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- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/04%3A_Measurement_Error_in_Dietary_assessment_(Chapter_5)/4.02%3A_Sources_of_measurement_errorThis page discusses the complexities and biases involved in reporting dietary intake, including recall, social desirability, and interviewer biases, which impact data reliability. It highlights strate...This page discusses the complexities and biases involved in reporting dietary intake, including recall, social desirability, and interviewer biases, which impact data reliability. It highlights strategies to improve accuracy, such as using automated reporting tools, shorter recall periods, and standardized coding methods. The importance of thorough data processing and adherence to guidelines is emphasized, alongside studies illustrating the effects of various biases on dietary assessments.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/19%3A_Riboflavin_(Chapter_20b)/19.02%3A_Biomarkers_of_riboflavin_status_(20b.2)This page discusses the challenges in diagnosing riboflavin deficiency, emphasizing the use of the erythrocyte glutathione reductase activity coefficient (EGR AC) for long-term status assessment. Howe...This page discusses the challenges in diagnosing riboflavin deficiency, emphasizing the use of the erythrocyte glutathione reductase activity coefficient (EGR AC) for long-term status assessment. However, sensitivity issues and variations in laboratory methods complicate prevalence comparisons. Riboflavin status is further explored through urinary excretion metrics, with different assays showing discrepancies.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/20%3A_Niacin_(Chapter_20c)/20.01%3A_Niacin_-_Introduction_(20c.1)This page discusses the importance of niacin (vitamin B3) in converting tryptophan into NAD, vital for metabolic processes, gene expression, and DNA repair. Niacin prevents deficiency symptoms like pe...This page discusses the importance of niacin (vitamin B3) in converting tryptophan into NAD, vital for metabolic processes, gene expression, and DNA repair. Niacin prevents deficiency symptoms like pellagra, which is common in areas with low niacin bioavailability. It has potential therapeutic uses in cholesterol regulation and neuroprotection. Dietary sources include meat and fortified cereals, with recommended intakes set at 12-16mg/day for men and 11-14mg/day for women.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/13%3A_Biomarkers_(Chapter_15)/13.03%3A_Biomarkers_of_status_(15.3)This page covers various methods of assessing nutrient status through biomarkers derived from biological fluids and tissues, emphasizing the complexity and technical challenges of sample collection an...This page covers various methods of assessing nutrient status through biomarkers derived from biological fluids and tissues, emphasizing the complexity and technical challenges of sample collection and analysis. Blood, urine, saliva, hair, and nails are discussed, each with unique benefits and limitations, such as contamination risks and variability in results. Techniques like ICP-MS and careful sample handling are crucial for accurate measurements.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/17%3A_Vitamin_C_(Chapater_19)/17.10%3A_Ascorbic_acid_in_erythrocytes_and_whole_blood_(19.10)This page discusses the limitations of using erythrocyte ascorbic acid concentrations to assess vitamin C status, noting that they are less sensitive to dietary intake compared to plasma concentration...This page discusses the limitations of using erythrocyte ascorbic acid concentrations to assess vitamin C status, noting that they are less sensitive to dietary intake compared to plasma concentrations. While useful for non-fasting individuals, variability and measurement challenges are present. Whole blood levels are also not commonly used for deficiency evaluation, with concentrations below 17 µmol/L indicating deficiency and above 28 µmol/L being acceptable.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/21%3A_Folate_(Chapter_22a)/21.02%3A_Biomarkers_of_folate_status_(Chapter_22a.2)This page highlights the importance of assessing folate status through biomarkers like serum folate, RBC folate, and plasma homocysteine. It discusses the role of various analytical methods in measuri...This page highlights the importance of assessing folate status through biomarkers like serum folate, RBC folate, and plasma homocysteine. It discusses the role of various analytical methods in measuring folate, their challenges, and the significance of cutoff values in diagnosing deficiencies and neonatal risks for neural tube defects.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/24%3A_Phosphorus_(Chapter_23b)This page explains the significance of phosphorus as phosphate in living organisms, highlighting its roles in energy, growth, and reproduction. It notes that the majority of phosphate is stored in bon...This page explains the significance of phosphorus as phosphate in living organisms, highlighting its roles in energy, growth, and reproduction. It notes that the majority of phosphate is stored in bones and teeth, with serum levels controlled by hormonal and organ interactions.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/26%3A_Magnesium_(Chapter_23c)/26.03%3A_Absorption_and_metabolism_(23c.3)This page discusses magnesium absorption, which primarily occurs in the jejunum and ileum. Absorption rates depend on dietary intake, with lower intake increasing efficiency and higher intake decreasi...This page discusses magnesium absorption, which primarily occurs in the jejunum and ileum. Absorption rates depend on dietary intake, with lower intake increasing efficiency and higher intake decreasing it. Active transport and passive diffusion facilitate absorption, the latter making up 90% of it. Factors like calcium and fiber can inhibit absorption, while vitamin D enhances it.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/24%3A_Phosphorus_(Chapter_23b)/24.04%3A_Phosphate_balance_(23b.4)This page discusses the phosphate balance in the body, highlighting the roles of intestinal absorption, renal excretion, and phosphate exchange among different pools. Serum phosphate concentration is ...This page discusses the phosphate balance in the body, highlighting the roles of intestinal absorption, renal excretion, and phosphate exchange among different pools. Serum phosphate concentration is a key clinical indicator, but it reflects only a fraction of total body phosphate. The kidneys reabsorb approximately 89% of filtered phosphate, while gastrointestinal absorption averages 60-65%.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/04%3A_Measurement_Error_in_Dietary_assessment_(Chapter_5)/4.01%3A_Measurement_error_in_dietary_intake_dataThis page discusses random and systematic errors in dietary intake measurement methods. Random errors lead to imprecise data from within-person variation, affecting reproducibility, while systematic e...This page discusses random and systematic errors in dietary intake measurement methods. Random errors lead to imprecise data from within-person variation, affecting reproducibility, while systematic errors introduce bias in self-reported data, distorting dietary estimates. Correcting systematic errors is more difficult and can undermine the validity of epidemiological studies. Although statistical modeling may help adjust for some errors, understanding their implications is critical in research.
- https://med.libretexts.org/Bookshelves/Nutrition/Principles_of_Nutritional_Assessment_3e_(Gibson_et_al.)/17%3A_Vitamin_C_(Chapater_19)/17.11%3A_Urinary_excretion_of_ascorbic_acid_and_metabolites_(19.11)This page discusses the excretion of ascorbic acid primarily through urine, highlighting that high intakes can increase oxalate levels. Urinary ascorbic acid reflects recent dietary intake but is not ...This page discusses the excretion of ascorbic acid primarily through urine, highlighting that high intakes can increase oxalate levels. Urinary ascorbic acid reflects recent dietary intake but is not a reliable indicator of vitamin C status. A renal threshold of about 60µmol/L requires intakes of at least 100mg/d for saturation. Careful measurement is necessary due to instability, with HPLC recommended as the preferred analysis method.
