Determination of resistance at zero and infinite frequencies in bioimpedance spectroscopy for assessment of body composition in babies.

Objective. Bioimpedance spectroscopy (BIS) is a popular technique for the assessment of body composition in children and adults but has not found extensive use in babies and infants. This due primarily to technical difficulties of measurement in these groups. Although improvements in data modelling have, in part, mitigated this issue, the problem continues to yield unacceptably high rates of poor quality data. This study investigated an alternative data modelling procedure obviating issues associated with BIS measurements in babies and infants.Approach.BIS data are conventionally analysed according to the Cole model describing the impedance response of body tissues to an appliedACcurrent. This approach is susceptible to errors due to capacitive leakage errors of measurement at high frequency. The alternative is to model BIS data based on the resistance-frequency spectrum rather than the reactance-resistance Cole model thereby avoiding capacitive error impacts upon reactance measurements.Main results.The resistance-frequency approach allowed analysis of 100% of data files obtained from BIS measurements in 72 babies compared to 87% successful analyses with the Cole model. Resistance-frequency modelling error (percentage standard error of the estimate) was half that of the Cole method. Estimated resistances at zero and infinite frequency were used to predict body composition. Resistance-based prediction of fat-free mass (FFM) exhibited a 30% improvement in the two-standard deviation limits of agreement with reference FFM measured by air displacement plethysmography when compared to Cole model-based predictions.Significance.This study has demonstrated improvement in the analysis of BIS data based on the resistance frequency response rather than conventional Cole modelling. This approach is recommended for use where BIS data are compromised by high frequency capacitive leakage errors such as those obtained in babies and infants.

Bioactive food compounds, epigenetics and chronic disease prevention: Focus on early-life interventions with polyphenols.

Consumption of bioactive compounds such as polyphenols, isothiocyanates, sulfur-containing compounds and terpenoids, found in fruits and vegetables, is associated with prevention of chronic disease. These bioactive food compounds elicit their protective effects through complex mechanisms at the cellular and molecular, including epigenetic levels. According to the Developmental Origins of Health and Disease (DOHaD) paradigm, in utero exposure to stressors such as malnutrition through maternal diet would impair fetal development and epigenetically program increased risk of metabolic diseases and some cancers in adult life. In addition, a role for fathers´ diet during preconception on their offspring health and chronic disease susceptibility has also emerged. This highlights early life as a promising window of opportunity for starting dietary interventions focusing on preventing chronic diseases. However, knowledge on the potential beneficial impact of early life exposure to bioactive food compounds is limited. Among the studies that have investigated bioactive food compounds in the context of DOHaD, most have focused on the impact of dietary polyphenols. Thus, in this review we discuss experimental evidence supporting a role for the dietary polyphenols resveratrol, genistein, epigallocatechin-3-gallate and anthocyanins in chronic disease prevention considering a perspective from early-life interventions through maternal and paternal diets and focusing on epigenetics as a potential underlying mechanism.

Hypercaloric Diet-Induced Obesity and Obesity-Related Metabolic Disorders in Experimental Models.

Overnutrition and obesity have developed into a major public health problem across different parts of the world. Epidemiological studies have shown that excessive intake of dietary components, such as fatty acids and/or sugars, can promote obesity. In this context, the use of dietary intervention in animal models that respond to a diet similar to humans is useful to understand this preventable, multifactorial disease. The aim of this chapter is to aid researchers in choosing specific nutritional interventions and animal strains to induce obesity and obesity-related morbidities in experimental models.