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The Influence of n-3PUFA Supplementation on Muscle Strength, Mass, and Function: A Systematic Review and Meta-Analysis.
Santo André, HC, Esteves, GP, Barreto, GHC, Longhini, F, Dolan, E, Benatti, FB
Advances in nutrition (Bethesda, Md.). 2023;14(1):115-127
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Omega 3 polyunsaturated fatty acids (n-3PUFA) are long-chain polyunsaturated fatty acids essential to human health. They play a role in cell membrane integrity, immune and inflammation regulation, cognition and neuromuscular function. As the human body cannot make these fatty acids, they need to be obtained through diet or supplementation. Regarding skeletal muscle, recent research showed that n-3PUFAs may increase the uptake of amino acids by increasing the membrane fluidity in the muscle, and by activating pathways that inhibit protein breakdown. This led to the hypothesis that n-3PUFAs may enhance muscle mass gain and strength. This systematic review sought to gather all available evidence about the impact of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. The review included 14 studies with a total of 1443 participants. The authors found that n-3PUFA supplementation had no significant effect on muscle mass or muscle function in healthy young and older adults, however, a very small but significant positive effect was noted regarding muscle strength. In the discussion section, the authors explain the challenges of their review and how these findings integrate with the current understanding and other research findings. They concluded more research is needed to get a better insight into the effects of n-3PUFA on muscle function and the variants.
Abstract
The effects of omega 3 polyunsaturated fatty acids (n-3PUFA) supplementation on skeletal muscle are currently unclear. The purpose of this systematic review was to synthesize all available evidence regarding the influence of n-3PUFA supplementation on muscle mass, strength, and function in healthy young and older adults. Four databases were searched (Medline, Embase, Cochrane CENTRAL, and SportDiscus). Predefined eligibility criteria were determined according to Population, Intervention, Comparator, Outcomes, and Study Design. Only peer-reviewed studies were included. The Cochrane RoB2 Tool and the NutriGrade approach were used to access risk of bias and certainty in evidence. Effect sizes were calculated using pre-post scores and analyzed using a three-level, random-effects meta-analysis. When sufficient studies were available, subanalyses were performed in the muscle mass, strength, and function outcomes according to participant's age (<60 or ≥60 years), supplementation dosage (<2 or ≥2 g/day), and training intervention ("resistance training" vs. "none or other"). Overall, 14 individual studies were included, total 1443 participants (913 females; 520 males) and 52 outcomes measures. Studies had high overall risk of bias and consideration of all NutriGrade elements resulted in a certainty assessment of moderate meta-evidence for all outcomes. n-3PUFA supplementation had no significant effect on muscle mass (standard mean difference [SMD] = 0.07 [95% CI: -0.02, 0.17], P = 0.11) and muscle function (SMD = 0.03 [95% CI: -0.09, 0.15], P = 0.58), but it showed a very small albeit significant positive effect on muscle strength (SMD = 0.12 [95% CI: 0.006, 0.24], P = 0.04) in participants when compared with placebo. Subgroup analyses showed that age, supplementation dose, or cosupplementation alongside resistance training did not influence these responses. In conclusion, our analyses indicated that n-3PUFA supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults. To our knowledge, this is the first review and meta-analysis investigating whether n-3PUFA supplementation can lead to increases in muscle strength, mass, and function in healthy adults. Registered protocol: doi.org/10.17605/OSF.IO/2FWQT.
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Association between Mediterranean Diet and Fatty Liver in Women with Overweight and Obesity.
Leone, A, Bertoli, S, Bedogni, G, Vignati, L, Pellizzari, M, Battezzati, A
Nutrients. 2022;14(18)
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Non-alcoholic fatty liver disease (NAFLD) is a condition resulting from excessive lipid accumulation in the liver in individuals with low alcohol consumption. Obesity is an established risk factor for the development of NAFLD, and 50% to 75% of people with obesity also have NAFLD. The aim of this study was to evaluate the association between Mediterranean diet and non-invasive indices of fatty liver in a large sample of women with overweight and obesity. This study is a cross-sectional study of 2967 consecutive women with overweight and obesity. Results show that higher adherence to the Mediterranean diet was associated with lower indices of fatty liver in women with overweight and obesity (particularly obese women than in women who are overweight). Authors conclude that women with obesity, especially during the premenopausal period, may benefit more from following a Mediterranean-style diet.
