The importance of environmental microbes for Drosophila melanogaster during seasonal macronutrient variability

Experiments manipulating the nutritional environment and the associated microbiome of animals have demonstrated their importance for key fitness components. However, there is little information on how macronutrient composition and bacterial communities in natural food sources vary across seasons in nature and on how these factors affect the fitness components of insects. In this study, diet samples from an orchard compost heap, which is a natural habitat for many Drosophila species and other arthropods, were collected over 9 months covering all seasons in a temperate climate. We developed D. melanogaster on diet samples and investigated stress resistance and life-history traits as well as the microbial community of flies and compost. Nutrient and microbial community analysis of the diet samples showed marked differences in macronutrient composition and microbial community across seasons. However, except for the duration of development on these diet samples and Critical Thermal maximum, fly stress resistance and life-history traits were unaffected. The resulting differences in the fly microbial community were also more stable and less diverse than the microbial community of the diet samples. Our study suggests that when D. melanogaster are exposed to a vastly varying nutritional environment with a rich, diverse microbial community, the detrimental consequences of an unfavourable macronutrient composition are offset by the complex interactions between microbes and nutrients.

Net energy value of canola meal, field pea, and wheat millrun fed to growing-finishing pigs

Two experiments were conducted to (1) determine NE values of soybean meal (SBM), Napus canola meal (NCM), Juncea canola meal (JCM), field pea, and wheat millrun (WM) using indirect calorimetry, and (2) compare the determined NE values with the calculated NE values of the same feedstuffs based on a prediction equation. In Experiment 1, 6 ileal-cannulated barrows (31 kg) were fed 5 diets in 5 × 6 Youden square to give 6 replicates per diet. Diets were cornstarch-based diets containing soybean meal (SBM), NCM, JCM, field pea, or WM. The SBM was included as a reference. In Experiment 2, 6 ileal-cannulated barrows (70 kg) were fed a N-free diet for determining energy digestibility and NE values of test feedstuffs fed in Experiment 1 by difference method. The NE values of test feedstuffs were also calculated from the DE values and analyzed macronutrient content of the test feedstuffs (NRC, 2012). On DM basis, SBM, NCM, JCM, field pea, and WM contained 51, 41, 42, 28, and 18% CP; 1.52, 2.95, 2.36, 1.33, and 3.12% ether extract; 2.93, 0.14, 1.44; 36.7, and 28.7% starch; and 5.30, 21.0, 13.4, 9.49, and 16.1% ADF, respectively. The determined NE value for SBM (2.29 Mcal/kg) did not differ from that of NCM (1.72 Mcal/kg DM) or JCM (2.14 Mcal/kg DM). The NCM and JCM did not differ in NE value. Also, the determined NE value did not differ between field pea (2.00 Mcal/kg) and WM (2.55 Mcal/kg). The calculated NE values for SBM (2.18 Mcal/kg DM), NCM (1.73 Mcal/kg DM), and JCM (1.86 Mcal/kg DM) did not differ from the corresponding determined NE values of the same feedstuffs. However, the calculated NE value for field pea (2.51 Mcal/kg DM) was greater (P = 0.004) than the determined NE value of field pea, whereas the calculated NE value for WM (2.27 Mcal/kg DM) tended to be lower (P = 0.054) than the determined NE value of WM. In conclusion, the NE value for SBM and canola meals can be predicted based on the DE value and the macronutrient composition of the same feedstuffs. However, the NE value for field pea and WM may not be predicted precisely based on the DE value and the macronutrient composition of the same feedstuffs.

