Effects of total fat intake on body fatness in adults.

BACKGROUND: The ideal proportion of energy from fat in our food and its relation to body weight is not clear. In order to prevent overweight and obesity in the general population, we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population. OBJECTIVES: To assess the effects of proportion of energy intake from fat on measures of body fatness (including body weight, waist circumference, percentage body fat and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) of at least six months duration. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, Clinicaltrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) to October 2019. We did not limit the search by language. SELECTION CRITERIA: Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included adults aged at least 18 years, 3) randomised to a lower fat versus higher fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party. DATA COLLECTION AND ANALYSIS: We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of body fatness (body weight, BMI, percentage body fat and waist circumference) independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity, funnel plot analyses and GRADE assessment. MAIN RESULTS: We included 37 RCTs (57,079 participants). There is consistent high-quality evidence from RCTs that reducing total fat intake results in small reductions in body fatness; this was seen in almost all included studies and was highly resistant to sensitivity analyses (GRADE high-consistency evidence, not downgraded). The effect of eating less fat (compared with higher fat intake) is a mean body weight reduction of 1.4 kg (95% confidence interval (CI) -1.7 to -1.1 kg, in 53,875 participants from 26 RCTs, I2 = 75%). The heterogeneity was explained in subgrouping and meta-regression. These suggested that greater weight loss results from greater fat reductions in people with lower fat intake at baseline, and people with higher body mass index (BMI) at baseline. The size of the effect on weight does not alter over time and is mirrored by reductions in BMI (MD -0.5 kg/m2, 95% CI -0.6 to -0.3, 46,539 participants in 14 trials, I2 = 21%), waist circumference (MD -0.5 cm, 95% CI -0.7 to -0.2, 16,620 participants in 3 trials; I2 = 21%), and percentage body fat (MD -0.3% body fat, 95% CI -0.6 to 0.00, P = 0.05, in 2350 participants in 2 trials; I2 = 0%). There was no suggestion of harms associated with low fat diets that might mitigate any benefits on body fatness. The reduction in body weight was reflected in small reductions in LDL (-0.13 mmol/L, 95% CI -0.21 to -0.05), and total cholesterol (-0.23 mmol/L, 95% CI -0.32 to -0.14), with little or no effect on HDL cholesterol (-0.02 mmol/L, 95% CI -0.03 to 0.00), triglycerides (0.01 mmol/L, 95% CI -0.05 to 0.07), systolic (-0.75 mmHg, 95% CI -1.42 to -0.07) or diastolic blood pressure(-0.52 mmHg, 95% CI -0.95 to -0.09), all GRADE high-consistency evidence or quality of life (0.04, 95% CI 0.01 to 0.07, on a scale of 0 to 10, GRADE low-consistency evidence). AUTHORS' CONCLUSIONS: Trials where participants were randomised to a lower fat intake versus a higher fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI, waist circumference and percentage body fat compared with higher fat arms. Greater fat reduction, lower baseline fat intake and higher baseline BMI were all associated with greater reductions in weight. There was no evidence of harm to serum lipids, blood pressure or quality of life, but rather of small benefits or no effect.

Device-Measured Sedentary Behavior Patterns in Office-Based University Employees.

OBJECTIVE: The aim of this study was to describe device-measured patterns of sedentary behavior in self-identified sedentary university employees. METHODS: Participants (n = 78) wore the ActiGraph GT3X+ and the activPAL3 for 7 days. Data from the ActiGraph were used to identify time in sedentary behavior, light-intensity, and moderate-to-vigorous physical activity. Data from the activPAL identified time sitting/lying, standing, and stepping. Breaks in sedentary time and prolonged sedentary bouts were described. RESULTS: During workdays, participants spent 65% to 79% of time sedentary, 16% in light-intensity physical activity, and 4% in moderate-to-vigorous physical activity, 76% of time was spent sitting/lying, 16% standing, and 8% stepping. Between 10 and 12 breaks in sedentary time were accumulated. CONCLUSION: Office-based university employees spend a high proportion of their time sedentary, but accumulate a high number of breaks. Whether these breaks are appropriate in timing, duration, and intensity to elicit health benefits seen in laboratory studies requires further investigation.