Abstract
Obesity is a risk factor for NAFLD. However, not all people with obesity have an excessive intrahepatic fat content. Adherence to a high-quality dietary pattern may also promote liver health in obesity. A cross-sectional study of 2967 women with overweight and obesity was carried out to assess the association between a Mediterranean diet and fatty liver. All women underwent clinical examination, anthropometric measurements, blood sampling, ultrasound measurements of abdominal visceral and subcutaneous fat, and assessment of adherence to the Mediterranean diet using the 14-item MEDAS questionnaire. Fatty liver index (FLI), NAFLD fatty liver steatosis (NAFLD-FLS) and hepatic steatosis index (HSI) were calculated. In women with obesity, the MEDAS score was inversely associated with FLI (β = -0.60, 95% CI: -1.04, -0.16, p = 0.008), NAFLD-FLS (β = -0.092, 95% CI: -0.134, -0.049, p < 0.001) and HSI (β = -0.17, 95% CI: -0.30, -0.04, p = 0.011). Stronger associations were observed in premenopausal women with obesity. Mediterranean diet was inversely associated with NAFLD-FLS in women with overweight, independently of menopausal status. In conclusion, Mediterranean diet is associated with a better liver status in women with overweight and obesity. This may have a public health impact and be useful in drafting nutritional guidelines for NAFLD.
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Prospective association between organic food consumption and the risk of type 2 diabetes: findings from the NutriNet-Santé cohort study.
Kesse-Guyot, E, Rebouillat, P, Payrastre, L, Allès, B, Fezeu, LK, Druesne-Pecollo, N, Srour, B, Bao, W, Touvier, M, Galan, P, et al
The international journal of behavioral nutrition and physical activity. 2020;17(1):136
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The prevalence of type 2 diabetes (T2D) has significantly increased over recent decades, concomitantly to the obesity epidemic. Among the emergent risk factors, exposure to environmental contaminants including pesticides is of major concern. In fact, a recent European Food Safety Authority report indicated that 44% of conventional crop-based food contained at least one quantifiable pesticide residue, vs 6.5% in organic-labelled foods (OF). The aims of this study were (a) to investigate the prospective association between OF consumption and the risk of T2D, and (b) to estimate the mediation effect by the potential healthiness of a plant-based diet. This study is prospective cohort study based on the data from the web-based NutriNet-Santé study with an analysis sample of 33,256 participants. Results indicate an inverse association between organic plant-based food consumption and T2D risk especially in women. The association persisted after accounting for potential confounding effects of various factors, including lifestyles, dietary patterns and adiposity. Authors conclude that further studies are needed to replicate these findings for confirmation purposes and to elucidate underlying mechanisms.