Maternal Dietary Intake, Nutritional Status, and Macronutrient Composition of Human Breast Milk: Systematic Review

Introduction: Human breast milk is the best source of nutrition in early life, particularly during the first six months. Nevertheless, human breast milk composition is variable and more insight in the exact factors contributing to this variability is warranted. In this review, we explored the impact of maternal dietary intake and nutritional status (e.g., anthropometric measures, body mass index, bioimpedance) on human milk macronutrient composition. Method: PubMed, Scopus and Cochrane were systematically searched till November 2019. Results: In total, 4946 publications underwent title-abstract screening; 101 publications underwent full-text screening. Eventually, 50 publications were included in this review, investigating either associations between maternal dietary intake (n=29) and/or maternal nutritional status (n=29), and macronutrient composition of human breast milk. Reported energy composition ranged from 51-72 kcal/dl, and 67% and 54% of the studies reported associations between with maternal nutritional intake and status, respectively. Protein content ranged from 0.8-3.3g/dl and four studies suggested a negative association with nutritional status. Fat content ranged from 2.1- 9.8g/dl, and 68% of the studies reported positive associations with nutritional status. Carbohydrate content ranged from 5.8-7.5g/dl, and 67% of the included studies did not report an association between intake or status. Conclusion: Literature investigating associations of maternal dietary intake and nutrition status with breast milk composition of macronutrients and energy content is diversified, both in terms of used methodology as well as results. Further studies using well defined and standard parameters are essential to aid the formulation of scientific recommendations.

Trends and Urban-Rural Disparities of Energy Intake and Macronutrient Composition among Chinese Children: Findings from the China Health and Nutrition Survey (1991 to 2015)

The nutrition status of children is gaining more attention with a rapid nutrition transition. This study aimed to investigate trends and urban-rural differences in dietary energy and macronutrient composition among Chinese children. A total of 7565 participants aged 6 to 17 years were obtained from three rounds (1991, 2004 and 2015) of the Chinese Health and Nutrition Survey (CHNS). The individual diet was evaluated via three consecutive 24-hour dietary recalls and compared with the Chinese Dietary Reference Intakes (DRIs). From 1991 to 2015, there was a significant increase in children’s fat intake, the proportion of energy intake from fat, and the proportion of children with more than 30% of energy from fat and less than 50% of energy from carbohydrates (p < 0.001). Compared with the DRI, the proportion with higher fat and lower carbohydrate intakes were, respectively, 64.7% and 46.8% in 2015. The urban-rural disparities in fat and carbohydrate intake gradually narrowed, while the gap in protein intake increased notably over time (p < 0.001). Chinese children experienced a rapid transformation to a low-carbohydrate and high-fat diet. Urban-rural disparities persistently existed; further nutritional interventions and education were of great significance, so as to ensure a more balanced diet for Chinese children.

Macronutrient Composition of the Meal May Influence Postprandial Plasma IL-6 Concentration in Men With Overweight or Obesity: An Analysis of Pooled Clinical Trial Data

Objectives Risk of cardiovascular disease (CVD) is markedly associated with poor diet quality (e.g., a high intake of saturated fats, refined carbohydrates; and a low intake of whole grains, fruits, and vegetables). Numerous clinical studies report that consuming a high-saturated fat meal (HFM) induces postprandial inflammation. However, few studies have evaluated proinflammatory mediators after consuming a HFM compared to an average American meal (AAM). The objective of study was to investigate plasma proinflammatory cytokine levels after consumption of a HFM compared to an AAM in middle-aged men with overweight or obesity. Methods This pooled analysis included data from two randomized controlled trials designed to evaluate the anti-inflammatory effect of consuming a spice blend delivered in two different meals with similar calories (∼1000 kcal): (1) a HFM (33% kcal from saturated fat, 36% kcal from carbohydrate, 16% kcal from protein) or (2) an AAM (16% from saturated fat, 49% kcal from carbohydrate, ∼21% kcal from protein). Both meals had a minimal amount of spices added for palatability. The results reported are from subjects in the control group on each trial: a HFM with 1.4 g of garlic powder and an AAM with 0.6 g of a spice blend. Data from non-smoking, middle-aged (40–65 y) men with overweight/obesity (BMI ≥25 and ≤35 kg/m2), elevated waist circumference (≥94 cm), and at least one other risk factor for CVD were included in the analysis (Total n = 26; HFM consumption n = 12, AAM consumption n = 14). Plasma cytokine concentrations (IL-1β, IL-6, IL-8, TNF-α, and MCP-1) were measured at 0, 60,120, 180,240 min after meal consumption. Results There was a significant time-by-meal interaction on plasma IL-6 concentration (P &lt; 0.05). Plasma IL-6 concentration was significantly higher 180 min and 240 min (1189% and 362%, respectively; P &lt; 0.05) after consuming a HFM compared to an AAM. There was no effect of meal or time-by-meal interaction on other plasma cytokines. Conclusions Consumption of a HFM compared to an AAM resulted in a greater circulating IL-6 in men with overweight or obesity. Macronutrient composition of the meal may influence postprandial inflammatory responses. Funding Sources McCormick Science Institute and the National Center for Advancing Translational Sciences, NIH (1UL1TR002014–01).