The Acute Metabolic and Vascular Impact of Interrupting Prolonged Sitting: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim was to conduct a systematic review and meta-analysis analyzing the impact of up to 24 h of prolonged sitting on postprandial glucose, insulin and triglyceride responses, blood pressure and vascular function, in comparison to sitting interrupted with light- to moderate-intensity physical activity. METHODS: To be included, studies had to examine the impact of prolonged sitting lasting < 24 h in apparently healthy males or females of any age. Studies were identified from searches of the MEDLINE, CINAHL and SportDISCUS databases on July 6, 2016. Study quality was assessed using the Downs and Black Checklist; publication bias was assessed via funnel plot. RESULTS: Forty-four studies met the inclusion criteria for the systematic review; of these, 20 were included in the meta-analysis, which compared prolonged sitting to the effects of interrupting sitting with regular activity breaks on postprandial glucose, insulin and triglycerides. When compared to prolonged sitting, regular activity breaks lowered postprandial glucose (d = - 0.36, 95% confidence interval [CI] - 0.50 to - 0.21) and insulin (d = - 0.37, 95% CI - 0.53 to - 0.20), but not triglyceride responses (d = 0.06, 95% CI - 0.15 to 0.26). Subgroup analyses indicated reductions in postprandial triglyceride responses only occurred 12-16 h after the intervention. The magnitude of the reductions in glucose, insulin or triglyceride response was not modified by the intensity of the activity breaks, the macronutrient composition of the test meal, or the age or body mass index of participants. CONCLUSION: Prolonged sitting results in moderate elevations in postprandial glucose and insulin responses when compared to sitting interrupted with activity breaks. PROSPERO ID: CRD42015020907.

Effect of supplementation with flaxseed oil and different doses of fish oil for 2 weeks on plasma phosphatidylcholine fatty acids in young women.

BACKGROUND/OBJECTIVES: Although assumed, it remains unclear that fatty acid (FA) biomarkers of n-3 long-chain PUFA reflect wide ranges of intake. However, to be utilised as biomarkers, to predict dietary intake, dose-response curves that cover a spectrum of intakes are required. The aim of the study was to investigate whether the FA composition of plasma phosphatidylcholine (PC) is a sensitive biomarker of n-3 FAs from fish oil, across a range of supplementation doses, and alpha-linolenic acid (ALA) supplementation, in young, healthy women. SUBJECTS/METHODS: A total of 303 young women were randomised to intakes ranging between 0.33 and 4.50 g EPA+DHA/day from fish oil (not all doses used in each year) or flaxseed oil (5.90-6.60 g/d) daily for 14 days in a series of trials, over 5 years. Fasting blood was collected at baseline (day 0) and day 14 and plasma PC FA composition, total and HDL-cholesterol and triglyceride concentrations measured. RESULTS: Fourteen days supplementation with fish oil significantly (P < 0.01) increased, in a dose-dependent fashion, plasma PC EPA, DPA and DHA at all doses except 1 and 3 mL/day. For the combined group of women who consumed any fish oil there was a 16% (P < 0.01) decrease in plasma triacylglycerol concentrations after 14 days supplementation. Flaxseed oil supplementation for 14 day resulted in significant (P < 0.01) increases in ALA, EPA and DPA, whilst DHA remained unchanged. CONCLUSION: Our data demonstrate plasma PC is a sensitive biomarker of n-3 FA intake and reflects changes within 14 days across a range of intakes.

Red Meat Consumption and Serum Lipids and Fatty Acids in Toddlers: Secondary Outcomes of a Randomized Controlled Trial.

