Effects of Coffee Components on Muscle Glycogen Recovery: A Systematic Review.

Coffee is one of the most consumed beverages in the world, and it can improve insulin sensitivity, stimulating glucose uptake in skeletal muscle when adequate carbohydrate intake is observed. The aim of this review is to analyze the effects of coffee and coffee components on muscle glycogen metabolism. A literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis, and seven studies were included, that explored the effects of coffee components on various substances and signaling proteins. In one of the studies with humans, caffeine was shown to increase glucose levels, Ca2+/calmodulin-dependent protein kinase phosphorylation, glycogen resynthesis rates, and glycogen accumulation after exercise. After intravenous injection of caffeine in rats, caffeine increased adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, and glucose transport. In in vitro studies, caffeine raised AMPK and ACC phosphorylation, increasing glucose transport activity and reducing energy status in rat muscle cells. Cafestol and caffeic acid increased insulin secretion in rat beta cells and glucose uptake into human muscle cells. Caffeic acid also increased AMPK and ACC phosphorylation, reducing the energy status and increasing glucose uptake in rat muscle cells. Chlorogenic acid did not show any positive or negative effect. The findings from this review must be taken with caution due to the limited number of studies on the subject. In conclusion, various coffee components had a neutral or positive role in the metabolism of glucose and muscle glycogen, whereas no detrimental effect was described. Coffee beverages should be tested as an option for athletes' glycogen recovery.

Coffee Increases Post-Exercise Muscle Glycogen Recovery in Endurance Athletes: A Randomized Clinical Trial.

Coffee is one of the most widely consumed beverages worldwide and caffeine is known to improve performance in physical exercise. Some substances in coffee have a positive effect on glucose metabolism and are promising for post-exercise muscle glycogen recovery. We investigated the effect of a coffee beverage after exhaustive exercise on muscle glycogen resynthesis, glycogen synthase activity and glycemic and insulinemic response in a double-blind, crossover, randomized clinical trial. Fourteen endurance-trained men performed an exhaustive cycle ergometer exercise to deplete muscle glycogen. The following morning, participants completed a second cycling protocol followed by a 4-h recovery, during which they received either test beverage (coffee + milk) or control (milk) and a breakfast meal, with a simple randomization. Blood samples and muscle biopsies were collected at the beginning and by the end of recovery. Eleven participants were included in data analysis (age: 39.0 ± 6.0 years; BMI: 24.0 ± 2.3 kg/m2; VO2max: 59.9 ± 8.3 mL·kg-1·min-1; PPO: 346 ± 39 W). The consumption of coffee + milk resulted in greater muscle glycogen recovery (102.56 ± 18.75 vs. 40.54 ± 18.74 mmol·kg dw-1; p = 0.01; d = 0.94) and greater glucose (p = 0.02; d = 0.83) and insulin (p = 0.03; d = 0.76) total area under the curve compared with control. The addition of coffee to a beverage with adequate amounts of carbohydrates increased muscle glycogen resynthesis and the glycemic and insulinemic response during the 4-h recovery after exhaustive cycling exercise.

[Calcium intake, serum vitamin D and obesity in children: is there an association?]. / Ingestão de cálcio, níveis séricos de vitamina D e obesidade infantil: existe associação?

OBJECTIVE: To evaluate the association between calcium intake and serum vitamin D levels and childhood obesity by an integrative review. DATA SOURCE: The research was conducted in the databases PubMed/medLine, Science Direct and SciELO with 2001 to 2014 publications. We used the combined terms in English: "children" and "calcium" or "children" and "vitamin D" associated with the descriptors: "obesity", "adiposity" or "body fat" for all bases. Cross-sectional and cohort studies, as well as clinical trials, were included. Review articles or those that that have not addressed the association of interest were excluded. DATA SYNTHESIS: Eight articles were part of this review, five of which were related to calcium and three to vitamin D. Most studies had a longitudinal design. The analyzed studies found an association between calcium intake and obesity, especially when age and sex were considered. Inverse relationship between serum vitamin D and measures of adiposity in children has been observed and this association was influenced by the sex of the patient and by the seasons of the year. CONCLUSIONS: The studies reviewed showed an association between calcium and vitamin D with childhood obesity. Considering the possible protective effect of these micronutrients in relation to childhood obesity, preventive public health actions should be designed, with emphasis on nutritional education.

Calcium intake, serum vitamin D and obesity in children: is there an association? / Ingestão de cálcio, níveis séricos de vitamina D e obesidade infantil: existe associação?

OBJECTIVE: To evaluate the association between calcium intake and serum vitamin D levels and childhood obesity by an integrative review. DATA SOURCE: The research was conducted in the databases PubMed/medLine, Science Direct and SciELO with 2001 to 2014 publications. We used the combined terms in English: ''children'' and ''calcium'' or ''children'' and ''vitamin D'' associated with the descriptors: ''obesity'', ''adiposity'' or ''body fat'' for all bases. Cross-sectional and cohort studies, as well as clinical trials, were included. Review articles or those that that have not addressed the association of interest were excluded. DATA SYNTHESIS: Eight articles were part of this review, five of which were related to calcium and three to vitamin D. Most studies had a longitudinal design. The analyzed studies found an association between calcium intake and obesity, especially when age and sex were considered. Inverse relationship between serum vitamin D and measures of adiposity in children has been observed and this association was influenced by the sex of the patient and by the seasons of the year. CONCLUSIONS: The studies reviewed showed an association between calcium and vitamin D with childhood obesity. Considering the possible protective effect of these micronutrients in relation to childhood obesity, preventive public health actions should be designed, with emphasis on nutritional education.

OBJETIVO: Avaliar a associação da ingestão de cálcio e níveis séricos de vitamina D e a obesidade infantil, por meio de uma revisão integrativa. FONTES DE DADOS: A pesquisa foi feita nas bases Pubmed/MedLine, Science Direct e SciELO com publicações de 2001 a 2014. Usaram-se os termos em inglês combinados: "children" e "calcium" ou "children" e "vitamina D" associados, cada um, aos descritores: "obesity", "adiposity" ou "body fat", para todas as bases. Foram incluídos estudos que relacionassem as palavraschave da pesquisa, com delineamento transversal, estudos de coorte e ensaios clínicos. Foram excluídos artigos de revisão ou artigos que não estudaram a associação de interesse. SÍNTESE DOS DADOS: Oito artigos fizeram parte dessa revisão, dos quais cinco eram referentes ao cálcio e três abordaram a vitamina D. A maioria dos estudos foi de delineamento longitudinal. Os estudos analisados encontraram associação entre ingestão cálcio e obesidade, especialmente quando consideradas características como idade e sexo. Tem-se observado relação inversa entre concentrações séricas de vitamina D e medidas de adiposidade em crianças. Essas são influenciadas pelo sexo e pelas estações do ano. CONCLUSÕES: Os estudos avaliados mostraram associação entre cálcio e vitamina D com a obesidade na infância. Assim, considerando o possível efeito protetor desses micronutrientes em relação à obesidade infantil, as ações preventivas de saúde pública podem ser pautadas com ênfase na educação nutricional.