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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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Effect of Serum Lipid Profile on the Risk of Breast Cancer: Systematic Review and Meta-Analysis of 1,628,871 Women.
Nouri, M, Mohsenpour, MA, Katsiki, N, Ghobadi, S, Jafari, A, Faghih, S, Banach, M, Mazidi, M
Journal of clinical medicine. 2022;11(15)
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Elevated fats in the blood have been associated with an increased risk for breast cancer. However, exact relationships between which fats is still unclear. This systematic review and meta-analysis of 26 studies with 36,590 women aimed to investigate the relationship between fat in the blood and breast cancer risk. The results showed that high levels of high-density lipoprotein (HDL) in the blood decreased a woman’s risk of developing breast cancer, however other fats in the blood such as triglycerides, cholesterol and low-density lipoprotein had no relationship with breast cancer risk. It was concluded that low levels of HDL in the blood are related to an increased risk for breast cancer. This study could be used by healthcare professionals to understand that it is important to recommend exercise, which is a way of increasing HDL’s, in women who are at risk of breast cancer development.
Abstract
Dyslipidemia has been linked to breast cancer incidence. The aim of the present meta-analysis was to further investigate the relationship between the serum lipid profile and breast cancer risk. Databases such as PubMed, EMBASE, and Web of Sciences were searched up to the end of January 2021 using certain MeSH and non-MeSH keywords and combinations to extract related published articles. Twenty-six prospective studies involving 1,628,871 women, of whom 36,590 were diagnosed with breast cancer during the follow-up period met the inclusion criteria. A negative and significant association was found between the HDL-C level and the risk of breast cancer (relative risk (RR): 0.85, 95% CI: 0.72-0.99, I2: 67.6%, p = 0.04). In contrast, TG (RR: 1.02, 95% CI: 0.91-1.13, I2: 54.2%, p = 0.79), total cholesterol (TC) (RR: 0.98, 95% CI: 0.90-1.06, I2: 67.2%, p = 0.57), apolipoprotein A (ApoA) (RR: 0.96, 95% CI: 0.70-1.30, I2: 83.5%, p = 0.78) and LDL-C (RR: 0.93, 95% CI: 0.79-1.09, I2: 0%, p = 0.386) were not associated with breast cancer development. In studies adjusting for hormone use and physical activity, breast cancer risk was positively correlated with TC (RR: 1.05, 95% CI: 1.01-1.10). Similarly, TG was significantly related to breast cancer development after adjustment for baseline lipids (RR: 0.92, 95% CI: 0.85-0.99) and race (any races mentioned in each study) (RR: 1.80, 95% CI: 1.22-2.65). In the present meta-analysis, HDL-C was inversely related to breast cancer risk. Overall, data on the links between lipids and breast cancer are conflicting. However, there is increasing evidence that low HDL-C is related to an increased risk for this type of malignancy.
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Effect of dietary nitrate on human muscle power: a systematic review and individual participant data meta-analysis.
Coggan, AR, Baranauskas, MN, Hinrichs, RJ, Liu, Z, Carter, SJ
Journal of the International Society of Sports Nutrition. 2021;18(1):66
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Previous reviews have concluded that dietary nitrate (NO3−) improves maximal neuromuscular power in humans, but these were based on a limited number of studies. This is the first systematic review and meta-analysis evaluating the effects of dietary NO3− supplementation on muscular power in humans. The study also aims to quantify the size of this beneficial effect. 19 studies with a total of 268 participants were included. Most of these used concentrated beetroot juice as the source of NO3− given as an acute dose (short term high level). A positive effect of dietary NO3− on muscle power was observed in all 19 studies. Analyses were done on sub groups - age, sex and the amount of muscle mass engaged in the activity. Dietary NO3− intake significantly increases maximal muscle power in humans. The magnitude of this effect has practical and clinical importance; not just for athletes but also for patient groups. This effect is independent of subject age, sex, or the amount of muscle mass engaged in the activity but may be greater with acute vs. repeated dosing. Further research is needed to determine factors such as the optimal supplementation regimen and target population.
Expert Review
Conflicts of interest:
None
Take Home Message:
- This meta-analysis lends quantitative support to previous narrative reviews that nitrate supplementation can enhance maximal power output.
- These findings are highly relevant to team and strength sport athletes, who may not otherwise be supplementing with nitrates.
- These findings are also highly relevant for older populations, where risk of falls and fractures are high and can lead to significant adverse effects on health and quality of life.
