Dietary intakes of monounsaturated fatty acids and risk of mortality from all causes, cardiovascular disease and cancer: A systematic review and dose-response meta-analysis of prospective cohort studies

Nervonic acid, a long chain monounsaturated fatty acid, improves mitochondrial function in adrenomyeloneuropathy fibroblasts

BACKGROUND AND PURPOSE

Nervonic acid plays a vital role in maintaining normal brain and neuronal function. Nervonic acid has gained increasing attention because of its potential neuroprotective and anti-inflammatory properties. Nonetheless, the beneficial effects of nervonic acid are yet to be fully investigated. Adrenomyeloneuropathy (AMN), a type of X-linked adrenoleukodystrophy (ALD), is a progressive inherited metabolic disease characterised by accumulation of saturated very long-chain fatty acids (VLCFAs) in plasma and tissues, leading to increasing oxidative stress, mitochondrial dysfunction, neuroinflammation, cognitive dysfunction and disability. We previously found that nervonic acid can biochemically reverse the accumulation of saturated VLCFAs and increase cellular ATP production in ALD. Here, we investigated nervonic acid as a potential therapy for ALD by assessing its impact on mitochondrial function.

EXPERIMENTAL APPROACH

We assessed the effect of nervonic acid on cellular bioenergetics and oxidative stress in AMN patient-derived fibroblasts. We employed Seahorse real-time cell metabolic analysis and imaging of cells treated with increasing concentrations of nervonic acid. Normal dermal fibroblasts served as the healthy control.

KEY RESULTS

AMN cells demonstrate significantly impaired basal respiration, ATP production, maximal respiration and spare respiratory capacity compared to healthy fibroblasts. These mitochondrial respiration parameters significantly improved on treatment with nervonic acid in a concentration-dependent manner. Nervonic acid treatment also significantly reduced mitochondria-derived and total cellular reactive oxygen species, indicating mitigation of total oxidative stress.

CONCLUSION AND IMPLICATIONS

Our findings indicate a new mechanism of action for nervonic acid in ALD and other mitochondrial dysfunction-associated diseases. This can also indirectly prevent downstream inflammation, thus altering disease progression.

Bacteria-microalgae interactions from an evolutionary perspective and their biotechnological significance

Interactions between bacteria and microalgae have been studied in natural environments and in industrial consortia. As results of co-evolution for millions of years in nature, they have developed complex symbiotic relationships, including mutualism, commensalism and parasitism, the nature of which is decided by mechanisms of the interaction. There are two main types of molecular interactions between microalgae and bacteria: exchange of nutrients and release of signalling molecules. Nutrient exchange includes transport of organic carbon from microalgae to bacteria and nutrient nitrogen released from nitrogen-fixing bacteria to microalgae, as well as reciprocal supply of micronutrients such as B vitamins and iron. Signalling molecules such as phytohormones secreted by microalgae and quorum sensing molecules secreted by bacteria have been shown to positively affect growth and metabolism of the symbiotic partner. However, there are still a number of potential microalgae-bacteria interactions that have not been well explored, including cyclic peptides, other quorum signalling molecules, and extracellular vesicles involved in exchange of genetic materials. A more thorough understanding of these interactions may not only result in a deeper understanding of the relationships between these symbiotic organisms but also have potential biotechnological applications. Upon new mechanisms of interaction being identified and characterized, novel bioprocesses of synthetic ecology might be developed especially for wastewater treatment and production of biofertilizers and biofuels.

Macronutrients and cardiovascular diseases: A narrative review of recent scientific literature

BACKGROUND & AIMS

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide. This narrative review explores the relationship between macronutrient intake and CVD risk, focusing on carbohydrates, proteins, and fats. The goal is to examine how specific types of macronutrients influence cardiovascular health and how dietary guidelines, such as those from the World Health Organization (WHO), can reduce the incidence of both fatal and non-fatal cardiovascular events.

METHODS

This narrative review draws upon existing research and WHO dietary guidelines to assess the impact of various macronutrients on cardiovascular outcomes. We searched the relevant literature up to December 2024 using Pubmed and Google Scholar. Key macronutrient groups-carbohydrates (with a focus on glycemic index and glycemic load), proteins (plant-based vs. animal-based), and fats (saturated, trans, polyunsaturated, and monounsaturated)-were analyzed to understand their roles in CVD prevention.

RESULTS

Low glycemic index (GI) and glycemic load (GL) were found to be associated with reduced CVD risk. Protein intake showed no significant direct association with CVD risk, but higher consumption of plant-based proteins was correlated with a reduced risk. Replacing animal proteins with plant-based alternatives led to improved lipid profiles, including reductions in total and low-density lipoprotein (LDL) cholesterol levels. Fats, particularly saturated and trans fats, were strongly linked to increased CVD risk. WHO guidelines recommend limiting these fats and replacing them with healthier alternatives, such as polyunsaturated and monounsaturated fats or slow-digesting carbohydrates, to lower CVD risk.

CONCLUSIONS

Macronutrients play a critical role in cardiovascular health, with specific types of carbohydrates, proteins, and fats having varying impacts on CVD risk. Future research should explore the complex interactions between these macronutrients, dietary patterns, and cultural factors to optimize global dietary guidelines for CVD prevention. Replacing high-GI carbohydrates, saturated fats, and trans fats with healthier alternatives is crucial for reducing cardiovascular risk globally.

