Efeitos da suplementação com ferro versus ferro dietético sobre o estado nutricional em ferro: revisão sistemática com metanálise de ensaios clínicos aleatórios

Abstract

Anemia remains a public health problem throughout the world. According to data from the World Health Organization (WHO), approximately 24,8% of the world's population is afflicted by this disease, with prevalence of approximately 23% and 52% in developed and underdeveloped countries respectively. It is estimated that about 50% of anemia cases are due to iron deficiency, or iron deficiency (ID). The main causes are the insufficient intake of food sources of the mineral, impaired nutrient absorption, intestinal parasitosis and blood loss. There are several strategies of prevention and combat of the ID around the world, emphasizing the supplementation with salts of iron, like the most widespread, with less attention for alimentary approaches. Although the effectiveness of iron supplementation is proven, the prevalence of anemia has remained high, especially in the less developed countries. One of the justifications for this situation is the low adherence to the use of the supplement, mainly because of the side effects such as nausea, vomiting, colic and diarrhea, causing the treatment to be discontinued, decreasing its effectiveness. The present dissertation was divided into two parts: the first one is a narrative review chapter, which seeks to explain the repercussions of anemia on health, at different stages of the life cycle. Before there is an original meta-analysis systematic review of 12 randomized clinical trials to assess whether individuals allocated for a dietary intervention, focusing on the supply of iron naturally present in food or provided through fortified food, present better levels of biochemical parameters that interfere with the state of nutrition in iron, than those individuals allocated for iron supplementation in the standard treatment period, defined as 12 weeks or more follow-up. The results showed that supplementation with iron significantly increased the hemoglobin concentration of anemic or iron deficient children when compared to dietary intervention. On the other hand, dietary intervention was compared to the use of supplementation, with an equal recovery power of hemoglobin in adolescents and adults. There was lower concentration of soluble transferrin receptor in children and total iron binding capacity in adolescents / adults with the drug strategy compared to dietary treatment. Thus, among the therapeutic options investigated here, the use of supplementation is the strategy of choice in the recovery of hemoglobin from anemic or iron deficient children. However, for adolescents and adults, dietary intervention is a better alternative, with an equal recovery power of the hemoglobin serum concentration, with a reduced risk of rejection and side effects, associated with drug treatment with iron. Studies with longer follow-up after the intervention period are needed.