Atypical monocyte dynamics in healthy humans in response to fasting and refeeding are distinguished by fasting HDL and postprandial cortisol.

Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow where upon refeeding they are re-released back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. To investigate monocyte dynamics in humans we measured blood monocyte fluctuations in 354 clinically healthy individuals after a 12-hour overnight fast and at 3- and 6-hours after consuming a mixed macronutrient challenge meal. Using cluster analysis, we identified three distinct monocyte behaviors. Group 1 was characterized by relatively low fasting monocyte counts that markedly increased after consuming the test meal. Group 2 was characterized by relatively high fasting monocyte counts which decreased after meal consumption. Group 3, like Group 1, was characterized by lower fasting monocyte counts but increased to a lesser extent after consuming the meal. While monocyte fluctuations observed in Groups 1 and 3 align with the current paradigm of monocyte dynamics in response to fasting and refeeding, the atypical dynamic observed in Group 2 does not. While generally younger in age, Group 2 subjects had lower whole-body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or BMI. Taken together these results highlight distinct patterns of monocyte responsiveness to natural fluctuations in dietary fuel availability.

Cumulative physiological stress is associated with age-related changes to peripheral T lymphocyte subsets in healthy humans.

BACKGROUND: Progressive age-associated change in frequencies and functional capacities of immune cells is known as immunosenescence. Despite data linking chronic environmental, physiological, and psychosocial stressors with accelerated aging, how stress contributes to immunosenesence is not well characterized. OBJECTIVE: To help delineate the contribution of cumulative physiological stress on immunosensence we assessed relationships between a composite measurement of cumulative physiological stress, reflecting the functioning of the hypothalamic-pituitary-adrenal axis, sympathetic nervous system, cardiovascular system, and metabolic processes, and lymphocyte changes typically affiliated with aging in a cohort of healthy volunteers ranging from 18 to 66 y. RESULTS: Physiological stress load positively correlated with subject age in the study cohort and was significantly higher in adults 50-66 y compared to adults 18-33 y and 34-49 y. Using physiological stress load, we identified a significant age-dependent association between stress load and frequencies of circulating regulatory T lymphocytes (Tregs). Frequencies were higher in younger participants, but only in participants exhibiting low physiological stress load. As stress load increased, frequencies of Tregs decreased in young participants but were unchanged with increasing stress load in middle and older age individuals. Follow-up analysis of stress load components indicated lower circulating DHEA-S and higher urinary norepinephrine as the primary contributors to the effects of total stress load on Tregs. In addition, we identified age-independent inverse associations between stress load and frequencies of naïve Tregs and naïve CD4 T cells and positive associations between stress load and frequencies of memory Tregs and memory CD4 T cells. These associations were primarily driven by stress load components waist circumference, systolic and diastolic blood pressure, CRP, and HbA1c. In summary, our study results suggest that, in younger people, physiological stress load may diminish regulatory T cell frequencies to levels seen in older persons. Furthermore, independent of age, stress load may contribute to contraction of the naïve Treg pool and accumulation of memory Treg cells. CLINICAL TRIAL: Registered on ClincialTrials.gov (Identifier: NCT02367287).

Increased risk of preterm delivery with high cortisol during pregnancy is modified by fetal sex: a cohort study.

BACKGROUND: Previous studies show an association between maternal plasma and salivary cortisol and preterm birth but have been primarily conducted in high-income countries. It is unknown whether salivary cortisol is a risk factor for preterm birth in Ghana. Our objective was to determine whether maternal salivary cortisol during pregnancy was associated with pregnancy duration and preterm delivery in Ghana. METHODS: We conducted a cohort study of 783 pregnant women in Ghana. We measured salivary cortisol at baseline (mean 16 wk), 28 wk., and 36 wk. gestation. Pregnancy duration was determined primarily by ultrasound. We used adjusted linear regression models to examine the association between cortisol and pregnancy duration and Poisson regression models to determine the risk of preterm delivery among women with high cortisol at baseline or 28 wk. gestation. RESULTS: Mean pregnancy duration was 39.4 ± 1.8 wk. and 6.6% had a preterm delivery. Mean maternal cortisol increased throughout pregnancy, from 4.9 ± 2.7 nmol/L at baseline (16 wk) to 6.4 ± 3.2 nmol/L at 28 wk. and 7.9 ± 3.0 nmol/L at 36 wk. gestation. In adjusted analyses, higher cortisol concentrations at baseline (ß = - 0.39, p = .002) and 28 wk. (ß = - 0.49, p = .001), but not 36 wk. (ß = - 0.23, p = .084) were associated with a shorter pregnancy duration. Women with high cortisol at baseline (> 6.3 nmol/L) had an increased relative risk of preterm delivery (RR (95% CI): 1.96 (1.13, 3.40)), but the association between high cortisol at 28 wk. and preterm delivery was not significant. There was a significant interaction with fetal sex (p-for-interaction = 0.037): among women carrying male fetuses, high cortisol at baseline increased the risk of preterm delivery threefold (3.18 (1.51, 6.71)) while there was no association (1.17 (0.50, 2.74)) among women carrying female fetuses. CONCLUSION: Higher maternal cortisol is associated with a shorter pregnancy duration and an increased risk of preterm delivery. Subgroup analysis by fetal sex revealed that this association is evident primarily among women carrying male fetuses. Future studies of cortisol and preterm delivery should include consideration of fetal sex as a potential effect modifier.

