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Frontiers in Nutrition 2021The association between α-linolenic acid (ALA) and mortality is inconsistent and has not been summarized systematically. The purpose was to conduct a meta-analysis...
The association between α-linolenic acid (ALA) and mortality is inconsistent and has not been summarized systematically. The purpose was to conduct a meta-analysis that synthesized the results of prospective cohort studies to investigate associations between ALA intake and mortality. We conducted a comprehensive search on PubMed, Embase, and Web of Science databases on May 1, 2021, for relevant prospective cohort studies which reported associations of ALA (assessed by dietary surveys and/or ALA concentrations in body tissues) with mortality from all-cause, cardiovascular disease (CVD), and other diseases. Multivariable-adjusted relative risks (RRs) were pooled by a random or fixed-effects model. A total of 34 prospective cohort studies, of which 17 reported dietary ALA intake, 14 for ALA biomarkers, and the remaining 3 reported both of intake and biomarkers. The studies included 6,58,634 participants, and deaths were classified into all-cause mortality (56,898), CVD mortality (19,123), and other diseases mortality (19,061). Pooled RRs of ALA intake were 0.93 (95% CI: 0.86, 1.01, = 71.2%) for all-cause mortality, 0.90 (95% CI: 0.83, 0.98, = 22.1%) for CVD mortality, and 0.94 (95% CI: 0.83, 1.06, = 73.3%) for other diseases mortality. The two-stage random-effects dose-response analysis showed a linear relationship between dietary ALA intake and CVD-mortality and each 0.5% energy increment of ALA intake was associated with a 5% lower risk of CVD-mortality (RR: 0.95; 95% CI: 0.90, 1.00). Pooled RRs per SD increment of ALA biomarkers were 0.99 (95% CI: 0.96, 1.01, = 27%) for all-cause mortality, 1.00 (95% CI: 0.98, 1.03, = 0%) for CVD mortality and 0.98 (95% CI: 0.95, 1.01, = 0%) for other diseases mortality. This meta-analysis summarizing the available prospective cohort studies indicated that ALA intake was associated with reduced risk of mortality, especially CVD mortality. Our findings suggest that ALA consumption may be beneficial for death prevention. https://www.crd.york.ac.uk/PROSPERO; identifier: CRD42021264532.
PubMed: 34805241
DOI: 10.3389/fnut.2021.743852 -
International Journal of Molecular... Sep 2023The objective of this meta-analysis was to examine the impact of a low-ratio linoleic acid/α-linolenic acid (LA/ALA) diet on the glycemic profile of adults. A... (Meta-Analysis)
Meta-Analysis Review
The objective of this meta-analysis was to examine the impact of a low-ratio linoleic acid/α-linolenic acid (LA/ALA) diet on the glycemic profile of adults. A comprehensive search was performed across four databases (Web of Science, Scopus, Embase, and PubMed) to evaluate the influence of the low-ratio LA/ALA. Relevant references were screened up until February 2023. Intervention effects were analyzed by calculating change values as weighted mean differences (WMD) and 95% confidence intervals (CI) using fixed-effects models. Additionally, subgroup analysis and meta-regression were employed to investigate potential sources of heterogeneity. Twenty-one randomized controlled trials (RCTs) were included, and the low-ratio LA/ALA diet had no significant effect on fasting blood sugar (FBS, WMD: 0.00 mmol/L, 95% CI: -0.06, 0.06, = 0.989, I = 0.0%), insulin levels (WMD: 0.20 μIU/mL, 95% CI: -0.23, 0.63, = 0.360, I = 3.2%), homeostatic model assessment insulin resistance (HOMA-IR, WMD: 0.09, 95% CI: -0.06, 0.23, = 0.243, I = 0.0%), and hemoglobin A1c (HbA1c, WMD: -0.01%, 95% CI: -0.07, 0.06, = 0.836, I = 0.0%). Based on subgroup analyses, it was observed that the impact of a low-ratio LA/ALA diet on elevated plasma insulin (WMD: 1.31 μIU/mL, 95% CI: 0.08, 2.54, = 0.037, I = 32.0%) and HOMA-IR (WMD: 0.47, 95% CI: 0.10, 0.84, = 0.012, I = 0.0%) levels exhibited greater prominence in North America compared to Asian and European countries. Publication bias was not detected for FBS, insulin, HOMA-IR, and HbA1c levels according to the Begg and Egger tests. Furthermore, the conducted sensitivity analyses indicated stability, as the effects of the low-ratio LA/ALA diet on various glycemic and related metrics remained unchanged even after removing individual studies. Overall, based on the available studies, it can be concluded that the low-ratio LA/ALA diet has limited impact on blood glucose-related biomarker levels.
