Egg intake moderates the rate of memory decline in healthy older adults

Eggs contain important compounds related to enhanced cognition, but it is not clear if egg consumption, as a whole, has a direct impact on memory decline in older adults. This study aimed to determine whether egg intake levels predict the rate of memory decline in healthy older adults after sociodemographic and dietary controls. We conducted a secondary analysis of data from 470 participants, age 50 and over, from the Biospsychosocial Religion and Health Study. Participants completed a food frequency questionnaire, which was used to calculate egg intake and divide participants into Low (<23 g/week, about half an egg), Intermediate (24-63 g/week, half to 1½ eggs) and High (≥63 g/week, about two or more eggs) tertiles. Participants were administered the California Verbal Learning Test - 2nd Edition (CVLT-II) Short Form in 2006-2007, and 294 of them were again tested in 2010-2011. Using linear mixed model analysis, no significant cross-sectional differences were observed in CVLT-II performance between egg intake levels after controlling for age, sex, race, education, body mass index, cardiovascular risk, depression and intake of meat, fish, dairy and fruits/vegetables. Longitudinally, the Intermediate egg group exhibited significantly slower rates of decline on the CVLT-II compared to the Low egg group. The High egg group also exhibited slower rates of decline, but not statistically significant. Thus, limited consumption of eggs (about 1 egg/week) was associated with slower memory decline in late life compared to consuming little to no eggs, but a dose-response effect was not clearly evident. This study may help explain discrepancies in previous research that did not control for other dietary intakes and risk factors.

Effects of Consuming Ounce-Equivalent Portions of Animal- vs. Plant-Based Protein Foods, as Defined by the Dietary Guidelines for Americans on Essential Amino Acids Bioavailability in Young and Older Adults: Two Cross-Over Randomized Controlled Trials

BACKGROUND

The Dietary Guidelines for Americans (DGA) recommends consuming a variety of "Protein Foods" based on "ounce-equivalent" (oz-eq) portions. No study has assessed the same oz-eq portions of animal- vs. plant-based protein foods on essential amino acid (EAA) bioavailability for protein anabolism in young and older adults.

OBJECTIVES

We assessed the effects of consuming two oz-eq portions of pork, eggs, black beans, and almonds on postprandial EAA bioavailability in young and older adults.

METHODS

We conducted two investigator-blinded, randomized crossover trials in young (n = 30; mean age ± SD: 26.0 ± 4.9 y) and older adults (n = 25; mean age ± SD: 64.2 ± 6.6 y). Participants completed four testing sessions where they consumed a standardized meal with two oz-eq of either unprocessed lean pork, whole eggs, black beans, or sliced almonds. Blood samples were taken at baseline and 30, 60, 120, 180, 240, and 300 min postprandially. Plasma EAA bioavailability was based on postprandial integrated positive areas under the curve.

RESULTS

Participant age did not affect EAA bioavailability among the four protein foods tested. Two oz-eq portions of pork (7.36 g EAA) and eggs (5.38 g EAA) resulted in greater EAA bioavailability than black beans (3.02 g EAA) and almonds (1.85 g EAA) in young and older adults, separately or combined (p < 0.0001 for all). Pork resulted in greater EAA bioavailability than eggs in young adults (p < 0.0001), older adults (p = 0.0007), and combined (p < 0.0001). There were no differences in EAA bioavailability between black beans and almonds.

CONCLUSIONS

The same "oz-eq" portions of animal- and plant-based protein foods do not provide equivalent EAA content and postprandial bioavailability for protein anabolism in young and older adults.

Study protocol for a 15-week randomised controlled trial assessing the independent effects of high-cholesterol and high-saturated fat diets on LDL cholesterol

INTRODUCTION

Previous research has associated high dietary cholesterol intake with raised low-density lipoprotein cholesterol (LDL-C) and thus increased risk for cardiovascular disease (CVD). Emerging research suggests that it is saturated fat, not dietary cholesterol, associated with increased CVD risk. Despite being high in cholesterol, eggs, low in saturated fat, are not adversely associated with blood lipids or CVD risk. This paper describes a randomised controlled counter-balanced, cross-over trial assessing the effects of a high-cholesterol/low-saturated fat (egg) diet and a low-cholesterol/high-saturated fat diet (egg free) on blood lipids and lipoproteins, while accounting for physical activity levels which can also influence these parameters. The primary aim is to demonstrate that high cholesterol intake (from eggs) within a healthy, low-saturated fat diet does not adversely affect blood lipid levels and lipoprotein profiles. Instead, we propose that adverse effects on these parameters are mediated by saturated fat intake. The secondary aim is to explore relationships between changes in blood lutein and zeaxanthin concentrations and alterations in physical activity, examining whether changes in physical activity mediate effects on blood lipids and lipoproteins.