Machine Learning Identifies Stool pH as a Predictor of Bone Mineral Density in Healthy Multiethnic US Adults.

BACKGROUND: A variety of modifiable and nonmodifiable factors such as ethnicity, age, and diet have been shown to influence bone health. Previous studies are usually limited to analyses focused on the association of a few a priori variables or on a specific subset of the population. OBJECTIVE: Dietary, physiological, and lifestyle data were used to identify directly modifiable and nonmodifiable variables predictive of bone mineral content (BMC) and bone mineral density (BMD) in healthy US men and women using machine-learning models. METHODS: Ridge, lasso, elastic net, and random forest models were used to predict whole-body, femoral neck, and spine BMC and BMD in healthy US men and women ages 18-66 y, with a BMI (kg/m2) of 18-44 (n = 313), using nonmodifiable anthropometric, physiological, and demographic variables; directly modifiable lifestyle (physical activity, tobacco use) and dietary (via FFQ) variables; and variables approximating directly modifiable behavior (circulating 25-hydroxycholecalciferol and stool pH). RESULTS: Machine-learning models using nonmodifiable variables explained more variation in BMC and BMD (highest R2 = 0.75) compared with when using only directly modifiable variables (highest R2 = 0.11). Machine-learning models had better performance compared with multivariate linear regression, which had lower predictive value (highest R2 = 0.06) when using directly modifiable variables only. BMI, body fat percentage, height, and menstruation history were predictors of BMC and BMD. For directly modifiable features, betaine, cholesterol, hydroxyproline, menaquinone-4, dihydrophylloquinone, eggs, cheese, cured meat, refined grains, fruit juice, and alcohol consumption were predictors of BMC and BMD. Low stool pH, a proxy for fermentable fiber intake, was also predictive of higher BMC and BMD. CONCLUSIONS: Modifiable factors, such as diet, explained less variation in the data compared with nonmodifiable factors, such as age, sex, and ethnicity, in healthy US men and women. Low stool pH predicted higher BMC and BMD. This trial was registered at www.clinicaltrials.gov as NCT02367287.

Technician-Scored Stool Consistency Spans the Full Range of the Bristol Scale in a Healthy US Population and Differs by Diet and Chronic Stress Load.

BACKGROUND: Prior studies of adults with constipation or diarrhea suggest that dietary intake, physical activity, and stress may affect stool consistency. However, the influence of these factors is unresolved and has not been investigated in healthy adults. OBJECTIVES: We assessed the relations of technician-scored stool consistency in healthy adults with self-reported diet, objectively monitored physical activity, and quantifiable markers of stress. METHODS: Stool consistency was scored by an independent technician using the Bristol Stool Form Scale (BSFS) to analyze samples provided by healthy adults, aged 18-65 y, BMI 18-44 kg/m2, in the USDA Nutritional Phenotyping Study (n = 364). A subset of participants (n = 109) were also asked to rate their sample using the BSFS. Dietary intake was assessed with two to three 24-h recalls completed at home and energy expenditure from physical activity was monitored using an accelerometer in the 7-d period preceding the stool collection. Stress was measured using the Wheaton Chronic Stress Inventory and allostatic load (AL). Statistical and machine learning analyses were conducted to determine which dietary, physiological, lifestyle, and stress factors differed by stool form. RESULTS: Technician-scored BSFS scores were significantly further (P = 0.003) from the central score (mean ± SEM distance: 1.41 ± 0.089) than the self-reported score (1.06 ± 0.086). Hard stool was associated with higher (P = 0.005) intake of saturated fat (13.8 ± 0.40 g/1000 kcal) than was normal stool (12.5 ± 0.30 g/1000 kcal). AL scores were lower for normal stool (2.49 ± 0.15) than for hard (3.07 ± 0.18) (P = 0.009) or soft stool (2.89 ± 0.18) (P = 0.049). Machine learning analyses revealed that various dietary components, physiological characteristics, and stress hormones predicted stool consistency. CONCLUSIONS: Technician-scored stool consistency differed by dietary intake and stress hormones, but not by physical activity, in healthy adults.This trial was registered at clincialtrials.gov as NCT02367287.

