Efeitos da suplementação com creatina sobre a homocisteína e a função endotelial microvascular sistêmica de indivíduos vegetarianos estritos.
Efeitos da suplementação com creatina sobre a homocisteína e a função endotelial microvascular sistêmica de indivíduos vegetarianos estritos.
Data
2016
Autores
Bezerra, Diogo Van Bavel
Journal Title
Journal ISSN
Volume Title
Publisher
Instituto Nacional de Cardiologia
Resumo
Fundamentação: A dieta vegetariana vem sendo implementada há décadas em diferentes culturas e mais recentemente foi associada a terapias para redução dos fatores de risco de doença cardiovascular tais como sobrepeso, resistência à insulina, hipertensão e dislipidemia. Apesar disso, o vegetarianismo impõe inúmeras restrições de micronutrientes relacionadas à exclusão do consumo de alimentos de origem animal, e os tradicionais efeitos cardio-protetores da dieta tem sido questionados em alguns estudos. Neste contexto, deficiências de vitamina B12 e creatina, micronutrientes exclusivamente presentes em alimentos de origem animal, podem elevar o risco cardiovascular particularmente através do aumento dos níveis plasmáticos de homocisteína, molécula capaz de aumentar o estresse oxidativo vascular e promover disfunção de células endoteliais. Assim o estudo visou investigar o efeito da suplementação com creatina sobre a reatividade microvascular e os níveis plasmáticos de homocisteína em indivíduos vegetarianos estritos. Métodos: Os voluntários veganos estritos de ambos os sexos foram recrutados através de redes sociais e comunidades de vegetarianos localizadas no Rio de Janeiro e randomicamente alocados nos grupos de suplementação com creatina (Scr, n=27) ou placebo (PLA, n=18). Todos os procedimentos seguiram a mesma sequencia, começando com a coleta das amostras de sangue, acompanhada por uma avaliação clínica e física e concluindo com a avaliação da microcirculação por fluxometria laser de contraste de imagem (LCSI) e vídeo-capilaroscopia intravital. Os mesmos procedimentos foram repetidos após três semanas de suplementação com creatina. Os voluntários do grupo suplementado com creatina receberam 5 g diárias de creatina monohidratada micronizada durante três semanas, enquanto os voluntários do grupo suplementado com placebo receberam 5 g por dia de maltodextrina. Resultados: Houve redução significativa dos níveis plasmáticos de homocisteína (Hcy) no grupo Scr [12,11 (8,57-17,12) vs. 10,58 (8,15-13,22); p = 0,0199], já a perfusão capilar basal aumentou significativamente após o período de suplementação apenas do grupo Scr (136 ± 8 vs. 147 ± 13 capilares/mm²; p = 0,0001) e o recrutamento capilar após a hiperemia reativa pós-oclusiva (HRPO) elevou-se significativamente apenas no grupo Scr (141 ± 9 vs. 155 ± 14 capilares/mm²; p = 0,0001). Após o período de Scr, tanto a perfusão capilar basal quanto aquela observada após a hiperemia, foram significativamente mais elevadas no grupo Scr em relação ao PLA. Conclusão: A Scr reduz os níveis de Hcy após três semanas em veganos, sendo mais eficaz quando há presença de indivíduos com hiperhomocisteinemia, além de correlacionar o tempo de vegetarianismo e níveis de Hcy e demonstrar uma relação inversa com níveis de vitamina B12 e Hcy. A Scr por três semanas também mostrou um aumento na perfusão capilar em repouso e após a hiperemia reativa, entretanto não exibiu respostas na reatividade microvascular significativas na fluxometria laser, evidenciando que a Scr pode influenciar na abertura dos esfíncteres pré-capilares sem alterar a dilatação arteriolar
Background: The vegetarian diet has been used for decades in different cultures and has been recently associated to treatments aiming at reducing risk factors for cardiovascular diseases such as overweight, insulin resistance, hypertension and dyslipidemia. However, vegetarianism also results in the restriction of the ingestion of micronutrients related to the exclusion of food from animal origin. Thus, the traditional cardioprotective effects of the vegetarian diet have been questioned in some studies. In this context, the dietary restriction of vitamin B12 and creatine, micronutrients which are present only in food from animal origin, can induce pathophysiological alterations that increase cardiovascular risk, mainly through the increase of the plasma levels of homocysteine (Hcy), a molecule capable to increase vascular oxidative stress and induce endothelial cell dysfunction. Thus, the present study investigated the effects of creatine supplementation on the systemic microvascular reactivity and plasma levels of homocysteine in strict (vegan) vegetarian individuals. Methods: Vegan vegetarian individuals of both sexes were recruited through advertisement in social networking services and vegetarian communities in the State of Rio de Janeiro and randomly allocated to two groups: creatine supplementation (Scr, n=27) or placebo supplementation (PLA, n=18). In the morning