Beverage consumption and risk of obesity among Native Americans in Arizona

Aegle marmelos impedes onset of insulin resistance syndrome in rats provided with drinking fructose from weaning to adulthood stages of development — a mechanistic study

In this study, we explored the effect of aqueous extract of leaves of Aegle marmelos (AM) on hepatic carbohydrate metabolism and insulin downstream signalling in rats given fructose (15%) in drinking water from weaning to adulthood. Wistar albino rats (4 weeks old) were randomly divided into normal control (NC), fructose control (FC), and treatment (AMT) groups and were fed for a period of 8 weeks the following diets: chow + water, chow + fructose (15%), and chow + fructose (15%) + AM (500 mg/kg per day, p.o.), respectively. Compared with the NC group, the FC group was found to have significantly (p < 0.05) raised levels of fasting blood glucose, lipid, visceral mass, plasma insulin and leptin, glycogen, and gluconeogenesis enzyme but decreased glycolytic enzyme activity. Raised levels of glucose transporter 2 protein but decreased activity of phosphatidylinositol-3-kinase (PI3K/Akt) and Janus kinase – signal transducer and activator of transcription-3 (JAK–STAT3) in hepatic tissue indicate a state of insulin and leptin resistance in the FC group. A significant (p < 0.05) lowering of physical and glycemic parameters, strengthening of the hepatic glycolytic pathway over the gluconeogenic pathway, and upregulation of the PI3K/Akt and JAK–STAT3 pathways was observed in the AMT group, as compared with the FC group. For the first time, the mechanism underlying the development of insulin resistance syndrome is delineated here, along with the potential of A. marmelos to impede it.

Exercise prevents fructose-induced hypertriglyceridemia in healthy young subjects

Excess fructose intake causes hypertriglyceridemia and hepatic insulin resistance in sedentary humans. Since exercise improves insulin sensitivity in insulin-resistant patients, we hypothesized that it would also prevent fructose-induced hypertriglyceridemia. This study was therefore designed to evaluate the effects of exercise on circulating lipids in healthy subjects fed a weight-maintenance, high-fructose diet. Eight healthy males were studied on three occasions after 4 days of 1) a diet low in fructose and no exercise (C), 2) a diet with 30% fructose and no exercise (HFr), or 3) a diet with 30% fructose and moderate aerobic exercise (HFrEx). On all three occasions, a 9-h oral [(13)C]-labeled fructose loading test was performed on the fifth day to measure [(13)C]palmitate in triglyceride-rich lipoprotein (TRL)-triglycerides (TG). Compared with C, HFr significantly increased fasting glucose, total TG, TRL-TG concentrations, and apolipoprotein (apo)B48 concentrations as well as postfructose glucose, total TG, TRL-TG, and [(13)C]palmitate in TRL-TG. HFrEx completely normalized fasting and postfructose TG, TRL-TG, and [(13)C]palmitate concentration in TRL-TG and apoB48 concentrations. In addition, it increased lipid oxidation and plasma nonesterified fatty acid concentrations compared with HFr. These data indicate that exercise prevents the dyslipidemia induced by high fructose intake independently of energy balance.

Sweetness and food preference

Human desire for sweet taste spans all ages, races, and cultures. Throughout evolution, sweetness has had a role in human nutrition, helping to orient feeding behavior toward foods providing both energy and essential nutrients. Infants and young children in particular base many of their food choices on familiarity and sweet taste. The low cost and ready availability of energy-containing sweeteners in the food supply has led to concerns that the rising consumption of added sugars is the driving force behind the obesity epidemic. Low-calorie sweeteners are one option for maintaining sweet taste while reducing the energy content of children's diets. However, their use has led to further concerns that dissociating sweetness from energy may disrupt the balance between taste response, appetite, and consumption patterns, especially during development. Further studies, preferably based on longitudinal cohorts, are needed to clarify the developmental trajectory of taste responses to low-calorie sweeteners and their potential impact on the diet quality of children and youth.