Topics: Adult; Humans; Glycated Hemoglobin; Linoleic Acid; alpha-Linolenic Acid; Glucose; Insulin
PubMed: 37762686
DOI: 10.3390/ijms241814383 -
Cancers May 2020Several immunotherapy agents are the standard of care of many solid malignancies. Nevertheless, the majority of patients do not benefit from the currently available... (Review)
Review
Several immunotherapy agents are the standard of care of many solid malignancies. Nevertheless, the majority of patients do not benefit from the currently available immunotherapies. It is therefore of paramount importance to identify the prognostic and predictive factors of tumor response/resistance and to design effective therapeutic strategies to overcome primary resistance and improve the efficacy of immunotherapy. The aim of this review is to underline the influence of the tumor and host metabolism on the antitumor immune response and to discuss possible strategies to improve the efficacy of available treatments by targeting the specific metabolic pathways in tumors or immune cells and by modifying patients' nutritional statuses. A systematic search of the Medline and EMBASE databases was carried out to identify scientific papers published until February 2020, which reported original research articles on the influence of tumor or host metabolism on antitumor immune response. The literature data showed the key role of glycolysis and mitochondrial oxidative phosphorylation, arginine, tryptophan, glutamine, lipid metabolism and microbiome on immune cell function. Moreover, specific nutritional behaviors, such as a low dietary intake of vitamin C, low glycemic index and alpha-linolenic acid, eicosapentenoic acid, docosahexaenoic acid, ornithine ketoglutarate, tryptophan and probiotic supplementation were associated with the potential clinical benefits from the currently available immunotherapies.
PubMed: 32375310
DOI: 10.3390/cancers12051153 -
Food Science & Nutrition Jan 2022Bone metabolism is a complicated process, which involves bone modeling and remodeling. If this process is unbalanced, bone loss and resultant osteoporosis might occur.... (Review)
Review
Bone metabolism is a complicated process, which involves bone modeling and remodeling. If this process is unbalanced, bone loss and resultant osteoporosis might occur. Recently, nutrition supplementations such as n-3 polyunsaturated fatty acids (PUFAs) are considered to be used on improving the bone metabolism and reducing the risk of osteoporosis. To more precisely assess the effects of n-3 PUFA supplementation on bone mass and clarify its potential mechanism, we have conducted a systematic review and meta-analysis. Based on the strict inclusion and exclusion criteria, 12 articles were included in this meta-analysis. The results in articles show that n-3 PUFAs could slightly enhance the level of bone mineral density (BMD) (0.005 g/cm; 95% CI, 0.000-0.010) ( = 7), which was the primary outcome for the research in comparison with the control group. In addition, the results also illustrate that the increasing effect on BMD (0.024 g/cm; 95% CI, 0.020-0.028) became more significant for postmenopausal women. N-3 PUFAs had no significance on the level of bone-specific alkaline phosphatase (BALP) (-0.24 µg/L; 95% CI, -0.86 to 0.39) and osteocalcin (-0.63 μg/L; 95% CI, -1.84 to 0.57) ( = 5), which are the specific markers of bone formation. When compared with the eicosapentaenoic acid + docosahexaenoic acid supplementation, the supplementation form of α-linolenic acid significantly increased the content of BALP (0.396 µg/L; 95% CI, 0.069-0.724). The effects of n-3 PUFAs on bone resorption biomarkers containing type I collagen cross-linked C-terminal peptide (CTX) and type I collagen cross-linked N-terminal peptide (NTX) are considered and used in our study. Results indicated that participants who received n-3 PUFAs significantly decreased the level of CTX in the human body (-0.367 μg/L; 95% CI, -0.726 to -0.007) ( = 4). However, there was no significant difference in NTX levels in humans after supplementation with n-3 PUFA (-1.744 µg/L; 95% CI, -3.970-0.481) ( = 3). For postmenopausal women, it presented a significant decreasing level of CTX (-0.393 µg/L; 95% CI, -0.651 to -0.135) and NTX (-2.082 µg/L; 95% CI, -2.970 to -1.195) within their bodies. In conclusion, these findings suggested that n-3 PUFAs might have a beneficial effect on bone health, especially for α-linolenic acid supplementation form or for postmenopausal women.