of the examinations, peripheral blood was collected after an overnight fasting period, followed by clinical and physical evaluations and finally assessment of the cutaneous microvascular reactivity and density using microvascular flowmetry with laser speckle contrast imaging and intravital video-microscopy. The same procedures were repeated after three weeks of Scr. The volunteers of the Scr group received an oral dose of 5 g of monohydrate micronized creatine, while individual of the PLA group received 5 g of maltodextrin, during three weeks. Results: There was a significant reduction in the plasma levels of Hcy in the Scr group [12.11 (8.57-17.12) vs. 10.58 (8.15-13.22); p=0.0199]. Basal capillary density also increased significantly in the Scr group (136 ± 8 vs. 147 ± 13 capillaries/mm²; p=0.0001), as well as capillary recruitment during post-occlusive reactive hyperemia (141 ± 9 vs. 155 ± 14 capillaries/mm²; p=0.0001). Conclusions: Scr induced a reduction of the plasma levels of Hcy in vegan vegetarians, which was greater in individuals presenting with hiperhomocisteinemia. Moreover, there was a correlation between the time of vegetarian diet and plasma levels of Hcy and an inverse correlation between plasma levels of vitamin B12 and Hcy. Scr during three weeks also increased skin capillary perfusion both at rest and after post-occlusive reactive hyperemia. Nevertheless, Scr did not change skin microvascular reactivity, showing that Scr could influence capillary recruitment without changing arteriolar tone.
Background: The vegetarian diet has been used for decades in different cultures and has been recently associated to treatments aiming at reducing risk factors for cardiovascular diseases such as overweight, insulin resistance, hypertension and dyslipidemia. However, vegetarianism also results in the restriction of the ingestion of micronutrients related to the exclusion of food from animal origin. Thus, the traditional cardioprotective effects of the vegetarian diet have been questioned in some studies. In this context, the dietary restriction of vitamin B12 and creatine, micronutrients which are present only in food from animal origin, can induce pathophysiological alterations that increase cardiovascular risk, mainly through the increase of the plasma levels of homocysteine (Hcy), a molecule capable to increase vascular oxidative stress and induce endothelial cell dysfunction. Thus, the present study investigated the effects of creatine supplementation on the systemic microvascular reactivity and plasma levels of homocysteine in strict (vegan) vegetarian individuals. Methods: Vegan vegetarian individuals of both sexes were recruited through advertisement in social networking services and vegetarian communities in the State of Rio de Janeiro and randomly allocated to two groups: creatine supplementation (Scr, n=27) or placebo supplementation (PLA, n=18). In the morning of the examinations, peripheral blood was collected after an overnight fasting period, followed by clinical and physical evaluations and finally assessment of the cutaneous microvascular reactivity and density using microvascular flowmetry with laser speckle contrast imaging and intravital video-microscopy. The same procedures were repeated after three weeks of Scr. The volunteers of the Scr group received an oral dose of 5 g of monohydrate micronized creatine, while individual of the PLA group received 5 g of maltodextrin, during three weeks. Results: There was a significant reduction in the plasma levels of Hcy in the Scr group [12.11 (8.57-17.12) vs. 10.58 (8.15-13.22); p=0.0199]. Basal capillary density also increased significantly in the Scr group (136 ± 8 vs. 147 ± 13 capillaries/mm²; p=0.0001), as well as capillary recruitment during post-occlusive reactive hyperemia (141 ± 9 vs. 155 ± 14 capillaries/mm²; p=0.0001). Conclusions: Scr induced a reduction of the plasma levels of Hcy in vegan vegetarians, which was greater in individuals presenting with hiperhomocisteinemia. Moreover, there was a correlation between the time of vegetarian diet and plasma levels of Hcy and an inverse correlation between plasma levels of vitamin B12 and Hcy. Scr during three weeks also increased skin capillary perfusion both at rest and after post-occlusive reactive hyperemia. Nevertheless, Scr did not change skin microvascular reactivity, showing that Scr could influence capillary recruitment without changing arteriolar tone.
Description
Palavras-chave
Suplementação com creatina, Homocisteína, Veganismo, Vegetarianismo, Fluxo microvascular, Creatine supplementation, Homocisteine, Vegans, Vegetarianism, Microvascular flow
Citação
Bezerra DVB. Efeitos da suplementação com creatina sobre a homocisteína e a função endotelial microvascular sistêmica de indivíduos vegetarianos estritos. Rio de Janeiro. Dissertação [Mestrado Profissional em Ciências Cardiovasculares] - Instituto Nacional de Cardiologia; 2016.