Isotopic estimates of sugar intake are related to chronic disease risk factors but not obesity in an Alaska native (Yup'ik) study population.

BACKGROUND/OBJECTIVES: Sugar intake may be causally associated with chronic disease risk, either directly or by contributing to obesity. However, evidence from observational studies is mixed, in part due to the error and bias inherent in self-reported measures of sugar intake. Objective biomarkers may clarify the relationship between sugar intake and chronic disease risk. We have recently validated a biomarker of sugar intake in an Alaska Native (Yup'ik) study population that incorporates red blood cell carbon and nitrogen isotope ratios in a predictive model. This study tested associations of isotopic estimates of sugar intake with body mass index (BMI), waist circumference (WC) and a broad array of other physiological and biochemical measures of chronic disease risk in Yup'ik people. SUBJECTS/METHODS: In a cross-sectional sample of 1076 Yup'ik people, multiple linear regression was used to examine associations of sugar intake with BMI, WC and other chronic disease risk factors. RESULTS: Isotopic estimates of sugar intake were not associated with BMI (P=0.50) or WC (P=0.85). They were positively associated with blood pressure, triglycerides (TG) and leptin, and are inversely associated with total-, high-density lipoprotein- and low-density lipoprotein-cholesterol and adiponectin. CONCLUSIONS: Isotopic estimates of sugar intake were not associated with obesity, but were adversely associated with other chronic disease risk factors in this Yup'ik study population. This first use of stable isotope markers of sugar intake may influence recommendations for sugar intake by Yup'ik people; however, longitudinal studies are required to understand associations with chronic disease incidence.

Associations of obesity with triglycerides and C-reactive protein are attenuated in adults with high red blood cell eicosapentaenoic and docosahexaenoic acids.

BACKGROUND: N-3 fatty acids are associated with favorable, and obesity with unfavorable, concentrations of chronic disease risk biomarkers. OBJECTIVE: We examined whether high eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid intakes, measured as percentages of total red blood cell (RBC) fatty acids, modify associations of obesity with chronic disease risk biomarkers. METHODS: In a cross-sectional study of 330 Yup'ik Eskimos, generalized additive models (GAM) and linear and quadratic regression models were used to examine associations of BMI with biomarkers across RBC EPA and DHA categories. RESULTS: Median (5th-95th percentile) RBC EPA and DHA were 2.6% (0.5-5.9%) and 7.3% (3.3-8.9%), respectively. In regression models, associations of BMI with triglycerides, glucose, insulin, C-reactive protein (CRP) and leptin differed significantly by RBC EPA and DHA. The GAM confirmed regression results for triglycerides and CRP: at low RBC EPA and RBC DHA, the predicted increases in triglycerides and CRP concentrations associated with a BMI increase from 25 to 35 were 99.5±45.3 mg/dl (106%) and 137.8±71.0 mg/dl (156%), respectively, for triglycerides and 1.2±0.7 mg/l (61%) and 0.8±1.0 mg/l (35%), respectively, for CRP. At high RBC EPA and RBC DHA, these predicted increases were 13.9±8.1 mg/dl (23%) and 12.0±12.3 mg/dl (18%), respectively, for triglycerides and 0.5±0.5 mg/l (50%) and -0.5±0.6 mg/l (-34%), respectively, for CRP. CONCLUSIONS: In this population, high RBC EPA and DHA were associated with attenuated dyslipidemia and low-grade systemic inflammation among overweight and obese persons. This may help inform recommendations for n-3 fatty acid intakes in the reduction of obesity-related disease risk.

Dietary adherence and weight loss success among overweight women: results from the A TO Z weight loss study.

BACKGROUND: Dietary adherence has been implicated as an important factor in the success of dieting strategies; however, studies assessing and investigating its association with weight loss success are scarce. OBJECTIVE: We aimed to document the level of dietary adherence using measured diet data and to examine its association with weight loss success. DESIGN: Secondary analysis was performed using data from 181 free-living overweight/obese women (mean+/-s.d. age=43+/-5 years, body mass index=31+/-4 kg m(-2)) participating in a 1-year randomized clinical trial (the A TO Z study) comparing popular weight loss diets (Atkins, Zone and Ornish). Participants' dietary adherence was assessed as the difference between their respective assigned diet's recommended macronutrient goals and their self-reported intake. Association between dietary adherence and 12-month weight change was computed using Spearman's correlations. Differences in baseline characteristics and macronutrient intake between the most and least adherent tertiles for diet groups were compared using t-tests. RESULTS: Within each diet group, adherence score was significantly correlated with 12-month weight change (Atkins, r(s)=0.42, P=0.0003; Zone, r(s)=0.34, P=0.009 and Ornish, r(s)=0.38, P=0.004). Twelve-month weight change in the most vs least adherent tertiles, respectively, was -8.3+/-5.6 vs -1.9+/-5.8 kg, P=0.0006 (Atkins); -3.7+/-6.3 vs -0.4+/-6.8 kg, P=0.12 (Zone) and -6.5+/-6.8 vs -1.7+/-7.9 kg, P=0.06 (Ornish). CONCLUSIONS: Regardless of assigned diet groups, 12-month weight change was greater in the most adherent compared to the least adherent tertiles. These results suggest that strategies to increase adherence may deserve more emphasis than the specific macronutrient composition of the weight loss diet itself in supporting successful weight loss.