PubMed: 35035917
DOI: 10.1002/fsn3.2655 -
Foods (Basel, Switzerland) Aug 2023This meta-analysis aimed to investigate the impact of low-ratio linoleic acid/alpha-linolenic acid (LA/ALA) supplementation on the blood lipid profiles in adults. We...
This meta-analysis aimed to investigate the impact of low-ratio linoleic acid/alpha-linolenic acid (LA/ALA) supplementation on the blood lipid profiles in adults. We conducted a systematic search for relevant randomized controlled trials (RCTs) assessing the effects of low-ratio LA/ALA using databases including PubMed, Embase, Cochrane, and Web of Science, as well as screened related references up until February 2023. The intervention effects were analyzed adopting weighted mean difference (WMD) and 95% confidence interval (CI). The meta-analysis indicated that low-ratio LA/ALA supplementation decreased total cholesterol (TC, WMD: -0.09 mmol/L, 95% CI: -0.17, -0.01, = 0.031, I = 33.2%), low-density lipoprotein cholesterol (LDL-C, WMD: -0.08 mmol/L, 95% CI: -0.13, -0.02, = 0.007, I = 0.0%), and triglycerides (TG, WMD: -0.05 mmol/L, 95% CI: -0.09, 0.00, = 0.049, I = 0.0%) concentrations. There was no significant effect on high-density lipoprotein cholesterol concentration (HDL-C, WMD: -0.00 mmol/L, 95% CI: -0.02, 0.02, = 0.895, I = 0.0%). Subgroup analysis showed that low-ratio LA/ALA supplementation significantly decreased plasma TC, LDL-C, and TG concentrations when the intervention period was less than 12 weeks. In the subgroup analysis, a noteworthy decrease in both TC and LDL-C levels was observed in individuals receiving low-ratio LA/ALA supplementation in the range of 1-5. These findings suggest that this specific range could potentially be effective in reducing lipid profiles. The findings of this study provide additional evidence supporting the potential role of low-ratio LA/ALA supplementation in reducing TC, LDL-C, and TG concentrations, although no significant impact on HDL-C was observed.
PubMed: 37628004
DOI: 10.3390/foods12163005 -
The British Journal of Nutrition Apr 2024Maternal diet influences breast milk nutritional profile; however, it is unclear which nutrients and contaminants are particularly responsive to short- and long-term... (Review)
Review
Maternal diet influences breast milk nutritional profile; however, it is unclear which nutrients and contaminants are particularly responsive to short- and long-term changes in maternal intake, and the impact of specific exclusion diets, such as vegan or vegetarian. This study systematically reviewed the literature on the effects of maternal nutrient intake, including exclusion diets, on both the nutrient and contaminant content of breast milk. The electronic databases, PubMed, CENTRAL, Web of Science and CINALH were systematically searched until 4 June 2023, with additionally searches of reference lists (PROSPERO, CRD42020221577). The quality of the studies was examined using Cochrane Risk of Bias tool and Newcastle-Ottawa scale. Eighty-eight studies ( 6577) met the search criteria. Due to high heterogeneity, meta-analysis was not possible. There was strong evidence of response to maternal intakes for DHA and EPA, vitamins A, E and K, iodine and Se in breast milk composition, some evidence of response for -linolenic acid, B vitamins, vitamin C and D, ovalbumin, tyrosine and contaminants, and insufficient evidence to identify the effects arachidonic acid, Cu, Fe, Zn and choline. The paucity of evidence and high heterogeneity among studies reflects the need for more high-quality trials. However, this review identified the importance of maternal intake in the nutritional content of breast milk for a wide range of nutrients and supports the recommendation for supplementation of DHA and vitamin B for those on restrictive diets.
Topics: Humans; Female; Milk, Human; Lactation; Vitamins; Diet; Eating
PubMed: 38053371
DOI: 10.1017/S0007114523002775 -
Nutrition Reviews Aug 2020Polyunsaturated fatty acids (PUFA) are important during pregnancy for fetal development and child health outcomes. The fatty acid desaturase (FADS) genes also influence...
CONTEXT
Polyunsaturated fatty acids (PUFA) are important during pregnancy for fetal development and child health outcomes. The fatty acid desaturase (FADS) genes also influence PUFA status, with the FADS genes controlling how much product (eg, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid) is metabolized from the precursor molecules linoleic acid and α-linolenic acid.
OBJECTIVE
The current review discusses the influence of FADS genotype on PUFA status of pregnant women, breast milk, and children, and also how FADS may influence child health outcomes.