Energy intake and season interact to influence physiological stress load among midlife women.

Allostatic load (AL) is an index that measures physiologic stress associated with chronic disease risk. One factor that may influence overall physiologic stress load and AL is energy consumption, but whether this association differs across different seasons is unknown. We tested whether energy consumption interacted with the season to influence AL in 52 mid-life (40-60 years) women from the Life in All Seasons Study. Women completed an online 24-h recall every 10 days and had components of allostatic load measured seasonally. Women were from the greater Grand Forks, ND catchment area and were followed for one year between July 2012 and July 2014. We found a significant (p = 0.01) interaction between season and energy consumption on AL. Further inspection showed that, during the summer and winter seasons, the average allostatic load rose with relatively higher energy consumption. We also observed a linear and positive association between AL and energy intake in summer (ß = 0.0013 ± 0.0004; p = 0.001; r2 = 0.14) and winter (ß = 0.0011 ± 0.0004; p = 0.007; r2 = 0.10), but not in fall or spring. These results suggest that factors associated with distinct times of the year promote or prevent the effects of higher energy consumption on physiological stress load. Since allostatic load is linked to elevated disease risk, our results provide additional information that may help to explain seasonal differences in disease risk of some women.

Infant cortisol stress-response is associated with thymic function and vaccine response.

Stress can impair T cell-mediated immunity. To determine if infants with high stress responses had deficits in T-cell mediated immunity, we examined the association of pain-induced cortisol responsiveness with thymic function and vaccine responses in infants. This study was performed among 306 (male = 153 and female = 153) participants of a randomized, controlled trial examining the effect of neonatal vitamin A supplementation on immune function in Bangladesh (NCT01583972). Salivary cortisol was measured before and 20 min after a needle stick (vaccination) at 6 weeks of age. The thymic index (TI) was determined by ultrasonography at 1, 6, 10 and 15 weeks. T-cell receptor excision circle and blood T-cell concentrations were measured at 6 and 15 weeks. Responses to Bacillus Calmette-Guérin (BCG), tetanus toxoid, hepatitis B virus and oral poliovirus vaccination were assayed at 6 and 15 weeks. Cortisol responsiveness was negatively associated with TI at all ages (p < .01) in boys only, was negatively associated with naïve helper T-cell concentrations in both sexes at both 6 (p = .0035) and 15 weeks (p = .0083), and was negatively associated with the delayed-type hypersensitivity (DTH) skin test response to BCG vaccination at 15 weeks (p = .034) in both sexes. Infants with a higher cortisol response to pain have differences in the T-cell compartment and a lower DTH response to vaccination. Sex differences in the immune system were seen as early as 6 weeks of age in these healthy infants.

A Clear Difference Emerges in Hormone Patterns Following a Standard Midday Meal in Young Women Who Regularly Eat or Skip Breakfast.