The aim of the study was to examine the effects of promoting increased lean red meat consumption on serum concentrations of total and high-density lipoprotein (HDL) cholesterol, and serum fatty acid composition, among toddlers. In a 20-week randomized controlled trial healthy 12 to 20-month-old children were assigned to: red meat (n = 90; parents were encouraged to add 56 g/day of lean red meat to their toddler's usual diet), or control (n = 90) groups. Food and nutrient intakes were assessed with 3-day weighed food records (baseline, week 4, and week 20). Serum was analyzed for total and HDL cholesterol concentrations, and fatty acid composition (baseline and week 20). At week 20, relative to control, the red meat group had higher intakes of red meat, all meat, and carbohydrate; and lower intakes of milk, energy, cholesterol, and total, saturated, and monounsaturated fat (P = 0.043 for energy, all others P ≤ 0.002). No effects associated with the intervention were found for total cholesterol, HDL cholesterol, total to HDL cholesterol ratio, or serum fatty acid composition (all P ≥ 0.059) aside from pentadecanoic acid (P = 0.047). An ∼3-fold increase in lean red meat intake, from ∼10 to ∼30 g/day, resulted in no consistent changes in serum lipids or fatty acid composition, suggesting that the addition of ∼2 tablespoons/day of lean red meat to toddlers' diets will likely not adversely affect serum lipids or serum fatty acids.

Interrupting Prolonged Sitting with Regular Activity Breaks does not Acutely Influence Appetite: A Randomised Controlled Trial.

Regular activity breaks increase energy expenditure; however, this may promote compensatory eating behaviour. The present study compared the effects of regular activity breaks and prolonged sitting on appetite. In a randomised, cross-over trial, 36 healthy adults (BMI (Body Mass Index) 23.9 kg/m² (S.D. = 3.9)) completed four, two-day interventions: two with prolonged sitting (SIT), and two with sitting and 2 min of walking every 30 min (RAB). Standardized meals were provided throughout the intervention, with an ad libitum meal at the end of Day 2. Appetite and satiety were assessed throughout both days of each intervention using five visual analogue scales. The five responses were combined into a single appetite response at each time point. The area under the appetite response curve (AUC) was calculated for each day. Intervention effects for appetite response AUC and ad libitum meal intake were tested using linear mixed models. Appetite AUC did not differ between interventions (standardised effect of RAB compared to SIT: Day 1: 0.11; 95% CI: -0.28, 0.06; p = 0.212; Day 2: 0.04; 95% CI: -0.15, 0.24; p = 0.648). There was no significant difference in energy consumed at the ad libitum lunch meal on Day 2 between RAB and SIT. Interrupting prolonged sitting with regular activity breaks does not acutely influence appetite or volume of food consumed, despite inferred increases in energy expenditure. Longer-term investigation into the effects of regular activity breaks on energy balance is warranted.

Vitamin D3 Supplementation Does Not Improve Sprint Performance in Professional Rugby Players: A Randomized, Placebo-Controlled, Double-Blind Intervention Study.

Vitamin D insufficiency is common in athletes and may lower physical performance. Many cross-sectional studies associate vitamin D status with physical performance in athletes; however, there have been few prospective randomized controlled trials with adequate statistical power to test this relationship, and none in the southern hemisphere. Thus, a prospective double-blind, randomized, placebo-controlled intervention trial was conducted involving 57 professional rugby union players in New Zealand. Participants were randomized to receive 50,000 IU of cholecalciferol (equivalent to 3,570 IU/day) or placebo once every two weeks over 11-12 weeks. Serum 25(OH)D concentrations and physical performance were measured at baseline, weeks 5-6, and weeks 11-12. Mean (SD) serum 25(OH)D concentrations for all participants at baseline was 94 (18) nmol/L, with all players above 50 nmol/L. Vitamin D supplementation significantly increased serum 25(OH)D concentrations compared to placebo, with a 32 nmol/L difference between groups at 11-12 weeks (95% CI, 26-38; p < 0.001). Performance in five of the six tests at study completion, including the primary outcome variable of 30-m sprint time, did not differ between the vitamin D supplemented and placebo groups (p > 0.05). Performance on the weighted reverse-grip chin up was significantly higher in players receiving vitamin D compared with placebo, by 5.5 kg (95% CI, 2.0-8.9; p = 0.002). Despite significantly improving vitamin D status in these professional rugby union players, vitamin D supplementation had little impact on physical performance outcomes. Thus, it is unlikely that vitamin D supplementation is an ergogenic aid in this group of athletes.