DATA SOURCES
The Ovid Medline, Scopus, Embase, Cochrane Library, CINAHL Plus, PubMed and Web of Science databases were searched from their inception to September 2018.
DATA EXTRACTION
Eligible studies reported FADS genotype and blood concentrations of PUFA during pregnancy, in childhood, breast milk concentrations of PUFA or child health outcomes.
DATA ANALYSIS
In pregnant and lactating women, minor allele carriers have higher concentrations of linoleic acid and α-linolenic acid, and lower concentrations of arachidonic acid, in blood and breast milk, respectively. In children, FADS genotype influences PUFA status in the same manner and may impact child outcomes such as cognition and allergies; however, the direction of effects for the evidence to date is not consistent.
CONCLUSION
Further studies are needed to further investigate associations between FADS and outcomes, as well as the diet-gene interaction.
Topics: Adolescent; Adult; Alleles; Arachidonic Acid; Child; Child Health; Child, Preschool; Docosahexaenoic Acids; Fatty Acid Desaturases; Fatty Acids, Unsaturated; Female; Humans; Infant; Linoleic Acid; Milk, Human; Polymorphism, Single Nucleotide; Pregnancy; Young Adult
PubMed: 31943072
DOI: 10.1093/nutrit/nuz086 -
PLoS Medicine Dec 2020The role of fat quantity and quality in type 2 diabetes (T2D) prevention is controversial. Thus, this systematic review and meta-analysis aimed to investigate the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The role of fat quantity and quality in type 2 diabetes (T2D) prevention is controversial. Thus, this systematic review and meta-analysis aimed to investigate the associations between intake of dietary fat and fatty acids and T2D, and to evaluate the certainty of evidence.
METHODS AND FINDINGS
We systematically searched PubMed and Web of Science through 28 October 2019 for prospective observational studies in adults on the associations between intake of dietary fat and fatty acids and T2D incidence. The systematic literature search and data extraction were conducted independently by 2 researchers. We conducted linear and nonlinear random effects dose-response meta-analyses, calculated summary relative risks (SRRs) with their corresponding 95% confidence intervals (95% CIs), and assessed the certainty of evidence. In total, 15,070 publications were identified in the literature search after the removal of duplicates. Out of the 180 articles screened in full text, 23 studies (19 cohorts) met our inclusion criteria, with 11 studies (6 cohorts) conducted in the US, 7 studies (7 cohorts) in Europe, 4 studies (5 cohorts) in Asia, and 1 study (1 cohort) in Australia. We mainly observed no or weak linear associations between dietary fats and fatty acids and T2D incidence. In nonlinear dose-response meta-analyses, the protective association for vegetable fat and T2D was steeper at lower levels up to 13 g/d (SRR [95% CI]: 0.81 [0.76; 0.88], pnonlinearity = 0.012, n = 5 studies) than at higher levels. Saturated fatty acids showed an apparent protective association above intakes around 17 g/d with T2D (SRR [95% CI]: 0.95 [0.90; 1.00], pnonlinearity = 0.028, n = 11). There was a nonsignificant association of a decrease in T2D incidence for polyunsaturated fatty acid intakes up to 5 g/d (SRR [95% CI]: 0.96 [0.91; 1.01], pnonlinearity = 0.023, n = 8), and for alpha-linolenic acid consumption up to 560 mg/d (SRR [95% CI]: 0.95 [0.90; 1.00], pnonlinearity = 0.014, n = 11), after which the curve rose slightly, remaining close to no association. The association for long-chain omega-3 fatty acids and T2D was approximately linear for intakes up to 270 mg/d (SRR [95% CI]: 1.10 [1.06; 1.15], pnonlinearity < 0.001, n = 16), with a flattening curve thereafter. Certainty of evidence was very low to moderate. Limitations of the study are the high unexplained inconsistency between studies, the measurement of intake of dietary fats and fatty acids via self-report on a food group level, which is likely to lead to measurement errors, and the possible influence of unmeasured confounders on the findings.
CONCLUSIONS
There was no association between total fat intake and the incidence of T2D. However, for specific fats and fatty acids, dose-response curves provided insights for significant associations with T2D. In particular, a high intake of vegetable fat was inversely associated with T2D incidence. Thus, a diet including vegetable fat rather than animal fat might be beneficial regarding T2D prevention.