BACKGROUND: Multiple hormones are involved in the regulation of food intake and glucose metabolism. Past intervention studies showed a benefit of eating breakfast on satiety, but this was possibly confounded by the disruption of habitual meal patterns. OBJECTIVE: The objective of this study was to compare hormonal responses, including insulin, leptin, glucagon-like peptide-1, ghrelin, peptide YY (PYY3-36), and cholecystokinin (CCK), between habitual breakfast eaters (Br-Es) and habitual skippers (Br-Ss) to a standard midday meal. METHODS: Thirty-two women [mean ± SD age: 22.6 ± 3.3 y; body mass index (in kg/m2): 21.8 ± 2.0] participated in a cross-sectional study that consisted of a 3-h test protocol that included a standard test meal served at 1230 with pre- and postmeal blood sampling. The protocol required that Br-Es eat a typical breakfast between 0700 and 1000, whereas Br-Ss had no breakfast meal and had fasted for 12 h. Blood was drawn 35 and 5 min prelunch and 5, 20, 35, 50, and 110 min postlunch. RESULTS: Repeated-measures ANOVA revealed a group difference for PYY3-36 (P = 0.001), with the Br-E group exhibiting 50-90% higher concentrations throughout the test period. Leptin tended to be different (P = 0.08) between groups, with higher mean ± SD values for the Br-S group (27.6 ± 29.6 ng/mL) compared with the Br-E group (11.5 ± 9.8 ng/mL). Partial least squares regression analysis confirmed that these 2 hormones were important contributors to the patterns of the hormones, anthropometric, clinical, and behavioral variables that differed between groups; insulin and CCK were important as well. CONCLUSION: We found differences between the Br-E and Br-S groups in circulating gut and adipose-derived hormones measured midday, indicating that the breakfast habit is associated with the hormonal milieu before and after a midday meal. The different patterns may be short-lived or may impact metabolism later in the day. This report is a secondary analysis of a trial registered at clinicaltrials.gov as NCT01427556.

Maternal plasma cholesterol and duration of pregnancy: A prospective cohort study in Ghana.

Low plasma cholesterol may be associated with preterm birth; however, results are mixed and limited primarily to high-income countries. Our objective was to determine whether maternal plasma lipid concentrations are associated with pregnancy duration. We performed a nested cohort (n = 320) study of pregnant Ghanaian women enrolled in a randomized controlled trial. Total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and triglyceride concentrations were analyzed in plasma at ≤20and 36 weeks gestation as continuous variables and also categorized into low, referent, or high (<10th, 10th-90th, >90th percentile). At ≤20 weeks, plasma lipid concentrations were not associated with pregnancy duration. At 36 weeks, total cholesterol and triglyceride concentrations were not associated with pregnancy duration. Higher HDL-C at 36 weeks was associated with a longer pregnancy duration (adjusted ß-coefficient ± standard error: 0.05 ± 0.02 days mg-1 /dL, p = .02); pregnancy duration was 5.9 ± 2.0 (mean ± standard error) days shorter among women with low HDL-C compared with the referent group (10th-90th percentile) (p = .02) and 8.6 ± 2.6 days shorter when compared with the high HDL-C group (p = .003). Pregnancy duration was 4.9 ± 2.1 days longer among women with low low-density lipoprotein cholesterol at 36 weeks gestation when compared with the referent group (p = .051). Our data suggest that low HDL-C in the third trimester of pregnancy is associated with a shorter duration of pregnancy in this study population but do not support the hypothesis that low total cholesterol is associated with a shorter pregnancy duration.

Late-Pregnancy Salivary Cortisol Concentrations of Ghanaian Women Participating in a Randomized Controlled Trial of Prenatal Lipid-Based Nutrient Supplements.

BACKGROUND: High circulating cortisol is associated with miscarriage, preterm birth, and low birth weight. Research in nonpregnant individuals suggests that improved nutrition may lower cortisol concentrations. It is unknown whether nutritional supplementation during pregnancy lowers cortisol. OBJECTIVE: Our objective was to determine whether women receiving a lipid-based nutrient supplement (LNS) throughout pregnancy would have lower salivary cortisol at 36 wk gestation compared with women receiving other nutrient supplements. METHODS: We conducted a randomized controlled trial in 1320 pregnant Ghanaian women at ≤20 wk gestation who were assigned to receive daily throughout pregnancy: 1) 60 mg iron + 400 µg folic acid (IFA), 2) multiple micronutrients (MMNs), or 3) 20 g LNS (containing 118 kcal, 22 micronutrients, and protein). Morning salivary cortisol was collected from a subsample at baseline and at 28 and 36 wk gestation. RESULTS: A total of 758 women had cortisol measurements at 28 or 36 wk gestation. Salivary cortisol at 36 wk gestation did not differ between groups and was (mean ± SE) 7.97 ± 0.199 in the IFA group, 7.84 ± 0.191 in the MMN group, and 7.77 ± 0.199 nmol/L in the LNS group, when adjusted for baseline cortisol, time of waking, and time between waking and saliva collection (P = 0.67). There was an interaction between supplementation group and women's age (continuous variable, P-interaction = 0.03); and when age was dichotomized by the median, significant differences in salivary cortisol concentrations between groups were seen in women ≤26 y of age (IFA = 8.23 ± 0.284 nmol/L, MMN = 8.20 ± 0.274 nmol/L, and LNS = 7.44 ± 0.284 nmol/L; P = 0.03) but not in women >26 y old (IFA = 7.71 ± 0.281 nmol/L, MMN = 7.50 ± 0.274 nmol/L, and LNS = 8.08 ± 0.281 nmol/L; P = 0.13). CONCLUSIONS: We conclude that supplementation with LNSs or MMNs during pregnancy did not affect the cortisol concentration in the study population as a whole, in comparison with IFA, but that LNS consumption among younger women may lead to lower cortisol at 36 wk gestation. This trial was registered at clinicaltrials.gov as NCT00970866.