Sedentary Behavior and Body Weight and Composition in Adults: A Systematic Review and Meta-analysis of Prospective Studies.

BACKGROUND: The cumulative effect of too much sedentary behavior may contribute to weight gain and obesity. OBJECTIVE: The aim of this study was to conduct a systematic review and meta-analysis of prospective cohorts and randomized controlled studies to determine the association between sedentary behavior and body weight and obesity in adults. DATA SOURCES AND STUDY SELECTION: Relevant studies were identified from searches of the MEDLINE, Embase, AMED and PubMed databases up to May 2017, and by manual searches of in-text citations. Studies that evaluated the association in adults between sedentary behavior and body weight or obesity, while controlling for physical activity, were included. Overall, 31 publications met the eligibility criteria, including 23 prospective cohort studies with data that could be extracted for a quantitative meta-analysis, and a single randomized controlled trial. RESULTS: There were no significant associations between sedentary behavior and any measure of body weight or obesity, with the exception of waist circumference. For the latter outcome, over a 5-year follow-up period, each 1 h per day increase-from baseline to follow-up-in sedentary behavior was associated with a 0.02 mm [95% confidence interval (CI) 0.01-0.04; p = 0.001) increase in waist circumference. The odds ratio of becoming overweight or obese was 1.33 (95% CI 1.11-1.60; p = 0.001) in the highest compared with lowest categories of sedentary behavior. CONCLUSIONS: Meta-analysis of data from prospective cohort studies showed small, inconsistent and non-significant associations between sedentary behavior and body weight.

Regular activity breaks combined with physical activity improve postprandial plasma triglyceride, nonesterified fatty acid, and insulin responses in healthy, normal weight adults: A randomized crossover trial.

BACKGROUND: Compared with prolonged sitting, regular activity breaks immediately lower postprandial glucose and insulin, but not triglyceride responses. Postprandial triglycerides can be lowered by physical activity but the effect is often delayed by ∼12 to 24 hours. OBJECTIVE: The objective of the study was to determine whether regular activity breaks affect postprandial triglyceride response in a delayed manner similar to physical activity. METHODS: In a randomized crossover trial, 36 adults (body mass index 23.9 kg/m2 [standard deviation 3.9]) completed four 2-day interventions: (1) prolonged sitting (SIT); (2) prolonged sitting with 30 minutes of continuous walking (60% VO2max), at the end of Day 1 (SIT + PAD1); (3) Sitting with 2 minutes of walking (60% VO2max) every 30 minutes (RAB); (4) A combination of the continuous walking and regular activity breaks in 2 and 3 above (RAB + PAD1). Postprandial plasma triglyceride, nonesterified fatty acids, glucose, and insulin responses were measured in venous blood over 5 hours on Day 2. RESULTS: Compared with SIT, both RAB (difference: -43.61 mg/dL·5 hours; 95% confidence interval [CI] -83.66 to -2.67; P = .035) and RAB + PAD1 (-65.86 mg/dL·5 hours; 95% CI -112.14 to -19.58; P = .005) attenuated triglyceride total area under the curve (tAUC). RAB + PAD1 produced the greatest reductions in insulin tAUC (-23%; 95% CI -12% to -31%; P < .001), whereas RAB resulted in the largest increase in nonesterified fatty acids (tAUC, 10.08 mg/dL·5 hours; 95% CI 5.60-14.84; P < .001). There was no effect on glucose tAUC (P = .290). CONCLUSIONS: Postprandial triglyceride response is attenuated by regular activity breaks, when measured ∼24 hours after breaks begin. Combining regular activity breaks with 30 minutes of continuous walking further improves insulinemic and lipidemic responses.

