Ceramide concentrations in liver, plasma, and very low-density lipoproteins of humans with severe obesity.

We investigated the relationships between ceramide species concentrations in liver, plasma and very low-density lipoproteins (VLDL) particles of humans with obesity as well as the relationships between hepatic fat content and hepatic ceramide concentrations and proportional distribution. Twenty-five obese (body mass index >35 kg/m ) adults participated in this study. Plasma, VLDL and hepatocellular ceramide concentrations were measured by liquid chromatography/tandem mass spectrometry.

Adipocyte Proteins and Storage of Endogenous Fatty Acids in Visceral and Subcutaneous Adipose Tissue in Severe Obesity.

Objective: This study tested whether substrate concentrations or fatty acid storage proteins predict storage of endogenous lipids in visceral adipose tissue (VAT) and upper body subcutaneous adipose tissue (UBSQ) fat.

Methods: The day prior to surgery, 25 patients undergoing bariatric procedures received an infusion of autologous [1- C]triolein-labeled very low-density lipoprotein (VLDL) particles, and during surgery, they received a continuous [U- C]palmitate infusion/bolus [9,10- H]palmitate tracer. VAT and UBSQ fat were collected to measure VLDL-triglyceride (TG) storage, direct free fatty acid (FFA) storage rates, CD36 content, lipoprotein lipase (LPL), acyl-CoA synthetase, diacylglycerol acetyl-transferase, and glycerol-3-phosphate acyltransferase activities.

Diet pattern may affect fasting insulin in a large sample of black and white adults.

Objective: Dietary modification of insulin resistance may be a strategy for reducing chronic disease. For this study, we tested the hypothesis that higher fasting insulin, a marker for insulin resistance, would be related to diet patterns with a high proportion of carbohydrates, those with a high glycemic index, and those characterized by added sugar and processed starches.

Study Design: Data were analyzed on 13,528 nondiabetic participants of the REasons for Geographic and Ethnic Differences in Stroke (REGARDS), an observational study of adults aged ≥45 years residing in 1855 counties across the continental USA.

Effects of weight loss during a very low carbohydrate diet on specific adipose tissue depots and insulin sensitivity in older adults with obesity: a randomized clinical trial.

Background: Insulin resistance and accumulation of visceral adipose tissue (VAT) and intermuscular adipose tissue (IMAT) place aging adults with obesity at high risk of cardio-metabolic disease. A very low carbohydrate diet (VLCD) may be a means of promoting fat loss from the visceral cavity and skeletal muscle, without compromising lean mass, and improve insulin sensitivity in aging adults with obesity.

Objective: To determine if a VLCD promotes a greater loss of fat (total, visceral and intermuscular), preserves lean mass, and improves insulin sensitivity compared to a standard CHO-based/low-fat diet (LFD) in older adults with obesity.

Sex and Depot Differences in Palmitoleic Acid Content of Human Blood and Fat.

Palmitoleic acid has been classified as an insulin-sensitizing lipokine, but evidence for this from human studies has been inconsistent. We hypothesized that this is related to either the types of samples or conditions under which samples are collected. We measured plasma palmitoleic acid and total free fatty acids (FFA) using ultra-performance liquid chromatography in blood samples collected from 34 adults under a variety of conditions.

Race affects the association of obesity measures with insulin sensitivity.

Background: Race differences in body composition and fat distribution may in part explain the differences in insulin sensitivity and the disproportionate burden of type 2 diabetes in African Americans.

Objective: To determine if differences in body composition and fat distribution explain race differences in insulin sensitivity and identify obesity measures that were independently associated with insulin sensitivity.

Methods: Participants were 113 lean, overweight, and obese African-American and Caucasian-American adults without diabetes.

Hepatic Fatty Acid Balance and Hepatic Fat Content in Humans With Severe Obesity.

Objective: Nonalcoholic fatty liver disease can lead to hepatic inflammation/damage. Understanding the physiological mechanisms that contribute to excess hepatic lipid accumulation may help identify effective treatments.