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:
- In 2007, researchers uncovered the ingestion of dietary nitrates reduced the oxygen cost of submaximal exercise, and since, over 100 studies have examined the effects of nitrates on endurance performance.
- With regards to the impact of nitrates on maximal force output, only trivial results had been previously found.
- This review study found that while nitrates do not impact force development, they do demonstrate primary effect on the speed of muscle contraction (i.e. muscular power is the product of force x speed).
- The reviews primary finding was that nitrate intake can significantly enhance muscular power, regardless of subject age or sex.
Clinical practice applications:
- These new findings highlight the ability of dietary nitrates to improve neuromuscular power production is highly relevant for team sport athletes, due to the explosive nature of these sports with constant accelerations and decelerations during training and competition.
- In the general population, falls and fractures amongst older adults significantly reduces quality of life and costs the healthcare system hundreds of millions of pounds to treat.
- Improved contractile properties of muscle, most notably speed of contraction, may offer protection to older adults as well as the benefit of additional nitric oxide (NO) to support vascular health as well.
- The typical intake of dietary nitrates in the general population is about 31-185mg/day in Europe and 40-100mg/day in North America. Most studies use doses between 300-600mg of dietary nitrates. Increasing dietary or supplemental intake is key to achieving the neuromuscular effect.
Considerations for future research:
- The results of the present meta-analysis clearly demonstrate that dietary nitrates increases muscle power in humans, but the mechanism responsible for this effect is still unclear.
- There are notable differences between rodent and human metabolism of dietary nitrates, therefore the biochemical mechanism by which nitrate intake improves human muscle power requires additional study.
Abstract
BACKGROUND Previous narrative reviews have concluded that dietary nitrate (NO3-) improves maximal neuromuscular power in humans. This conclusion, however, was based on a limited number of studies, and no attempt has been made to quantify the exact magnitude of this beneficial effect. Such information would help ensure adequate statistical power in future studies and could help place the effects of dietary NO3- on various aspects of exercise performance (i.e., endurance vs. strength vs. power) in better context. We therefore undertook a systematic review and individual participant data meta-analysis to quantify the effects of NO3- supplementation on human muscle power. METHODS The literature was searched using a strategy developed by a health sciences librarian. Data sources included Medline Ovid, Embase, SPORTDiscus, Scopus, Clinicaltrials.gov , and Google Scholar. Studies were included if they used a randomized, double-blind, placebo-controlled, crossover experimental design to measure the effects of dietary NO3- on maximal power during exercise in the non-fatigued state and the within-subject correlation could be determined from data in the published manuscript or obtained from the authors. RESULTS Nineteen studies of a total of 268 participants (218 men, 50 women) met the criteria for inclusion. The overall effect size (ES; Hedge's g) calculated using a fixed effects model was 0.42 (95% confidence interval (CI) 0.29, 0.56; p = 6.310 × 10- 11). There was limited heterogeneity between studies (i.e., I2 = 22.79%, H2 = 1.30, p = 0.3460). The ES estimated using a random effects model was therefore similar (i.e., 0.45, 95% CI 0.30, 0.61; p = 1.064 × 10- 9). Sub-group analyses revealed no significant differences due to subject age, sex, or test modality (i.e., small vs. large muscle mass exercise). However, the ES in studies using an acute dose (i.e., 0.54, 95% CI 0.37, 0.71; p = 6.774 × 10- 12) was greater (p = 0.0211) than in studies using a multiple dose regimen (i.e., 0.22, 95% CI 0.01, 0.43; p = 0.003630). CONCLUSIONS Acute or chronic dietary NO3- intake significantly increases maximal muscle power in humans. The magnitude of this effect-on average, ~ 5%-is likely to be of considerable practical and clinical importance.
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Impact of Nutritional Changes on Nonalcoholic Fatty Liver Disease.
