were enrolled. Participants were randomly assigned to the vegan or the control group and examined at baseline and 16 weeks. Results show that: - in overweight individuals, both fat quantity and quality were associated with changes in body weight, body composition, insulin resistance and insulin secretion. - decreased intake of saturated, trans, or total fat was linked to decreased fat mass. - changes in the fatty acid composition of the diet were associated with changes in insulin resistance and insulin secretion. Authors conclude that selecting foods so as to limit the intake of saturated and trans fats and increase the relative content of polyunsaturated fatty acids, may be a useful strategy for metabolic health.
Abstract
Macronutrient composition of the diet influences the development of obesity and insulin resistance. The aim of this study was to assess the role of dietary fat quantity and fatty acid composition in body composition, insulin resistance, and insulin secretion. An open parallel randomized trial design was used. Overweight participants (n = 75) were randomized to follow a low-fat vegan (n = 38) or control diet (n = 37) for 16 weeks. Dual X-ray absorptiometry was used to measure body composition. Insulin resistance was assessed with the Homeostasis Model Assessment (HOMA-IR) index. Insulin secretion was assessed after stimulation with a liquid breakfast (Boost Plus, Nestle, Vevey, Switzerland). Self-reported 3-day diet records were used to assess dietary intake. A linear regression model was used to test the relationship between fat intake and body composition, insulin resistance, and insulin secretion. Changes in fat intake expressed as percent of total energy consumed correlated positively with changes in fat mass (r = 0.52; p < 0.001; and 0.347; p = 0.006, respectively), even after adjustment for changes in body-mass index (BMI) and energy intake (0.33; p = 0.01). Decreased intakes of C18:0 (r = 0.37, p = 0.004) and CLA-trans-10-cis12 (r = 0.40, p = 0.002), but increased intake of C18:2 (r = -0.40, p = 0.002) and C18:3 (p = -0.36, p = 0.006), were associated with a decrease in HOMA-IR, independent on changes in BMI and energy intake. The main fatty acids associated with changes in fasting insulin secretion were C12:0 (r = -0.31, p = 0.03), and TRANS 16:1 (r = -0.33, p = 0.02), both independent on changes in BMI and energy intake. Our findings demonstrate that, in the context of a low-fat vegan diet, decreased intake of saturated and trans fats and increased relative content of polyunsaturated fatty acids, particularly linoleic and α-linolenic acids, are associated with decreased fat mass and insulin resistance, and enhanced insulin secretion.