Circulating fatty acid profiles impact total, cardiovascular disease, and cancer mortality in a population-based prospective cohort study

BACKGROUND

Evidence linking circulating fatty acids (FAs) to mortality from age-related chronic diseases was limited and inconsistent. We aimed to investigate the associations of plasma FAs with total, cardiovascular disease (CVD), and cancer mortality and explore the potential mechanism.

METHODS

117,871 individuals were prospectively followed in the UK Biobank. Circulating FAs were measured by a high-throughput NMR-based metabolic platform. Causes and dates of death were collected from death certificates according to the code of International Statistical Classification of Diseases (ICD-10).

RESULTS

Over a median follow-up of 11.9 years, 7805 (6.6 %) deaths occurred. Plasma saturated FAs (SFAs) were positively associated with total mortality risk while plasma polyunsaturated FAs (PUFAs) exhibited an inverse association. For cause-specific mortality, circulating PUFAs, linoleic acid (LA), and n-3 PUFAs were associated with 34 %, 30 %, and 37 % lower risk of CVD mortality, respectively. Moreover, plasma n-3 PUFAs were related to a 24 % lower risk of cancer mortality. However, circulating non-LA n-6 PUFAs were associated with 11 % and 22 % higher risk of total and cancer mortality, respectively. Serum levels of C-reactive protein (CRP) and apolipoprotein A (ApoA) had significant mediation effects on these associations. Additionally, the inverse association of plasma n-6 PUFAs with total mortality only existed among carriers of the GG genotype at rs16966952 and the inverse association of plasma PUFAs with CVD mortality was only observed among TT genotype carriers at rs174547.

CONCLUSIONS

Circulating PUFAs, particularly n-3 PUFAs and LA, were inversely related to premature death from chronic diseases and longevity. Inflammatory and lipid metabolism partially explained these associations. Genetic interactions with rs16966952 and rs174547 further modified these associations.

Effects of black soldier fly larvae (Hermetia illucens L.) as feed supplements on muscle nutrient composition, meat quality, and antioxidant capacity in Qianbei goat

OBJECTIVE

Black soldier fly (BSF) as an animal protein feed source is currently becoming a hot research topic. This study investigated the effects of the BSF as a protein feed source for goats on slaughter performance, muscle nutrient composition, amino acids, fatty acids, minerals, and antioxidant levels.

METHODS

Thirty Qianbei Ma goats (20.30±1.09 kg) were randomly divided into three groups: the control group (GRPC) supplemented with 10% full-fat soybean, treatment 1 (GRPU) supplemented with 10% untreated BSF, and treatment 2 (GRPT) supplemented with 10% heat-treated BSF. One-way analysis of variance among groups (with Fisher's least significant difference post hoc comparison) was used in this study.

RESULTS

The nutrients, amino acids, fatty acids, minerals, and antioxidants in muscle were analyzed. The results showed that there were no significant differences in the moisture, dry matter, crude protein, ash, amino acids, and mineral content of the muscles among the three feeding groups. The slaughter rate and carcass weight of the GRPU and GRPT groups were significantly lower (p<0.05). The overall meat quality of the GRPU and GRPT groups decreased (p<0.05). The individual unsaturated fatty acids and total unsaturated fatty acids in the GRPU group were higher (p<0.05) than those in the GRPC and GRPT groups. Both GRPU and GRPT decreased (p<0.05) the antioxidant capacity of the meat.

CONCLUSION

Therefore, the heat-treated BSF had a better effect on meat quality compared to untreated BSF, but there were greater negative effects on the meat quality of GRPU and GRPT than GRPC.

Association of dietary patterns derived by reduced-rank regression with colorectal cancer risk and mortality

PURPOSE

Unhealthy dietary patterns contribute to an increased risk of colorectal cancer (CRC). Limited prior research has used reduced rank regression (RRR) to assess dietary patterns relative to CRC risk. This study aimed to identify dietary patterns derived by RRR and assess their associations with CRC risk and mortality.

METHODS

We used data from the multicentre Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) trial. Dietary intake was assessed using a Dietary History Questionnaire. In the RRR intake of fibre, folate, and the percentage of energy from carbohydrates, saturated and unsaturated fatty acids were used as response variables. Cox models and competing risk survival regression, with age as the time scale, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC risk and mortality, respectively.

RESULTS

The median follow-up time for CRC risk (n = 1044) and mortality (n = 499) was 9.4 years (Interquartile Range: 8. 0, 10.1) and 16.9 years (11.9, 18.6), respectively. Two dietary patterns were identified: the first was characterised by high carbohydrate, folate and low fatty acid intake, and the second by high fibre and unsaturated fatty acid. Compared to participants in the first tertile of the high fibre and unsaturated fatty acid pattern, those in the third tertile had a lower risk of CRC (HR = 0.88; 95% CI: 0.76, 1.03), and colon cancer (HR = 0.85; 95% CI: 0.72, 1.01). Conversely, the high carbohydrate, high folate and low fatty acid pattern had no association with CRC outcomes. None of the dietary patterns showed associations with rectal cancer or CRC mortality.