Topics: Diabetes Mellitus, Type 2; Dietary Fats; Fatty Acids; Humans; Incidence; Observational Studies as Topic; Protective Factors; Risk Assessment; Risk Factors
PubMed: 33264277
DOI: 10.1371/journal.pmed.1003347 -
Clinical Nutrition ESPEN Apr 2022Bariatric, also termed metabolic, surgery is an increasingly common treatment for severe and complex obesity. It decreases macronutrient intake, influences nutrient...
BACKGROUND AND AIMS
Bariatric, also termed metabolic, surgery is an increasingly common treatment for severe and complex obesity. It decreases macronutrient intake, influences nutrient absorption and modifies gastrointestinal physiology with the aim of reducing adiposity, improving metabolism and reducing disease risk. Bariatric surgery has been shown to result in micronutrient deficiencies. Whether it results in deficiencies of essential fatty acids (EFAs) and their bioactive polyunsaturated fatty acid (PUFA) derivatives is not clear. The aim of this systematic review is to identify whether there are effects of bariatric surgery on the blood levels of EFAs and other PUFAs.
METHODS
A database search was conducted up to November 2020 using Medline, Embase and Cinahl databases, using relevant search terms identified by a PICO protocol. Only human studies reporting on PUFAs in a blood pool, published in the English language and available in full text were included. The Cochrane tool for assessing risk of bias was used and data were extracted.
RESULTS
Fifteen papers from fourteen studies with relevant data were identified for inclusion. Studies differed according to surgical intervention, duration, measured timepoints, sample size and PUFAs reported. Both increases and decreases in selected PUFAs were reported in different studies. For the EFAs linoleic acid and α-linolenic acid and for the longer-chain omega-3 PUFA eicosapentaenoic acid, bariatric surgery is associated with a transient decline in status (to about 6 months post-surgery) with a later return to pre-surgery levels. All studies had some risk of bias and most studies were of small size.
CONCLUSION
There is a decrease in blood levels of both EFAs and of eicosapentaenoic acid in the months following bariatric surgery. This may partly counter the desired effects of the surgery on blood lipids, insulin sensitivity and inflammation. Nutritional strategies (e.g. use of modified formulas or of supplements) may be able to correct the decrease in those PUFAs. Nevertheless, the observed decrease in PUFAs is transient.
Topics: Bariatric Surgery; Dietary Supplements; Fatty Acids, Omega-3; Fatty Acids, Unsaturated; Humans; Insulin Resistance
PubMed: 35331483
DOI: 10.1016/j.clnesp.2022.02.001 -
British Journal of Cancer Apr 2020The relationship between long-chain omega-3 (LCn3), alpha-linolenic acid (ALA), omega-6 and total polyunsaturated fatty acid (PUFA) intakes and cancer risk is unclear. (Meta-Analysis)
Meta-Analysis
BACKGROUND
The relationship between long-chain omega-3 (LCn3), alpha-linolenic acid (ALA), omega-6 and total polyunsaturated fatty acid (PUFA) intakes and cancer risk is unclear.
METHODS
We searched Medline, Embase, CENTRAL and trials registries for RCTs comparing higher with lower LCn3, ALA, omega-6 and/or total PUFA, that assessed cancers over ≥12 months. Random-effects meta-analyses, sensitivity analyses, subgrouping, risk of bias and GRADE were used.
RESULTS
We included 47 RCTs (108,194 participants). Increasing LCn3 has little or no effect on cancer diagnosis (RR1.02, 95% CI 0.98-1.07), cancer death (RR0.97, 95% CI 0.90-1.06) or breast cancer diagnosis (RR1.03, 95% CI 0.89-1.20); increasing ALA has little or no effect on cancer death (all high/moderate-quality evidence). Increasing LCn3 (NNTH 334, RR1.10, 95% CI 0.97-1.24) and ALA (NNTH 334, RR1.30, 95% CI 0.72-2.32) may slightly increase prostate cancer risk; increasing total PUFA may slightly increase risk of cancer diagnosis (NNTH 125, RR1.19, 95% CI 0.99-1.42) and cancer death (NNTH 500, RR1.10, 95% CI 0.48-2.49) but total PUFA doses were very high in some trials.
CONCLUSIONS
The most extensive systematic review to assess the effects of increasing PUFAs on cancer risk found increasing total PUFA may very slightly increase cancer risk, offset by small protective effects on cardiovascular diseases.
Topics: Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Humans; Incidence; Neoplasms; Randomized Controlled Trials as Topic; Risk; alpha-Linolenic Acid
PubMed: 32114592
DOI: 10.1038/s41416-020-0761-6