METHODS AND ANALYSIS

Fifty-two adults aged 18-60 years with LDL-C less than 3.5 mmol/L will be randomly allocated to three isocaloric diets for 5 weeks each: a high-cholesterol (600 mg)/low-saturated fat (6%) (egg) diet, a low-cholesterol (300 mg)/high-saturated fat (12%) (egg free) diet and a control diet that is high in both cholesterol (600 mg) and saturated fat (12%). Lipid and lipoprotein levels, lipoprotein size and concentrations, blood pressure, blood glucose, physical activity levels, and plasma lutein and zeaxanthin concentrations will be measured. Treatment effects will be analysed using linear mixed effects models.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the University of South Australia Human Research Ethics Committee no. 204 327. Results will be disseminated through peer-reviewed journals and national and international presentations.

TRIAL REGISTRATION NUMBER

NCT05267522.

Modeling the Substitution of One Egg Increased the Nutrient Quality of Choline and Vitamin D in Exemplary Menus

Background/Objectives: Eggs, a nutritious and affordable food, are not widely consumed by adolescents, who show many nutrient inadequacies. Modeling dietary substitutions with eggs and their costs can provide dietary insights while considering economic constraints. This study theoretically modeled the impact of substituting an egg for another protein source, considering nutrient quality and cost, using exemplary menus with application to adolescents. Methods: The substitution was modeled in four different seven-day exemplary menus: (1) the Healthy U.S.-Style Dietary Pattern (HUSS), (2) Harvard Medical School's Heathy Eating Guide, (3) the National Heart, Lung, and Blood Institute's Dietary Approaches to Stop Hypertension (DASH) diet and (4) the Healthy U.S.-Style Vegetarian Dietary Pattern (HVEG). One egg replaced the gram amount and nutrient profile of a protein source food in each menu. Micronutrient quality was assessed using the Food Nutrient Index (FNI), scored 0-100. The Center for Nutrition Policy and Promotion Food Price Database informed the food prices. Pairwise t-tests compared the effects of egg substitution on micronutrient scores and daily costs. Results: The daily egg substitution increased FNI scores for choline and vitamin D in the HUSS (83 to 95 and 69 to 75, respectively), DASH (80 to 91 and 55 to 59, respectively), and HVEG (91 to 100 and 44 to 51, respectively), and choline alone (89 to 98) in the Harvard menu. Daily menu prices were not significantly different after the egg substitution (p > 0.01). Conclusions: Substituting one egg for another protein source food increased the micronutrient quality of choline and vitamin D in exemplary menus without increasing the cost; however, factors such as food preferences and the economic accessibility of eggs in different contexts should also be considered.

Nutritional Intake and Sensory Processing in School-Aged Children with Autism Spectrum Disorder

Background: Individuals diagnosed with autism spectrum disorder (ASD) commonly experience sensory processing that differs from general-population norms, and the autistic lived experience of eating includes preferences for routine, and sensory processing difficulty related to scents, tastes, temperatures, and textures of food. Meanwhile, research indicates that nutrients involved in one-carbon metabolism (OCM) may be related to sensory processing. Methods: This study enrolled 33 school-aged children with autism to assess whether OCM nutrient intake is associated with sensory processing. Parents completed two parent-report assessments: the youth and adult food frequency questionnaire (YAFFQ), and a sensory processing tool, Sensory Profile 2 (SP2). Results: Participant data showed generally good nutritional profiles mirroring those of general-population U.S. children. A group-binarized linear regression model showed the following relationships (p < 0.05): vitamin B12 consumption had a negative association with the SP2 Oral and Sensor domain scores. Choline intake had a positive association with the SP2 Avoider domain score. Vitamin B1 showed a positive association with the SP2 Visual domain score. Conclusions: These results support the possible existence of a relationship between sensory symptoms and OCM nutrient consumption levels in school-aged children diagnosed with autism. Future research is needed to confirm and explore the potential for causality.