CONCLUSION

A diet enriched with high fibre and unsaturated fatty acids may reduce the risk of CRC. These results highlight the potential protective effect of adequate fibre intake in conjunction with high consumption of unsaturated fatty acids against CRC.

Perspective on the health effects of unsaturated fatty acids and commonly consumed plant oils high in unsaturated fat

Epidemiological and clinical trial evidence indicates that n-6 polyunsaturated fatty acid (PUFA) intake is cardioprotective. Nevertheless, claims that n-6 PUFA intake promotes inflammation and oxidative stress prevail. This narrative review aims to provide health professionals with an up-to-date evidence overview to provide the requisite background to address patient/client concerns about oils containing predominantly unsaturated fatty acids (UFA), including MUFA and PUFA. Edible plant oils, commonly termed vegetable oils, are derived from vegetables, nuts, seeds, fruits and cereal grains. Substantial variation exists in the fatty acid composition of these oils; however, all are high in UFA, while being relatively low in saturated fatty acids (SFA), except for tropical oils. Epidemiological evidence indicates that higher PUFA intake is associated with lower risk of incident CVD and type 2 diabetes mellitus (T2DM). Additionally, replacement of SFA with PUFA is associated with reduced risk of CVD and T2DM. Clinical trials show higher intake of UFA from plant sources improves major CVD risk factors, including reducing levels of atherogenic lipids and lipoproteins. Importantly, clinical trials show that increased n-6 PUFA (linoleic acid) intake does not increase markers of inflammation or oxidative stress. Evidence-based guidelines from authoritative health and scientific organisations recommend intake of non-tropical vegetable oils, which contain MUFA and n-6 PUFA, as part of healthful dietary patterns. Specifically, vegetable oils rich in UFA should be consumed instead of rich sources of SFA, including butter, tallow, lard, palm and coconut oils.

Predictive value of serological indices for guiding bundle of care to prevent the occurrence of poststroke fatigue for ischemic stroke survivors

Almost half of ischemic stroke (IS) survivors have poststroke fatigue (PSF) during rehabilitation, which can reduce their rehabilitation compliance and quality of life. The primary link of PSF management is early identification, which can guide bundle of care for prevention. This study aimed to explore the predictive value of serological indicators for guiding bundle of care to prevent the occurrence of PSF among IS survivors. This study was a prospective observational study. A total of 350 patients with IS who were hospitalized in 2 tertiary hospitals in Nanning from October 2022 to September 2023 were selected. The general data of patients and serological indicators within 24 hours of admission were collected. Based on the follow-up results, the patients were divided into the PSF group and the NPSF group. Multivariate logistic regression analysis was used to screen the risk factors affecting the occurrence of PSF, and the receiver operating characteristic curve (ROC curve) method was used to analyze the predictive value of this factor. The incidence of acute-phase PSF among elderly patients with IS was 49.26%. The elevated levels of fasting plasma glucose (FPG) (OR = 1.485, 95% CI: 1.145-1.925, P = .003), total cholesterol (TC) (OR = 1.394, 95% CI: 1.013-1.917, P = .041), C-reactive protein (CRP) (OR = 1.394, 95% CI: 1.013-1.917, P = .041), and homocysteine (Hcy) (OR = 1.370, 95% CI: 1.233-1.524, P < .001) were risk factors of PSF in elderly patients with acute IS (P < .05). FPG (area under the curve = 0.632), TC (area under the curve = 0.621), CRP (area under the curve = 0.889), and Hcy (area under the curve = 0.807) had a good predictive value for acute-phase PSF, and the combination of the 4 indicators could further improve the predictive efficacy (area under the curve = 0.938, sensitivity 86.2%, specificity 90.7%, P < .05). The elevated levels of FPG, TC, CRP, and Hcy could predict the risk of PSF, and the combination of the 4 indicators can effectively improve prediction efficiency and provide a reference for guiding the formulation of bundle nursing programs.

Association between substituting macronutrients and all-cause mortality: a network meta-analysis of prospective observational studies

Background

Suboptimal diet quality is a key risk factor for premature death. Assuming relatively stable energy intake among individuals, changes in nutrient intakes occur by exchanging different nutrients. Therefore we aimed to examine the association of isocaloric substitution of dietary (macro)nutrients with all-cause mortality using network meta-analysis (NMA).

Methods

For this systematic review and NMA of prospective observational studies MEDLINE, Embase, and Scopus were searched from inception to February 13th, 2024. Eligible studies reported substitution analyses for quantity and/or quality of macronutrients, including carbohydrates, proteins, and fatty acids on all-cause mortality. Random-effects NMA were used in order to evaluate the pooled hazard ratios (HR) and 95% confidence intervals (CI) of substituting each included nutrient with another. We assessed risk of bias with the ROBINS-E tool, and the certainty of evidence (CoE) using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach. This study is registered with PROSPERO (CRD42023450706).

