Diet is largely considered to be a major factor in the occurrence of disease. The science of nutritional epidemiology involves evaluating the relationship between dietary and nutritional factors and disease and health outcomes. Findings from nutritional epidemiology studies play a key role in formulating dietary recommendations and guidance. However, Investigating the link between diet and health outcomes is complex and challenging, as it is difficult to disentangle the association between a food group, single food, or nutrient and disease risk. Thus, critically examining the underlying methodology is of paramount importance. EpidStat epidemiologists and health scientists have extensive expertise in research methodology and interpreting results from nutritional epidemiology studies.
Standard enteral nutrition (EN) formulas can worsen hyperglycemia in diabetic patients. We hypothesized that altering the proportion of macronutrients in a formula; increasing protein while decreasing carbohydrate concentrations would improve glycemic response. The objective of this study was to demonstrate that an EN formula containing a very high concentration of protein (in the form of whey peptides) and low concentration of carbohydrate provide better control of postprandial blood glucose relative to a very high-protein/higher-carbohydrate formula.
This was a randomized crossover clinical trial of 12 ambulatory adult subjects with type 2 diabetes. The primary outcome was glycemic response following a bolus of isocaloric amounts of two EN formulas; the secondary outcome was insulin response. Subjects were randomized to the experimental or the control formula, on two separate days, 5-7 days apart.
Mean blood glucose concentrations at 10-180 min post-infusion and mean area under the curve for glucose over 240 min post-infusion were significantly lower with the experimental formula than with the control formula (71.99 ± 595.18 and 452.62 ± 351.38, respectively; p = 0.025). There were no significant differences in the mean insulin concentrations over time, insulinogenic indices, and first-phase insulin measurements.
An EN formula containing high-protein and low-carbohydrate loads can significantly improve glucose control in subjects with type 2 diabetes in […]
Interpreting epidemiologic studies of diet and health is often complex because it involves many methodological issues and sources of uncertainty. Pertinent examples are false-positive and false-negative results, that is, findings that erroneously indicate the presence or absence, respectively, of association. Our objective in this commentary is to help nutrition and other health professionals interpret epidemiological studies when faced with this task. Our aim is not to provide an exhaustive discussion of all the methodological nuances of nutritional epidemiology; rather, we focus on some of the salient factors when interpreting findings from dietary studies, and the role that uncertainty (namely, from false-positives) plays, using relevant examples from the past few decades.
Nutrition Today: May/June 2014 – Volume 49 – Issue 3 – p 147-152
Nearly five percent of Americans suffer from functional constipation, many of whom may benefit from increasing dietary fiber consumption. The annual constipation-related healthcare cost savings associated with increasing intakes may be considerable but have not been examined previously. The objective of the present study was to estimate the economic impact of increased dietary fiber consumption on direct medical costs associated with constipation.
Literature searches were conducted to identify nationally representative input parameters for the U.S. population, which included prevalence of functional constipation; current dietary fiber intakes; proportion of the population meeting recommended intakes; and the percentage that would be expected to respond, in terms of alleviation of constipation, to a change in dietary fiber consumption. A dose-response analysis of published data was conducted to estimate the percent reduction in constipation prevalence per 1 g/day increase in dietary fiber intake. Annual direct medical costs for constipation were derived from the literature and updated to U.S. $ 2012. Sensitivity analyses explored the impact on adult vs. pediatric populations and the robustness of the model to each input parameter.
The base case direct medical cost-savings was $12.7 billion annually among adults. The base case assumed that 3% of men and 6% of women currently met recommended […]
The objective of the present meta-analysis was to examine the effect of whey protein (WP), with or without resistance exercise, onbody weight and body composition in randomized controlled trials (RCTs) conducted in generally healthy adult study populations.
A comprehensive literature search was conducted to identify RCTs that investigated WP (concentrate, isolate, or hydrolystate) and bodyweight, body mass index (BMI), body fat, lean body mass (LBM), fat-free mass (FFM), and waist circumference. Random effects meta-analyses were conducted to generate weighted group mean differences (WGMD) for between-group comparisons (WP vs other protein sources or carbohydrates) and within-WP group comparisons (i.e., differences from baseline to trial end). Studies were classified into 2 distinct groups-WP as a supplement without dietary modification (WPS) and WP as a replacement for other sources of calories (WPR)-and were meta-analyzed separately. Subgroup analyses included examining the effect of resistance exercise and type of WP on the relationship between WP and body composition.
Fourteen RCTs were included, with a total of 626 adult study completers. Five studies examined the effects of WPR and the remaining 9 studies examined the effects of WPS. Body weight (WGMD: -4.20 kg, 95% confidence interval [CI], -7.67, -0.73) and body fat (WGMD: -3.74 kg, 95% CI, -5.98, -1.50) were significantly decreased from baseline in the WPR within-group analyses. In the between-group analyses, the effects of WP were more favorable when compared with carbohydrates than protein sources other than whey, although findings did not reach […]