Maternal cortisol and stress are associated with birth outcomes, but are not affected by lipid-based nutrient supplements during pregnancy: an analysis of data from a randomized controlled trial in rural Malawi.

BACKGROUND: Prenatal micronutrient supplements have been found to increase birth weight, but mechanisms for increased growth are poorly understood. Our hypotheses were that 1) women who receive lipid-based nutrient supplements (LNS) during pregnancy would have lower mean salivary cortisol concentration at 28 wk and 36 wk gestation compared to the multiple micronutrient (MMN) and iron-folic acid (IFA) supplement groups and 2) both salivary cortisol and perceived stress during pregnancy would be associated with shorter duration of gestation and smaller size at birth. METHODS: Women were enrolled in the trial in early pregnancy and randomized to receive LNS, MMN, or iron-folic acid (IFA) supplements daily throughout pregnancy. At enrollment, 28 wk and 36 wk gestation, saliva samples were collected and their cortisol concentration was measured. Self-report of perceived stress was measured using questionnaires. Gestation duration was indicated by ultrasound dating and newborn anthropometric measurements (weight, length, head circumference) provided indicators of intrauterine growth. RESULTS: Of the 1391 women enrolled in the trial, 1372, 906 and 1049 saliva samples were collected from women at baseline, 28 wk and 36 wk, respectively. There were no significant differences in mean cortisol concentrations by intervention group at 28 wk or 36 wk gestation. Cortisol concentrations were negatively associated with duration of gestation (Baseline: ß = -0.05, p = 0.039; 36 wk: ß = -0.04, p = 0.037) and birth weight (28 wk: ß = -0.08, p = 0.035; 36 wk: ß = -0.11, p = 0.003) but not associated with length-for-age or head circumference-for-age z-scores. Perceived stress at 36 wk was significantly associated with shorter newborn LAZ (p = 0.001). There were no significant associations with the risk of small for gestational age, preterm birth, or low birth weight. CONCLUSIONS: Maternal salivary cortisol concentration was strongly associated with birth weight and duration of gestation in rural Malawi, but these data do not support the hypothesis that LNS provision to pregnant women would influence their salivary cortisol concentrations. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT01239693.

Dairy food consumption and meal-induced cortisol response interacted to influence weight loss in overweight women undergoing a 12-week, meal-controlled, weight loss intervention.

Dairy food enhances weight loss in animal models, possibly by modifying the metabolic effects of cortisol. This study determined in overweight women (ages 20.0-45.9 y; n = 51) whether including dairy food in an energy-restricted diet affects cortisol concentrations and whether differences in provoked cortisol explain the magnitude of weight loss. Women received either an adequate amount of dairy food (AD), the equivalent of ≥711 mL/d milk, or a low amount of dairy food (LD), the equivalent to ≤238 mL/d milk, in a 12-wk, energy-restricted dietary intervention. Participants were tested in a 12-h laboratory visit, which included 2 standard meals and a dinner buffet that was consumed ad libitum. Salivary cortisol was measured from waking to bedtime. Energy restriction increased (P ≤ 0.04) the minimum and decreased (P ≤ 0.02) the diurnal amplitude in the salivary cortisol concentration from baseline to postintervention. Energy restriction enhanced the dinner meal-stimulated salivary cortisol response (DMR) (P ≤ 0.02) but only in the LD group. Compared with the LD treatment, the AD treatment induced (P ≤ 0.04) greater reductions in body weight and fat, but only in women characterized as having a baseline DMR (responders) (n = 26); weight and fat lost in the AD and LD groups were similar in nonresponders (n = 25). Overall, energy restriction dampened diurnal salivary cortisol fluctuations [symptomatic of hypothalamic-pituitary-adrenal (HPA) axis dysfunction] and enhanced dinner meal-stimulated salivary cortisol concentrations. The AD treatment prevented the latter. Furthermore, certain phenotypic markers of HPA axis function may help to expose the weight-reducing effects of consuming dairy food.