Design: We recruited 25 nondiabetic patients with severe obesity scheduled for bariatric surgery.

A High-Fat Compared with a High-Carbohydrate Breakfast Enhances 24-Hour Fat Oxidation in Older Adults.

Background: The ability to oxidize fat is associated with a lower risk of chronic metabolic disease. Preclinical data in mice showed that a high-fat "breakfast" increased 24-h fat oxidation relative to a high-carbohydrate breakfast.

Objectives: The objectives of this study were to determine whether the timing of macronutrient intake in humans affects daily fuel utilization and to examine associations between fuel utilization and metabolic indexes.

Contribution of very low-density lipoprotein triglyceride fatty acids to postabsorptive free fatty acid flux in obese humans.

Objective: In the fasting state, plasma free fatty acids (FFA) are thought to derive almost exclusively from adipose tissue lipolysis. However, there are mixed reports as to whether the spillover of fatty acids (FA) from very low-density lipoprotein triglyceride (VLDL-TG) hydrolysis contributes significantly to the plasma FFA pool. Because substantial VLDL-TG fatty acid spillover into the plasma FFA pool would profoundly impact the interpretation of isotope dilution measures of FFA flux, we investigated the contribution of VLDL-TG spillover to plasma FFA appearance.

Insulin sensitivity affects propensity to obesity in an ethnic-specific manner: results from two controlled weight loss intervention studies.

Background: Risk for obesity differs with ethnicity/race and is associated with insulin sensitivity (SI), insulin responsiveness, and dietary glycemic load (GL). The objective of this study was to test the hypotheses that, 1) obesity-prone, normal weight, African-American (AA) women would be more insulin sensitive than BMI-matched, never overweight AA women; 2) increased adiposity over time would be associated with greater baseline SI and higher dietary GL in AA but not European-American (EA) women; and 3) increased adiposity over time would be predicted by SI in women with high but not low acute insulin response to glucose (AIRg).

Methods: Two controlled weight loss interventions were conducted involving overweight (BMI 25.

Insulin-mediated FFA suppression is associated with triglyceridemia and insulin sensitivity independent of adiposity.

Context: A central/visceral fat distribution and excess free fatty acid (FFA) availability are associated with dyslipidemia and insulin resistance. However, these two characteristics often coexist, making it difficult to detect the independent contributions of each. Whether FFA suppression is more closely linked to metabolic abnormalities is not clear.

Higher maternal gestational glucose concentration is associated with lower offspring insulin sensitivity and altered beta-cell function.

Context: Intrauterine exposure to elevated glucose concentrations may be a mediating factor in prenatal programming of offspring diabetes risk. However, studies examining the effects of maternal glucose concentration on measures of insulin sensitivity and β-cell response in prepubertal children are limited.

Objective: We tested the hypothesis that maternal gestational glucose concentration would be inversely associated with children's insulin sensitivity independent of adiposity and positively associated with children's β-cell response independent of adiposity and insulin sensitivity.

Maternal glucose concentration during pregnancy predicts fat and lean mass of prepubertal offspring.

Objective: Intrauterine exposure to high maternal glucose is associated with excess weight gain during childhood, but it is not clear whether the excess weight represents increased fat or lean mass. The purpose of this study was to examine the relationship between maternal glucose concentrations during pregnancy and offspring body composition. A secondary goal was to examine whether the association between maternal glucose and children's body fat was independent of energy intake, energy expenditure, or physical activity.

Self-reported low vitality, poor mental health, and low dietary restraint are associated with overperception of physical exertion.

Objective. We investigated whether perceived exertion, in comparison to the physiological response to exercise, was associated with self-reported vitality, mental health, and physical function during daily activities, or weight control behaviors. Design.

Vitamin D intake is associated with insulin sensitivity in African American, but not European American, women.

Background: The prevalence of type 2 diabetes is higher among African Americans (AA) vs European Americans (EA), independent of obesity and other known confounders. Although the reason for this disparity is not known, it is possible that relatively low levels of vitamin D among AA may contribute, as vitamin D has been positively associated with insulin sensitivity in some studies. The objective of this study was to test the hypothesis that dietary vitamin D would be associated with a robust measure of insulin sensitivity in AA and EA women.