Findings

Thirty-nine studies with 1,737,644 participants, 395,491 deaths, 297 direct comparisons, and seven nutrient-specific networks were included. Moderate CoE was found for an association with lower mortality risk when replacing 5% of energy intake from carbohydrates with polyunsaturated fatty acids (PUFA; HR: 0.90; 95%CI: 0.84, 0.95), n-6 PUFA (0.85; 0.77, 0.94), n-3 PUFA (0.72; 0.59, 0.86), and plant monounsaturated fatty acids (MUFA; 0.90; 0.85, 0.95), and when replacing 5% of energy from saturated fatty acids (SFA) and trans-fatty acids (TFA), with PUFA, MUFA, and plant-MUFA (HRrange: 0.75 to 0.91). A lower mortality risk was additionally found when 5% of animal-MUFA was replaced with plant-MUFA, and when replacing animal protein, and SFA with plant protein (HRrange: 0.81 to 0.87, moderate CoE).

Interpretation

Our results provide practical knowledge for public health professionals and can inform upcoming dietary guidelines. The beneficial association of increasing PUFA (both n-3 and n-6) and (plant-) MUFA intake while reducing carbohydrates, SFA and TFA, along with replacing animal protein and animal-MUFA with plant-based sources of protein and fat (MUFA) on the all-cause mortality risk, underscores the importance of plant-based dietary recommendations.

Funding

None.

Gut Microbiota Regulate Saturated Free Fatty Acid Metabolism in Heart Failure

AIMS

Heart failure (HF) is associated with profound changes in cardiac metabolism. At present, there is still a lack of relevant research to explore the key microbiome and their metabolites affecting the progression of HF. Herein, the interaction of gut microbiota and circulating free fatty acid (FFA) in HF patients and mice is investigated.

METHODS AND RESULTS

In HF patients, by applying metagenomics analysis and targeted FFA metabolomics, enriched abundance of Clostridium sporogenes (C.sp) in early and late stage of HF patients, which negatively correlated to saturated free fatty acid (SFA) levels, is identified. KEGG analysis further indicates microbiota gene enrichment in FFA degradation in early HF, and decreased gene expression in FFA synthesis in late HF. In HF mice (C57BL/6J) induced by isoproterenol (ISO), impaired intestinal permeability is observed, and decreased fecal C.sp and increased SFA are further validated. At last, by supplementing C.sp to ISO-induced HF mice, the cardiac function, fibrosis, and myocardial size are partially rescued, together with decreased circulating SFA levels.

CONCLUSIONS

Clostridium abundance is increased in HF, compensating cardiac function deterioration via downregulation of circulating SFA levels. The results demonstrate that the gut microbiota-SFA axis plays an important role in HF protection, which may provide a strategic advantage for the probiotic therapy development in HF.

Effect of Meal-Timing on the Association of Unsaturated Fatty Acids with All-Cause and Cardiovascular Mortality among Adults: A Prospective Cohort Study with 10-Year Follow-Up

BACKGROUND

Conflicting results have been reported on the association of dietary unsaturated fatty acids (UFAs) with longevity and cardiovascular health. Most previous studies have focused only on the amount of UFAs consumed, not the timing of intake.

METHODS

This prospective cohort study used data from 30,136 adults aged 18 years and older. Intakes of UFAs by meal time and types were assessed by a 24-h dietary recall for two days. The covariate-adjusted survey-weighted Cox proportional hazards models were performed to evaluate the associations of dietary total unsaturated fatty acid (TUFA), polyunsaturated fatty acid (PUFA), and monounsaturated fatty acid (MUFA) intakes throughout the day and three meals with mortality.

RESULTS

During a median of 10.0 years of follow-up, 4510 total deaths occurred. All-cause mortality decreased with increasing intakes at dinner of TUFA (HR: 0.87 [0.77-0.98]), PUFA (HR: 0.81 [0.73-0.91]), and MUFA (HR: 0.88 [0.77-0.99]). With an increased intake of PUFA at dinner, CVD mortality showed a decreasing trend. However, the inverted L-shaped non-linear trend in all-cause mortality was found with increasing intake at breakfast of TUFA (HR: 1.35 [1.17-1.57], Q3 vs. Q1), PUFA (HR: 1.30 [1.13-1.50]), and MUFA (HR: 1.28 [1.13-1.45]). Meanwhile, increased breakfast intake of UFAs was associated with increased CVD and heart disease mortality.

CONCLUSIONS

Meal timing influences the association of UFAs with all-cause and CVD-related mortality.

Pork Meat Composition and Health: A Review of the Evidence

Meat has been part of the human diet for centuries and it is a recognizable source of high-biologic-value protein and several micronutrients; however, its consumption has been associated with an increased risk of non-communicable diseases (e.g., cardiovascular diseases, cancer). These concerns are mostly related to red meat. However, meat composition is quite variable within species and meat cuts. The present study explores the composition of pork meat, and the differences among different pork meat cuts and it reviews the evidence on the influence of its consumption on health outcomes. Pork meat contributes to 30% of all meat consumed worldwide and it offers a distinct nutrient profile; it is rich in high-quality protein, B-complex vitamins, and essential minerals such as zinc and iron, though it contains moderate levels of saturated fat compared to beef. Additionally, research on sustainability points out advantages from pork meat consumption considering that it is a non-ruminant animal and is included in one of the five more sustainable dietary patterns. In what concerns the data on the influence of pork meat consumption on health outcomes, a few clinical studies have shown no harmful effects on cardiovascular risk factors, specifically blood lipids. Several arguments can justify that pork meat can be an option in a healthy and sustainable diet.