Preschool children with lower executive function may be more vulnerable to emotional-based eating in the absence of hunger.

Decreased executive function (EF) has been linked to unhealthy eating behaviors and obesity in older children and adults, however little is known about this relationship in young children. One possible reason for this association is that individuals with degraded EF are more vulnerable to emotional-based overeating. Emotional eating may thus be more likely to occur in persons with lower self-control or ability to regulate emotions. A pilot project in a research-based preschool was conducted to examine the relationships between executive function, emotional arousal and eating in the absence of hunger (EAH) in 3-6year-old children. Executive function was measured through child-completed tasks, parent questionnaires, and standardized teacher reports. Emotional arousal was measured via skin conductance. Children who had lower cognitive development scores as indicated by teacher reports had higher EAH. Increased emotional arousal was associated with increased EAH, but only in a subgroup of children who had a lower capacity for emotional regulation as suggested by lower delay of gratification scores, lower effortful control (parent questionnaire), and overall lower teacher-reported cognitive development. Further studies are necessary to determine whether interventions to improve executive function and emotional regulation in young children may also have the benefit of improving eating behaviors and decreasing risk of obesity in the long run.

A Diet Pattern Characterized by Sugar-Sweetened Beverages Is Associated with Lower Decision-Making Performance in the Iowa Gambling Task, Elevated Stress Exposure, and Altered Autonomic Nervous System Reactivity in Men and Women.

The executive brain mediates and facilitates a set of cognitive functions, such as decision making, planning, self-regulation, emotional regulation, and attention. Executive dysfunction and related diseases are a rising public health concern. Evidence supports a link between nutritional factors and executive function (EF), but relatively little information exists about the relationship between diet patterns and this higher order cognitive ability. We and others have reported on the relationships between body weight regulation and affective decision making, as measured by performance in the Iowa Gambling Task (IGT). However, little is known about the relationships between performance in this decision-making task and whole diet patterns. In this study, we tested whether data-derived diet patterns based on energy-adjusted food intake data from the Block Food Frequency Questionnaire were associated with decision-making performance in the IGT. Secondarily, we examined the influence of these diet patterns on self-reported chronic stress exposure and heart rate variability, which is a marker of autonomic nervous system (ANS) activity. In prior studies, stress and ANS activity were shown to influence decision-making performance in the IGT. In this study, five distinct diet patterns were identified by cluster and factor analyses. A diet pattern best characterized by elevated sugar-sweetened beverage and added sugar consumption was associated with the lowest decision-making performance (p = 0.0049) and higher stress exposure (p = 0.0097). This same diet pattern was associated (p = 0.0374) with an IGT-affiliated decline in high-frequency HRV and an increase in low-frequency HRV, suggesting diet-induced ANS regulatory shifts in response to performing the EF task. Compared to the sugar-sweetened beverage diet pattern, diet patterns defined by more fruits/vegetables and low red meat (p = 0.0048) or higher omega-3 fatty acids and seafood (p = 0.0029) consumption were associated with lower chronic stress exposure. All outcomes were statistically adjusted for differences in BMI, age, sex, education level, and sensorimotor ability. Our findings provide new information that further supports the potential importance of whole diet patterns on cognitive disease prevention.

Waking Salivary Cortisol Associated with Magnitude of Cholesterol Reduction in Women Fed a Healthy Whole-Food Diet for 8 Weeks.