Effects of food form on food intake and postprandial appetite sensations, glucose and endocrine responses, and energy expenditure in resistance trained v. sedentary older adults

Limited research has suggested that the food form of nutritional supplements (FFNS) and resistance training (RT) influence ingestive behaviour and energy balance in older adults. The effects of the FFNS and RT on acute appetitive, endocrine and metabolic responses are not adequately documented. The present study assessed the effects of the FFNS and RT on postprandial appetite sensations (hunger and fullness), endocrine responses (plasma insulin, cholecystokinin, ghrelin and glucagon-like peptide-1 (GLP-1)), metabolism (glucose, energy expenditure and RER) and food intake (satiation) in older adults. On separate days, eighteen sedentary (Sed) and sixteen RT healthy adults (age 62-84 years) consumed 12·5 % of their energy need as an isoenergetic- and macronutrient-matched solid or beverage. Postprandial responses were assessed over 4 h. No RT × FFNS interactions were observed for any parameter. Fasting cholecystokinin was higher in the RT v. Sed group (P < 0·05). RT did not influence fullness, but fullness was higher following the solid v. beverage intake (P < 0·01). Neither RT nor FFNS influenced hunger. Glucose and insulin were higher after the solid v. beverage intake (P < 0·01). Ghrelin, GLP-1 and energy expenditure were not different between the RT and FFNS groups. Postprandial cholecystokinin was higher in the RT v. Sed group (P < 0·01) and for solid v. beverage (P < 0·05). RER was lower for solid v. beverage (P < 0·001). Neither RT nor FFNS independently or interactively influenced food intake 2 h after post-nutritional supplements. In conclusion, RT had little influence on ingestive behaviour. The appetitive and endocrine responses suggested the solid-promoted satiety; however, the FFNS did not alter subsequent food intake.

Soda intake and osteoporosis risk in postmenopausal American-Indian women

OBJECTIVE

Low bone mass often leads to osteoporosis and increased risk of bone fractures. Soda consumption may contribute to imbalances that lead to decreased bone mineral density (BMD) and general bone health. We examined the relationship between soda consumption and osteoporosis risk in postmenopausal American-Indian women, an at-risk population because of nutritional and other lifestyle-related factors.

DESIGN

Cross-sectional analysis using logistic regression to examine associations between soda consumption and osteoporosis, and linear regression to examine the association between soda consumption and BMD, with and without adjustment for demographic and lifestyle factors. Quantitative ultrasound of the heel was performed to estimate BMD (g/cm2).

SETTING

American-Indian communities in the Northern Plains and Southwestern USA.

SUBJECTS

A total of 438 postmenopausal American-Indian women.

RESULTS

Women with osteoporosis were significantly older and had lower BMI, average daily soda intakes, BMD levels and use of hormones than women without osteoporosis (P < 0·05). Soda consumption was not associated with increased odds of osteoporosis in either unadjusted or adjusted models (P > 0·05), although age (increased), BMI (decreased) and past hormone use (decreased) were all significantly associated with osteoporosis risk (P < 0·05).

CONCLUSIONS

Although the present study did not find associations between soda consumption and osteoporosis risk in postmenopausal American-Indian women, analyses did confirm confounding between soda consumption and age and BMI. This suggests that any potential effects of soda consumption on bone health are largely mediated through these factors.

Fructose, insulin resistance, and metabolic dyslipidemia

Obesity and type 2 diabetes are occurring at epidemic rates in the United States and many parts of the world. The "obesity epidemic" appears to have emerged largely from changes in our diet and reduced physical activity. An important but not well-appreciated dietary change has been the substantial increase in the amount of dietary fructose consumption from high intake of sucrose and high fructose corn syrup, a common sweetener used in the food industry. A high flux of fructose to the liver, the main organ capable of metabolizing this simple carbohydrate, perturbs glucose metabolism and glucose uptake pathways, and leads to a significantly enhanced rate of de novo lipogenesis and triglyceride (TG) synthesis, driven by the high flux of glycerol and acyl portions of TG molecules from fructose catabolism. These metabolic disturbances appear to underlie the induction of insulin resistance commonly observed with high fructose feeding in both humans and animal models. Fructose-induced insulin resistant states are commonly characterized by a profound metabolic dyslipidemia, which appears to result from hepatic and intestinal overproduction of atherogenic lipoprotein particles. Thus, emerging evidence from recent epidemiological and biochemical studies clearly suggests that the high dietary intake of fructose has rapidly become an important causative factor in the development of the metabolic syndrome. There is an urgent need for increased public awareness of the risks associated with high fructose consumption and greater efforts should be made to curb the supplementation of packaged foods with high fructose additives. The present review will discuss the trends in fructose consumption, the metabolic consequences of increased fructose intake, and the molecular mechanisms leading to fructose-induced lipogenesis, insulin resistance and metabolic dyslipidemia.