Association of cord blood vitamin D with early childhood growth and neurodevelopment.

AIM: The association between fetal vitamin D [25-hydroxyvitamin D (25(OH)D)] exposure and early child growth and neurodevelopment is controversial. The aim of this study was to investigate the association between cord blood 25(OH)D and birth size, childhood growth and neurodevelopment. METHODS: Cord blood samples from 1040 Australian women enrolled in a randomised trial of docosahexaenoic acid (DHA) supplementation during pregnancy were analysed for 25(OH)D using mass spectroscopy. Infant length, weight and head circumference were measured at delivery. A sub-sample of 337 infants with cord blood samples were selected for growth and neurodevelopment assessment at 18 months and 4 years of age. Associations between standardised 25(OH)D and outcomes were assessed, taking into account DHA treatment, social and demographic variables. RESULTS: Standardised 25(OH)D in cord blood was not associated with length, weight or head circumference at birth, 18 months or 4 years of age. 25(OH)D was not associated with cognitive, motor, social-emotional or adaptive behaviour scores at 18 months, or cognitive score at 4 years of age. A 10 nmol/L increase in cord blood 25(OH)D was associated with a modest increase in average Language scores of 0.60 points at 18 months (adjusted 95% CI 0.04-1.17, P = .04) and 0.68 points at 4 years (adjusted 95% CI 0.07-1.29, P = .03) of age. CONCLUSIONS: Cord blood vitamin D was modestly, positively associated with language development in early childhood in our sample, although the magnitude of the association was small. Randomised controlled trials are needed to confirm a causal association and establish the potential clinical significance of the relationship between vitamin D status and language development.

Serum and erythrocyte folate status of New Zealand women of childbearing age following a countrywide voluntary programme by the baking industry to fortify bread with folic acid.

OBJECTIVE: To estimate the folate status of New Zealand women of childbearing age following the introduction, in 2010, of a new voluntary folic acid fortification of bread programme. DESIGN: The 2011 Folate and Women's Health Survey was a cross-sectional survey of women aged 18-44 years carried out in 2011. The survey used a stratified random sampling technique with the Electoral Roll as the sampling frame. Women were asked about consumption of folic-acid-fortified breads and breakfast cereals in a telephone interview. During a clinic visit, blood was collected for serum and erythrocyte folate measurement by microbiological assay. SETTING: A North Island (Wellington) and South Island (Dunedin) city centre in New Zealand. SUBJECTS: Two hundred and eighty-eight women, of whom 278 completed a clinic visit. RESULTS: Geometric mean serum and erythrocyte folate concentrations were 30 nmol/l and 996 nmol/l, respectively. Folate status was 30-40 % higher compared with women of childbearing age sampled as part of a national survey in 2008/09, prior to the introduction of the voluntary folic acid bread fortification programme. In the 2011 Folate and Women's Health Survey, reported consumption of fortified bread and fortified breakfast cereal in the past week was associated with 25 % (P=0·01) and 15 % (P=0·04) higher serum folate concentrations, respectively. CONCLUSIONS: Serum and erythrocyte folate concentrations have increased in New Zealand women of childbearing age since the number of folic-acid-fortified breads was increased voluntarily in 2010. Consumption of fortified breads and breakfast cereals was associated with a higher folate status.

Trends in serum total cholesterol and dietary fat intakes in New Zealand between 1989 and 2009.

