Metabolic responses to high-fat diets rich in n-3 or n-6 long-chain polyunsaturated fatty acids in mice selected for either high body weight or leanness explain different health outcomes

<p>Abstract</p> <p>Background</p> <p>Increasing evidence suggests that diets high in polyunsaturated fatty acids (PUFA) confer health benefits by improving insulin sensitivity and lipid metabolism in liver, muscle and adipose tissue.</p> <p>Methods</p> <p>The present study investigates metabolic responses in two different lines of mice either selected for high body weight (DU6) leading to rapid obesity development, or selected for high treadmill performance (DUhTP) leading to a lean phenotype. At 29 days of age the mice were fed standard chow (7.2% fat, 25.7% protein), or a high-fat diet rich in <it>n</it>-3 PUFA (n-3 HFD, 27.7% fat, 19% protein) or a high-fat diet rich in <it>n</it>-6 PUFA (n-6 HFD, 27.7% fat, 18.6% protein) for 8 weeks. The aim of the study was to determine the effect of these PUFA-rich high-fat diets on the fatty acid profile and on the protein expression of key components of insulin signalling pathways.</p> <p>Results</p> <p>Plasma concentrations of leptin and insulin were higher in DU6 in comparison with DUhTP mice. The high-fat diets stimulated a strong increase in leptin levels and body fat only in DU6 mice. Muscle and liver fatty acid composition were clearly changed by dietary lipid composition. In both lines of mice n-3 HFD feeding significantly reduced the hepatic insulin receptor β protein concentration which may explain decreased insulin action in liver. In contrast, protein kinase C ζ expression increased strongly in abdominal fat of n-3 HFD fed DUhTP mice, indicating enhanced insulin sensitivity in adipose tissue.</p> <p>Conclusions</p> <p>A diet high in <it>n</it>-3 PUFA may facilitate a shift from fuel deposition in liver to fuel storage as fat in adipose tissue in mice. Tissue specific changes in insulin sensitivity may describe, at least in part, the health improving properties of dietary <it>n</it>-3 PUFA. However, important genotype-diet interactions may explain why such diets have little effect in some population groups.</p

Fat Sensation: Fatty Acid Taste and Olfaction Sensitivity and the Link with Disinhibited Eating Behaviour

Perception of fat taste, aroma, and texture are proposed to influence food preferences, thus shaping dietary intake and eating behaviour and consequently long-term health. In this study, we investigated associations between fatty acid taste, olfaction, mouthfeel of fat, dietary intake, eating behaviour, and body mass index (BMI). Fifty women attended three sessions to assess oleic acid taste and olfaction thresholds, the olfactory threshold for n-butanol and subjective mouthfeel ratings of custard samples. Dietary intake and eating behaviour were evaluated using a Food Frequency and Three-Factor Eating Questionnaire, respectively. Binomial regression analysis was used to model fat taste and olfaction data. Taste and olfactory detection for oleic acid were positively correlated (r = 0.325; p &lt; 0.02). Oleic acid taste hypersensitive women had significantly increased n-butanol olfactory sensitivity (p &lt; 0.03). The eating behaviour disinhibition and BMI were higher in women who were hyposensitive to oleic acid taste (p &lt; 0.05). Dietary intake of nuts, nut spreads, and seeds were significantly correlated with high olfactory sensitivity to oleic acid (p &lt; 0.01). These findings demonstrate a clear link between fatty acid taste sensitivity and olfaction and suggest that fat taste perception is associated with specific characteristics of eating behaviour and body composition

Predictors and risks of body fat profiles in young New Zealand European, Māori and Pacific women: study protocol for the women’s EXPLORE study

Body mass index (BMI) (kg/m(2)) is used internationally to assess body mass or adiposity. However, BMI does not discriminate body fat content or distribution and may vary among ethnicities. Many women with normal BMI are considered healthy, but may have an unidentified &quot;hidden fat&quot; profile associated with higher metabolic disease risk. If only BMI is used to indicate healthy body size, it may fail to predict underlying risks of diseases of lifestyle among population subgroups with normal BMI and different adiposity levels or distributions. Higher body fat levels are often attributed to excessive dietary intake and/or inadequate physical activity. These environmental influences regulate genes and proteins that alter energy expenditure/storage. Micro ribonucleic acid (miRNAs) can influence these genes and proteins, are sensitive to diet and exercise and may influence the varied metabolic responses observed between individuals. The study aims are to investigate associations between different body fat profiles and metabolic disease risk; dietary and physical activity patterns as predictors of body fat profiles; and whether these risk factors are associated with the expression of microRNAs related to energy expenditure or fat storage in young New Zealand women. Given the rising prevalence of obesity globally, this research will address a unique gap of knowledge in obesity research