Beneficial Effects of Flavonoids on Skeletal Muscle Health: A Systematic Review and Meta-Analysis.

Skeletal muscle (SkM) is a highly dynamic tissue that responds to physiological adaptations or pathological conditions, and SkM mitochondria play a major role in bioenergetics, regulation of intracellular calcium homeostasis, pro-oxidant/antioxidant balance, and apoptosis. Flavonoids are polyphenolic compounds with the ability to modulate molecular pathways implicated in the development of mitochondrial myopathy. Therefore, it is pertinent to explore its potential application in conditions such as aging, disuse, denervation, diabetes, obesity, and cancer. To evaluate preclinical and clinical effects of flavonoids on SkM structure and function. We performed a systematic review of published studies, with no date restrictions applied, using PubMed and Scopus. The following search terms were used: "flavonoids" OR "flavanols" OR "flavones" OR "anthocyanidins" OR "flavanones" OR "flavan-3-ols" OR "catechins" OR "epicatechin" OR "(-)-epicatechin" AND "skeletal muscle." The studies included in this review were preclinical studies, clinical trials, controlled clinical trials, and randomized-controlled trials that investigated the influence of flavonoids on SkM health. Three authors, independently, assessed trials for the review. Any disagreement was resolved by consensus. The use of flavonoids could be a potential tool for the prevention of muscle loss. Their effects on metabolism and on mitochondria function suggest their use as muscle regulators.

High Flavonoid Cocoa Supplement Ameliorates Plasma Oxidative Stress and Inflammation Levels While Improving Mobility and Quality of Life in Older Subjects: A Double-Blind Randomized Clinical Trial.

BACKGROUND: The age-related decline in mass, strength, and performance of skeletal muscle is associated with loss of independence, falls risk, disability, institutionalization, and death. METHODS: To determine whether a cocoa supplement enriched in flavonoids can improve plasma markers of oxidative stress and inflammation, physical performance and frailty in middle-aged and older subjects, we conducted a two-phase, randomized, double-blind, clinical trial. The initial study included 60 subjects (55- to 70-year-old) allocated into placebo (P), highly alkalinized (no-flavonoid; NF), or flavonoid-rich natural cocoa (F) beverage groups. The follow-up study included 74 older subjects (65- to 90-year-old) randomly distributed into NF or F groups. Subjects were instructed to consume the beverages once/day for up to 12-weeks. A comprehensive (aging relevant) set of end points were assessed, which included mean change in blood plasma metabolic and oxidative stress indicators, in physical performance tests and quality of life (QoL). RESULTS: In the initial study, the F group showed improved glycemia, triglyceridemia, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, triglyceridemia/HDL index, and oxidative markers. Performance on the Up and Go test, skeletal muscle index, and quality of life also improved. In the follow-up study, F treatment was associated with significant improvements in metabolic, oxidative stress, and inflammatory endpoints and positive effects on physical performance, frailty indicators, and quality of life (F vs. NF group). CONCLUSIONS: Regular flavonoids consumption positively affects blood oxidative stress and inflammation end points, cardiometabolic risk markers, physical performance, and quality of life. The sum of such effects may help to mitigate the extent of frailty development in the elderly people. TRIAL REGISTRATION: NCT03585868.

Beneficial effects of a flavanol-enriched cacao beverage on anthropometric and cardiometabolic risk profile in overweight subjects / Efectos beneficiosos de una bebida de cocoa enriquecida con flavanol en el perfil antropométrico y de riesgo cardiometabólico en sujetos con sobrepeso

Overweight and obesity are associated with systemic inflammation and oxidative stress which, in turn, enhance the development of cardiometabolic disruptions. Lifestyle changes and pharmacologic approaches show moderately effective results regarding overall health improvements. Evidence suggests that cacao flavonoids are associated with a reduced cardiometabolic risk, due to the modulation of molecular pathways subjacent to glucose and lipids metabolism. The aim of this study was to assess the effects of cacao flavonoids supplementation on anthropometric and cardiometabolic risk factors in overweight subjects. A double-blind, placebo-controlled, pilot clinical trial was conducted in overweight subjects with borderline criteria of metabolic syndrome. Participants were randomly assigned to either, supplement of cacao flavonoids (80 mg) or placebo, daily, for 4 weeks. Cardiometabolic variables were blood pressure, glycemia and lipid profile. Serum markers of oxidative damage (free protein carbonyls and malondialdehyde) were also analyzed. Anthropometric measurements included body weight, body mass index, waist circumference, and fat and fat-free mass. We found significant reductions in body weight (p = 0.04), waist circumference (p = 0.03), triacylglycerols (p < 0.01), TG/HDL ratio (p = 0.01), MDA (p = 0.02) and protein carbonyls (p = 0.01) in the flavonoid-supplemented group. Results from this study show that cacao flavonoids can effectively modulate anthropometric and cardiometabolic risk factors.

El sobrepeso y la obesidad están asociados con la inflamación sistémica y el estrés oxidativo, que, a su vez, incrementan el desarrollo de trastornos cardiometabólicos. Cambios en el estilo de vida y tratamientos farmacológicos muestran resultados moderadamente eficaces en relación con la mejora general de la salud. La evidencia sugiere que los flavonoides del cacao se asocian con un riesgo cardiometabólico reducido, debido a la modulación de las vías moleculares subyacentes al metabolismo de la glucosa y de los lípidos. El objetivo de este estudio fue evaluar los efectos de la suplementación de flavonoides del cacao sobre factores de riesgo cardiometabólico y antropométrico en sujetos con sobrepeso. Se llevó a cabo un ensayo clínico piloto, doble ciego y controlado con placebo en sujetos con sobrepeso y criterios limítrofes de síndrome metabólico. Los participantes fueron asignados al azar a cuatro semanas de tratamiento con suplemento oral de flavonoides de cacao (80 mg) diario o placebo. Las variables cardiometabólicas analizadas fueron presión arterial sistémica, glicemia y perfil lipídico. También se analizaron los marcadores séricos de estrés oxidativo (carbonilos proteicos libres y malondialdehído). Las medidas antropométricas incluyeron el peso corporal, índice de masa corporal, circunferencia de la cintura, masa grasa y masa libre de grasa. Se encontró una reducción significativa en el peso corporal (p = 0.04), circunferencia de la cintura (p = 0.03), triglicéridos (p < 0.01), la relación TG/HDL (p = 0.01), MDA (p = 0.02) y carbonilos (p = 0.01) en el grupo con suplemento de flavonoides. Los resultados de este estudio muestran que los flavonoides del cacao pueden modular efectivamente factores de riesgo cardiometabólico y antropométricos.