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Browsing by Author "Jahren, A. Hope"

Now showing 1 - 3 of 3
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    The Potential for a Carbon Stable Isotope Biomarker of Dietary Sugar Intake
    Jahren, A. Hope; Bostic, Joshua N.; Davy, Brenda M. (The Royal Society of Chemistry, 2014-02-10)
    Added sugar is sweetener added to foods during processing or preparation that offers no health benefits to the consumer. The mean U.S. intake of added sugar is ~16% of total calories; at the highest level of consumption, this value exceeds 35%. In addition, 78% of added sugar typically consumed is refined from C4 plants (e.g., corn and sugar cane) and it follows that the d13C value of these sweeteners is conspicuously high compared to carbohydrates derived from C3 plants. We first suggested in 2006 the potential for the d13C of human tissues to indicate corn- and cane-sugar intake for use in a clinical setting. At present, self-reported dietary assessment methods are commonly used to measure added sugar intake, but are subject to underreporting, particularly for sugar-rich foods. If a carbon isotope technique could produce a quantitative indicator of dietary sugar intake, it would be invaluable to the prevention and clinical treatment of chronic diseases associated with excess sugar consumption. Research to date has focused upon testing the correlation between diet as characterized either by bulk food d13C value or by food composition (e.g., added sugar intake quartile) and the d13C values of human tissues. Analysis of hair, nail and red blood cells in modern humans with known diet has revealed associations between the d13C value of bulk diet and the d13C value of these tissues. With respect to added sugar, the d13C values of blood serum and fingerstick blood have both been shown to be associated with added sugar intake, even after adjustment for meat intake. Researchers have attempted to isolate specific compounds in blood that are uniquely derived from dietary carbohydrates, such as direct endogenous carbohydrate sources (blood glucose) and specific non-essential amino acids (red blood cell alanine), and have seen strong correlations with added sugar intake. Recognized dietary confounders such as meat/animal products have been addressed using statistical adjustments and a dual-isotope analytical approach that invokes d15N as a correction factor. Further controlled feeding studies and epidemiological surveys complete with Institutional Review Board approval are needed to establish the sensitivity of d13C tissue assay as an objective biomarker for added sugar intake.
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    A Single-Carbon Stable Isotope Ratio Model Prediction Equation Can Estimate Self-Reported Added Sugars Intake in an Adult Population Living in Southwest Virginia
    Hedrick, Valisa E.; Halliday, Tanya M.; Davy, Brenda M.; Zoellner, Jamie M.; Jahren, A. Hope (MDPI, 2021-10-28)
    The δ13C value of blood is a novel proposed biomarker of added sugars (AS) intake. AS prediction equations using either a single- (δ13C) or dual-isotope model (δ13C and δ15N) were previously developed in an adult population with high AS intake living in southwest Virginia (reference group). The purpose of this investigation was to test the δ13C single- and δ13C and δ15N dual-isotope prediction equations for AS intake in adults with a lower mean AS intake and different demographic characteristics (test group). The blood samples for the reference (n = 257 for single-isotope, n = 115 for dual-isotope) and test groups (n = 56) were analyzed for δ13C and δ15N values using natural abundance stable isotope mass spectrometry and were compared to reported dietary AS intake. When the δ13C single-isotope equation was applied to the test group, predicted AS intake was not significantly different from reported AS intake (mean difference ± standard error = −3.6 ± 5.5 g, Z = −0.55, p = 0.51). When testing the dual-isotope equation, predicted AS was different from reported AS intake (mean difference ± SEM = 13.0 ± 5.4 g, Z = −2.95, p = 0.003). δ13C value was able to predict AS intake using a blood sample within this population subset. The single-isotope prediction equation may be an alternative method to assess AS intake and is more objective, cost-feasible, and efficient than traditional dietary assessment methods. However, more research is needed to assess this biomarker with rigorous study designs such as controlled feeding.
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    Stable Isotope Variability in the American Food Supply: Implications for Dietary Reconstruction Applications
    Bostic, Joshua Neilson (Virginia Tech, 2015-07-06)
    Stable isotope ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) in human tissues, which reflect the stable isotope composition of the diet, offer numerous applications in the field of nutrition. One of the biggest contributors to uncertainty in stable isotope dietary reconstruction applications is potential variability in the isotopic composition of foods. No prior studies have evaluated the existing food carbon and nitrogen stable isotope data in an effort to determine broad-scale patterns and characterize the degree of variability of stable isotopes within the American diet. The purpose of this investigation was to improve our understanding of the isotopic composition of the modern American food supply by 1.) Determining geographically representative means and inter-sample variability of animal foods 2.) Assessing the impact of cooking on food stable isotope composition.To define the range of δ¹³C and δ¹⁵N values of animal proteins within the American food supply, we analyzed nationally-collected milk, fish, and shellfish samples from the USDA’s National Nutrient Database for Standard Reference and compared these to previously published data from the international literature. USDA milk samples were characterized by low overall variability, although regional variations in δ¹³C values were present. In contrast, seafood samples exhibited high overall variability but were consistent throughout the domestic and international samples. No variations in δ¹³C or δ¹⁵N values were detected throughout the baking or fermentation process in yeast buns or cookies. The representative values determined in this study can be used as a foundation for interpreting the stable isotope composition of the American diet.