OBJECTIVE: To describe trends in serum cholesterol and dietary fat intakes for New Zealand adults between 1989 and 2008/09. METHODS: Serum total cholesterol concentrations and dietary fat intakes were analysed for 9,346 New Zealanders aged 15-98 years (52% women) who participated in three national surveys in 1989, 1997 and 2008/09. RESULTS: Population mean serum cholesterol decreased from 6.15 mmol/L in 1989 to 5.39 mmol/L in 2008/09. Mean saturated fat intake decreased from 15.9% of energy intake in 1989 to 13.1% in 2008/09. Between 1997 and 2008/09, unsaturated fat intake increased and fat from butter and milk decreased. Older adults had the largest decrease in serum cholesterol (1.35 mmol/L). CONCLUSIONS: The decrease in serum cholesterol is substantially larger than reported for many other high-income countries, and occurred in parallel with changes in dietary fat intakes and, for older adults, increased use of cholesterol-lowering medications. IMPLICATION: Given the demonstrated role of reduced saturated fat intake on lowering serum cholesterol, and as population average serum cholesterol levels and saturated fat intakes exceed recommended levels, initiatives to further encourage reductions in saturated fat are imperative.

Effects of total fat intake on body weight.

BACKGROUND: In order to prevent overweight and obesity in the general population we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population. OBJECTIVES: To assess the effects of proportion of energy intake from fat on measures of weight and body fatness (including obesity, waist circumference and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) and cohort studies in adults, children and young people SEARCH METHODS: We searched CENTRAL to March 2014 and MEDLINE, EMBASE and CINAHL to November 2014. We did not limit the search by language. We also checked the references of relevant reviews. SELECTION CRITERIA: Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included children (aged ≥ 24 months), young people or adults, 3) randomised to a lower fat versus usual or moderate fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We also included cohort studies in children, young people and adults that assessed the proportion of energy from fat at baseline and assessed the relationship with body weight or fatness after at least one year. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party. DATA COLLECTION AND ANALYSIS: We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of weight and body fatness independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity and funnel plot analyses. MAIN RESULTS: We included 32 RCTs (approximately 54,000 participants) and 30 sets of analyses of 25 cohorts. There is consistent evidence from RCTs in adults of a small weight-reducing effect of eating a smaller proportion of energy from fat; this was seen in almost all included studies and was highly resistant to sensitivity analyses. The effect of eating less fat (compared with usual diet) is a mean weight reduction of 1.5 kg (95% confidence interval (CI) -2.0 to -1.1 kg), but greater weight loss results from greater fat reductions. The size of the effect on weight does not alter over time and is mirrored by reductions in body mass index (BMI) (-0.5 kg/m(2), 95% CI -0.7 to -0.3) and waist circumference (-0.3 cm, 95% CI -0.6 to -0.02). Included cohort studies in children and adults most often do not suggest any relationship between total fat intake and later measures of weight, body fatness or change in body fatness. However, there was a suggestion that lower fat intake was associated with smaller increases in weight in middle-aged but not elderly adults, and in change in BMI in the highest validity child cohort. AUTHORS' CONCLUSIONS: Trials where participants were randomised to a lower fat intake versus usual or moderate fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI and waist circumference compared with controls. Greater fat reduction and lower baseline fat intake were both associated with greater reductions in weight. This effect of reducing total fat was not consistently reflected in cohort studies assessing the relationship between total fat intake and later measures of body fatness or change in body fatness in studies of children, young people or adults.

Association of cord blood vitamin D at delivery with postpartum depression in Australian women.