Association between polyunsaturated fatty acids in adipose tissue and mortality of colorectal cancer patients

INTRODUCTION

Nutritional intake and dysregulation of fatty acid metabolism play a role in the progression of various tumors, but the consumption of fatty acids is difficult to assess accurately with dietary questionnaires. Biomarkers can objectively assess intake, storage and bioavailability.

OBJECTIVE

We studied the association between the polyunsaturated fatty acid (PUFA) composition of abdominal subcutaneous adipose tissue (good indicator of dietary intake over 2-3 years) and all-cause mortality.

METHODS

In the multicenter AGARIC study, samples from 203 patients with colorectal cancer (CRC) undergoing curative surgery, were harvested from subcutaneous adipose tissue, which were then analyzed for PUFA composition.

RESULTS

After a median follow-up of 45 months, 76 patients died. These patients were more often men (72.4% versus 57.5%, P = 0.04), diabetic (32.9% versus 13.4%, P = 0.001), old (median: 74.5 versus 66.6 years, P < 0.001) and with high alcohol consumption (47.4% versus 30.7%, P = 0.005). An increased risk of death was observed with higher levels of 20:2 ω-6 (hazard ratiotertile3 vstertile1 (HRT3vsT1) 2.12; 95% confidence interval (CI) 1.01-4.42; p-trend = 0.04), 22:4 ω-6 (HRT3vsT1 = 3.52; 95% CI = 1.51-8.17; p-trend = 0.005), and 22:5 ω-6 (HRT3vsT1 = 3.50; 95% CI = 1.56-7.87; p-trend = 0.002). Conversely, the risk of death seemed lower when higher concentrations of 18:3 ω-6 (HRT3vsT1 = 0.52; 95% CI = 0.27-0.99; p-trend = 0.04) and the essential fatty acid, α-linolenic acid 18:3 ω-3 (HRT3vsT1 = 0.47; 95% CI = 0.24-0.93; p-trend = 0.03) were observed.

CONCLUSION

The risk of death was increased in CRC patients with higher concentrations of certain ω-6 PUFAs and lower concentrations of α-linolenic acid in their subcutaneous adipose tissue. These results reflect dietary habits and altered fatty acid metabolism. Our exploratory results warrant confirmation in larger studies with further exploration of the mechanisms involved.

Effects of omega-3, omega-6, and total dietary polyunsaturated fatty acid supplementation in patients with atherosclerotic cardiovascular disease: a systematic review and meta-analysis

Background: Uncertainty exists about the link between omega-3 fatty acid, omega-6 fatty acid, and total polyunsaturated fatty acid (PUFA) intake and mortality in atherosclerotic cardiovascular disease (ASCVD) patients, and no meta-analyses summarize the relationship between these various types of PUFAs and ASCVD. Methods: Web of Science, PubMed, EBSCO and Cochrane Library up to November 30, 2022 were searched for prospective randomized controlled studies investigating the relationships among omega-3, omega-6, and PUFA intake and mortality and cardiovascular events in ASCVD patients. This study has been registered at PROSPERO (No. CRD42023407566). Results: This meta-analysis included 21 publications from 17 studies involving 40 861 participants published between 1965 and 2022. In ASCVD patients, omega-3 may lower all-cause mortality (RR: 0.90, 95% CI [0.83, 0.98], I2 = 8%), CVD mortality (RR: 0.82, 95% CI [0.73, 0.91], I2 = 34%) and CVD events (RR: 0.90, 95% CI [0.86, 0.93], I2 = 79%). Subgroup analyses showed that EPA or EPA ethyl ester supplementation reduced CVD events, while the mixture of EPA and DHA had no significant impact. Long-chain omega-3 consumption of 1.0-4.0 g per d reduced death risk by 3.5% for each 1 g per d increase. Omega-6 and PUFA had no significant effect on mortality or CVD events, with low-quality evidence and significant heterogeneity. Conclusions: omega-3 intake is associated with a reduced risk of all-cause mortality, CVD mortality, and CVD events in ASCVD patients, while omega-6 or total PUFA intake showed no significant association. Increasing the omega-3 intake by 1 g per d resulted in a 3.5% decrease in the risk of death. These findings support the recommendation of supplements with omega-3 fatty acids for the secondary prevention of ASCVD.

Restricted carbohydrate diets below 45% energy are not associated with risk of mortality in the National Health and Nutrition Examination Survey, 1999-2018

Introduction

Cardiometabolic diseases (CMD) are the leading causes of death for people living in the United States. Dietary strategies, such as restricting carbohydrate intake, are becoming popular strategies for improving health status. However, there is limited and often contradictory evidence on whether restricting carbohydrate intake is related to all-cause, CMD, or cardiovascular disease (CVD) mortality.