Background: Diet and cortisol are independently linked to cardiometabolic function and health, but underlying alterations in circulating cortisol may influence beneficial cardiometabolic effects of consuming a healthy diet. Objective: This study was a secondary analysis to examine whether baseline concentrations of waking salivary cortisol interacted with 8-wk whole-food diet interventions to affect cardiometabolic outcomes. Methods: A randomized, double-blind, controlled 8-wk diet intervention was conducted in 44 participants. The trial was conducted at the Western Human Nutrition Research Center in Davis, California. Participants were overweight or obese women aged 20-64 y, minimally active, and insulin resistant and/or dyslipidemic. Diets were randomly assigned and based on the 2010 Dietary Guidelines for Americans (DGA) or a typical American diet (TAD). Cardiometabolic risk factors and salivary cortisol were assessed at baseline and at 8 wk. Primary outcome measures included 8-wk change in overnight fasted cardiometabolic risk factors, including blood pressure, BMI, and circulating triglycerides, cholesterol, glycated hemoglobin (HbA1c), nonesterified fatty acids, and high-sensitivity C-reactive protein. This trial was approved by the University of California, Davis, Institutional Review Board. Results: Baseline waking cortisol concentrations interacted (P = 0.0474) with diet to affect 8-wk changes in fasting total cholesterol. Compared with a TAD, a DGA diet was associated with 8-wk decreases in total cholesterol in participants with low (10th percentile of all participants; 2.76 nmol/L) or average (7.76 nmol/L) but not higher (90th percentile of all participants; 13.44 nmol/L) baseline waking cortisol. Consistent with this finding, there was a DGA-specific positive association (P = 0.0047; b: 2.88 ± 0.94) between baseline waking cortisol and 8-wk increases in total cholesterol. Conclusions: The underlying status of waking cortisol may explain interindividual variability in total cholesterol responses to whole-food diets. This trial was registered at www.clinicaltrials.gov (https://clinicaltrials.gov/ct2/show/NCT02298725) as NCT02298725.

Pathways of parental influence on adolescent diet and obesity: a psychological stress-focused perspective.

Youth obesity has become increasingly prevalent, with 34.5% of US adolescents 12-19 years old estimated to have overweight or obesity. Disordered eating and weight concern peak in adolescence, and overeating to cope with negative emotions can affect long-term health and obesity risk. Parents significantly influence adolescent diet quality, and parental stress may influence parenting behaviors that increase the risk for stress-motivated eating and obesity in adolescents. Chronic or repeated exposure to parental stress may lead to stress-related neurophysiological changes that promote consumption of palatable foods and obesogenic eating habits in adolescents. Understanding how parental stress influences adolescents' eating behavior may reveal novel access points for reducing adolescent obesity. Here, we aim to provide a new stress-focused framework for developing intervention strategies targeted at obesity prevention in adolescents.

Association of Diet and Antimicrobial Resistance in Healthy U.S. Adults.

Antimicrobial resistance (AMR) represents a significant source of morbidity and mortality worldwide, with expectations that AMR-associated consequences will continue to worsen throughout the coming decades. Since resistance to antibiotics is encoded in the microbiome, interventions aimed at altering the taxonomic composition of the gut might allow us to prophylactically engineer microbiomes that harbor fewer antibiotic resistant genes (ARGs). Diet is one method of intervention, and yet little is known about the association between diet and antimicrobial resistance. To address this knowledge gap, we examined diet using the food frequency questionnaire (FFQ; habitual diet) and 24-h dietary recalls (Automated Self-Administered 24-h [ASA24®] tool) coupled with an analysis of the microbiome using shotgun metagenome sequencing in 290 healthy adult participants of the United States Department of Agriculture (USDA) Nutritional Phenotyping Study. We found that aminoglycosides were the most abundant and prevalent mechanism of AMR in these healthy adults and that aminoglycoside-O-phosphotransferases (aph3-dprime) correlated negatively with total calories and soluble fiber intake. Individuals in the lowest quartile of ARGs (low-ARG) consumed significantly more fiber in their diets than medium- and high-ARG individuals, which was concomitant with increased abundances of obligate anaerobes, especially from the family Clostridiaceae, in their gut microbiota. Finally, we applied machine learning to examine 387 dietary, physiological, and lifestyle features for associations with antimicrobial resistance, finding that increased phylogenetic diversity of diet was associated with low-ARG individuals. These data suggest diet may be a potential method for reducing the burden of AMR. IMPORTANCE Antimicrobial resistance (AMR) represents a considerable burden to health care systems, with the public health community largely in consensus that AMR will be a major cause of death worldwide in the coming decades. Humans carry antibiotic resistance in the microbes that live in and on us, collectively known as the human microbiome. Diet is a powerful method for shaping the human gut microbiome and may be a tractable method for lessening antibiotic resistance, and yet little is known about the relationship between diet and AMR. We examined this relationship in healthy individuals who contained various abundances of antibiotic resistance genes and found that individuals who consumed diverse diets that were high in fiber and low in animal protein had fewer antibiotic resistance genes. Dietary interventions may be useful for lessening the burden of antimicrobial resistance and might ultimately motivate dietary guidelines which will consider how nutrition can reduce the impact of infectious disease.