Perdomo, CM, Frühbeck, G, Escalada, J
Nutrients. 2019;11(3)
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The major established risk factors for non-alcoholic fatty liver disease (NAFLD) include obesity, insulin resistance and dyslipidaemia. This in-depth review looks at research into the effects of macronutrient composition and dietary patterns on NAFLD. Lifestyle modifications leading to weight reduction and/or increased physical activity consistently showed improvements in NAFLD. Based on the reviewed studies, the authors recommend a diet that includes whole grains, mono-unsaturated fatty acids (in moderation), omega 3 poly-unsaturated fatty acids, vegetable protein and fibre, whilst avoiding simple sugars, trans and saturated fats, and red and processed meats. The effects of these macronutrients were independent of weight loss. There was insufficient evidence for a beneficial role of probiotics, resveratrol, coffee, taurine and choline. The Western dietary pattern, characterised by high intakes of saturated fats and fructose, was associated with an increased risk of NAFLD. The Mediterranean Diet (MD), characterised by a high consumption of plant-based foods (whole grains, cereals, seeds, nuts, legumes, vegetables and fruits), moderate consumption of protein-source foods (fish, seafood, and poultry), low to moderate red wine consumption, low consumption of meat, milk and dairy products, was thought to be beneficial. The “Dietary Approach to Stop Hypertension” (DASH) diet, with an emphasis on low intake of sodium, total fat, saturated fat, cholesterol and added sugars, was also found to be beneficial. The effects of low carbohydrate diets were unclear, as any benefits may be due to the associated weight loss rather than the macronutrient composition per se. The authors point out that much of the research is observational (i.e. epidemiological) and that more prospective clinical trials are needed.
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a major global health threat due to its growing incidence and prevalence. It is becoming the leading cause of liver disease in addition to its strong association with cardio-metabolic disease. Therefore, its prevention and treatment are of strong public interest. Therapeutic approaches emphasize lifestyle modifications including physical activity and the adoption of healthy eating habits that intend to mainly control body weight and cardio-metabolic risk factors associated with the metabolic syndrome. Lifestyle interventions may be reinforced by pharmacological treatment in advanced stages, though there is still no registered drug for the specific treatment of NAFLD. The purpose of this review is to assess the evidence available regarding the impact of dietary recommendations against NAFLD, highlighting the effect of macronutrient diet composition and dietary patterns in the management of NAFLD.
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Nutritional issues in patients with obesity and cirrhosis.
Schiavo, L, Busetto, L, Cesaretti, M, Zelber-Sagi, S, Deutsch, L, Iannelli, A
World journal of gastroenterology. 2018;24(30):3330-3346
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Non-alcoholic fatty liver disease (NAFLD) occurs when fats accumulate in the liver in the absence of excess alcohol intake and if unmanaged can advance to severe liver disease known as cirrhosis. NAFLD and cirrhosis can be associated with obesity, muscle wastage and nutrient deficiencies. This review of 165 papers aimed to discuss muscle wastage and nutrient deficiencies in patients with obesity and cirrhosis with a view to making supplementation recommendations. The authors first discussed that the risk of muscle wastage in patients with obesity and cirrhosis is high and when combined with obesity may affect other chronic diseases and impact the progression of NAFLD to cirrhosis. The paper then discusses that vitamin and mineral deficiencies are common in patients with cirrhosis possibly due to reduced intake, poor absorption and the reduction of carrier protein production in the liver. Deficiencies in vitamins D and E and zinc and magnesium were extensively featured. Protein and calorie intake were also reviewed and although weight loss should be encouraged in patients with obesity and cirrhosis, over-restriction could exacerbate muscle breakdown. Any low-calorie diets should contain adequate protein content. Bariatric surgery, in patients with obesity and cirrhosis needs to be performed on a case-by-case basis involving many different medical disciplines. It was concluded that obesity and cirrhosis are commonly occurring simultaneously and poses a management challenge for medical professionals. This paper could be used by health care professionals to understand the possible nutritional deficiencies that need to be monitored in patients with obesity and cirrhosis and where bariatric surgery may be indicated.
Abstract
Obesity and metabolic syndrome are considered as responsible for a condition known as the non-alcoholic fatty liver disease that goes from simple accumulation of triglycerides to hepatic inflammation and may progress to cirrhosis. Patients with obesity also have an increased risk of primary liver malignancies and increased body mass index is a predictor of decompensation of liver cirrhosis. Sarcopenic obesity confers a risk of physical impairment and disability that is significantly higher than the risk induced by each of the two conditions alone as it has been shown to be an independent risk factor for chronic liver disease in patients with obesity and a prognostic negative marker for the evolution of liver cirrhosis and the results of liver transplantation. Cirrhotic patients with obesity are at high risk for depletion of various fat-soluble, water-soluble vitamins and trace elements and should be supplemented appropriately. Diet, physical activity and protein intake should be carefully monitored in these fragile patients according to recent recommendations. Bariatric surgery is sporadically used in patients with morbid obesity and cirrhosis also in the setting of liver transplantation. The risk of sarcopenia, micronutrient status, and the recommended supplementation in patients with obesity and cirrhosis are discussed in this review. Furthermore, the indications and contraindications of bariatric surgery-induced weight loss in the cirrhotic patient with obesity are discussed.