Abstract
BACKGROUND Organic food (OF) consumption has substantially increased in high income countries, mostly driven by environmental concerns and health beliefs. Lower exposure to synthetic pesticides has been systematically documented among consumers of organic products compared to non-consumers. While experimental studies suggest that pesticides currently used in food production may be associated with type 2 diabetes (T2D), no well-conducted prospective studies have investigated the potential association between consumption of organic products and the risk of T2D, controlling for potential confounding factors. The objective of this prospective study was to estimate the association between OF consumption and the risk of T2D. METHODS A total of 33,256 participants (76% women, mean (SD) age: 53 years (14)) of the French NutriNet-Santé prospective cohort study who completed the organic food frequency questionnaire were included (2014-2019). The proportion of OF in the diet (as weight without drinking water) was computed. The associations between the proportion of OF in the diet (as 5% increment and as quintiles) and the risk of T2D were estimated using multivariable Hazard Ratio (HR) and 95% confidence interval (95% CI) derived from proportional hazards models adjusted for confounders (sociodemographic, anthropometric, lifestyle, medical and nutritional factors). RESULTS During follow-up (mean = 4.05 y, SD = 1.03 y, 134,990 person-years), 293 incident cases of T2D were identified. After adjustment for confounders including lifestyle (physical activity, smoking status, alcohol consumption) and nutritional quality of the diet assessed by the adherence to the French food-based dietary guidelines, OF consumption was associated with a lower risk of T2D. Participants with the highest quintile of OF consumption, compared with those with the lowest quintile, had 35% lower risk of T2D (95% CI = 0.43-0.97). Each increment of 5% in the proportion of OF in the diet was associated with 3% lower risk of T2D (HR 0.97, 95% CI = 0.95-0.99). CONCLUSIONS In this large prospective cohort study, OF consumption was inversely associated with the risk of T2D. Further experimental and prospective studies should be conducted to confirm these observations. CLINICAL TRIAL REGISTRY The study was registered at ClinicalTrials.gov ( NCT03335644 ).
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A Low ω-6 to ω-3 PUFA Ratio (n-6:n-3 PUFA) Diet to Treat Fatty Liver Disease in Obese Youth.
Van Name, MA, Savoye, M, Chick, JM, Galuppo, BT, Feldstein, AE, Pierpont, B, Johnson, C, Shabanova, V, Ekong, U, Valentino, PL, et al
The Journal of nutrition. 2020;150(9):2314-2321
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Non-alcoholic fatty liver disease (NAFLD) is characterised by the accumulation of fat in the liver of people who drink very little or no alcohol. NAFLD is a common problem in children with obesity and diet is a contributory factor. Recent research has suggested that the Western diet and its high omega-6 and low omega-3 fat intakes may lead to the development of NAFLD. This quasi-experimental study of twenty children with obesity and NAFLD aimed to determine whether 12 weeks of low omega-6: omega-3 ratio diet affected liver fat content. The results showed that the diet did not affect weight loss but still significantly decreased liver fat content, with one third of the participants returning their liver fat content to normal. In lieu of weight loss, improvements were also observed in markers for liver function, diabetes and blood cholesterol. Interestingly those who carry a certain gene increasing their risk of developing NAFLD, showed greater improvements in liver fat percentage and liver function. It was concluded that in the absence of weight loss, a diet high in omega-3 and low in omega-6 improves fatty liver disease, risk factors for heart disease and has the potential to revert liver fat content to normal levels. This study could be used by healthcare professionals to recommend a low omega-6:omega-3 diet in children with obesity and NAFLD.
Abstract
BACKGROUND Recent literature suggests that the Western diet's imbalance between high ω-6 (n-6) and low ω-3 (n-3) PUFA intake contributes to fatty liver disease in obese youth. OBJECTIVES We tested whether 12 wk of a low n-6:n-3 PUFA ratio (4:1) normocaloric diet mitigates fatty liver and whether the patatin-like containing domain phospholipase 3 (PNPLA3) rs738409 variant affects the response. METHODS In a single-arm unblinded study, obese youth 9-19 y of age with nonalcoholic fatty liver disease were treated with a normocaloric low n-6:n-3 PUFA ratio diet for 12 wk. The primary outcome was change in hepatic fat fraction (HFF%), measured by abdominal MRI. Metabolic parameters included alanine aminotransferase (ALT), lipids, measures of insulin sensitivity, and plasma oxidized linoleic acid metabolites (OXLAMs). Outcomes were also analyzed by PNPLA3 rs738409 genotype. Wilcoxon's signed rank test, the Mann-Whitney U test, and covariance pattern modeling were used. RESULTS Twenty obese adolescents (median age: 13.3 y; IQR: 10.5-16.4 y) were enrolled and 17 completed the study. After 12 wk of dietary intervention, HFF% decreased by 25.8% (P = 0.009) despite stable weight. We observed a 34.4% reduction in ALT (P = 0.001), 21.9% reduction in triglycerides (P = 0.046), 3.28% reduction in LDL cholesterol (P = 0.071), and a 26.3% improvement in whole body insulin sensitivity (P = 0.032). The OXLAMs 9-hydroxy-octadecandienoic acid (9-HODE) (P = 0.011), 13-HODE (P = 0.007), and 9-oxo-octadecadienoic acid (9-oxoODE) (P = 0.024) decreased after 12 wk. HFF% declined in both the not-at-risk (CC/CG) and at-risk (GG) PNPLA3 rs738409 genotype groups, with significant (P = 0.016) HFF% reduction in the GG group. Changes in 9-HODE (P = 0.023), 9-oxoODE (P = 0.009), and 13-oxoODE (P = 0.003) differed between the 2 genotype groups over time. CONCLUSIONS These data suggest that, independently of weight loss, a low n-6:n-3 PUFA diet ameliorates the metabolic phenotype of adolescents with fatty liver disease and that response to this diet is modulated by the PNPLA3 rs738409 genotype.This trial was registered at clinicaltrials.gov as NCT01556113.