BACKGROUND: Observational studies have implicated low serum vitamin D (25-hydroxyvitamin D (25(OH)D)) levels in the development of mood disorders. Postpartum depression (PPD) is an important public health issue, although little is known about its association with serum 25(OH)D. AIMS: To determine the association between 25(OH)D at delivery and the subsequent risk of PPD at six weeks and six months postpartum in a large cohort of Australian women. MATERIALS AND METHODS: Cord blood samples from 1040 women participating in the docosahexaenoic acid (DHA) to Optimise Maternal Infant Outcome randomised controlled trial were analysed for 25(OH)D by mass spectroscopy. Maternal PPD was assessed using the Edinburgh Postnatal Depression Scale at six weeks and six months postpartum. The association between standardised 25(OH)D and PPD was assessed, taking into account DHA treatment, social and demographic variables. RESULTS: There was no association between cord blood 25(OH)D concentration at delivery and PPD at either six weeks or six months postpartum. Cord blood 25(OH)D 25-50 and >50 nmol/L at delivery was associated with decreased risk of PPD at six weeks postpartum compared with 25(OH)D <25 nmol/L in the control group, but not the DHA group. There was no association between cord blood 25(OH)D <25 nmol/L at delivery and PPD at six months postpartum. CONCLUSIONS: This largest study to date of 25(OH)D levels at delivery and PPD did not reveal a consistent link with PPD.

Lack of effect of the apolipoprotein E ε4 genotype on cognition during healthy aging.

BACKGROUND: The apolipoprotein E (APOE) ε4 genotype is associated with an increased risk of Alzheimer's disease. In community surveys, older adults with this genotype have been found to have lower scores on neuropsychological tests than those who do not. It is possible that this is the consequence of subclinical changes in cognition in those persons who later develop dementia. The aim of this research was to determine whether the effect of APOE genotype on cognition would remain if those who subsequently became demented were retrospectively removed from the analysis of the baseline test data from a sample of healthy adults. METHOD: A sample of 241 nondemented persons over the age of 65 for whom APOE genotyping was available were administered a range of neuropsychological tests at baseline and were followed up 10 years later. RESULTS: Significant differences between the ε4-present and ε4-absent groups were found for the delayed recall trial of the Rey Auditory Verbal Learning Test and the Trail Making Test. When those participants known to have developed dementia during the follow-up period were excluded from the analysis of the baseline data these differences disappeared. A total of 113 nondemented survivors from the original sample were retested, and no difference was found in the rate of decline on any measure between the ε4-present and ε4-absent groups. CONCLUSIONS: It is likely that the reported effect of the ε4 APOE genotype on cognition is the consequence of the ε4-present group containing persons whose cognition is subtly affected by the early stages of a dementing process. It is also unlikely that the presence of the ε4 allele by itself leads to a significantly accelerated rate of cognitive decline in the nondemented elderly.

Plasma and erythrocyte fatty acids reflect intakes of saturated and n-6 PUFA within a similar time frame.

Erythrocytes, compared with plasma, are considered more robust markers of n-3 (ω-3) polyunsaturated fatty acid (PUFA) intake, because dietary-induced change in fatty acid (FA) composition takes longer to complete. The extent to which this applies to intakes of saturated fatty acid (SFA) or n-6 PUFA is unclear. We compared the pattern of change over time in the fatty acid composition of plasma, erythrocyte, buccal cell, and adipose tissue lipids when changing between diets high in SFA or n-6 PUFA. Twenty-four (n = 7 male) healthy participants were instructed to consume either an SFA-rich (18% energy) or n-6 PUFA-rich (10% energy) diet for 8 wk before crossing over, without washout, to the alternate diet. The FA composition of plasma triacylglycerol (TG), nonesterified FAs, cholesterol ester, total phospholipids, erythrocyte total phospholipids, erythrocyte phosphatidylcholine, and buccal cell total phospholipids was measured every 2 wk and adipose tissue TG every 4 wk during the 16-wk intervention. Linoleic acid composition of plasma, erythrocyte, and buccal cell lipids increased (P < 0.01) during the first 2 wk of the n-6 PUFA diet and remained unchanged during the remaining 6 wk. During the 8-wk SFA diet, the same pattern of change over time occurred for the pentadecanoic acid composition of plasma and erythrocyte lipids; however, the pentadecanoic acid composition of buccal cell lipids did not differ between the diet periods. There were no differences in linoleic or pentadecanoic acid composition of adipose tissue TG. These results suggest plasma and erythrocyte FAs reflect intakes of SFA and n-6 PUFA over a similar period of time.

