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Yacon effects in immune response and nutritional status of iron and zinc in preschool children.

  • 2014-06
  • Nutrition (Burbank, Los Angeles County, Calif.) 30(6)
    • Maria das Graças Vaz-Tostes
    • Mirelle Lomar Viana
    • Mariana Grancieri
    • Tereza Cecília dos Santos Luz
    • Heberth de Paula
    • Rogério Graça Pedrosa
    • Neuza Maria Brunoro Costa

Study Design

Type
Clinical Trial
Sample size
n = 59
Population
Preschool children ages 2 to 5 years from two nurseries, divided into a control group (n=58) and a yacon group (n=59)
Methods
The yacon group received yacon flour in preparations for 18 weeks at a quantity to provide 0.14 g of fructooligosaccharides/kg of body weight daily. Anthropometric parameters, dietary intake, iron and zinc status (erythrograms, serum iron, ferritin, plasma and erythrocyte zinc), and immune response biomarkers (IL-4, IL-10, IL-6, TNF-α, sIgA) were evaluated. Statistical significance was evaluated using paired t test.
Blinding
Open-label
Duration
18 wk
Funding
Unclear

Objective

The aim of this study was to evaluate the effect of yacon flour on iron and zinc nutritional status and immune response biomarkers in preschool children.

Methods

Preschool children ages 2 to 5 y were selected from two nurseries and were placed into a control group (n = 58) or a yacon group (n = 59). The yacon group received yacon flour in preparations for 18 wk at a quantity to provide 0.14 g of fructooligosaccharides/kg of body weight daily. Anthropometric parameters were measured before and after the intervention and dietary intake was measured during the intervention. To assess iron and zinc status, erythrograms, serum iron, ferritin, and plasma, and erythrocyte zinc were evaluated. Systemic immune response was assessed by the biomarkers interleukin IL-4, IL-10, IL-6, and tumor necrosis factor-alfa (TNF-α). Intestinal immune response was analyzed by secretory IgA (sIgA) levels before and after the intervention. Statistical significance was evaluated using the paired t test (α = 5%).

Results

Before and after the study, the children presented a high prevalence of overweight and an inadequate dietary intake of zinc and fiber. The yacon group presented with lower hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration at the end of the study (P < 0.05). Erythrocyte zinc was reduced in both groups at the end of the study (P < 0.05). Yacon intake increased the serum levels of IL-4 and fecal sIgA (P < 0.05). The control group had lower serum TNF-α after the study period (P < 0.05).

Conclusion

Yacon improved intestinal immune response but demonstrated no effect on the nutritional status of iron and zinc in preschool children.

Research Insights

  • Yacon→Improved Iron Levels

    To assess iron and zinc status, erythrograms, serum iron, ferritin, and plasma, and erythrocyte zinc were evaluated.

    Effect
    Neutral
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Increased Fecal Secretory IgA Levels

    Yacon intake increased the serum levels of IL-4 and fecal sIgA (P < 0.05).

    Effect
    Beneficial
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Increased Hemoglobin Levels

    The yacon group presented with lower hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration at the end of the study (P < 0.05).

    Effect
    Harmful
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Increased Interleukin-10 Levels

    To assess iron and zinc status, erythrograms, serum iron, ferritin, and plasma, and erythrocyte zinc were evaluated. Systemic immune response was assessed by the biomarkers interleukin IL-4, IL-10, IL-6, and tumor necrosis factor-alfa (TNF-α).

    Effect
    Neutral
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Reduced Erythrocyte Zinc Level

    Erythrocyte zinc was reduced in both groups at the end of the study (P < 0.05).

    Effect
    Harmful
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Reduced Interleukin-4 Levels

    Yacon intake increased the serum levels of IL-4 and fecal sIgA (P < 0.05).

    Effect
    Beneficial
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Reduced Interleukin-6 Levels

    To assess iron and zinc status, erythrograms, serum iron, ferritin, and plasma, and erythrocyte zinc were evaluated. Systemic immune response was assessed by the biomarkers interleukin IL-4, IL-10, IL-6, and tumor necrosis factor-alfa (TNF-α).

    Effect
    Neutral
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Reduced Mean Corpuscular Hemoglobin Concentration

    The yacon group presented with lower hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration at the end of the study (P < 0.05).

    Effect
    Harmful
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
  • Yacon→Reduced Tumor Necrosis Factor Alpha

    The control group had lower serum TNF-α after the study period (P < 0.05).

    Effect
    Neutral
    Effect size
    Small
    Dose
    0.14 g of fructooligosaccharides/kg of body weight daily
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