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Alpha-Linolenic and Linoleic Fatty Acids in the Vegan Diet: Do They Require Dietary Reference Intake/Adequate Intake Special Consideration?
Burns-Whitmore, B, Froyen, E, Heskey, C, Parker, T, San Pablo, G
Nutrients. 2019;11(10)
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Fish and seafood are good sources of long-chain omega-3 fatty acids, like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). A vegan diet does not include animal-sourced foods and is therefore void of EPA and DHA, unless algae-derived omega-3 supplements are consumed. Thus, vegans rely on the body's own production of long-chain fatty acids from plant-derived alpha-linolenic acid (ALA). However, adequate conversion can have several limitations. Vegan diets are generally rich in linoleic acid (LA), an omega-6 fatty acid, which in high levels can impede the conversion of ALA to EPA and DHA. Furthermore, the efficiency of conversion is influenced by gender, age or health conditions like obesity. This review sought to discuss whether vegans require special dietary recommendations for fatty acids and what these suggestions could be. Most studies assessing biological indicators of fatty acid status showed that vegans had lower levels of EPA and DHA compared to omnivores. Thus, the authors concluded that special consideration should be given to ALA and LA intake in vegan diets. In the absence of a set recommendation for a fatty acid ratio, a ratio of 4:1 (omega-6:omega-3) was proposed for vegans and omnivores. A reduction in LA and an increased intake of ALA of 2.2–4.4 g/day (or 1.1 g/day/1000 Kcals) was suggested to achieve such. This article is a useful guide when considering adequate fatty acid balance and omega-3 conversion for individuals following a vegan diet.
Abstract
Good sources of the long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) include cold-water fish and seafood; however, vegan diets (VGNs) do not include animal-origin foods. Typically, US omnivores obtain enough dietary EPA and DHA, but unless VGNs consume algal n-3 supplements, they rely on endogenous production of long-chain fatty acids. VGN diets have several possible concerns: (1) VGNs have high intakes of linoleic acid (LA) as compared to omnivore/non-vegetarian diets. (2) High intakes of LA competitively interfere with the endogenous conversion of alpha-linolenic acid (ALA) to EPA and DHA. (3) High somatic levels of LA/low ALA indicate a decreased ALA conversion to EPA and DHA. (4) Some, not all VGNs meet the Dietary Reference Intake Adequate Intake (DRI-AI) for dietary ALA and (5) VGN diets are high in fiber, which possibly interferes with fat absorption. Consequently, health professionals and Registered Dietitians/Registered Dietitian Nutritionists working with VGNs need specific essential fatty acid diet guidelines. The purpose of this review was: (1) to suggest that VGNs have a DRI-AI Special Consideration requirement for ALA and LA based on VGN dietary and biochemical indicators of status and (2) to provide suggestions to ensure that VGNs receive adequate intakes of LA and ALA.