Estimation of serum and erythrocyte folate concentrations in the New Zealand adult population within a background of voluntary folic acid fortification.

National data on the blood folate status of New Zealand adults is lacking. The objective of this study was to describe the blood folate status and examine the predictors of blood folate status in a national sample of adults from New Zealand, a country with voluntary folic acid fortification. The 2008/09 New Zealand Adult Nutrition Survey was a nationwide multistage systematic random cross-sectional survey. Serum and erythrocyte folate concentrations were measured by microbiologic assay. The survey included 4721 participants aged ≥15 y, 3359 of whom provided a nonfasting blood sample. Biochemical folate status was measured in 3277 participants. The median serum and erythrocyte folate concentrations were 23 and 809 nmol/L, respectively. The prevalence of biochemical folate deficiency, defined as plasma folate <6.8 nmol/L or erythrocyte folate <305 nmol/L, was 2%. Having breakfast daily compared with never eating breakfast was associated with 53% higher serum and 25% higher erythrocyte folate concentrations; consumers of fortified yeast extract spread had 17% higher serum and 14% higher erythrocyte folate concentrations than nonconsumers; daily users of folate-containing supplements compared with nonusers had 48% higher serum and 28% higher erythrocyte folate concentrations. The prevalence of biochemical folate deficiency in New Zealand adults is low. Participants who ate breakfast more frequently, consumed folate-fortified yeast, or used a daily folate supplement had higher blood folate concentrations.

Breaking prolonged sitting reduces postprandial glycemia in healthy, normal-weight adults: a randomized crossover trial.

BACKGROUND: Sedentary behavior is a risk factor for cardiometabolic disease. Regularly interrupting sedentary behavior with activity breaks may lower this risk. OBJECTIVE: We compared the effects of prolonged sitting, continuous physical activity combined with prolonged sitting, and regular activity breaks on postprandial metabolism. DESIGN: Seventy adults participated in a randomized crossover study. The prolonged sitting intervention involved sitting for 9 h, the physical activity intervention involved walking for 30 min and then sitting, and the regular-activity-break intervention involved walking for 1 min 40 s every 30 min. Participants consumed a meal-replacement beverage at 60, 240, and 420 min. RESULTS: The plasma incremental area under the curve (iAUC) for insulin differed between interventions (overall P < 0.001). Regular activity breaks lowered values by 866.7 IU · L(-1) · 9 h(-1) (95% CI: 506.0, 1227.5 IU · L(-1) · 9 h(-1); P < 0.001) when compared with prolonged sitting and by 542.0 IU · L(-1) · 9 h(-1) (95% CI: 179.9, 904.2 IU · L(-1) · 9 h(-1); P = 0.003) when compared with physical activity. Plasma glucose iAUC also differed between interventions (overall P < 0.001). Regular activity breaks lowered values by 18.9 mmol · L(-1) · 9 h(-1) (95% CI: 10.0, 28.0 mmol · L(-1) · 9 h(-1); P < 0.001) when compared with prolonged sitting and by 17.4 mmol · L(-1) · 9 h(-1) (95% CI: 8.4, 26.3 mmol · L(-1) · 9 h(-1); P < 0.001) when compared with physical activity. Plasma triglyceride iAUC differed between interventions (overall P = 0.023). Physical activity lowered values by 6.3 mmol · L(-1) · 9 h(-1) (95% CI: 1.8, 10.7 mmol · L(-1) · 9 h(-1); P = 0.006) when compared with regular activity breaks. CONCLUSION: Regular activity breaks were more effective than continuous physical activity at decreasing postprandial glycemia and insulinemia in healthy, normal-weight adults. This trial was registered with the Australian New Zealand Clinical Trials registry as ACTRN12610000953033.