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Anti-Obesity Effects of Medicinal and Edible Mushrooms.
Ganesan, K, Xu, B
Molecules (Basel, Switzerland). 2018;23(11)
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Medicinal mushrooms have long been considered healthful due to of their anti-oxidant and anti-inflammatory properties, such as high-quality proteins, polyunsaturated fatty acids, polyphenols etc. More recently they have been analysed for their anti-obesity effects. The health implications of obesity are extensive, often affecting all bodily systems. The purpose of this review was to analyse previous animal studies to determine whether consuming edible mushrooms has a positive effect on obesity related illnesses, such as Type 2 diabetes and cardiovascular disease etc. The authors explore and summarise the different methods used to treat obesity including pharmacotherapy (weight loss drugs), natural products such as Ayurveda medicine and exercise. They present promising results that suggest the therapeutic properties of edible mushrooms have anti-obesity potentials and propose that the findings from animal studies could likely be mirrored in humans and recommend consuming mushrooms to aid weight loss and therefore improve health.
Abstract
Obesity is a group of metabolic disorders caused by multiple factors, including heredity, diet, lifestyle, societal determinants, environment, and infectious agents, which can all lead to the enhancement of storage body fat. Excess visceral fat mass in adipose tissue generate several metabolic disorders, including cardiovascular diseases with chronic inflammation based pathophysiology. The objective of the current review is to summarize the cellular mechanisms of obesity that attenuate by antioxidant potentials of medicinal and edible mushrooms. Studies have showed that mushrooms potentially have antioxidant capacities, which increase the antioxidant defense systems in cells. They boost anti-inflammatory actions and thereby protect against obesity-related hypertension and dyslipidemia. The practice of regular consumption of mushrooms is effective in the treatment of metabolic syndrome, including obesity, and thus could be a good candidate for use in future pharmaceutical or nutraceutical applications.
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Silymarin in the prevention and treatment of liver diseases and primary liver cancer.
Féher, J, Lengyel, G
Current pharmaceutical biotechnology. 2012;13(1):210-7
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Non-alcoholic fatty liver disease (NAFLD) is a recognised health problem with no convincing interventions to date. This randomised trial aimed to examine the efficacy of silymarin plus vitamin E in the treatment of NAFLD. 36 patients were randomized to either group Ι or group ΙΙ. Group Ι was treated with 2 tablets of silymarin plus vitamin E per day, hypocaloric diet and exercise. Group ΙΙ was treated only with a hypocaloric diet. Study duration was 3 months for both groups. Diagnosis of NAFLD was confirmed for all participants by liver biopsy. Patients in group Ι showed significant decrease in anthropometric measurements. Both groups experienced reductions in markers of NAFLD, however in group I, these reductions were independent of weight loss, whereas in group II, those who failed to lose 5% of body weight didn’t show a change in biochemical markers. Authors conclude that intervention with silymarin plus vitamin E, alone or along with other treatments, can help NAFLD patients who fail to lose weight with diet.
Abstract
In chronic liver diseases caused by oxidative stress (alcoholic and non-alcoholic fatty liver diseases, drug- and chemical-induced hepatic toxicity), the antioxidant medicines such as silymarin can have beneficial effect. Liver cirrhosis, non-alcoholic fatty liver and steatohepatitis are risk factors for hepatocellular carcinoma (HCC). Insulin resistance and oxidative stress are the major pathogenetic mechanisms leading the hepatic cell injury in these patients. The silymarin exerts membrane-stabilizing and antioxidant activity, it promotes hepatocyte regeneration; furthermore it reduces the inflammatory reaction, and inhibits the fibrogenesis in the liver. These results have been established by experimental and clinical trials. According to open studies the long-term administration of silymarin significantly increased survival time of patients with alcohol induced liver cirrhosis. Based on the results of studies using methods of molecular biology, silymarin can significantly reduce tumor cell proliferation, angiogenesis as well as insulin resistance. Furthermore, it exerts an anti-atherosclerotic effect, and suppresses tumor necrosis factor-alpha-induced protein production and mRNA expression due to adhesion molecules. The chemopreventive effect of silymarin on HCC has been established in several studies using in vitro and in vivo methods; it can exert a beneficial effect on the balance of cell survival and apoptosis by interfering cytokines. In addition to this, anti-inflammatory activity and inhibitory effect of silymarin on the development of metastases have also been detected. In some neoplastic diseases silymarin can be administered as adjuvant therapy as well.