Tropical Beef: Is There an Axiomatic Basis to Define the Concept?

Cattle production in tropical regions has been estimated to account for just over half of cattle worldwide, yet it has not been demonstrated that sufficient similarities in the cattle exist to describe tropical cattle and, even less so, to characterize the meat from these animals. The aim of this review is to investigate the quality and nutrient composition of meat from cattle raised in the Tropics to determine if there is an axiomatic basis that would allow the definition of a concept of “tropical beef”. Tropical beef is the meat obtained from cattle raised in tropical environments, the population of which remains largely uncharacterized. Production systems in the Tropics are highly diverse but converge on the use of indigenous and Bos indicus breeds or Bos indicus-influenced crossbreeds under pasture feeding regimes. While some systems allow cattle to be slaughtered at ≤2 years of age, most often animals are ≥3 years. These production systems generally produce lean, low-yielding carcasses and tough (>46 N), lean (≤3.6% intramuscular fat) meat with a macronutrient composition otherwise similar to beef from animals raised elsewhere (72–74% moisture and 20–24% protein). Fatty acid profiles depend on the breed and production systems, while mineral content is influenced by the environment. Although lean and tough, tropical beef is highly acceptable to the consumers it serves, is culturally and traditionally relevant and, in many countries, contributes to food security. Consolidating the findings from animal and meat science studies in the Tropics has allowed the demonstration of an axiomatic basis defining “tropical beef” as a concept.

Dietary Aspects to Incorporate in the Creation of a Mobile Image-Based Dietary Assessment Tool to Manage and Improve Diabetes

Diabetes is the seventh leading cause of death in United States. Dietary intake and behaviors are essential components of diabetes management. Growing evidence suggests dietary components beyond carbohydrates may critically impact glycemic control. Assessment tools on mobile platforms have the ability to capture multiple aspects of dietary behavior in real-time throughout the day to inform and improve diabetes management and insulin dosing. The objective of this narrative review was to summarize evidence related to dietary behaviors and composition to inform a mobile image-based dietary assessment tool for managing glycemic control of both diabetes types (type 1 and type 2 diabetes). This review investigated the following topics amongst those with diabetes: (1) the role of time of eating occasion on indicators of glycemic control; and (2) the role of macronutrient composition of meals on indicators of glycemic control. A search for articles published after 2000 was completed in PubMed with the following sets of keywords “diabetes/diabetes management/diabetes prevention/diabetes risk”, “dietary behavior/eating patterns/temporal/meal timing/meal frequency”, and “macronutrient composition/glycemic index”. Results showed eating behaviors and meal macronutrient composition may affect glycemic control. Specifically, breakfast skipping, late eating and frequent meal consumption might be associated with poor glycemic control while macronutrient composition and order of the meal could also affect glycemic control. These factors should be considered in designing a dietary assessment tool, which may optimize diabetes management to reduce the burden of this disease.

Dietary Interventions for Weight Loss

Obesity is a complex and chronic condition that requires continuing care. A variety of diet plans are available for use in the clinical setting. Exactly what type of diet may be most beneficial remains controversial. Numerous clinical trials have been carried out over the years comparing an array of dietary interventions for weight loss, including calorie restriction diets, altered macronutrient composition diets or specific dietary patterns. This paper will provide an overview of the evidence-based dietary interventions for clinical practice.