Dietary calcium intake is associated with less gain in intra-abdominal adipose tissue over 1 year.

Calcium intake is reported to enhance weight loss with a preferential loss in trunk fat. Discrepant findings exist as to the effects of calcium intake on longitudinal changes in total fat mass and central fat deposition. Therefore, the purpose of this study was to determine associations between dietary calcium intake and 1-year change in body composition and fat distribution, specifically intra-abdominal adipose tissue (IAAT).

Ethnicity-specific anthropometric predictors of metabolic risk in women.

OBJECTIVE: The objective of this study was to determine associations of anthropometric measures of thigh and abdominal adipose tissue with metabolic risk factors, and whether these associations differed with ethnicity. We hypothesized that thigh circumference (ThC) would have an independent favorable association with insulin sensitivity, lipids, and blood pressure, whereas waist circumference (WC) would have an independent deleterious association with these variables in both African Americans (AA) and European Americans (EA). METHODS: Subjects were 228 healthy, overweight, premenopausal AA and EA women.

Glucose metabolism and diet predict changes in adiposity and fat distribution in weight-reduced women.

Among obesity-prone individuals, metabolic state may interact with diet in determining body composition. We tested the hypotheses that, among 103 weight-reduced women over 1 year, (i) insulin sensitivity would be positively associated with change in %fat; (ii) this association would be modulated by dietary glycemic load (GL); and (iii) changes in fat distribution would be related to indexes of glucose metabolism. Insulin sensitivity, glucose effectiveness, fasting and postchallenge insulin and glucose, and glucose tolerance were assessed during intravenous glucose tolerance test (IVGTT).

Associations among body size dissatisfaction, perceived dietary control, and diet history in African American and European American women.

European American (EA) women report greater body dissatisfaction and less dietary control than do African American (AA) women. This study investigated whether ethnic differences in dieting history contributed to differences in body dissatisfaction and dietary control, or to differential changes that may occur during weight loss and regain. Eighty-nine EA and AA women underwent dual-energy X-ray absorptiometry to measure body composition and completed questionnaires to assess body dissatisfaction and dietary control before, after, and one year following, a controlled weight-loss intervention.

Insulin sensitivity in African-American and white women: association with inflammation.

Whether the contribution of inflammation to risk for chronic metabolic disease differs with ethnicity is not known. The objective of this study was to determine: (i) whether ethnic differences exist in markers of inflammation and (ii) whether lower insulin sensitivity among African Americans vs. whites is due to greater inflammatory status.

Ethnicity and weight status affect the accuracy of proxy indices of insulin sensitivity.

This study tested the hypotheses that correlations between direct measures of insulin sensitivity and proxy indices of insulin sensitivity derived from fasting values, (i) would not be affected by ethnicity, and (ii) would be stronger in overweight vs. weight-reduced states. We further hypothesized that associations between proxy indices and fat distribution would be similar to those between directly measured insulin sensitivity and fat distribution.

Ability of the Harris Benedict formula to predict energy requirements differs with weight history and ethnicity.

The objective of this study was to assess the effects of weight history status and ethnicity on the ability of the Harris Benedict (HB) formula to: 1) predict measured resting energy expenditure (REE), and, 2) accurately estimate energy needs over a 2-week test period. Subjects were never-overweight (BMI View Article and Find Full Text PDF

Adiponectin is lower among African Americans and is independently related to insulin sensitivity in children and adolescents.

Adiponectin is inversely related to adiposity and positively correlated with insulin sensitivity (S(i)). Sparse data exist on the contributions of ethnicity and body fat distribution to variance in serum adiponectin. Hypotheses tested were that adiponectin would be lower in African Americans compared with Caucasians; that adiponectin would be inversely related to central, not peripheral, fat; that adiponectin would be positively associated with S(i); and that baseline adiponectin would predict change in S(i) over 2 years in 150 African-American and Caucasian youth.