Methods

The objective of the present study was to evaluate the association between restricted carbohydrate diets (<45%en) and mortality from all-causes, CMD, and CVD, stratified by fat amount and class. Data were acquired using the National Health and Nutrition Examination Survey (1999-2018) linked with mortality follow-up until December 31, 2019 from the Public-use Linked Mortality Files. Multivariable survey-weighted Cox proportional hazards models estimated hazard ratios for 7,958 adults (≥20 y) that consumed <45%en from carbohydrates and 27,930 adults that consumed 45-65%en from carbohydrates.

Results

During the study period a total of 3,780 deaths occurred, including 1,048 from CMD and 1,007 from CVD, during a mean follow-up of 10.2 y. Compared to individuals that met carbohydrate recommendations (45-65%en), those that consumed carbohydrate restricted diets (<45%en) did not have significantly altered risk of mortality from all-causes (HR: 0.98; 95% CI: 0.87, 1.11), CMD (1.18; 0.95, 1.46), or CVD (1.20; 0.96, 1.49). These findings were maintained when the restricted carbohydrate diet group was stratified by intake of total fat, saturated fat (SFA), monounsaturated fat (MUFA), and polyunsaturated fat (PUFA).

Discussion

Carbohydrate restriction (<45%en) was not associated with mortality from all-causes, CVD, or CMD. Greater efforts are needed to characterize the risk of mortality associated with varied degrees of carbohydrate restriction, e.g., low (<26%en) and high (>65%en) carbohydrate diets separately.

Association of saturated fatty acids with cancer risk: a systematic review and meta-analysis

OBJECTIVE

Extensive research has explored the link between saturated fatty acids (SFAs) and cardiovascular diseases, alongside other biological dysfunctions. Yet, their association with cancer risk remains a topic of debate among scholars. The present study aimed to elucidate this association through a robust meta-analysis.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched systematically to identify relevant studies published until December 2023. The Newcastle-Ottawa Scale was used as the primary metric for evaluating the quality of the included studies. Further, fixed- or random-effects models were adopted to determine the ORs and the associated confidence intervals using the Stata15.1 software. The subsequent subgroup analysis revealed the source of detection and the cancer types, accompanied by sensitivity analyses and publication bias evaluations.

RESULTS

The meta-analysis incorporated 55 studies, comprising 38 case-control studies and 17 cohort studies. It revealed a significant positive correlation between elevated levels of total SFAs and the cancer risk (OR of 1.294; 95% CI: 1.182-1.416; P-value less than 0.001). Moreover, elevated levels of C14:0, C16:0, and C18:0 were implicated in the augmentation of the risk of cancer. However, no statistically significant correlation of the risk of cancer was observed with the elevated levels of C4:0, C6:0, C8:0, C10:0, C12:0, C15:0, C17:0, C20:0, C22:0, and C24:0. Subgroup analysis showed a significant relationship between excessive dietary SFA intake, elevated blood SFA levels, and heightened cancer risk. Increased total SFA levels correlated with higher risks of breast, prostate, and colorectal cancers, but not with lung, pancreatic, ovarian, or stomach cancers.

CONCLUSION

High total SFA levels were correlated with an increased cancer risk, particularly affecting breast, prostate, and colorectal cancers. Higher levels of specific SFA subtypes (C14:0, C16:0, and C18:0) are also linked to an increased cancer risk. The findings of the present study would assist in providing dietary recommendations for cancer prevention, thereby contributing to the development of potential strategies for clinical trials in which diet-related interventions would be used in combination with immunotherapy to alter the levels of SFAs in patients and thereby improve the outcomes in cancer patients. Nonetheless, further high-quality studies are warranted to confirm these associations.

Fat and fatty acids - a scoping review for Nordic Nutrition Recommendations 2023

Two de novo NNR2022 systematic reviews (SRs) as well as 21 qualified SRs (qSRs) were available. A literature search yielded an additional ~70 SRs, meta-analyses and biomarker papers. Diets lower in total fat are associated with reductions in body weight and blood pressure compared with diets higher in total fat in adults. Partial replacement of saturated fatty acid (SFA) with n-6 polyunsaturated fatty acid (PUFA) improves blood lipid profile, decreases the risk of cardiovascular disease (CVD), improves glucose-insulin homeostasis and may decrease the risk of total mortality. Long-chain n-3 PUFAs (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) decrease triglycerides and are associated with lower risk of CVD. Dietary PUFAs, both n-3 and n-6, may be associated with reduced risk of type 2 diabetes (T2D). There is inconclusive evidence to suggest that the type of dietary fat is associated with blood pressure, risk of hypertension or musculoskeletal health. Higher intake of total PUFA is associated with lower mortality from any cancer. Long-chain n-3 PUFA is associated with reduced risk of breast cancer, whereas biomarker levels of n-6 PUFA are associated with lower risk of any cancer. Intake of long-chain n-3 PUFA during pregnancy increases length of gestation and child birth weight and reduces the risk of preterm delivery, but there is inconclusive evidence to suggest that it may influence child neurodevelopment, growth or development of allergic disease. In studies with higher versus lower dietary cholesterol intake levels, total blood cholesterol increased or were unaffected by the dietary cholesterol, resulting in inconclusive results. Trans fatty acid (TFA), regardless of source, impairs blood lipid profile compared to unsaturated fat. In observational studies, TFA is positively associated with CVD and total mortality but whether associations differ by source is inconclusive. Ruminant TFA, as well as biomarker levels of odd-chain fatty acids, might be associated with lower risk of T2D.

