Dietary n-3-polyunsaturated fatty acids and energy balance in overweight or moderately obese men and women: a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Dietary n-3-polyunsaturated fatty acids (n-3-PUFA) have been shown to reduce body weight and fat mass in rodents as well as in humans in one small short-term study. We conducted this controlled randomized dietary trial to test the hypothesis that n-3-PUFA lower body weight and fat mass by reducing appetite and <it>ad libitum </it>food intake and/or by increasing energy expenditure.</p> <p>Methods</p> <p>Twenty-six overweight or moderately obese (body mass index 28–33 kg/m²) men and women were included, and received either a diet rich in n-3-PUFA from both plant and marine sources or a control diet. Diets were administered in an isocaloric fashion for 2 weeks followed by 12 weeks of <it>ad libitum </it>intake. The n-3-PUFA and control diets were identical in all regards except for the fatty acid composition. All foods were provided to subjects, and leftovers were weighed back to assess actual food intake accurately for each day of the study. This design gave us 80% power to detect a difference in weight change between the n-3-PUFA and control diet groups of 2.25 kg at an α-error level of 5%.</p> <p>Results</p> <p>Both groups lost similar amounts of weight when these diets were consumed <it>ad libitum </it>for 12 weeks [mean (SD): -3.5 (3.7) kg in the control group vs. -2.8 (3.7) kg in the n-3-PUFA group, F_(1,24)= 13.425, p = 0.001 for time effect; F_(1,24)= 0.385, p = 0.541 for time × group interaction]. Consistent with this finding, we also found no differences between the n-3-PUFA and control groups with regard to appetite as measured by visual analogue scale, <it>ad libitum </it>food intake, resting energy expenditure as measured by indirect calorimetry, diurnal plasma leptin concentrations, or fasting ghrelin concentrations.</p> <p>Conclusion</p> <p>Our results suggest that dietary n-3-PUFA do not play an important role in the regulation of food intake, energy expenditure, or body weight in humans.</p

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İbrahim Ethem'in Çocuklara Mahsus Gazete'de tefrika edilen Seyyie-i Sefahat adlı roman

Nasty Viruses, Costly Plasmids, Population Dynamics, and the Conditions for Establishing and Maintaining CRISPR-Mediated Adaptive Immunity in Bacteria

Clustered, Regularly Interspaced Short Palindromic Repeats (CRISPR) abound in the genomes of almost all archaebacteria and nearly half the eubacteria sequenced. Through a genetic interference mechanism, bacteria with CRISPR regions carrying copies of the DNA of previously encountered phage and plasmids abort the replication of phage and plasmids with these sequences. Thus it would seem that protection against infecting phage and plasmids is the selection pressure responsible for establishing and maintaining CRISPR in bacterial populations. But is it? To address this question and provide a framework and hypotheses for the experimental study of the ecology and evolution of CRISPR, I use mathematical models of the population dynamics of CRISPR-encoding bacteria with lytic phage and conjugative plasmids. The results of the numerical (computer simulation) analysis of the properties of these models with parameters in the ranges estimated for Escherichia coli and its phage and conjugative plasmids indicate: (1) In the presence of lytic phage there are broad conditions where bacteria with CRISPR-mediated immunity will have an advantage in competition with non-CRISPR bacteria with otherwise higher Malthusian fitness. (2) These conditions for the existence of CRISPR are narrower when there is envelope resistance to the phage. (3) While there are situations where CRISPR-mediated immunity can provide bacteria an advantage in competition with higher Malthusian fitness bacteria bearing deleterious conjugative plasmids, the conditions for this to obtain are relatively narrow and the intensity of selection favoring CRISPR weak. The parameters of these models can be independently estimated, the assumption behind their construction validated, and the hypotheses generated from the analysis of their properties tested in experimental populations of bacteria with lytic phage and conjugative plasmids. I suggest protocols for estimating these parameters and outline the design of experiments to evaluate the validity of these models and test these hypotheses

Effect of dietary n-3 polyunsaturated fatty acids on plasma total and high-molecular-weight adiponectin concentrations in overweight to moderately obese men and women.

BackgroundRecent studies indicated that dietary n-3 polyunsaturated fatty acids (PUFAs) increase circulating adiponectin concentrations in rodents.ObjectiveWe aimed to investigate whether a diet rich in n-3 PUFAs increased plasma concentrations of total or high-molecular-weight (HMW) adiponectin in healthy overweight-to-moderately obese men and women.DesignSixteen women and 10 men with a body mass index (in kg/m(2)) between 28 and 33 were randomly assigned to consume a diet rich in n-3 PUFAs (3.5% of energy intake) from both plant and marine sources or a control diet (0.5% of energy intake from n-3 PUFAs). For the first 2 wk, these diets were consumed under isocaloric conditions; then followed a 12-wk period of ad libitum consumption that was associated with a moderate loss of approximately 3.5% of body weight in both groups. Total and HMW adiponectin plasma concentrations were measured before and after each diet phase.ResultsPlasma fasting adiponectin concentrations did not change during the isocaloric period, but they increased modestly ( approximately 10%) during the ad libitum period when subjects lost weight [P = 0.009 for time in repeated-measures analysis of variance] and to a similar extent in subjects consuming the control (x +/- SD: 0.42 +/- 0.69 microg/mL) and n-3 PUFA (0.45 +/- 0.85 microg/mL) diets (P = 0.920 for time x treatment interaction). Plasma concentrations of HMW adiponectin did not change significantly during the study.ConclusionDietary n-3 PUFAs consumed at levels of 3.5% of energy intake do not significantly increase plasma or HMW adiponectin concentrations in overweight-to-moderately obese healthy men and women over the course of 14 wk