Relationship between perceived stress and dietary and activity patterns in older adults participating in the Boston Puerto Rican Health Study.

Previous research supports a relationship between psychological stress and chronic disease in Puerto Rican adults living in the Boston, Massachusetts area. Stress may affect health by influencing dietary and physical activity patterns. Therefore, perceived stress and two hypothesized mediators of stress-related food intake, insulin and cortisol, were examined for possible associations with dietary and activity patterns in >1300 Puerto Ricans (aged 45-75 years; 70% women) living in the Boston, Massachusetts area. Data were analyzed using multiple linear regression and ANCOVA. Greater perceived stress was associated with lower fruit, vegetable, and protein intake, greater consumption of salty snacks, and lower participation in physical activity. Stress was associated with higher intake of sweets, particularly in those with type 2 diabetes. Cortisol and stress were positively associated in those without diabetes. Cortisol was associated with higher intake of saturated fat and, in those with diabetes, sweet foods. Independent of diabetes, perceived stress was associated with higher circulating insulin and BMI. Our findings support a link between stress, cortisol, and dietary and activity patterns in this population. For high-sugar foods, this relationship may be particularly important in those with type 2 diabetes. Longitudinal research to determine causal pathways for these identified associations is warranted.

Association between physiological stress load and diet quality patterns differs between male and female adults.

A promising, yet relatively unexplored factor that may influence a person's stress response, is diet. Diet can affect the physiological response to stress, but relationships between diet quality and the chronic stress marker allostatic load (AL) are insufficiently studied. Furthermore, sex, age, and BMI may interact with diet quality to influence AL. 358 adults were recruited across predetermined sex, age, and BMI ranges. Cluster analysis of 13 Healthy Eating Index (HEI) sub-scores across all participants revealed six distinct diet quality patterns (HEI-P). We found sex and HEI-P interacted (PHEIxSex = 0.0232) to affect AL, reflecting a significantly different AL between women and men consuming a diet more closely aligned with the Dietary Guidelines for Americans for dairy, refined grains, and sodium consumption, but less aligned for added sugar, saturated fat, and fruits/vegetables intake. Sex and HEI-P also interacted to affect cholesterol (PHEIxSex = 0.0157), norepinephrine (PHEIxSex = 0.0315), epinephrine (PHEIxSex = 0.0204), and systolic blood pressure (PHEIxSex = 0.0457) but, compared to total allostatic load, no individual component of this biomarker explained the entire array of sex by HEI-P interactions. Our results suggest that differences in HEI-P and sex interact to influence physiological stress load which, in turn, may help resolve discrepancies in diet and sex-related disease risk.

Accretion of Dietary Docosahexaenoic Acid in Mouse Tissues Did Not Differ between Its Purified Phospholipid and Triacylglycerol Forms.

Recent studies suggest that dietary krill oil leads to higher omega-3 polyunsaturated fatty acids (n-3 PUFA) tissue accretion compared to fish oil because the former is rich in n-3 PUFA esterified as phospholipids (PL), while n-3 PUFA in fish oil are primarily esterified as triacylglycerols (TAG). Tissue accretion of the same dietary concentrations of PL- and TAG-docosahexaenoic acid (22:6n-3) (DHA) has not been compared and was the focus of this study. Mice (n = 12/group) were fed either a control diet or one of six DHA (1%, 2%, or 4%) as PL-DHA or TAG-DHA diets for 4 weeks. Compared with the control, DHA concentration in liver, adipose tissue (AT), heart, and eye, but not brain, were significantly higher in mice consuming either PL- or TAG-DHA, but there was no difference in DHA concentration in all tissues between the PL- or TAG-DHA forms. Consumption of PL- and TAG-DHA at all concentrations significantly elevated eicosapentaenoic acid (20:5n-3) (EPA) in all tissues when compared with the control group, while docoshexapentaenoic acid (22:5n-6) (DPA) was significantly higher in all tissues except for the eye and heart. Both DHA forms lowered total omega-6 polyunsaturated fatty acids (n-6 PUFA) in all tissues and total monounsaturated fatty acids (MUFA) in the liver and AT; total saturated fatty acid (SFA) were lowered in the liver but elevated in the AT. An increase in the DHA dose, independent of DHA forms, significantly lowered n-6 PUFA and significantly elevated n-3 PUFA concentration in all tissues. Our results do not support the claim that the PL form of n-3 PUFA leads to higher n-3 PUFA tissue accretion than their TAG form.