Dietary Macronutrient Intake and Cardiovascular Disease Risk and Mortality: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Many epidemiological studies have evaluated the intake of macronutrients and the risk of mortality and cardiovascular disease (CVD). However, current evidence is conflicting and warrants further investigation. Therefore, we carried out an umbrella review to examine and quantify the potential dose-response association of dietary macronutrient intake with CVD morbidity and mortality. Prospective cohort studies from PubMed, Embase, and CENTRAL were reviewed, which reported associations of macronutrients (protein, fat, and carbohydrate) with all-cause, CVD, cancer mortality, or CVD events. Multivariable relative risks (RR) were pooled, and heterogeneity was assessed. The results of 124 prospective cohort studies were included in the systematic review and 101 in the meta-analysis. During the follow-up period from 2.2 to 30 years, 506,086 deaths and 79,585 CVD events occurred among 5,107,821 participants. High total protein intake was associated with low CVD morbidity (RR 0.88, 95% confidence interval 0.82-0.94), while high total carbohydrate intake was associated with high CVD morbidity (1.08, 1.02-1.13). For fats, a high intake of total fat was associated with a decreased all-cause mortality risk (0.92, 0.85-0.99). Saturated fatty acid intake was only associated with cancer mortality (1.10, 1.06-1.14); Both monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) intake was associated with all-cause mortality (MUFA: 0.92, 0.86-0.98; PUFA: 0.91, 0.86-0.96). This meta-analysis supports that protein intake is associated with a decreased risk of CVD morbidity, while carbohydrate intake is associated with an increased risk of CVD morbidity. High total fat intake is associated with a low risk of all-cause mortality, and this effect was different in an analysis stratified by the type of fat.

Dietary fatty acids intake and all-cause and cardiovascular mortality in patients on peritoneal dialysis

BACKGROUND & AIMS

The relationship between dietary fatty acids (FA) and clinical outcomes are relatively lacking in non-dialyzed and dialyzed chronic kidney disease (CKD) population, resulting in insufficient guide about the dietary FA intake in this population. In this study, we aimed to observe the association between the intake of total or different types of FA and all-cause and cardiovascular (CV) mortality in patients undergoing peritoneal dialysis (PD).

METHODS

This is a prospective cohort study with data retrospectively analyzed in 881 patients undergoing PD. Dietary FA intake measured by 3-day dietary records. The outcomes were defined as all-cause and CV death. Baseline FA intake and time-averaged FA intake were categorized by tertiles based on the distribution among the study population. We used univariate and multivariate Cox proportional regression models to determine the association between amounts and types of FA and all-cause and CV mortality.

RESULTS

During a median follow up of 45 months, 93 patients were still being maintained on PD, 467 had died, including 189 (40.5%) attributable to CV death. Compared to patients in the low tertile of total FA (TFA) intake at baseline group, the middle or/and high tertile groups were more likely to be male, younger, well-educated and better nutritional status (P < 0.05). At the baseline, no association was found between all-cause and CV death in either total or different types of FA after adjusting for nutritional variables. As for time-averaged analyses, the associations of TFA, saturated FA (SFA), monounsaturated FA (MUFA), ω-3 and ω-6 polyunsaturated FA (PUFA) and all-cause mortality were weakened after adjustment for laboratory and nutrients variables. However, PUFA independently reduced 5% of mortality even after adjustment for laboratory and nutrients variables [HR 0.95 (0.91, 0.99), P = 0.023], and the ratio of MUFA/PUFA was positively associated with the risk for all-cause mortality [HR 1.05 (1.01, 1.09), P = 0.008]. Furthermore, each 10% increase of the ratio of ω-6/ω-3 was only weakly associated with the risk for all-cause mortality [HR 1.02 (1.00, 1.04), P = 0.034]. As for CVD mortality, the impacts of total and each type of FA disappeared after adjustment for laboratory or nutrients variables.

CONCLUSIONS

Time-averaged PUFA intake was independently associated with a lower risk for all-cause mortality in our PD cohort, while the higher ratio of MUFA/PUFA and ω-6/ω-3 increased all-cause mortality. More observational and interventional researches are needed to determine these associations.

Associations of low-carbohydrate diets with breast cancer survival

BACKGROUND

The objective of this study was to evaluate the role of low-carbohydrate diets after breast cancer diagnosis in relation to breast cancer-specific and all-cause mortality.

METHODS

For 9621 women with stage I-III breast cancer from two ongoing cohort studies, the Nurses' Health Study and Nurses' Health Study II, overall low-carbohydrate, animal-rich low-carbohydrate, and plant-rich low-carbohydrate diet scores were calculated by using food frequency questionnaires collected after breast cancer diagnosis.

