Advances in nutrition
-
Advances in nutrition · Jan 2015
ReviewDietary selenium in adjuvant therapy of viral and bacterial infections.
Viral and bacterial infections are often associated with deficiencies in macronutrients and micronutrients, including the essential trace element selenium. In selenium deficiency, benign strains of Coxsackie and influenza viruses can mutate to highly pathogenic strains. Dietary supplementation to provide adequate or supranutritional selenium supply has been proposed to confer health benefits for patients suffering from some viral diseases, most notably with respect to HIV and influenza A virus (IAV) infections. ⋯ Supranutritional selenium promotes proliferation and favors differentiation of naive CD4-positive T lymphocytes toward T helper 1 cells, thus supporting the acute cellular immune response, whereas excessive activation of the immune system and ensuing host tissue damage are counteracted through directing macrophages toward the M2 phenotype. This review provides an up-to-date overview on selenium in infectious diseases caused by viruses (e.g., HIV, IAV, hepatitis C virus, poliovirus, West Nile virus) and bacteria (e.g., M. tuberculosis, Helicobacter pylori). Data from epidemiologic studies and intervention trials, with selenium alone or in combination with other micronutrients, and animal experiments are discussed against the background of dietary selenium requirements to alter immune functions.
-
In response to rising rates of obesity in the United States due in part to excess food consumption, researchers and policy makers have argued that levying food taxes on obesity-promoting foods, perhaps combined with subsidies on healthier options, would be an effective tool to stem the obesity epidemic. The extent to which overall energy intake or weight outcomes will improve as a result of these policies is ultimately an empirical question. ⋯ Current evidence indicates that, by themselves, targeted food taxes and subsidies as considered to date are unlikely to have a major effect on individual weight or obesity prevalence. While research suggests that the effects are modest, food taxes and subsidies may play an important role in a multifaceted approach to reducing obesity incidence.