RESULTS

Participants were followed up for a median 12.4 years after breast cancer diagnosis. We documented 1269 deaths due to breast cancer and 3850 all-cause deaths. With the use of Cox proportional hazards regression and after controlling for potential confounding variables, we observed a significantly lower risk of overall mortality among women with breast cancer who had greater adherence to overall low-carbohydrate diets (hazard ratio for quintile 5 vs. quintile 1 [HRQ5vsQ1 ], 0.82; 95% CI, 0.74-0.91; ptrend  = .0001) and plant-rich low-carbohydrate diets (HRQ5vsQ1 , 0.73; 95% CI, 0.66-0.82; ptrend < .0001) after breast cancer diagnosis but not animal-rich low-carbohydrate diets (HRQ5vsQ1 , 0.93; 95% CI, 0.84-1.04; ptrend  = .23). However, greater adherence to overall, animal-rich, or plant-rich low-carbohydrate diets was not significantly associated with a lower risk of breast cancer-specific mortality.

CONCLUSIONS

This study showed that greater adherence to low-carbohydrate diets, especially plant-rich low-carbohydrate diets, was associated with better overall survival but not breast cancer-specific survival among women with stage I-III breast cancer.

The balanced unsaturated fatty acid supplement constituted by woody edible oils improved lipid metabolism and gut microbiota in high-fat diet mice

The dietary intervention has demonstrated effectiveness in improving hyperlipidemia and obesity. Woody edible oils are rich in unsaturated fatty acids (UFAs) that could positively affect lipid metabolism. In this study, the blended oil (BLO), a balanced UFA supplement, constituted by Zanthoxylum bungeanum (Chinese Red Pepper) seed oil, walnut (Juglans regia) oil, camellia (Camema oleifera) seed oil and perilla (Perilla frutescens) seed oil was established referring to the Chinese dietary reference intakes, in which the ratios of monounsaturated/polyunsaturated fatty acids and ω-6/ω-3 polyunsaturated fatty acids were 1:1 and 4:1, respectively. The BLO was administrated to KM mice fed a high-fat diet (HFD) by gavage every day at a dose of 3.0 mL/kg·bw for 10 weeks to assess its effects on serum lipid levels, liver antioxidant activities and gut microbial composition. The results showed that the BLO improved hepatic steatosis, liver oxidative stress, and serum lipid levels. Additionally, there was an increased abundance of Lactobacillus, Allobaculum, and Blautia, along with a decreased abundance of Staphylococcus in cecal contents. These changes were found to be positively correlated with the metabolic improvements, as indicated by Spearman's correlation analysis. These findings implied the practicality of the balanced unsaturated fatty acid consumption in preventing hyperlipidemia and obesity.

Free-Fatty Acid Receptor-4 (FFA4/GPR120) differentially regulates migration, invasion, proliferation and tumor growth of papillary renal cell carcinoma cells

Kidney cancer is among the 10 most common cancers, and renal cell carcinoma (RCC), which represent 90% of all kidney cancers, has the highest mortality rate of all genitourinary cancers. Papillary RCC (pRCC) is the second most frequent subtype of RCC and demonstrates distinct characteristics compared to other subtypes, including a high degree of metastasis and resistance to treatments against the more common clear cell RCC (ccRCC) subtype. Here, we demonstrate that the Free-Fatty Acid Receptor-4 (FFA4), a G protein-coupled receptor that is endogenously activated by medium-to-long chain free-fatty acids, is upregulated in pRCC compared to patient-matched normal kidney tissue, and that the expression of FFA4 increases with the degree of pathological grading of pRCC. Our data also show that FFA4 transcript is not expressed in ccRCC cell lines, but is expressed in the well-characterized metastatic pRCC cell line ACHN. Furthermore, we show that agonism of FFA4 with the selective agonist cpdA positively regulates ACHN cell migration and invasion in a manner dependent on PI3K/AKT/NF-κB signaling to COX-2 and MMP-9, with partial-dependence on EGFR transactivation. Our results also demonstrate that FFA4 agonism induces STAT-3-driven epithelial-mesenchymal transition, suggesting a significant role for FFA4 in pRCC metastasis. On the contrary, FFA4 agonism significantly reduces cell proliferation and tumor growth, suggesting that the receptor may have opposing effects on pRCC cell growth and migration. Together, our data demonstrate that FFA4 has significant functional roles in pRCC cells and may be an attractive target for study of pRCC and development of RCC pharmacotherapeutics.

The Effect of MUFA-Rich Food on Lipid Profile: A Meta-Analysis of Randomized and Controlled-Feeding Trials

Since the effects of mono-unsaturated fatty acids (MUFA) on lipid profile are still controversial, a meta-analysis of randomized controlled trials was conducted in the present study to assess the effect of MUFA-rich food on lipid profiles. The study was designed, conducted, and reported according to the guidelines of the 2020 preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement. A systematic and comprehensive search was performed in several databases from inception up to 30 January 2022. The results showed that the intake of edible oil-derived MUFA (EDM) could increase the blood HDL-C level (mean difference = 0.08; 95%CI: -0.01, 0.17, p = 0.03), but did not affect the level of TC, TG, or LDL-C. Moreover, the consumption of other food-derived MUFA (ODM) significantly decreased TG concentration (mean difference = -0.35; 95%CI: -0.61, -0.09, p = 0.01)), but did not affect the level of TC, LDL-C, or HDL-C. Findings from this study suggest that MUFA-rich food might be beneficial to modulate the blood lipid profile.